An Observational Study of Factors affecting CA125 Levels in Premenopausal Women.

CA125 is one of the known markers, which is being used for ovarian cancer. It is a high molecular weight glycoprotein, which is recognized by the monoclonal antibody OC-125.[ 1 ] Apart from its use in ovarian cancer, it has been seen that the gene that encodes it, that is, MUC16, is being expressed by a variety of tissues such as respiratory, reproductive tract, gastrointestinal, and body cavities, and thus its values may depend on a variety of conditions rather than by ovarian cancer alone.[ 1 ] Not only the medical conditions can affect CA125 levels but also other baseline demographic characteristics like age, body mass index (BMI), race, parity, and use of drugs can also affect it.[ 2 3 4 5 6 7 8 9 ] At one end, CA125 is primarily assessed in postmenopausal women for ascertaining ovarian cancer risk, but on the other end, its role and fluctuations in the premenopausal state remain to be explored. Also, it remains unknown as to in what time period of the menstrual cycle one should determine CA125 levels whether it should be during menstruation or after menstruation or mid-cycle.[ 7 ] Keeping these factors in mind, the present study was conducted wherein we determined CA125 levels during menses and at the mid-cycle stage to determine the difference in the values during the menstrual cycle. Also, we determined the demographic and clinical factors that show an association with the CA125 levels. The study results will be helpful for family physicians as they will allow them to monitor CA125 levels in specific stages of menstruation, and it will also allow them to give a guarded interpretation to the women for CA125 values based on the baseline demographic and other characteristics. Since CA125 levels have become an important marker for ovarian cancer, so CA125 carries a fear associated with it, especially if the value comes above the baseline value of 35 U/ml (as assessed in the postmenopausal stage). Cancer screening remains an important hallmark in medical science and so women undergo frequently CA125 levels during health check-ups; this requires the family physicians to thoroughly familiarize themselves with the factors affecting the CA125 levels in different ethnicities, thereby allowing them to counsel the women nicely in the general practice.

The mean age of the patients was 28.71 ± 6.14 years, and the mean age of menarche was 13.96 ± 0.9 years. The number of nullipara women was 60 (54.55%), Para 1 was 34 (30.91%), and Para 2 was 16 (14.55%). Regarding menstrual history, dysmenorrhea was present in 28 (25.45%) women. The mean cycle length was 29.45 ± 1.92 days, and mean days of menses were 3.91 ± 1.03 days. History of use of analgesics, previous ovarian cyst, OCP usage, tubal ligation, and infertility treatment was present in 17.27%, 16.36%, 8.18%, 3.64%, and 2.73%, respectively. Regular caffeine consumption was present in 18 (16.36%) women. There were four (3.64%) obese women. History of the first degree relative with ovarian cancer, second degree with ovarian cancer, first degree relative with breast cancer, and second-degree relative with breast cancer was present in 4.55%, 10.00%, 6.36%, and 10.91% women, respectively [ Table 1 ]. Distribution of demographic characteristics of study subjects The median day of sample collection during menses was day 2 where the mean values were 24.74 ± 17.43 (range of 2.9–89.4 U/ml), while the median day of sample collection in mid-cycle was day 14 where the mean values were 12.39 ± 7.3 (range of 1.2–32.5 U/ml). Compared to mid-cycle CA125 values, values during menses were significantly higher ( P < 0.0001) with a mean difference of 12.35 ± 15.04 [ Figure 1 ]. Comparison of CA 125 (U/mL) between during menstruation and mid-cycle values. (non-parametric variable, box–whisker plot, Wilcoxon signed ranks test, P < 0.0001) On performing univariate regression, days of menses, dysmenorrhea and regular caffeine consumption were significant risk factors of CA125 levels. With the increase in days of menses for by 1 day, CA125 levels significantly increased by 4.242 U/mL. Patients with dysmenorrhea and regular caffeine consumption had significantly high CA125 levels with beta coefficients of 8.111 (3.552 to 12.669) and 9.144 (3.75 to 14.537), respectively [ Table 2 ]. On performing multivariate regression, days of menses and regular caffeine consumption were significant independent risk factors of CA125 levels after adjusting for confounding factors. With the increase in days of menses for by 1 day, CA125 levels significantly increased by 3.49 U/mL. Patients with regular caffeine consumption had significantly high CA125 levels with beta coefficient of 7.074 (1.971 to 12.176) [ Table 3 ]. Univariate linear regression to find out significant factors affecting CA125 levels Multivariate linear regression to find out significant factors affecting CA125 levels

In conclusion, the level of serum CA125 is significantly elevated during menstruation than mid-cycle among premenopausal women. Days of menses and caffeine consumption were the significant factors that led to higher CA125 levels. Overall, it is recommended that an elevated CA125 level in premenopausal women must be approached carefully to avoid unnecessary investigations and apprehension to the patient. Future studies should evaluate the underlying biological and pathological mechanisms of the observed associations on more diverse study population. If the results of the present study are confirmed, they could help in recognizing factors that affect CA125 levels in premenopausal women and eventually aid in improving, preventing, or detecting ovarian cancer at an early stage with a good prognosis. Nil. There are no conflicts of interest.

