Age-dependent variations in clinical features and operative time for endometriotic cysts

A total of 994 patients with surgically and pathologically confirmed ovarian endometriotic cysts were included in this study. The age distribution of the patients was non-normal ( p  < 0.001), with a median age of 30.5 years (interquartile range: 26–37 years), predominantly involving women of reproductive age. Based on the median age and clinical relevance, patients were divided into two groups: ≤ 30 years ( n  = 496) and > 30 years ( n  = 498). A case-control analysis was then performed to compare clinical characteristics between the two age groups. Significant differences were observed between the two groups in terms of disease duration before diagnosis, proportion of first surgeries, and history of hormonal therapy (all p   30-year group, suggesting a cumulative diagnostic delay with increasing age. (2) Proportion of first surgeries: first-time endometriosis surgeries accounted for 84.7% (420/496) in the ≤ 30-year group and 67.7% (337/498) in the > 30-year group, indicating a higher rate of repeat surgeries among older patients. (3) Hormonal therapy history: the > 30-year group showed a higher rate of standardized preoperative hormonal therapy (68.5%, 341/498) and longer average treatment duration (10.2 ± 3.5 months) compared with the ≤ 30-year group (45.2%, 224/496; 6.8 ± 2.1 months). Regarding BMI differences, the two groups showed a statistically significant difference (Z = -10.643, p   30-year group (Fig.  1 ), indicating a positive association between increasing age and higher body mass index. Fig. 1 Comparison of BMI between different age groups in patients with endometriotic cysts. Note Blue dots represent the ≤ 30-year-old group ( n  = 496); red squares represent the > 30-year-old group ( n  = 498). Error bars indicate the Mean ± SD. Double asterisks (**) indicate a statistically significant difference between the two groups ( p <  0.01). Data were analyzed using an independent samples t-test. Age was positively correlated with BMI ( r  = 0.32, p  30-year-old group ( n  = 498). Error bars indicate the Mean ± SD. Double asterisks (**) indicate a statistically significant difference between the two groups ( p <  0.01). Data were analyzed using an independent samples t-test. Age was positively correlated with BMI ( r  = 0.32, p  30-year groups regarding obstetric history, disease duration before confirmed diagnosis, first endometriosis-related surgery, recurrence history, coexisting uterine disorders (including endometrial polyps, adenomyosis, and leiomyoma), and standardized hormonal therapy history (including treatment duration and time since discontinuation). The results showed statistically significant differences between the two age groups in multiple parameters: obstetric history (χ² =351.338, p  < 0.001), duration before diagnosis (Z = − 4.216, p  < 0.001), first endometriosis-related surgery (χ² = 18.752, p  < 0.001), recurrence history (χ² = 20.303, p  < 0.001), coexisting endometrial polyps (χ²=4.709, p  = 0.030), adenomyosis (χ²=29.526, p  < 0.001), uterine leiomyoma (χ²=116.545, P  < 0.001), and standardized hormonal therapy history (χ² = 9.364, p  = 0.002) (Fig.  2 , Table S1 ). These findings indicate that patients over 30 years are more likely to present with prior pregnancy, recurrence, and coexisting uterine disorders, suggesting that advancing age may be associated with greater disease complexity and comorbidity burden. Fig. 2 Prevalence of coexisting uterine diseases in patients with endometriotic cysts by age group. Note This figure shows the percentage distribution of six clinical indicators in females aged ≤ 30 years and > 30 years. Statistical significance is indicated by asterisks (** p <  0.01, * p <  0.05, ns = not significant). Based on the χ 2 test for categorical variables and the Mann-Whitney U test for continuous variables converted to categorical form, a total of 994 patients were analyzed: 496 in the ≤ 30-year group and 498 in the > 30-year group. Prevalence of coexisting uterine diseases in patients with endometriotic cysts by age group. Note This figure shows the percentage distribution of six clinical indicators in females aged ≤ 30 years and > 30 years. Statistical significance is indicated by asterisks (** p <  0.01, * p <  0.05, ns = not significant). Based on the χ 2 test for categorical variables and the Mann-Whitney U test for