What Predicts Recurrence and Outcome in Clear Cell Ovarian Carcinoma?

Patients with clear cell ovarian carcinoma have high recurrence rates, even in early-stage disease and when complete resection is achieved, according to a new analysis of a randomized phase III trial comparing paclitaxel plus carboplatin vs irinotecan plus cisplatin in this setting. Post-progression survival (PPS) was shorter in patients with platinum-resistant disease than in those who were platinum-sensitive.

“Clear cell carcinoma is a histologic subtype that demonstrates resistance to chemotherapy and poor outcomes in epithelial ovarian cancer,” wrote study authors led by Eiji Kondo, MD, of the Mie University School of Medicine in Japan, in a poster presentation (abstract 5515) from the 2019 American Society of Clinical Oncology (ASCO) Annual Meeting. The prevalence of clear cell carcinoma is higher among Asian women; in Japan, it accounts for 24% to 26.9% of all epithelial ovarian cancers. “There are currently no concise data on prognosis in patients with recurrent or persistent clear cell carcinoma,” noted Kondo.

The researchers analyzed outcomes from the JGOG3017/GCIG trial, a phase III randomized trial that included 619 patients. Of these patients, a total of 166 had recurrent disease (46.4% received paclitaxel and carboplatin, 53.6% received irinotecan and cisplatin).

About 6% of patients with stage IA/IB disease had recurrence. For those with stage IC disease, the recurrence rate was 14.6%; for those with stages II–IV disease, the rate was 54.8%. “Even in patients with early stage or complete surgery, the recurrence rate…was high,” the authors wrote.

The median PPS was 14.0 months for all patients; in the paclitaxel and carboplatin group the median PPS was 13.5 months, and in the irinotecan and cisplatin group it was 14.4 months, for a hazard ratio (HR) of 1.02 (95% CI, 0.71–1.47; P = .898). The median PPS was shorter in those with platinum-resistant disease, at 10.9 months, compared with 18.8 months with platinum-sensitive disease, for an HR of 1.88 (95% CI, 1.30–2.72; P < .001).

The authors noted that Japanese ethnicity was a prognostic factor in the study, along with stage and maximum diameter of residual disease. “New strategies for the treatment of clear cell carcinoma should be developed,” the authors wrote.

In a poster discussion session at ASCO, BJ Rimel, MD, of Cedars-Sinai Medical Center in Los Angeles, praised the authors for re-examining the data from a large trial of a rare type of malignancy. “This study highlights the incredible value of investigating and publishing data on populations that we study,” she said. “With 40% of cancer clinical trials closing early, it’s important to be able to design our trials accurately.”

She noted that it is difficult to draw conclusions from the analysis when divided by stages, since the stage IA and IB group have too few patients for a rigorous analysis. Lumping them together, though, gives us more information on a rare population of patients.