Primary neuroendocrine tumors of the ovary: Management and outcomes

Background There is currently no recognized first-line treatment strategy for ovarian neuroendocrine tumors (NETs). Furthermore, because of the low incidence of ovarian NETs, no studies have reported prognostic statistics derived from large samples. This retrospective study aimed to investigate the clinical behavior of ovarian NETs. Methods The Surveillance, Epidemiology, and End Results database was used to identify women diagnosed with ovarian NETs from 2004 to 2015. Overall survival (OS), cancer-specific survival (CSS), and independent prognostic factors for ovarian NETs were evaluated. The effects of different treatments on prognosis were also compared, as were OS and CSS rates for histological subtypes. Results The 5-year OS rates were 83.3%, 30.0%, 20.3%, and 9.8% for patients in stages I (n = 159), II (n = 23), III (n = 101), and IV (n = 148), respectively. The 5-year CSS rates were 85.6%, 41.7%, 21.2%, and 9.8% for patients in stages I-IV, respectively. Age, American Joint Committee on Cancer (AJCC) stage, lymph node metastasis, treatment, and histological type were related to poor OS and CSS. In the early stage, the 5-year OS and CSS rates were 97.03% and 96.90%, respectively. For patients in the advanced stage receiving comprehensive treatment (surgery + chemotherapy + radiotherapy), the 5-year OS and CSS rates were 72.9% and 70.00%, respectively. When comparing low- and high-grade neuroendocrine carcinoma, 5-year OS rates were 93.96% and 7.01%, 5-year CSS rates were 97.44% and 7.31%, 10-year OS rates were 93.56% and 2.34%, and 10-year CSS rates were 97.44% and 4.88%, respectively. Conclusion Age, AJCC stage, treatment, and histological type are independent prognostic factors of ovarian NETs. OS and CSS are relatively good for early-stage cases treated with surgery alone, whereas more comprehensive treatment is required to improve OS and CSS in the advanced stage.