continuous variables converted to categorical form, a total of 994 patients were analyzed: 496 in the ≤ 30-year group and 498 in the > 30-year group. Among the 994 patients with endometriotic cysts, 146 (14.7%) underwent ultrasound reporting for DIE, and 848 patients underwent routine gynecological ultrasound examination. Among the 994 patients, 702 (70.6%) had unilateral endometriotic cysts, and 292 (29.4%) had bilateral cysts, indicating a higher prevalence of unilateral disease. A comparative analysis of cyst size between the ≤ 30 years and > 30 years groups showed statistically significant differences in the maximum cyst diameter (Z = -5.777, p <  0.001), the maximum diameter on the left side (Z = −4.987, p <  0.001), and the maximum diameter on the right side (Z = -2.709, p =  0.007) (Fig.  3 , Table S2 ). However, the relationship between age and cyst size was not linear, requiring further investigation. Overall, cyst diameters were generally larger in patients > 30 years, suggesting that advancing age may be associated with cyst progression or persistence. Fig. 3 Comparison of maximum ovarian cyst diameter across age groups. Note Distribution of cyst diameters in ≤ 30-year-old patients (blue dots) and > 30-year-old patients (red squares). Error bars represent Mean ± SD. Significance indicators: * p <  0.05, ** p <  0.01, *** p <  0.001 (Mann-Whitney U test). Sample sizes: left-sided cysts ( n  = 349/343), right-sided cysts ( n  = 290/305), all cysts ( n  = 496/498). Comparison of maximum ovarian cyst diameter across age groups. Note Distribution of cyst diameters in ≤ 30-year-old patients (blue dots) and > 30-year-old patients (red squares). Error bars represent Mean ± SD. Significance indicators: * p <  0.05, ** p <  0.01, *** p <  0.001 (Mann-Whitney U test). Sample sizes: left-sided cysts ( n  = 349/343), right-sided cysts ( n  = 290/305), all cysts ( n  = 496/498). Among the total patients, 263 had ultrasound records regarding the presence of DIE nodules, of whom 125 were found to have such nodules. Comparative analysis of the presence and size of DIE nodules between the ≤ 30 years and > 30 years groups showed no statistically significant differences ( p =  0.205 for the presence of nodules; p =  0.328 for nodule size) (Table S3 ). Among the 247 patients who underwent ultrasound evaluation of the posterior uterine wall sliding sign, 114 (46.2%) were positive, and 133 (53.8%) were negative. Of the 262 patients assessed for the POD sliding sign, 139 (53.1%) were positive, and 123 (46.9%) were negative. For the anterior uterine wall sliding sign, 235 out of 247 patients (95.1%) were positive and 12 (4.9%) were negative. Regarding the bladder peritoneal reflection sliding sign, 251 out of 262 patients (95.8%) were positive, and 11 (4.2%) were negative. When comparing the four types of sliding signs—posterior uterine wall, POD, anterior uterine wall, and bladder peritoneal reflection—between the ≤ 30 years and > 30 years groups, statistically significant differences were found in the posterior uterine wall sliding sign (χ 2  = 5.125, p =  0.024) and the POD sliding sign (χ 2  = 4.767, p =  0.029) (Fig.  4 , Table S4 ). These findings suggest that patients aged > 30 years with endometriotic cysts had a higher incidence of negative sliding signs in the posterior uterine wall and POD regions, indicating an increased likelihood of adhesions in the posterior uterine wall. Fig. 4 Impact of age on pelvic adhesion-related ultrasound sliding signs in patients with endometriotic cysts. Note This figure shows the distribution of sliding sign results for the posterior uterine wall, POD, anterior uterine wall, and bladder peritoneal reflection in female patients aged ≤ 30 years and > 30 years. In each pair of bars, blue indicates a positive result, and purple indicates a negative result. Asterisks denote statistical significance between groups based on the chi-square test: * p  < 0.05; ns = insignificant. Impact of age on pelvic adhesion-related ultrasound sliding signs in patients with endometriotic cysts. Note This figure shows the distribution of sliding sign results for the posterior uterine wall, POD, anterior uterine wall, and bladder peritoneal reflection in female patients aged ≤ 30 years and > 30 years. In each pair of bars, blue indicates a positive result, and purple indicates a negative result. Asterisks denote statistical significance between groups based on the chi-square