Primary peritoneal carcinoma: regional cancer institute experience.

Abstract

Primary peritoneal serous carcinoma (PPSC) is a rare malignancy that arises primarily from peritoneal surface epithelium. However there are limited studies on these tumors even in world literature. To study the clinical, pathologic profile, outcome and prognostic features of PPSC. A 5year retrospective study of PPSC diagnosed and treated at our centre was conducted. The pathological specimen of PPSC diagnosed from January 2008 to December 2012 were reviewed by gynaeconcopathologists. The diagnosis was based on GOG criteria, complemented with IHC. Majority of the patients underwent upfront de-bulking surgery. Postoperatively, six cycles of combination chemotherapy with paclitaxel (175mg/m(2)) and carboplatin (AUC 6) was administered every 3 weekly. These patients were analysed for progression free survival (PFS), this was correlated with stage and surgical adequacy. The median age of presentation was 56years. The total number of ovarian cancers treated during study period was 374. The 30 cases were clinically suspected to have primary peritoneal carcinoma (PPC) on pre- and intra-operatve gross findings, but further evaluation with histopathological examination, IHC and GOG criteria revealed only 10 cases were genuine PPSC. The remaing 20 cases; 13 were found to poorly differentiated ovarian carcinomas, six were primary fallopian tube carcinoma and one was appendicular carcinoma. The 10 (2.7%) cases of the 374 were eligible for the PPSC analysis. The two (20%) of the 10 cases had family history of breast and ovarian cancers, two (20%) cases were diagnosed as abdominal tuberculosis (TB) prior referral to our centre. Radiological presentation includes gross ascites, with omental caking and normal adenexa. The eight (80%) of 10 cases presented with stage IIIC and other two cases (20%) with stage IV disease. The eight (80%) of 10 cases underwent upfront surgery; six (75%) of these eight cases had optimal cytoreduction, i.e. residual disease (RD) <1cm or no visible disease (R0) and other two (25%) suboptimal cytoreduction. The two (20%) of 10 cases with stage IV disease received neoadjuvant chemotherapy (NACT) followed by interval cytoreduction. After debulking surgery the most useful IHC marker include CK7+, CK20-, CA125+, WT-1+, and GCDFP- . At median follow up of 24months (range 3-60months), the median progression free survival (PFS) was 22months, while the estimated 5year PFS was 18%. Stage IV disease and suboptimal surgery had poor outcome. The PPSC presents with advanced stage disease and are observed to be misdiagnosed abdominal TB in tropical countries. The GOG criteria and IHC complement the diagnosis. These have poor outcome despite optimal care, highlighting need for larger studies on this disease.