Menstrual cyclicity of CA-125 in patients with endometriosis*t*

Transcription

1 FERTILITY AND STERILITY Copyright 1992 The American Fertility Society Printed on acid-free paper in U.S.A. Menstrual cyclicity of CA-125 in patients with endometriosis*t* Mark D. Hornstein, M.D. II Phaedra P. Thomas, R.N. Ray E. Gleason, Ph.D.~ Robert L. Barbieri, M.D. Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts Objective: To examine the serum levels of CA-125 in the menstrual, follicular, and luteal phases of the menstrual cycle in women with endometriosis and to determine if serum CA-125 levels drawn during menses improve the clinical utility of the test in diagnosing endometriosis. Design: Serum CA-125 was measured in the menstrual, follicular, and luteal phases of the cycle preceding surgery. CA-125 levels for each phase were categorized by postoperative diagnosis and endometriosis stage. Setting: The reproductive endocrine unit of a tertiary care university-affiliated hospital. Patients: A total of 65 patients were recruited from the Fertility and Endocrine Unit and the Gynecology Service of Brigham and Women's Hospital. Main Outcome Measure: Serum CA-125 levels were measured by an immunoradiometric assay and were stratified by menstrual cycle phase, diagnosis, and stage of endometriosis. The menstrual cycle phase was confirmed by serum estradiol and progesterone measurements. Results: Serum CA-125 levels in patients with stages II to IV endometriosis were significantly elevated in the menstrual phase compared with levels drawn in the nonmenstrual follicular and luteal phases. The sensitivity and specificity of CA-125 for the diagnosis of endometriosis were not significantly better in the menstrual than in the follicular or luteal phases. Conchisions: Despite menstrual cyclicity of CA -125, measurement of serum CA -125 during menses does not improve the clinical utility of the test in the diagnosis of endometriosis. Fertil Steril 1992;58: Key Words: CA-125, endometriosis, menstrual cycle CA-125 is the antigenic determinant of an immunoglobulin G 1 monoclonal antibody, OC-125, obtained by somatic hybridization of B lymphocytes Received February 3, 1992; revised and accepted April 13, * Presented in part at the 47th Annual Meeting of The American Fertility Society, Orlando, Florida, October 19 to 24, t Supported in part by a grant from Centocor, Inc., Malvern, Pennsylvania, and by General Clinical Research Center grant 5- Mol-RR-02635, Brigham and Women's Hospital, Boston, Massachusetts. :j: Data organization and analysis assisted by the Computerized Data Base Management and Analysis System. Department of Obstetrics and Gynecology. II Reprint requests: Mark D. Hornstein, M.D., Department of Obstetrics and Gynecology, Brigham and Women's Hospital, 75 Francis Street, Boston, Massachusetts ) Department of Medicine. from mice immunized with cells from an ovarian carcinoma cell line. CA -125 is associated with a high molecular weight glycoprotein that is expressed on derivatives of the coelomic epithelium, including the epithelium of the endocervix, endometrium, fallopian tube, and pelvic peritoneum (1-4). The hypothesis that endometriotic implants are derived from coelomic epithelium led numerous investigators to study serum CA-125 levels in patients with endometriosis. Several groups have noted elevated CA-125 values in patients with advanced endometriosis (5-14); however, the sensitivity of a single CA-125 level as a diagnostic test for minimal and mild disease has been disappointing (5, 6, 11, 14). Recently, several teams have shown that serum CA- 125 levels are elevated during menses (15-18). Consequently, this study was undertaken for two pur- Hornstein et ai. Menstrual cyclicity of CA