test: * p  < 0.05; ns = insignificant. Among the 994 patients with endometriotic cysts, 864 (86.9%) underwent surgical treatment, while 130 (13.1%) received non-surgical management. The main surgical procedure was laparoscopic cystectomy for endometriotic cysts combined with pelvic and abdominal adhesiolysis, performed in 371 patients (42.9%). The second most common was laparoscopy combined with hysteroscopy, performed in 298 patients (34.5%), while the distribution of other additional procedures was relatively balanced. A comparative analysis of operative time and additional procedures was conducted using age (≤ 30 vs. > 30 years) as the grouping variable. The results showed statistically significant differences in operative time (χ 2 = −6.127, p <  0.001) and surgical procedures (Fisher = 86.464, p  30 years underwent more additional surgical procedures and had longer operative times, suggesting increased surgical complexity in this group. Among the 864 surgical patients, the POD was present in 266 cases (30.8%), partially obliterated in 265 cases (30.7%), and completely obliterated in 333 cases (38.5%) (Fig.  5 ). Fig. 5 Distribution of POD obliteration status between age groups. Note Stacked bar chart showing POD status distribution for ≤ 30-year-old (left) and > 30-year-old (right) groups. Total sample size: n  = 420 (≤ 30 years) and n  = 444 (> 30 years). ** indicates p  30-year-old (right) groups. Total sample size: n  = 420 (≤ 30 years) and n  = 444 (> 30 years). ** indicates p 30 years) as the grouping factor, an analysis of differences in the degree of obliteration of the POD revealed a statistically significant association between age group and obliteration status; however, the strength of the correlation was very weak (RS = 0.192, p <  0.001). Among the 864 surgical patients, 519 underwent assessment of the EFI. The median EFI score was 7, with an interquartile range of 6 to 8, indicating a moderate fertility potential. A comparison of EFI scores between the ≤ 30 years and > 30 years groups showed a statistically significant difference (Z = −6.205, p <  0.001) (Fig.  6 ). Since age contributes a maximum of 2 points to the EFI score and the mean difference between the two groups was less than 2, the influence of age on EFI could be considered minimal. Overall, the results showed that patients aged > 30 years had lower EFI scores, suggesting that fertility potential may decline with advancing age; however, age is not the sole determinant, and other clinical characteristics may also influence reproductive outcomes. Fig. 6 Distribution of EFI scores in patients with endometriotic cysts across age groups. Note Blue dots represent the ≤ 30-year-old group ( n  = 295); red squares represent the > 30-year-old group ( n  = 224). Error bars indicate Mean ± SD. Double asterisks (**) indicate a statistically significant difference ( p <  0.01) between the two groups. Mann-Whitney U test showed significant group differences (Z = −6.205, ** p  30-year-old group ( n  = 224). Error bars indicate Mean ± SD. Double asterisks (**) indicate a statistically significant difference ( p <  0.01) between the two groups. Mann-Whitney U test showed significant group differences (Z = −6.205, ** p <  0.01). All 864 surgical patients underwent ASRM staging and scoring. The median ASRM score was 42, with an interquartile range of 28 to 72. The overall distribution showed two peaks: the first between 20 and 35 points, and the second between 65 and 75 points, with most patients classified as Stage III or Stage IV. Specifically, 382 patients (44.2%) were classified as Stage III, and 447 (51.7%) as Stage IV. Age group comparisons of ASRM scores and stages revealed a statistically significant difference in ASRM scores (Z = −6.522, p <  0.001), with a weak but statistically significant correlation between age group and ASRM stage (RS = 0.185, p  30 years had higher ASRM scores and were more likely to be classified as Stage III-IV, suggesting that disease burden and severity may increase with advancing age. As shown in Fig.  7 and Table S7 , multivariate logistic regression analysis identified age > 30 years as an independent risk factor for prolonged operative time (OR = 3.76, 95% confidence interval [CI]: 2.61-5.00, p <  0.001). The ASRM score showed borderline statistical significance (OR = 0.99, 95% CI: 0.99-1.00, p =  0.059), suggesting a potential influence on operative time. Other