Chemotherapy in Resected Neuroendocrine Carcinomas of the Digestive Tract: A National Study from the French Group of Endocrine Tumours

Background: Neuroendocrine carcinomas (NECs) of the digestive tract are rare and aggressive tumours. In localised disease the treatment is surgery. Based on expert consensus, international guidelines recommend the administration of adjuvant chemotherapy combining etoposide and platinum derivatives, justified by the high risk of metastatic relapse. However, no clinical study has proven the benefit of neoadjuvant or adjuvant chemotherapy. Objectives: We aimed to evaluate the effect of neoadjuvant +/- adjuvant and adjuvant therapy in this indication. Methods: We performed a retrospective observational French study to evaluate overall survival (OS) and disease-free survival (DFS), prognostic factors for survival, and chemotherapy toxicity. Results: Seventy-three patients had surgical resection of a localised digestive NEC between January 1, 2000 and December 31, 2016. The majority of patients presented colorectal (35%) tumours and the median Ki-67 value was 70%. Forty-three patients received chemotherapy, either perioperative (neoadjuvant +/- adjuvant) or adjuvant. The median OS and DFS for the whole population was 24 and 9 months, respectively. The median OS and DFS for patients receiving chemotherapy was 62 and 13 months, respectively. Positive postoperative node status and Ki-67 ≥80% had a negative prognostic impact on OS and DFS. Administration of chemotherapy had a positive prognostic impact on OS and DFS. Sixteen grade 3/4 toxicities were reported without toxic death. Conclusions: Our results suggest a positive effect on survival of chemotherapy in resected digestive NECs, but further studies are needed to confirm these results.