Primary Peritoneal Carcinoma

Primary peritoneal carcinoma (PPC) is a rare malignant tumor of the peritoneal cavity of extra-ovarian origin, clinically and histologically similar to advanced-stage serous ovarian carcinoma (see this term).

Epidemiology

PPC accounts for about 10% of pelvic serous carcinomas.

Clinical description

It is almost exclusively found in women. PPC can occur many years after oophorectomy performed for benign diseases or prophylactic oophorectomy. The tumor appears during adulthood with a mean age at diagnosis of 60 years. Clinical features include abdominal swelling, constipation, gastrointestinal disorders, nausea, vomiting, anorexia and weight loss. The tumor develops in the peritoneum and spreads to the abdomen, pelvis and ovaries.

Etiology

Primary peritoneal carcinoma has an epithelial origin and probably derives from coelomatic embryonal epithelium. The fallopian tubes are suspected as the primary site. Women with breast cancer type 1 (BRCA1) gene mutations present an increased risk of developing a PPC.

Diagnostic methods

Diagnosis is based on elevated cancer markers, with elevated cancer antigen 125 (CA125), and on imaging examinations such as ultrasound and chest-abdominal computed tomography (CAP-CT). Diagnosis is confirmed by biopsies performed during laparotomy or laparoscopy, especially when ovaries are normal or absent.

Differential diagnosis

The main differential diagnosis is epithelial ovarian cancer. PPC and serous ovarian carcinoma are histologically similar, and it is often impossible to determine the organ of origin at late stages when the ovaries, abdominal cavity and fallopian tubes are all involved.

Management and treatment

Management should be multidisciplinary and must be discussed by a panel of physicians in a specialized center. There are currently no validated recommendations on clinical management and no cytotoxic agents have been granted a European Marketing Authorization (MA) in this indication. Combination of cytoreductive surgery (visceral resections and peritonectomy procedures) with hyperthermic intraperitoneal chemotherapy (HIPEC) (off-label use) has been considered in specific patients (i.e. young patients with good general status and low tumor volume) before or after systemic chemotherapy (off-label use) if the disease does not respond to optimal cytoreductive surgery.

Prognosis

Prognosis is poor, similar to or worse than that of ovarian carcinoma.