factors, including the presence of DIE nodules, maximum cyst diameter, and the type of additional procedures (e.g., combined laparoscopy and hysteroscopy, other procedures, or no additional procedures), did not demonstrate statistically significant associations ( p >  0.05). The Hosmer-Lemeshow goodness-of-fit test indicated a well-fitting model ( p =  0.215), and all variance inflation factors were  30 years, suggesting that age may be an important factor influencing surgical complexity, whereas the effects of ASRM score and other variables appeared limited. Fig. 7 Multivariate logistic regression analysis of risk factors for operative time > 150 min. Multivariate logistic regression analysis of risk factors for operative time > 150 min. To further investigate the dynamic impact of age on operative duration, a Cox proportional hazards model was applied. In this analysis, “completion of surgery” was defined as the event; therefore, a shorter “survival time” represented a shorter operative duration, and a higher HR > 1) indicated a greater probability of completing the procedure per unit time. The Cox model results (Fig.  8 A) demonstrated that, compared with patients aged ≤ 30 years, those > 30 years had a significantly slower surgical completion rate (HR = 0.41, 95% CI: 0.36–0.47, p  < 0.001), indicating a lower probability of surgery being completed within the same time interval and thus a longer operative duration. The ASRM score was not significantly associated with operative time in this model (HR = 1.002, 95% CI: 0.999–1.005, p  = 0.155), suggesting limited predictive value. Fig. 8 Impact of age and ASRM score on operative time. Note ( A ) Cox regression analysis showing HRs for age group and ASRM score; ( B ) Kaplan-Meier survival curves showing operative time distributions stratified by age group. Impact of age and ASRM score on operative time. Note ( A ) Cox regression analysis showing HRs for age group and ASRM score; ( B ) Kaplan-Meier survival curves showing operative time distributions stratified by age group. Kaplan-Meier survival analysis confirmed these findings (Fig.  8 B): the median operative time for patients ≤ 30 years was 132.29 min (95% CI: 127.52–136.60), significantly shorter than that for patients > 30 years, which was 168.28 min (95% CI: 160.59-178.52) (Log-rank test, p   30 years. This is consistent with the logistic regression findings, which identified age > 30 years as an independent risk factor for operative time > 150 min (OR = 3.76). However, the two models provide complementary perspectives: logistic regression quantifies the static risk of exceeding a defined time threshold, whereas Cox regression characterizes the dynamic probability of surgical completion over time.

From January 2022 to December 2023, a total of 994 patients diagnosed with ovarian endometriotic cysts were enrolled at the Department of Gynecology, the Third Affiliated Hospital of Sun Yat-sen University. Inclusion criteria were: (1) histopathological confirmation of ovarian endometriotic cyst following surgery; (2) laparoscopic complete cystectomy as the primary surgical intervention; and (3) complete clinical records documenting disease duration, prior surgeries, and hormonal treatment history. Exclusion criteria included: (1) primary surgery for deep infiltrating endometriosis (DIE), myomectomy, or other non-cystectomy procedures; (2) emergency surgery for ruptured cysts or cyst aspiration only; (3) concurrent ovarian malignancy or other malignant diseases; and (4) history of pelvic radiotherapy or bilateral oophorectomy. Among the included patients, 496 were aged ≤ 30 years and 498 were > 30 years. Approximately 86.9% underwent surgery, with indications including moderate to severe symptoms (e.g., dysmenorrhea, chronic pelvic pain), fertility desire with ultrasonographic evidence of cysts, failure of standard medical therapy, or suspected concomitant pelvic pathology requiring exploration. Sample size was estimated using G*Power: for Cox proportional hazards regression with age and American Society for Reproductive Medicine (ASRM) score as primary predictors, assuming hazard ratio (HR) = 1.5, α = 0.05, and power = 0.80, ≥ 200 cases were required; for logistic regression with seven covariates (e.g., age, ASRM score, cyst diameter), assuming medium effect size (odds ratio [OR] = 3.76), α = 0.05, and power = 0.80, ≥ 350 cases were required. The final cohort of 994 patients