In patients with stage I ovarian clear cell carcinoma, the use of adjuvant chemotherapy was associated with superior overall survival (OS), according to results of a large, retrospective cohort study.
The finding, published in Gynecologic Oncology, provides further evidence that adjuvant chemotherapy may provide a survival advantage for patients with this relatively common epithelial ovarian cancer subtype.
However, not all data to date point toward a benefit of adjuvant chemotherapy. “Its utility has yet to be established, especially for patients with stage IA disease,” wrote Dimitrios Nasioudis, MD, and his coauthors in the department of obstetrics and gynecology, Hospital of the University of Pennsylvania, Philadelphia.
In one recent large population-based study, chemotherapy was not associated with superior OS in patients with stage I disease, whereas two smaller retrospective studies suggested that chemotherapy may improve progression-free survival in that setting, noted Dr. Nasioudis and his colleagues.
Their study included data on 2,325 patients in the National Cancer Data Base diagnosed with stage I ovarian clear cell carcinoma between 2004 and 2014. That is the largest cohort of patients with stage I ovarian clear cell carcinoma with adequate staging reported to date in the medical literature, the investigators noted.
The rate of OS at 5 years was 89.2% for patients receiving adjuvant chemotherapy, versus 82.6% for those who did not (P less than .001). Furthermore, adjuvant chemotherapy was associated with improved OS after the researchers controlled for medical comorbidities, age, race, disease substage, and hospital type (hazard ratio, 0.59; 95% confidence interval, 0.45-0.78).
When the researchers looked at disease substage, women with stage IA or IB disease had superior OS with chemotherapy versus no chemotherapy, while in women with stage IC disease, there was a trend toward better OS with chemotherapy that did not reach statistical significance.
“The administration of adjuvant chemotherapy was associated with a survival benefit, even for those with stage IA disease,” the researchers wrote.
Ovarian clear cell carcinoma is the third most common subtype of epithelial ovarian carcinoma, accounting for up to 25% of new diagnoses, they said. Current U.S. and European clinical practice guidelines recommend adjuvant chemotherapy for all women with stage I disease because of a high risk of relapse associated with this subtype.
Observation could be acceptable for patients with surgical stage IA disease, in light of excellent survival rates, the Gynecologic Cancer Intergroup has suggested.
While the present study suggests a survival benefit associated with chemotherapy in stage I ovarian clear cell carcinoma, the investigators had no information on morbidity, cost, or quality-of-life impacts associated with treatment, which limit the findings.
“International collaboration, such as the creation of ovarian clear cell carcinoma registry, is greatly needed to further elucidate the optimal management of those patients,” they wrote.
Dr. Nasioudis and his coauthors had no conflicts of interest to report.
SOURCE: Nasioudis D et al. Gynecol Oncol. 2018 May 8. doi: 10.1016/j.ygyno.2018.04.567.