Oxaliplatin-Based Chemotherapy in Advanced Neuroendocrine Tumors: Clinical Outcomes and Preliminary Correlation with Biological Factors

Purpose: The role of chemotherapy in low-/intermediate-grade neuroendocrine tumors (NETs) is still debated. We present the results of an Italian multicenter retrospective study evaluating activity and toxicity of oxaliplatin-based chemotherapy in patients with advanced NETs. Methods: Clinical records from 5 referral centers were reviewed. Disease control rate (DCR) corresponding to PR + SD (partial response + stable disease) at 6 months, progression-free survival (PFS), overall survival (OS) and toxicity were calculated. Ki67 labeling index, grade of differentiation and excision- repair-cross-complementing group 1 (ERCC-1) were analyzed in tissue tumor samples. Results: Seventy-eight patients entered the study. Primary sites were: pancreas in 46, gastrointestinal in 24, lung in 19 and unknown in 10% of patients. The vast majority were G2 (2010 WHO classification). Eighty-six percent of the patients were metastatic, and 87% were pretreated and progressive to previous therapies. Sixty-five percent of the patients received capecitabine/oxaliplatin (CAPOX), 6% gemcitabine/oxaliplatin (GEMOX), and 29% leucovorin/fluorouracil/oxaliplatin (FOLFOX-6). PR occurred in 26% of the patients, half of them with pancreatic NETs, and SD in 54%. With a median follow-up of 21 months, the median PFS and OS were 8 and 32 months with 70 and 45 events, respectively. The most frequent G3 toxicities were neurological and gastrointestinal. ERCC-1 immunohistochemical overexpression was positive in 4/28 evaluated samples, with no significant correlation with clinical outcome. Conclusion: This analysis suggests that oxaliplatin-based chemotherapy can be active with a manageable safety profile in advanced NETs irrespective of the primary sites and tumor grade. The 80% DCR and 8-month PFS could justify a prospective study in NETs with intermediate biological characteristics, especially with pancreatic primary tumors.