exceeded these thresholds, ensuring sufficient statistical power for subsequent analyses. This study was a retrospective, single-center, clinical cohort study that adhered to the ethical principles of the Declaration of Helsinki and was approved by the Medical Ethics Committee of The Third Affiliated Hospital of Sun Yat-sen University (Approval No.: EY AF/SC-02-06-01/03.0). Data were collected between January and March 2024. As this was a retrospective study and all data were obtained from the hospital’s electronic medical record system, the Medical Ethics Committee waived the requirement for informed consent. Ultrasonographic assessment: Transvaginal ultrasonography was performed when feasible, and transrectal ultrasonography was applied in patients unsuitable for the transvaginal approach. Examinations included standardized evaluation of the uterus, ovaries, fallopian tubes, vagina, and rectovaginal septum, with measurement of relevant structures. The ultrasonographic diagnosis of adenomyosis was based on established criteria, including heterogeneous myometrial echotexture, small intramyometrial cysts, asymmetric myometrial thickening, and a thickened or blurred junctional zone. Diameters of cysts and nodules were measured in two perpendicular planes, and the mean value was recorded. The presence of ovarian endometriotic cysts was noted. Deep infiltrating endometriosis (DIE) lesions were systematically assessed with probe-induced tenderness guidance, focusing on the cervix, pouch of Douglas (POD), anterior rectal wall, rectosigmoid junction, rectovaginal septum, and vesicouterine pouch. Ovarian mobility, uterine sliding sign, and pelvic effusion were evaluated to determine adhesions and POD obliteration. All surgeries were performed under general anesthesia with the patient in the lithotomy position. A standard four-port laparoscopic approach was established via the umbilical margin, left periumbilical point, McBurney’s point, and its contralateral site. Intraoperative assessment included evaluation of uterine size and position, the degree of obliteration of the POD, and the extent of adhesions to surrounding organs. Superficial lesions were defined as bluish or flame-like implants on the peritoneal surface, while DIE lesions were defined as those infiltrating ≥ 5 mm beneath the peritoneum. Lesion diameter was measured using a laparoscopic scale. Bilateral ovarian volume, adhesion severity, and tubal conditions were documented. Disease severity was classified according to the American Society for Reproductive Medicine (ASRM) staging and scoring system, and fertility index was calculated for patients with infertility. The surgical procedure was individualized based on symptom severity, fertility requirements, and intraoperative findings such as DIE nodules, POD obliteration, or concurrent uterine fibroids. The primary procedure was laparoscopic cystectomy combined with pelvic or abdominal adhesiolysis. When indicated, additional procedures were performed, including DIE nodule excision, anatomic reconstruction of the POD, myomectomy, or hysteroscopic interventions for intrauterine lesions. All surgeries were performed by senior gynecologic surgeons with more than ten years of experience in endometriosis surgery. Preoperative medical records were reviewed to collect two key diagnostic variables. (1) Duration of diagnosis: defined as the interval from the patient’s first presentation with typical symptoms (such as secondary dysmenorrhea or chronic pelvic pain) and an initial clinical diagnosis of endometriosis based on ultrasound or elevated CA125, to the date of the current surgery. Considering the known 7–10 year diagnostic delay typical of endometriosis, the time of initial clinical diagnosis was used as the starting point. (2) History of prior surgery: used to determine whether the current operation was the patient’s first endometriosis-related surgery. A first surgery was defined as the absence of any prior targeted procedures, including cystectomy, adhesiolysis, or excision of DIE nodules. To minimize potential bias from surgical heterogeneity, patients were stratified in subsequent analyses according to surgical type (simple cystectomy vs. cystectomy with additional procedures) and surgical complexity (e.g., involving DIE excision, POD reconstruction, or myomectomy). This stratified approach ensured accurate reflection of real-world surgical variations and enhanced