Primary peritoneal carcinoma and ovarian carcinoma - a ten-year comparative analysis

Primary peritoneal carcinoma (PPC) at presentation often masquerades as epithelial ovarian carcinoma (OC) but behaves different with respect to treatment response, recurrence patterns and has inferior outcomes. The objective of this study is to compare the clinicopathological features and survival outcomes of PPC and OC.

Prospectively maintained database of patients presenting to the gynecologic oncology department at a tertiary hospital was reviewed between 1st January 2010 and 31st December 2020. A comparative analysis of high-grade serous stage III/IV PPC and OC was done. Demographics, treatment details, complications and survival outcomes were collected from electronic medical records.

151 OC and 69 PPC patients were included. A higher proportion of women with PPC had reduced performance status prior to hysterectomy with salpingo-oophorectomy, a shorter symptom to treatment interval, and large volume ascites. A significantly lower number of women with PPC (4.3 vs. 46.1%; P < 0.001) underwent primary cytoreduction, had a lower median surgical complexity score (3 vs. 4; P < 0.001) but higher recurrence rates (66.7 vs. 47.0%; P = 0.041) as compared to the patients with OC. The median progression-free survival (PFS) was 18 (15-20) months in PPC and 23 (17-28) months in OC patients (log-rank P = 0.034), while the median overall survival (OS) was similar (44 vs. 48 months; log-rank P = 0.696). The presence of extraperitoneal disease and interval cytoreduction was associated with shorter PFS. Suboptimal cytoreduction and delay in adjuvant chemotherapy beyond 6 weeks post-surgery was associated with reduced OS.

PPC is an aggressive disease with lower PFS compared to OC. Commonly presenting with large volume carcinomatosis, it is not amenable for primary cytoreduction, making the usage of neoadjuvant chemotherapy a common practice and pragmatic approach.