Systematic review and two new cases of primary upper urinary tract neuroendocrine carcinomas

Upper urinary tract neuroendocrine carcinoma (UUT-NEC) is extremely rare and has a poor prognosis. Although a few cases of successful treatment have been reported, no treatment has shown established efficacy.

We analyzed 70 UUT-NEC patients, including 68 with small cell neuroendocrine carcinoma (SCNEC) and large cell neuroendocrine carcinoma (LCNEC) reported between 1985 and 2017 and 2 treated at our hospital.

Median patient age was 66 years, 58.6% were men, and 60% were of Asian descent. Most UUT-NECs were SCNEC (68; 95.7%), whereas LCNEC was very rare (2; 2.9%). More than half of the patients had accompanying other histological components, the most common being urothelial carcinoma (51.5%), whereas 41.4% had NEC alone. Of the 70 patients, 27 underwent additional therapy (e.g., chemotherapy and radiotherapy) along with surgery. Median survival was 15 months. In univariate analysis, stages T1-2 disease showed better prognosis than stages T3-4 (P < 0.001). Additional treatment (e.g., chemotherapy and radiotherapy) significantly improved prognosis (P = 0.014). Moreover, platinum-based chemotherapy also was associated with improved prognosis (P = 0.017). For platinum-based chemotherapy, multicollinearity with additional treatments was strong, and, thus, these data were not included in the analysis. Multivariate analysis revealed pathological stage (T1-2 vs. T3-4; P = 0.003) and additional treatment (P = 0.028) to be independent predictors of improved prognosis.

Although UUT-NEC has a poor prognosis, additional treatment along with surgery and therapeutic intervention and stage T1-2 disease are independent factors to improve prognosis.