the reliability and comparability of study outcomes. Demographic information, including age and body mass index (BMI), was extracted from medical records. Clinical data included the duration of endometriosis prior to surgery (defined as the interval between the first occurrence of endometriosis-related symptoms with imaging or CA125 findings suggestive of an endometriotic cyst and the current surgery), and whether the current operation was the first surgery for endometriosis. A first surgery was defined as no prior targeted procedures such as cystectomy, adhesiolysis, or excision of deep infiltrating endometriosis (DIE) nodules. Additional variables included obstetric history, disease recurrence (defined as symptom relapse ≥ 6 months after prior treatment with imaging-confirmed endometriotic cysts), concomitant uterine disorders (e.g., endometrial polyps, adenomyosis, leiomyoma), and history of standardized hormonal therapy. Hormonal therapy was defined as receiving standardized treatment within three years before surgery, including combined oral contraceptives, high-dose progestins, or gonadotropin-releasing hormone agonists/antagonists (GnRH-a/GnRH-ant). Patients with irregular medication use or treatment duration < 1 month were not considered to have received hormonal therapy. Ultrasonographic parameters included maximum cyst diameter, maximum diameters of the left and right ovaries, presence and size of DIE nodules, and assessment of sliding signs at the posterior uterine wall, POD, anterior uterine wall, and bladder peritoneal reflection. Surgical parameters included operative time, additional procedures such as hysteroscopy, myomectomy, intrauterine device insertion or removal, dilation and curettage, and hydrotubation, status of POD obliteration, ASRM stage and score, and Endometriosis Fertility Index (EFI) values. Data analysis and visualization were performed using SPSS version 27.0 and GraphPad Prism version 10. Continuous variables were tested for normality; normally distributed data were expressed as mean ± standard deviation (Mean ± SD), while non-normally distributed data were expressed as median (interquartile range). Categorical variables were summarized as frequencies and percentages. Group comparisons were conducted using the t-test for normally distributed continuous variables and the Mann-Whitney U test for non-normally distributed data; the Wilcoxon signed-rank test was applied where appropriate. Chi-square tests were used for categorical variables with cell counts > 5, and Fisher’s exact test was used otherwise. Correlations were assessed using Spearman’s rank correlation coefficient. For missing ASRM scores, mean imputation was applied when the proportion of missing data was low and missingness was random. Multivariable logistic regression was used to identify risk factors for operative time > 150 min, including age, ASRM score, presence of deep nodules, maximum cyst diameter, and concomitant procedures. Cox proportional hazards models were additionally employed to explore the dynamic effects of age and ASRM score on operative time. As operative time is a fully observed continuous variable and does not strictly meet the censoring assumptions of survival analysis, Cox regression was considered an exploratory supplement, and the primary conclusions were based on logistic regression results.

In summary, the following preliminary conclusions can be drawn: This study analyzed the clinical characteristics of patients with endometriotic cysts across different age groups and found that age had a significant impact on BMI, pregnancy history, recurrence history, and the incidence of coexisting uterine diseases(Fig.  9 ). In addition, ultrasound findings revealed statistically significant differences in cyst size and maximum diameter between age groups, further supporting the role of age in disease manifestation. Logistic regression identified age > 30 as an independent predictor of prolonged surgery, with Cox analysis corroborating slower progression, jointly confirming its impact on surgical complexity. These findings provide substantial evidence for guiding individualized treatment strategies based on patient age in clinical practice. Fig. 9 Illustration of clinical and operative time differences in patients with endometriotic cysts by age group. Illustration of clinical and operative time differences in patients with endometriotic cysts by age group.

