Although some of the follow-up procedures done on study participants were not based on concern or suspicion of ovarian cancer (eg, the thickened endometrial stripes with postmenopausal bleeding), all subsequent procedures are shown in Table 4. In total, there were 20 laparoscopies, laparotomies, or vaginal hysterectomies performed in study participants within 6 months of a positive symptom index (0.4% of participating women). However, only six (0.12%) were done for a suspicious ovarian mass. Overall, among study participants with positive symptom index results, there was a false-positive rate resulting in a major surgical procedure of 0.4% (20/5,012) or one in 250 women (95% confidence interval [CI] 1/162–1/410). Because 14 of these surgeries were performed for clearly nonovarian conditions in the absence of a transvaginal ultrasound or CA 125 result deemed suspicious for ovarian cancer, the rate for surgical procedures associated with a positive follow-up test result in a symptom index–positive woman was 0.012% (6/5,012) or one woman out of 835 (95% CI 1/418–1/2,005).
Ovarian cancer outcomes were assessed for all 6,013 women through the Western Washington Surveillance, Epidemiology, and End Results Cancer Registry. Because studies have shown that most patients with ovarian cancer do not recognize symptoms until less than 1 year and more reliably 6 months before diagnosis, we were primarily interested in women who developed ovarian cancer within 6 months from participating in a symptom index. Table 5 shows the ovarian cancer outcomes for the study. There were two women who developed ovarian cancer within 6 months of completion of the symptom index. One was positive and was diagnosed 31 days later with distant disease (part of the 1,001 unscreened pilot group) and one who was symptom index-negative was diagnosed with local disease. Of note, this symptom index-negative patient had a family history of ovarian cancer and was being worked up as part of routine care for a pelvic mass at the time of her study participation. The other six patients with ovarian cancer were diagnosed 281–843 days (median 569 days) after participation in the study. Half of these patients (3/6) were diagnosed with regional disease.
Also of potential interest, 80 (38%) of the transvaginal ultrasound scans and 26 (12%) of the CA 125 tests done in the symptom index–positive women also were ordered by clinic physicians as part of routine clinical care based on their personal clinical judgment separate from our study activities. Although there were 20 major surgical procedures performed, only three laparoscopies and one laparotomy were performed solely as a result of participation in the study. Of the four procedures, one dermoid, two endometriomas, and one atypical leiomyoma were diagnosed. One patient who underwent a laparoscopy developed a postoperative wound infection. Overall, this corresponds to a false-positive rate for major surgery of 0.08% (4/5,012), or 1 of every 1,253 women evaluated (95% CI 1/489–1/4,599).
Currently there are no organizations that recommend screening for ovarian cancer in the general population.1–3 The U.S. Preventive Services Task Force reissued their grade D recommendation in 2012 based largely on the results from the Prostate Lung Colorectal and Ovarian cancer screening trial, which was reported in 2011.12 A second large screening trial from the United Kingdom has also shown that using transvaginal ultrasonography as part of the initial screen results in a significant false-positive rate and high rates of probable unindicated surgeries,13 reinforcing that transvaginal ultrasonography should be used as a diagnostic test but not as a screening test.
In our study population, symptom-triggered diagnostic evaluation resulted in 0.4% (20/5,012) of women undergoing surgery, 80% (16/20) of these were done for clinical indications, and only 4 of 20 (20%) were performed solely as a result of participation in the study. This rate of false-positive surgery 0.08% (1 of every 1,253 women evaluated) is important because concerns have been raised that monitoring for symptoms associated with ovarian cancer could lead to high rates of unindicated procedures. Although there is a low rate of potentially unindicated surgery, the possibility that symptom screening could lead to a 20% (4/20) increase in surgery must be considered a potentially negative consequence. However, although these were false-positives for ovarian cancer, each of these patients did have pelvic pathology and the surgery may have prevented future problems.