In this study, we assessed the difference between CA125 levels as assessed in the menstrual period and in the mid-cycle period, and we found that compared to the menstrual period, values of the mid-cycle period were significantly lower (12.39 ± 7.3 vs. 24.74 ± 17.43 U/ml, P < 0.0001), with a mean average difference of 12.35 ± 10.13 U/ml. This was in accordance with the findings by Oliveira MA P et al .,[ 11 ] where also the serum CA125 levels were lower in mid-cycle as compared to the menstrual phase (16.4 vs 16.6, P < 0.05). Kafali H et al .[ 12 ] also supported the present study findings and found that among healthy premenopausal women, the mean CA125 level during menstruation was 12.2 U/ml and during other days of the menstrual cycle was 10 U/ml with an average difference of 22% ( P < 0.001). Crosby DA et al .[ 13 ] also observed significant differences in serum CA125 levels during menses and mid-cycle whereby an increase in serum CA125 levels was found during menstruation. However, they evaluated serum CA125 levels in women with endometriosis, not in healthy women. Similar findings were also reported in the study by McLemore MR et al .,[ 14 ] where the highest CA125 levels were present during menses. Overall they reported that a reduction of 0.2 U/ml per day in CA125 levels was seen from menses to the end of the cycle, leading to a total reduction of 5.8 U/ml in the cycle. The CA125 levels in cervical mucus are under the control of ovarian sex steroids because significantly higher levels have been found in the follicular than in the luteal phase of the menstrual cycle. For such variations in the values of CA125 during different phases of menstruation, the reason has been ascribed on the breakdown of cervical mucus during menses. Normally, CA125 is released from the endometrium, and it gathers in the cervical mucus which is under the control of ovarian sex steroids. Since sex steroids are more during the follicular phase than the luteal phase, so are the lower values of CA125 in the mid-cycle. Also, it has been reasoned out that among premenopausal women, the cervical mucus barrier breaks during menstruation allowing for the diffusion of CA125 into the peripheral blood leading to increased levels of CA125 during menstruation. Another reason is possibly MUC16 expression on the endometrium as well as endometrial shedding in the early follicular phase that may result in high serum CA125 levels. Overall, higher values of CA125 during menses indicate that it is best to measure CA125 in the mid-cycle for correct interpretation of values among premenopausal women. Among the other factors that may affect the values of CA125, days of menses and regular caffeine consumption showed a significant positive association ( P < 0.05). In comparison, Sasamoto N et al .[ 9 ] also found that days of the menstrual cycle were associated with serum levels of CA125. Early follicular menstrual phase was significantly associated with the higher CA125 serum levels, while other days showed an association with lower levels. Pauler DK et al .[ 6 ] observed that regular intake of caffeine consumption reduced CA125 levels ( P < 0.001); however, they enrolled postmenopausal women in the study. The reason behind this may be that consumption of caffeine induces liver enzymes, which leads to an increase in the metabolic breakdown of CA125. However, the exact cause of increased CA125 in relation to excess caffeine consumption remains unknown and needs to be explored. One hypothesis by the authors is that the women may be under stressful lifestyle for which they are consuming excess coffee which may lead to increased CA125 levels.[ 7 ] Besides these two factors, other demographic characteristics like age, parity use of drugs like OCP, and family history failed to show a significant association in our study. In contrast, certain studies conducted in other countries showed varied factors to affect CA125 levels. Higher CA125 levels were found to correlate with younger age in the study by Hu X et al .[ 7 ] and Pauler DK et al .,[ 6 ] whereas age showed nonlinear association with CA125 levels in the study by Sasamoto N et al .[ 9 ] Hu X et al .[ 7 ] found that higher CA125 levels correlate with race, and Sasamoto N et al .[ 9 ] observed that non-white race showed significant association with lower CA125 levels. Lower BMI was also found to correlate with higher CA125 levels by Hu X et al .,[ 7 ] which is similar to other studies that mentioned obesity to be associated with lower CA125 level.[ 2 15 ] This may be possibly because of the dilution effect of high plasma volume. The duration of OCP use was also a factor related to CA125 levels among premenopausal women as seen in the study by Hu X et al .[ 7 ] who found that use of OCP for 5–10 years (in comparison with 4 years), compared to a duration <2 years, showed an association with lower CA125 level. Moreover, higher CA125 levels were found to correlate with current smoking as smoking exposure may lower CA125 levels.[ 7 8 ] Among the medical conditions, the increased CA125 levels were found to correlate with endometriosis also,[ 8 9 ] and thus, it can be a screening biomarker for endometriosis. A significant association is also reported between osteoporosis and lower CA125 levels,[ 7 ] which was supported by Ahn KH et al .,[ 16 ] suggesting that lower CA125 level in the hypoestrogenic state leads to reduced bone density. Higher CA125 levels were also found to correlate with coronary artery disease.[ 7 8 ] As CAD is rarely present among young women, it is difficult to interpret the relationship between CA125 level and CAD among premenopausal women. However, pleura, pericardial, or peritoneal irritations or reactions from effusions are the potential sources of increased CA125 levels in heart diseases including heart failure. Heart disease leads to overexpression of inflammatory cytokines, particularly interleukin-6, causing high CA125 levels. Hysterectomy also showed an association with lower CA125 levels among premenopausal women.[ 8 ] The observation that endometriosis increases CA125 levels and hysterectomy reduces it among premenopausal women indicates the significance of the uterus (specifically uterine lining) in the physiology of CA125. The colon polyps were also found to be associated with significantly lower CA125 levels among premenopausal women.[ 8 ] This can be explained by the fact that as colon polyps are precursors to colon cancer, higher CA125 levels may be present in those with polyps. The presence of fibroids is also reported to be significantly associated with CA125 levels as fibroids increase menstrual bleeding.[ 9 ] These factors remain unaddressed in the present study. One of the main limitations is that the present study excluded all patients with any benign or malignant conditions. Another limitation was that the values were not compared with postmenopausal women. Also, being a single-center study, its results cannot be generalized due to racial diversity in the Indian population.

