Analysis of outcomes in patients (pts) with recurrent ovarian clear cell carcinoma (ROCCC): Time to rethink our approach to treatment.

5548 Background: Advanced stage primary OCCC is associated with a poor prognosis following primary surgery and chemotherapy, but scant data exists regarding response rates (RR = RECIST PR/CR), progression free (PFS) and overall survival (OS) following treatment (rx) for ROCCC. Methods: We conducted a retrospective review of pts with ROCCC treated at 2 cancer centres to evaluate RR, clinical benefit rate (CBR=PR/CR or SD with PFS ≥12wks), PFS (time from start of rx to RECIST/clinical PD) and OS (time from 1st relapse after primary rx to death) following rx, and response/ symptomatic benefit after palliative radiotherapy (PRT). Platinum (plt) resistance was defined as PD < 6mths after plt. Results: In total, 137/256 pts developed ROCCC. Recurrences by FIGO stage at diagnosis were: Stage 1A/B (15/49, 29%), Stage 1C (16/67, 24%), Stage 2 (40/62, 65%), Stage 3 (46/54, 85%), Stage 4 (20/21, 91%), p<0.0001. Pts received a median of 1 line (range = 1-6, total = 166) of rx with an overall RR of 13/142 (9%) evaluable lines of treatment. Across all rxs, median PFS was 11 wks (95% CI: 8,14) and median OS was 40 wks (95% CI: 28,52). At 1st relapse, 72/86 treated pts were evaluable for response with RR=14% (10/72), CBR=31% (22/72) and median PFS=12wks (95% CI: 9,15). At 2nd relapse, 36/42 treated pts were evaluable for response with RR=8% (3/36) and CBR=33% (12/36) and median PFS=14wks (95% CI: 8,20). No significant PFS difference was observed for plt-sensitive pts treated with plt-based or non-plt-based rx at 1st relapse (HR=1.2; 95% CI: 0.6, 2.5; p=0.57) or at any relapse (HR=0.9; 95% CI: 0.4, 1.7; p=0.65). Outcomes for all rxs are shown in the Table. 6/12 (50%) pts derived benefit following PRT. Conclusions: ROCCC is a chemoresistant disease with a short median OS of 10mths. PRT offers symptomatic benefit. More clinical trials to identify effective systemic rxs for ROCCC are urgently required. Individual rx outcomes across all lines of rx. Rx N Plt Sensitive No. evaluable CR/PR% CBR% Median PFS wks Plt-based 63 Yes (46) 38 18 39 17 No (17) 14 14 36 11 Paclitaxel 8 7 0 14 8 Gemcitabine 7 7 14 14 4 Doxorubicin 29 25 4 16 10 Antiangiogenic agents 15 13 8 46 14 Topoisomerase inhibitors 30 27 4 19 8 Hormonal therapy 8 6 0 17 12 Others 6 5 0 0 11