This study, based on a large-sample analysis of 994 patients with ovarian endometriomas, demonstrates that age plays an important role in surgical complexity and clinical characteristics. Specifically, patients older than 30 years had significantly longer operative times, a higher prevalence of comorbidities such as adenomyosis, uterine fibroids, and endometrial polyps, larger cyst diameters, and a higher rate of negative sliding sign in the posterior compartment. Multivariate logistic regression and Cox regression further confirmed that age > 30 years was an independent predictor of prolonged operative time, whereas BMI, cyst size, and ASRM score showed limited influence after adjustment. Notably, ASRM stage/score failed to effectively predict surgical complexity, suggesting limitations in its clinical utility. Previous studies have primarily focused on lesion extent, pathological phenotype, and surgical technique 26 , but few have quantified and validated age as an independent predictor. Using dual modeling with logistic regression and Cox regression in a large real-world cohort, this study clearly identified age > 30 years as an independent factor influencing operative duration, thereby providing a clinically applicable cutoff for preoperative risk stratification. This finding is consistent with prior observations that increasing age is associated with greater lesion extent and pelvic adhesions 3 . In imaging findings, the higher rate of negative sliding sign in older patients aligns with established evidence showing its predictive value for pouch of Douglas obliteration, which is strongly associated with(DIE and surgical complexity 27 . Additionally, the limited predictive capacity of the r-ASRM score for operative time in this study is consistent with prior literature highlighting its shortcomings in describing DIE and adhesion complexity 28 . Recent classifications, such as AAGL 2021 guidelines, UBESS, #Enzian, and NMS-E, place greater emphasis on “anatomy-complexity” imaging-based preoperative assessment. Supporting evidence shows that NMS-E scoring outperforms r-ASRM in predicting operative duration and intraoperative blood loss, underscoring the added value of incorporating functional and adhesion-related dimensions. This study found that patients over 30 years of age more frequently presented with adenomyosis, fibroids, and endometrial polyps, in line with epidemiological findings 29 – 31 . Older patients also had significantly larger cyst diameters, corroborating previous reports 32 , 33 . Histopathological studies indicate that with disease progression, repeated hemorrhage and fibrosis within endometriomas lead to cyst wall thickening and firmness, which increases dissection difficulty 34 . This mechanism may partly explain the age-related differences observed in surgical complexity. Epidemiological data further reveal that ovarian endometriomas are associated with elevated risk of ovarian epithelial cancers, particularly clear cell carcinoma and endometrioid carcinoma, and that this risk rises with age 35 , 36 . The present study’s findings regarding higher clinical burden among older patients support this association. Age-related increases in surgical complexity are likely attributable to prolonged disease duration, resulting in cumulative pelvic adhesions, anatomical distortion, and greater difficulty in cyst dissection and hemostasis. The significantly larger cyst diameters observed in patients > 30 years suggest either longer-standing lesions or greater biological aggressiveness. Pathological evidence supports that repeated hemorrhage and progressive fibrosis within endometriomas contribute to thickened, fibrotic cyst walls 34 , consistent with our findings of increased surgical difficulty in older patients. Beyond disease course, comorbidities and malignancy risk also play a role. Higher rates of adenomyosis, fibroids, and endometrial polyps in older patients may be related to prolonged hormonal dysregulation, inflammatory microenvironment changes, and uterine structural degeneration, all of which add complexity to preoperative assessment and intraoperative management. Long-term inflammation, hormone stimulation, and accumulated genetic mutations may underlie malignant transformation in this subgroup. Importantly, the r-ASRM score did not capture age-related surgical complexity, as it fails to incorporate key factors such as adhesion location, extent, and cyst wall characteristics, echoing previous reports 28 . Thus, comprehensive evaluation should integrate age, imaging-based stratification, and advanced complexity scoring systems to better reflect operative difficulty. Age > 30 years emerges as a simple yet critical preoperative risk indicator, valuable for patient counseling, surgical time planning, and perioperative risk management. For such patients, preoperative transvaginal ultrasound following the IDEA protocol should be reinforced, with focus on sliding sign, cyst size, and comorbidities. When necessary, advanced scoring systems such as NMS-E and #Enzian should be incorporated to improve the prediction of operative time and complication risks. In clinical decision-making, fertility preservation and ovarian reserve must be carefully balanced against surgical radicality in older patients, avoiding excessive loss of function. For recurrent or long-standing cysts, vigilance toward malignant transformation should be heightened, with structured postoperative surveillance strategies in place. Multidisciplinary collaboration involving gynecology, anesthesiology, and radiology is essential to optimize vascular control, hemostasis, and tissue protection, thereby reducing complications and improving fertility and long-term outcomes. This single-center retrospective study is subject to selection bias, incomplete recording of key variables such as surgeon experience, and a lack of long-term outcome data, limiting external generalizability and mechanistic insights. Symptom onset times were inconsistently reported and incompletely documented, preventing standardized inclusion in analyses. Although preoperative hormonal therapy was recorded and compared as a baseline feature, details regarding drug types, treatment duration, and compliance were unavailable due to the retrospective design, precluding further exploration of their impact on surgical complexity. Future research should pursue multicenter, prospective cohort studies to systematically capture symptom duration and integrate age into multivariate analyses. More detailed documentation of hormonal treatment is also needed to elucidate its interaction with age in disease progression and surgical outcomes. Development of standardized databases, AI-assisted imaging analysis, and molecular biology research holds promise to improve surgical complexity assessment and advance individualized risk stratification and precision surgery for endometriosis.

