Prognosis for Poorly Differentiated, High-Grade Rectal Neuroendocrine Carcinomas

Introduction Rectal neuroendocrine carcinomas (rNECs) are poorly characterized and, given their aggressive nature, optimal management is not well-established. We therefore sought to describe clinicopathologic traits, treatment details, and survival patterns for patients with rNECs. Methods Patients captured in the National Cancer Database (NCDB; 2004-2016) with rNECs managed with observation, chemotherapy, or proctectomy +/- chemotherapy were considered for analysis. Results The inclusion criteria were met by 777 patients. Mean age was 62.4 years, 45% were male, 80% were Caucasian, 40% presented with lymph nodes metastases, and 49% presented with distant metastases. Chemotherapy and surgical resection were administered in 72 and 19% of cases, respectively. Median overall survival (OS) was 0.83 years (1 year, 41%; 3 years, 13%; 5 years, 10%). During the study interval, 659 (85%) patients died, with a median follow-up of 0.79 years. On multivariable analysis, age >= 60 years, male sex, and distant metastases were associated with worse survival; surgical resection and administration of chemotherapy were associated with a reduced risk of death. Among non-metastatic patients treated with surgical resection, administration of chemotherapy was protective, while a positive lymph node ratio (LNR) >= 42% (median value) was associated with an increased risk of death. There was no difference in the number of examined lymph nodes between LNR cohorts. Conclusions Patients with rNECs experience dismal survival outcomes, including those with non-metastatic disease treated with curative-intent surgical resection. Neoadjuvant therapy can serve as a useful biologic test, and surgical resection should be judiciously employed.

Automated summary

Rectal neuroendocrine carcinomas (rNECs) are poorly understood, with most patients being older Caucasian males and presenting with lymph node or distant metastases. Chemotherapy and surgery were used in some cases, but overall survival remains poor for these patients.