2 Table 1 Serum CA-125 Levels by Menstrual Cycle Phase* Group Normal pelvis (n = 4) Nonendometriosis (n = 22) Endometriosis stage I (n = 18) Endometriosis stage II (n = 8) Endometriosis stages III/IV (n = 13) * Values are means ± SD. t NS, not significant. Menstrual 22.0 ± ± ± ± ± 95.9:1: Follicular Luteal Probability 19.3 ± ± 5.8 NSt 15.3 ± ± 9.3 NSt 16.1 ± ± 6.7 NSt 23.7 ± ± 12.4 < ± ± 35.9:1: <0.02 :I: P < 0.05 compared with normal pelvis group. poses: (1) to study serum CA-125 levels in the menstrual, follicular, and luteal phases of the cycle in women with endometriosis, and (2) to determine if a CA -125 level drawn during menses improves the clinical utility of the test in the diagnosis of endometriosis compared with CA-125 measured during the nonmenstrual follicular or luteal phases. MATERIALS AND METHODS A iotal of 75 patients with the preoperative diagnosis of pelvic pain or infertility were recruited from the Fertility and Endocrine Unit and the Gynecology Service ofthe Brigham and Women's Hospital. The study was approved by the hospital's Institutional Review Board. Patients had peripheral blood drawn for CA-125, estradiol (E2), and progesterone (P) during the menstrual, follicular, and luteal phases of the cycle preceding laparoscopy or laparotomy. The phase of each patient's cycle was documented by last menstrual period and confirmed by serum E2 and P cutoff. The blood was immediately centrifuged and the serum stored at -70 C for later analysis. At surgery, the diagnosis was recorded, and patients found to have endometriosis were staged according to The American Fertility Society Revised Classification of Endometriosis (19). The surgeon was not aware of the patient's CA-125 levels. Of the 75 patients enrolled, 8 were subsequently found to have been anovulatory in the study cycle (luteal P < 2.5 ng/ml), and 2 did not undergo their scheduled surgery and thus were not included in the study, leaving 65 subjects for data analysis. The remaining patients were divided into five groups. Group I (n = 4) consisted of patients found to have a completely normal pelvis at surgery. Group II (n = 22) were patients found to have gynecological conditions other than endometriosis. Diagnoses in this group included pelvic adhesions (8), tubal obstruction (4), leiomyoma (3), intrauterine adhesions (2), ovarian cyst (2), congenital mullerian anomalies (2), and paratubal cyst (1). Group III (n = 18) included patients with stage I endometriosis. Group IV (n = 8) were women with stage II endometriosis. Group V (n = 13) consisted of patients with stages III and IV endometriosis. Blood was collected during menses from 55 patients, during the follicular phase from 57 women, and during the luteal phase from 61 women. CA-125 levels were determined by an immunoradiometric assay (Centocor, Malvern, PA) and are expressed in arbitrary units based on a primary reference standard. The interassay and intraassay coefficients of variation (CVs) were 11.5% and 9.5%, respectively. Estradiol was measured by a radioimmunoassay (RIA; Pantex, Santa Monica, CA). The interassay and intra-assay CVs were 11.0% and 10.0%, respectively. Progesterone was also measured by RIA (Diagnostic Products Corporation, Los Angeles, CA), with inter-assay and intra-assay CVs of 10.0% and 8.4%, respectively. Statistical analysis of CA-125 levels across the menstrual cycle was carried out using repeated measures ANOVA with pairwise comparisons among means performed by the Student-Newman-Keuls test. Analysis of CA-125 within each phase of the menstrual cycle was performed by ANOVA, again using the Student-Newman-Keuls test for pairwise comparisons. Results are reported as means ± SD. RESULTS Patients with endometriosis stages II (group IV), III, and IV (group V) had significantly higher serum CA-125 levels during their menses than in the nonmenstrual (follicular or luteal) phases oftheir cycles (P < 0.04 for stage II and P < 0.02 for stages III and IV). Patients with endometriosis stage I (group III), nonendometriosis gynecological conditions (group II), and a normal pelvis (group I) failed to demonstrate a statistically significant elevation in menstrual CA-125 levels (Table 1). 280 Hornstein et a1. Menstrual cyclicity of CA-125 Fertility and Sterility