An observational study was conducted in the Department of Obstetrics and Gynecology from December 2017 to May 2019. Institutional ethical clearance was taken before the start of the study (IEC KMC MLR 08-16/173, dated August 17, 2016). The inclusion criteria were women of the reproductive age group of 15–45 years with regular menstrual cycles. Those who were pregnant had endometriosis, pelvic inflammatory disease, and other infections, or any benign or malignant gynecological disorders were excluded from the study. The sample size calculation was based on the study results of Akinwunmi BO et al .[ 8 ] who observed that average CA125 levels in premenopausal women were 14.5 units/mL. Taking this value as a reference and assuming a standard deviation of 5, the minimum required sample size with the estimate to be within 7% of CA125 levels and 5% level of significance is 94 patients. To reduce the margin of error, the total sample size taken is 110. For the 110 eligible patients enrolled in the study, a written informed consent was taken after explaining them the study procedure. Sociodemographic characteristics of the patients such as age, age of menarche, parity, menstrual history, previous medical history, regular caffeine consumption, and history of ovarian cancer and relatives were recorded in the pre-designed study proforma. Obesity was defined as BMI ≥30 kg/m 2 . For assessing CA125 levels, trained phlebotomists collected the 5 ml of venous blood sample in a red-topped vacutainer, which was immediately sent to the laboratory. For each patient, two samples were taken—one during the menses and the other during mid-cycle (day 12–18). The centrifugation of samples was done at 2400 rpm for 10 minutes. The storage of plasma samples was done at −80°C. CA125 was measured on plasma samples of 100 μL each using The Roche Elecsys® CA125II assay.[ 10 ] The reportable range of the assay was 0.6 to 500 IU/L with the normal reference interval being considered as <35 U/ml. The outcomes were variations in the CA125 values in mid-cycle and during menses and the factors affecting CA125 values. The data were entered in an Excel spreadsheet and analyzed using Statistical Package for Social Sciences (SPSS) software, IBM manufacturer, Chicago, USA, version 25.0. An arithmetic mean of the two values of CA125 obtained during mid-cycle and at menses was obtained, based on which the factors affecting CA125 values were evaluated. Univariate and multivariate linear regression was used to find out significant factors affecting CA125 levels. Wilcoxon signed rank test was used for determining the association between mid-cycle and menses values of CA125. For statistical significance, a P value of less than 0.05 was considered statistically significant.