Ovarian squamous cell carcinoma: clinicopathological features, prognosis and immunotherapy outcomes

To explore the characteristics and survival outcomes of ovarian squamous cell carcinoma (SCC) and the treatment effectiveness of immune checkpoint inhibitors (ICIs).

Patients diagnosed with ovarian SCC at Peking Union Medical College Hospital between January 2000 and September 2023 were included. Overall survival (OS) and progression-free survival (PFS) were analyzed using the Kaplan-Meier method. Univariate and multivariate analysis of OS were performed using the Cox proportional hazards model.

A total of 42 patients were included, with a median age of 51.5 years (range, 23-74). The majority had SCC arising from teratomas (54.8%), followed by endometriosis (14.3%) and Brenner's tumor (2.4%). Patients undergoing molecular testing exhibited a median tumor mutation burden (TMB) of 10.00 mutations/Mb (range, 7.28-46.86), predominantly featuring PIK3CA mutations. Thirty-eight patients (90.5%) received adjuvant chemotherapy. The median OS was 42.0 months, with the 1- and 5-year OS rates were 73.7% and 48.7%, respectively. And the median PFS was 26.9 months, with the 1- and 5-year PFS rates were 57.5% and 43.8%, respectively. Five patients underwent first-line postoperative adjuvant therapy combining ICIs with chemotherapy. During the 9.5 to 25.1 months follow-up, 4 patients showed no evidence of disease, while 1 relapsed and received treatment. Late-stage disease and younger age at diagnosis were associated with worse survival outcomes.

The prognosis for ovarian SCC remains unfavorable. The stage and age were prognostic predictors for survival. ICIs may be beneficial for patients with ovarian SCC, particularly those with a high TMB.