The role of hormonal therapy in patients with relapsed high-grade ovarian carcinoma: a retrospective series of tamoxifen and letrozole

Background: Hormonal therapy is used as a treatment option in high-grade ovarian carcinoma (HGOC), but the role and choice of treatment remains unclear. Agents used include tamoxifen and aromatase inhibitors. Our aim was to evaluate the efficacy of tamoxifen (T) and letrozole (L) in HGOC in clinical practice and investigate factors influencing clinical outcome. Methods: A retrospective review of patients with relapsed HGOC treated with either tamoxifen or letrozole at the Royal Marsden Hospital between 2007 and 2012 was performed. The primary endpoint of the study was objective response rate (ORR). Secondary endpoints included CA125 response, clinical benefit rate (CBR) and duration of response. Platinum-sensitivity and ER-status were evaluated as predictors of treatment response. Results: 97 patients were included (43 T, 54 L); median age 63 years (20-92); 91% high-grade serous; median number of lines of prior chemotherapy 3 (1-8); 60% platinum-resistant, 40% platinum-sensitive; 52% ER + ve, 1% ER-ve, 47% unknown. 14 patients (6 T, 8 L) achieved a partial response, with ORR (RECIST) of 14% (T) and 15% (L). The CBR for >= 3 months was 65% (22/43) for tamoxifen and 56% (22/54) for letrozole. There was no significant difference in ORR (p = 0.99) or CBR (p = 0.14) between tamoxifen and letrozole. 22 patients (23%) had a CA-125 response with hormonal therapy (10 T - 23% and 12 L - 22%). ORR did not differ by platinum sensitivity (p = 0.42); or ER-status (positive vs unknown, p = 0.12). Responders to letrozole had longer durations of response than responders to tamoxifen (26 vs 11. 5 months, p = 0.03), but equivalent disease stability duration (9.6 vs 7.2 months respectively, p = 0.11). Conclusions: Within the constraints of a retrospective study, we identified that patients treated with letrozole had a significantly longer duration of response than those treated with tamoxifen. Treatment with either tamoxifen or letrozole is a rational treatment option for patients with ER + ve HGOC, with equivalent ORR, CBR and disease stability.