Primary peritoneal serous papillary carcinoma: a new epidemiologic trend? A matched-case comparison with ovarian serous papillary cancer.

The aim of the study was to examine the prevalence of primary peritoneal serous papillary carcinoma (PPSPC) as compared with ovarian serous papillary cancer (OSPC), and to study the clinicopathologic features and the frequency of germline BRCA1 and BRCA2 mutations in patients with PPSPC compared with those with OSPC. The study group included 28 cases of PPSPC. The comparison group included 35 female patients with OSPC, matched for stage, grade, and histologic subtype. All tumors were staged as either IIIB, IIIC or IV according to FIGO criteria. The patient characteristics, family and personal history of malignancies, the prevalence of germline BRCA mutations, clinicopathologic findings, presenting symptoms, pre- and intraoperative findings, and survival were compared in a matched-case retrospective study comparing patients with PPSPC vs. those with OSPC. Statistical analysis was made using Student's t-test, Chi-square, Wilcoxon, Kaplan-Meier and log-rank methods. Women with PPSPC had a significantly earlier menarche (P = 0.037) and a higher number or births (P = 0.03) than women with OSPC. No difference was found with regard to the prevalence of germline BRCA mutations in women with PPSPC compared with women with OSPC (7.1% vs. 25.7%). There was a significant increase (P = 0.02) in the incidence of abdominal distension as reported by PPSPC (64%) vs. OSPC patients (26%). Significantly more women with PPSPC than with OSPC presented with clinical ascites (P = 0.0001) and without palpable pelvic mass (P = 0.000001). On exploratory laparotomy, significantly more women with PPSPC than with OSPC had a minimal disease in the pelvis (P = 0.0087). Three-year survival analysis demonstrated a significantly worse survival rate for the PPSPC group than for the OSPC group (P = 0.017). A significant increase in the prevalence of PPSPC compared with OSPC was observed during the study years (P = 0.00001). We concluded that PPSPC and OSPC might be two distinct cancers, presenting a new epidemiologic trend regarding the increased incidence of PPSPC.