Sonographic Assessment of Ovarian Endometrioma Recurrence Six Months After Laparoscopic Cystectomy in Patients with Endometriosis

Our study showed a recurrence rate of 13.9% for endometrioma six months after the laparoscopic cystectomy. Many studies have evaluated the risk of recurrence after surgery ( 17, 22, 23), but a great variation is observed among different studies. The review study, reporting a range of 11% to 35% for a recurrence rate of postoperative ovarian endometrioma, mentioned that the main reason for this discrepancy could be related to the different definitions of endometrioma, as some have only considered ovarian endometrioma > 3 cm ( 24). Another review study reported the variation in the recurrence rate (ranging from 6% to 67%) in different studies is due to the different criteria used for diagnosis and duration of follow-up ( 25). Hayasaka et al. investigated 175 patients and reported a recurrence rate of 45% for endometrioma up to one year after laparoscopic excision ( 17). Koga et al. investigated the recurrence of ovarian endometrioma in 224 patients 2 years after laparoscopic excision and reported a recurrence rate of 30.4%, considering ultrasonographic mass of > 2 cm ( 22). A meta-analysis of 23 studies reported the average 2-years’ recurrence rate at 19.1%, but reported significant heterogeneity among studies ( 21). The recurrence rate in these studies is higher than that of ours, but are not exactly comparable, due to different diagnostic criteria, study design, and follow up period. According to the results of the study by Muzii et al., a minimum of three to six months was reported to be appropriate for studying the ultrasonographic evidence of endometrioma recurrence ( 23); therefore, we selected six months for follow-up. Nevertheless, most studies have focused on longer follow-up periods. One other pitfall is that studies have not reported whether the recurrence appeared in the ipsi- or contra-lateral ovary. Although researchers have reported that more than 85% of recurrence occurs on the operated ovary, the rest may appear on the contralateral untreated ovary ( 26, 27). Meanwhile, most studies have only reported the general entity of the recurrence and have not defined the ovary’s side. Another important factor is that all these studies have used TVS as the diagnostic tool ( 17, 21- 27), while a percentage of our patients were not married and should have undergone abdominal ultrasonography because their hymen should not damage. Furthermore, the differences in the surgical techniques used could affect the recurrence rate ( 28). The difference in the accuracy of sonographic methods could also be attributed to the difference in the recurrence rates. Despite these variations among studies ( 17, 21- 25), the results of all these studies confirm that of the present study on the high risk of recurrence of endometrioma after surgery, which is of great importance and has to be considered by gynecologists. Studying a wide range of demographic characteristics in this study showed that none of the factors, including age, age at menarche or marriage, BMI, or family history affected the rate of recurrence, although some have determined younger age as a significant risk factor ( 27, 29). The two factors, including positive infertility and a history of surgery for endometrioma were significantly higher in the group of patients with recurrence after 6 months. Previous surgery was reported as a predictive risk factor of the recurrence in several studies ( 15, 24). Infertility and previous surgery may indicate the presence of anatomical abnormalities and adhesions, but may also refer to the severity of disease that caused a higher risk of the recurrence. However, the results of the present study indicated that the disease stage (the presence of DIE) and cyst’s size were not associated with the recurrence of endometrioma. In the study by Porpora et al., deep lesions and cyst’s size were not associated with recurrence ( 15), which is consistent with the results of our study. The study by Liu et al. also reported that patients’ age, number, and size of cysts were no longer associated with the risk of the recurrence, after adjustment for COX-2 overexpression, suggested as an important etiology of endometrioma recurrence ( 30). These results are in line with the results of our study; meanwhile, some researchers have reported the size and stage of the disease as significant risk factors for the recurrence of endometrioma ( 22, 31), which is contradictory to the results of the present study. Exacoustos et al. stated that the size of the recurrent endometrioma, even if associated with the risk of recurrence, is not as important as the patients’ symptoms and the choice of reoperation should be determined based on the severity of patients’ symptoms rather than the cyst’s size ( 26). The choice of medical treatment after surgery is also controversial. In the present study, we did not perform any intervention in this regard, but recorded any treatment the patients received during this period and the results showed that 34.1% used OCP or GnRH agonist after laparoscopic cystectomy, but medical treatment was not associated with increasing or decreasing the risk of recurrence. Other researchers have reported that previous medical treatment had no effect on the recurrence of endometrioma ( 17, 18), which confirm the results of the present study. On the contrary, the results of the study by Dimitrijevic and colleagues showed later recurrence in patients using GnRH analog treatment. Seracchioli et al. also reported that long term use of OCP (24 months) could reduce the risk of endometrioma recurrence ( 32) and Vercellini et al. reported lower recurrence rate in patients using OCP after 28 months ( 29). The difference in the results of these studies with that of ours could be due to the shorter follow-up in our study and OCP might show protective effects in longer follow-up periods. Hence, even if long term OCP has a protective effect on the recurrence of endometrioma, its usage will be challenging, as many patients suffered from infertility and are suggested to conceive after surgery. As evidence shows, pregnancy has a protective effect on the risk of recurrence of endometrioma ( 17). Therefore, the choice of pregnancy or long term use of OCP is an important issue that should be chosen individually for each patient ( 33). The present study evaluated the rate and risk factors of endometrioma recurrence at a tertiary medical center; however, this study could also have some limitations. The most important limitation was the limited follow-up period and sample size; meanwhile, after six months, some patients didn't refer for the follow up. In conclusion, the results of the present study showed a recurrence rate of 13.9% for endometrioma six months after laparoscopic cystectomy, significantly associated with infertility and previous surgery for endometrioma. Possibly, damages in the previous surgery and Cellular and molecular abnormalities that encountered more deeply in endometriosis-associated infertility predispose the patients to more recurrence rate, which can be further investigated. Studying the mechanism of this association can help the diagnosis of the etiology underlying this high recurrence rate and appropriate treatments for the prevention of endometrioma recurrence.