The efficacy of a symptom-triggered approach cannot be adequately assessed in this study because of the low number of ovarian cancers. There were only two cases of ovarian cancer diagnosed within 6 months of symptom index completion. This is the time window when most nonrecall-biased studies show that patients begin to experience and report symptoms.14–17 Only one of the patients diagnosed within 6 months had a positive symptom index and she had advanced-stage disease; therefore, no patients were diagnosed with early-stage disease within 6 months. The other six patients were diagnosed beyond 6 months. If we had used 12 months as a cutoff, only one of four (25%) would have been identified through symptoms. Fortunately, only 4.8% of participants were symptom index–positive; therefore, if universal symptoms screening was found to be an effective method to identify women who should receive diagnostic evaluations for ovarian cancer, more than 95% of women would not require any testing. However, if symptoms were to be used as the only means of screening for ovarian cancer, the sensitivity of a symptom-based screening program would be low and would need to be improved, possibly through more frequent screening or the addition of biomarkers to a multimodal strategy.
Long-term follow-up of study participants identified six women who developed ovarian cancer more than 6 months after their participation in the study. Of these six women, three had their ovarian cancers identified at the regional stage. Although it is impossible to determine the details leading to this better than would be expected stage distribution in women who had previously participated in our study, and it is possible that with such a small sample this result is coincidental, it may be possible that study participation provided these women with valuable education about ovarian cancer symptoms spurring them to seek evaluation of subsequent symptoms that were associated with the cancers they eventually developed. Such a result would be consistent with the findings of Gilbert et al,14 who found that prompt aggressive evaluation of approximately 1,500 women with symptoms resulted in an ovarian cancer prevalence 10 times greater than the general population and an improved prognosis in a majority of cases.
In the Diagnosing Ovarian Cancer Early study, women were recruited through radio, newsprint, and flyers.18 Women who met symptom entry inclusion criteria were offered CA 125 and transvaginal ultrasound testing within 2 weeks. If the CA 125 result was indeterminant, it was repeated in 4 weeks. If it was normal and women persisted in having symptoms, it was repeated in 4 months. Of the 1,455 women enrolled, 11 or 1/132 women had ovarian cancer. Of the 11 cases diagnosed, four (36%) were early-stage disease, four (36%) were small-volume stage III disease that was optimally cytoreduced, and three (27%) were advanced suboptimally cytoreduced disease. Comparison to the general clinic population in Montreal found that 56% of the ovarian cancer population was advanced suboptimally cytoreduced at the time of diagnosis. Also, in the study population, 11 endometrial cancers were diagnosed as a result of a thickened endometrial stripe11 and postmenopausal bleeding; therefore, 1 of every 66 symptomatic women in this study was diagnosed with a gynecologic malignancy. Both the Gilbert et al and our study emphasize the need to further study the prompt response to symptoms as a low-cost method to triage women for diagnostic tests.
Limitations to our study include the low number of cancers, which limits the ability to evaluate sensitivity, specificity, and the potential for early diagnosis. However, with 5,000 screens, we only expected two to three cancers to be diagnosed within 6 months of a positive symptom index. Other limitations include the fact that ultrasonographers knew patients were in a study and may have done a more thorough evaluation of adnexa. Health care providers were also aware of patient participation, which may reduce the external validity of the study. In a different setting, physician and patient concerns could drive the rate of surgical intervention higher. In addition, we did not have a control group who did not participate in a symptom-triggered evaluation so that surgical interventions could be compared.
Overall, we found that proactive symptom-triggered diagnostic evaluation would increase rates of potentially unindicated surgery by one patient in 1,253 evaluated. We found that 50% of the ovarian cancers detected in our study population were diagnosed in local or regional stages. Although our numbers are small, based on Surveillance, Epidemiology, and End Results statistics, only 20–30% are expected to be found in this more favorable stage category. Although the actual symptom-triggered evaluation process may not have led to earlier diagnosis, it is speculated that some of these cancers may have been diagnosed early because women had increased awareness of symptoms, which may have prompted them to seek care earlier resulting in identification of ovarian cancer at an earlier stage. The real value of a symptom index may lie in its ability to act indirectly as an educational tool.
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