3 Patients with stages III and IV endometriosis had significantly higher (menstrual: 99.4 ± 95.9 U /ml and luteal: 44.3 ± 35.9 U/mL) CA-125 levels compared with the normal pelvis group (menstrual: 22.0 ± 2.7 U/mL and luteal: 15.4 ± 5.8 U/mL, P < 0.05). The difference seen between these groups in the follicular phase failed to reach statistical significance (Table 1). The clinical utility of CA-125 in the diagnosis of endometriosis across the menstrual cycle was studied by comparing the sensitivity, specificity, and positive and negative predictive values of CA-125 within each phase of the cycle. A value of 35 U /ml was chosen as the upper limit of normal (5-7). Sensitivity was defined as the number of patients with all stages of endometriosis who had CA-125 levels > 35 U /ml, divided by the total number of patients with endometriosis (Table 2). Specificity was defined as the number of patients who did not have endometriosis and had CA-125 levels < 35 U/mL divided by the total number of patients without endometriosis. Sensitivity and specificity also were calculated in this manner for patients with stages III and IV endometriosis (Table 3). For all patients with endometriosis, the sensitivity of CA-125 in the menstrual phase was 0.35 and the specificity of the test was The positive and negative predictive values of the test were 0.79 and 0.51, respectively (Table 2). These calculations for CA-125 measured in the follicular and luteal phases are found in Table 2. For patients with stages III and IV disease only, the sensitivity and specificity of a CA -125 level> 35 U /ml in the menstrual phase were 0.80 and 0.88, respectively. The positive predictive value of the test was 0.73, and the negative predictive value during menses was 0.91 (Table 3). Similar calculations for patients with stages III and IV endometriosis during the follicular and luteal phases of the cycle are found in Table 3. Receiver-operator characteristic curves were constructed to determine if an increase in menstrual CA-125 levels over a follicular or luteal baseline Table 2 Reliability of Serum CA-125 Levels for the Diagnosis of Endometriosis by Menstrual Cycle Phase* Parameter Sensitivity Specificity Positive predictive value Negative predictive value * CA-125 > 35 U/mL. Menstrual Follicular Luteal Table 3 Reliability of Serum CA-125 Levels for the Diagnosis of Endometriosis Stages III and IV by Menstrual Cycle Phase' Parameter Sensitivity Specificity Positive predictive value Negative predictive value, CA-125 > 35 U/mL. Menstrual Follicular Luteal could be used to increase the reliability of the test for the diagnosis of endometriosis. When menstrual CA-125 levels were at least 20 U/mL greater than the follicular or luteal CA -125 values, the sensitivity and specificity were 0.22 and 0.87, respectively, for the diagnosis of all stages of endometriosis and 0.70 and 0.87 for the diagnosis of stages III or IV endometriosis. The positive and negative predictive values for this method were 0.75 and 0.48 for all stages of endometriosis and 0.70 and 0.87 for stages III and IV disease. DISCUSSION Since the initial reports that serum CA-125 levels are elevated in women with advanced endometriosis, numerous investigators have attempted to use this antigen in the preoperative diagnosis of endometriosis. The low sensitivity and specificity of random serum CA-125 levels have limited its applicability in the diagnosis of endometriosis. This study was undertaken to determine if serum CA-125 levels are increased during menses in patients with endometriosis and if timing the CA -125 test during menses would increase the sensitivity and specificity of CA- 125 in the diagnosis of endometriosis. The major findings in this report indicate that serum CA-125 levels increase during menses in women with stages II, III, and IV endometriosis. However, the measurement of CA-125 during menses does not appreciably increase the clinical utility of the assay in diagnosing endometriosis. A number of investigators have studied the value of CA-125 as a diagnostic test for endometriosis. As reviewed by Schenken et al. (20), most researchers have found the sensitivity of a single CA-125 blood level of >35 U /ml to be too low to use as a screening test for endometriosis, even in patients with advanced disease. The correlation between levels of the antigen and milder degrees of endometriosis was even lower (20). Although single serum values of Hornstein et al. Menstrual cyclicity of CA