Endometriosis is a common estrogen-dependent benign gynecological disease 1 , characterized by the ectopic implantation of functional endometrial-like tissue outside the uterine cavity, including locations such as the ovaries, pelvic peritoneum, uterosacral ligaments, bladder, and intestinal surfaces, leading to inflammatory responses and tissue adhesions. The disease primarily affects women of reproductive age, with an estimated prevalence of approximately 10% 2 , 3 , and commonly presents clinically as progressive dysmenorrhea, chronic pelvic pain, dyspareunia, and infertility 4 – 7 . Endometriotic cysts (commonly referred to as “chocolate cysts”) represent one of the most prevalent manifestations of the disease 8 . These cysts are frequently associated with impaired ovarian function and distortion of pelvic anatomy, significantly affecting fertility and quality of life 9 . Although multiple conservative treatments are available, surgical excision of the cyst remains a cornerstone of therapy, especially for patients with fertility demands or severe symptoms 10 . With an increasing understanding of the disease, researchers have begun to explore various factors that influence disease progression and surgical complexity, aiming to provide a basis for individualized treatment 3 . Among these, age—as a fundamental demographic variable—has attracted growing attention. Women of different age groups may exhibit distinct clinical presentations and disease evolution in endometriosis 11 , 12 . On one hand, younger patients may delay seeking medical attention due to milder symptoms or early-stage lesions. On the other hand, older patients are more likely to present with more extensive lesions, severe pelvic adhesions, and coexisting pelvic pathologies 8 . Studies have shown that increasing age is closely associated with larger cyst volumes and a higher incidence of concurrent uterine fibroids and adenomyosis 13 , 14 . In addition, due to reduced tissue healing capacity and increased intraoperative anatomical difficulty, older patients tend to experience longer postoperative recovery periods and higher surgical risks 10 . However, there is no consensus in clinical practice on whether significant differences exist in surgical complexity and treatment outcomes among patients with endometriotic cysts in different age groups. Systematic and quantitative research data on this issue remain limited. Therefore, further investigation into the impact of age on disease manifestation and treatment processes is of particular importance. Surgery is the key treatment for ovarian endometrioma, and operative time is an essential parameter reflecting surgical complexity, technical difficulty, and recovery outcomes 15 – 17 . Prolonged operative time increases anesthesia exposure and intraoperative risks, while also indicating more complex lesions and severe pelvic anatomical distortion 18 . Determinants of operative time include cyst size, recurrence, concomitant uterine disorders, and bilateral distribution. Preoperative prediction models have been proposed to improve surgical preparation and efficiency 19 – 21 . Whether age independently affects operative duration and complexity remains controversial: some studies suggest its impact is mediated through disease course and lesion severity 15 , while others argue that age itself is a direct determinant of surgical performance 22 , 23 . Real-world comparative analyses across age groups are therefore necessary to refine risk assessment, enhance doctor-patient communication, strengthen patient cooperation, and improve treatment efficiency and satisfaction. Clinical management of ovarian endometrioma is shifting toward precision and individualization 24 . A single treatment pathway is insufficient, and surgical planning must integrate age, medical history, symptom severity, and fertility intentions 25 . Current research emphasizes pathological characteristics but often neglects patient-related factors, leaving the evaluation of surgical complexity, intraoperative planning, and anticipation of potential difficulties as pressing challenges in clinical practice. This study aimed to assess the impact of age on clinical characteristics and operative time in patients with endometriotic cysts, evaluating its role as a potential risk factor in treatment decision-making. By comparing baseline features, comorbidities, imaging, and surgical outcomes across age groups, it sought to clarify how age influences disease progression and surgical difficulty. The results are expected to support more accurate preoperative assessments, guide personalized and risk-controlled treatment plans, and provide evidence for patient-centered strategies to refine endometriosis management and improve outcomes and quality of life.

Below is the link to the electronic supplementary material. Supplementary Material 1 Supplementary Material 1