Chemotherapy response in low-grade serous ovarian carcinoma at a comprehensive cancer center: Readdressing the roles of platinum and cytotoxic therapies

Abstract

Background: Data on platinum sensitivity of low-grade serous ovarian carcinoma (LGSOC) in the upfront setting is lacking, and there is limited and contradictory information on chemotherapy responses in recurrent disease.

Methods: Patients with LGSOC seen at a comprehensive cancer center from January 1, 1998 to September 30, 2021 were identified from institutional databases. Response to neoadjuvant chemotherapy (NACT) or adjuvant platinum-based chemotherapy and to second- to fifth-line regimens was retrospectively characterized by Response Evaluation Criteria in Solid Tumors (RECIST) v1.1. Wilcoxon rank-sum and two-tailed Fisher exact tests were employed.

Results: Of 50 patients, 12 received platinum doublets for suboptimal residual disease and 11 as NACT. Of 12 patients with suboptimal residual disease, seven (58%) achieved objective responses (five partial responses [PRs] and two complete responses); of the 11 patients who underwent NACT, one (9%) achieved a PR (p = .027). The 15 remaining patients had stable disease on first-line platinum chemotherapy. Of 44 patients who recurred, 20 had RECIST-evaluable responses to second-line and 27 to third-line chemotherapy. Objective response rates to platinum-based chemotherapy were 22% (two of nine) in the second line and 10% (one of 10) in the third. In second and third lines, highest response rates were observed with nonplatinum chemotherapy with bevacizumab, at 100% (two of two) and 30% (three of 10), respectively.

Conclusions: Primary platinum-based chemotherapy has moderate activity in LGSOC and minimal activity in the recurrent setting, suggesting standard definitions of platinum sensitivity may not apply in LGSOC. In the second and third lines, nonplatinum chemotherapy/bevacizumab elicited the highest response rates.

Keywords: KRAS; chemotherapy; cytoreduction surgical procedures; low-grade serous ovarian cancer; neoadjuvant.

Figure 1a:

Characteristics of study population MSK, Memorial Sloan Kettering Cancer Center; RECIST, Response Evaluation Criteria in Solid Tumors; CT, computed tomography

Figure 1b:

Patients treated for recurrent disease Patients are represented by columns and lines of treatment by rows. Regimens are color-coded according to the legend. Bev, bevacizumab.

Figure 2:

Response to first-line platinum therapy (patients receiving NACT [n=11] or postoperative chemotherapy for suboptimal residual disease [n=12]) *Disease change by 0% NACT, neoadjuvant chemotherapy

Figure 3:

Response to second-line cytotoxic treatment (n=20 patients) *Disease change by 0% **One patient had progressive disease in non-target lesions Bev, bevacizumab

Figure 4:

Response to third-line cytotoxic treatment (n=26 patients) *Disease change by 0% **Disease increase by +816.67% Bev, bevacizumab

Figure 5:

Response to fourth-line cytotoxic treatment (n=18 patients) *Disease change by 0% Bev, bevacizumab