Low-grade serous primary peritoneal carcinoma.

OBJECTIVE: 10% of women with serous ovarian cancer have low-grade carcinomas. These patients are diagnosed at a younger age, have a longer overall survival and a lower response rate to platinum-based chemotherapy compared to women with high-grade serous ovarian carcinoma. It remains unclear if these features are similar in women with low-grade primary peritoneal cancer (PPC). To further explore this issue, a retrospective analysis of the clinical and pathologic characteristics of women with low-grade serous PPC was performed.
METHODS: A retrospective study of 53 patients with low-grade serous PPC evaluated at a single institution from 1986 to 2009 was performed. All cases were reviewed by a gynecologic pathologist to confirm low-grade serous PPC.
RESULTS: Median age at diagnosis was 51.7 years (range 27.1-82.4). 46 patients (86.8%) underwent primary surgery, with optimal tumor reduction achieved in 30 patients (65.2%). 48 patients (90.6%) received chemotherapy as part of their initial treatment. At the completion of primary treatment, 66.7% of patients were noted to have persistent or progressive disease. With a median follow-up of 66.1 months, the 5-year PFS was 16%, yet the 5-year OS was 69%.
CONCLUSION: To our knowledge, this is the first report of women with low-grade serous PPC. Similar to low-grade serous ovarian carcinoma, patients with low-grade serous PPC have high rates of persistent disease at the completion of primary treatment yet a long overall survival. Further study focusing specifically on low-grade serous ovarian and primary peritoneal carcinomas is needed to determine the optimal treatment of these diseases.