Rare Histologies and Infrequent Indications for Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy

This single-centre study evaluated cytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC) for patients with rare histologies and uncommon tumour origins.

Prospectively collected data from the data registry of a single institution was retrospectively investigated. We present a series of selected patients who underwent CRS and HIPEC between 2011 and 2021 for peritoneal metastases arising from infrequent tumour entities.

The study included 76 patients. From the wide range of histologies, seven groups were formed: Cancer of unknown primary, uncommon ovarian cancer types, other gynaecological tumours (endosalpingiosis, endometrial and cervical cancer), small bowel carcinoma, recurrent peritoneal mesothelioma, desmoplastic small round-cell tumour, and other rare malignancies. The median peritoneal cancer index was 8. Fifty-five patients with primary and 22 patients with recurrent disease were examined. Complete macroscopic tumour resection was achieved in 84% of cases. The median survival was 68.53 months considering the entire cohort, whilst the longest survival rate was registered in the group with rare ovarian cancer, and the shortest in the group of patients with small round-cell tumour, at 112.3 and 11.4 months, respectively (small round-cell tumour versus rare ovarian cancer, hazard ratio=15.6817; 95% confidence interval=2.6585-92.5030; p=0.0024).

Based on the encouraging results in some test groups, especially in rare ovarian cancer, CUP, small bowel cancer and recurrent mesothelioma, multicenter prospective studies examining such rare tumour histologies are needed to reach a higher number of cases and, thus, explore the impact of multimodal therapy on these patients.