4 CA-125 appear to have insufficient discriminatory power for use as a screening test for endometriosis, many investigators have shown that the test is helpful in monitoring the progress of patients after medical or surgical therapy (5, 8, 9, 13, 17). Pittaway and Fayez (8) suggested using a cutoff of 16 U/mL as a better discriminator for distinguishing between patients with endometriosis and without. Using a modification of the CA-125 assay designed to increase the sensitivity of the assay in its lower ranges, Pittaway and Douglas (21) were able to achieve a sensitivity of 1.00 and a specificity of 0.68 for endometriosis in patients with stages III and IV disease. The current study found a sensitivity of 0.35 and a specificity of 0.88, with positive and negative predictive values of 0.79 and 0.51, respectively, for the diagnosis of all stages of disease, when blood was drawn during the menstrual phase. These indices were not appreciably different from samples taken during the follicular and luteal phases and are in agreement with the sensitivity and specificity reported by others (20). As expected, the reliability of the antigen in the diagnosis of stages III and IV disease was better. The sensitivity was 0.80, the specificity 0.88, and the positive and negative predictive values were 0.73 and 0.91, respectively, for blood drawn during patient's menses. Again, these parameters were similar in the follicular and luteal phases. These results were also comparable with those reported by previous researchers (20). The findings in this study, in a patient population highly enriched for endometriosis (prevalence of 60%), suggest that collecting serum CA -125 samples during the menses does not significantly improve the accuracy of the test in diagnosing endometriosis. In addition, an attempt was made to determine if a rise in menstrual CA-125 values over a follicular or luteal phase baseline could be used to increase the reliability of CA-125 to predict the diagnosis of endometriosis. To arrive at an appropriate difference in CA-125 levels between menstrual and nonmenstrual samples, a series of receiver-operator characteristic curves were constructed using various differences in CA-125 values between the menstrual and nonmenstrual phases of the cycle. A difference of at least 20 U/mL between the menstrual and follicular or luteal phase values was selected as having the greatest discriminating ability. The sensitivity and specificity of 0.22 and 0.87 for all stages and of 0.70 and 0.87 for stages III and IV endometriosis were no better than those found using the traditional limit of 35 U /ml. 282 Hornstein et al. Menstrual cyclicity of CA-125 The issue of whether serum CA-125 is elevated during menses in normal women is controversial (15, 16, 22). This study failed to find an elevation in serum CA-125 in normal women during their menses, compared with CA-125 levels in the follicular and luteal phases. The power of this observation is limited by the small number of patients in this group. There was, however, no statistically significant difference in serum CA-125 values between the menstrual and nonmenstrual phases in 22 women with benign (nonendometriosis) gynecological conditions. In this study, patients with stages II to IV disease were found to have significantly higher serum levels of CA-125 during the menses than during the follicular or luteal phases of their cycles. This difference was greatest in those with stage III or IV endometriosis. No differences across the menstrual cycle were observed in stage I patients. Several groups have also studied the relationship of serum CA-125 and the menstrual phase in endometriosis patients. Pittaway and Fayez (15) observed a significant elevation of serum CA-125 during menses in 11 patients with endometriosis, compared with levels obtained before menses. Masahashi et al. (16) reported that the percentage of women with CA-125 levels> 35 U /ml with stages III or IV endometriosis increased from 65% in the nonmenstrual phase to 100% when the serum was taken during their menses and from 0% to 63% in patients with stages I or II disease. Takahashi and co-workers (17) also found higher serum levels of CA-125 in the serum of women with advanced endometriosis during their menses. Takahashi et al. (17) have recently noted high levels of CA-125 in the menstrual effluent of patients with endometriosis. This observation suggests a promising new approach to the diagnosis of this enigmatic disease. In summary, this study demonstrates that women with mild, moderate, and severe endometriosis have elevated serum levels of CA -125 during menses. 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