Small cell carcinoma of the ovary of hypercalcemic type (SCCOHT) is a rare and rapidly lethal disease affecting young women. Cytoreductive surgery associated with chemotherapy followed by a high dose chemotherapy regimen (HDC) demonstrated improved outcomes in a unique prospective and several retrospective studies, and this report aimed to confirm these results in an independent and larger cohort.

Between 2006 and 2018, we conducted a multicentric prospective study on 44 women diagnosed with SCCOHT. Patients were treated homogeneously with optimal cytoreductive surgery and chemotherapy protocol for four to six cycles (PAVEP). In case of complete response, patients received HDC with stem-cell support, followed by pelvic radiotherapy. The primary endpoint was the event-free survival (EFS) in the per-protocol cohort. Secondary analysis explored the effect of HDC with outcomes.

Mean age at diagnosis was 33 years old (range 13.8-75.8). 14 patients presented with stage FIGO I, 21 with stage III and 9 with stage IV. Median follow-up was 53.4 months. 38 patients underwent optimal surgery with up to 6 cycles of PAVEP. 30 received HDC, and 21 pelvic radiotherapy. 21 relapses were reported leading to death for 18 patients. Median EFS in the per-protocol cohort was 18.2 months, and 2-year EFS rate was 40%. HDC was significantly associated with better overall survival (p < .001). Grades 3/4 adverse events were frequent but, in most cases, manageable, although one grade-5 adverse-event occurred during HDC.

Intensive regimen containing multidrug chemotherapy, HDC and pelvic radiotherapy, for the management of SCCOHT, demonstrated encouraging survival and should be proposed for all patients. However, the significant toxicity cost associated is of concern and it should be restricted to expert centers.