Search Results

A rechallenge is common after the initial efficacy of alkylating-based chemotherapy (ALK) in pancreatic neuroendocrine tumors (PanNET). High MGMT expression seems associated with a lower response to ALK. We aimed to evaluate the efficacy and toxicity of ALK rechallenge in PanNET, and to assess the evolution of MGMT expression under ALK. All consecutive patients with advanced PanNETs who received initial ALK (achieving tumor control) followed by a pause of > 3 months, then an ALK rechallenge (ALK2) upon progression were retrospectively studied (cohort A). The primary endpoint was progression-free survival under ALK2 (PFS2). The MGMT expression was retrospectively assessed by immunohistochemistry (H-score) in consecutive PanNET surgically resected following ALK (cohort B). We found that Cohort A included 62 patients (median Ki67 8%), for whom ALK1 followed by a pause achieved an objective response rate of 55% and a PFS1 of 23.7 months (95% IC, 19.8–27.6). ALK2 achieved no objective response and stability in 62% of patients. The median PFS2 was 9.2 months (IC 95% 7.1–11.3). At multivariable analysis, a hormonal syndrome (P = 0.032) and a pause longer than 12 months (P = 0.041) were associated with a longer PFS2. In cohort B (17 patients), the median MGMT H-score increased from 45 (IQR 18–105) before ALK to 100 (IQR 56–180) after ALK (P = 0.003). We conclude that after the initial efficacy of ALK treatment, a pause followed by ALK rechallenge might be appropriate to prolong tumor control, improve quality of life and limit long-term adverse events. Increased MGMT expression under ALK might explain the low efficacy of ALK rechallenge.

There is no standardized treatment for grade 3 neuroendocrine tumors (G3 NETs). We aimed to describe the treatments received in patients with advanced G3 NETs and compare their efficacy. Patients with advanced digestive G3 NETs treated between 2010 and 2018 in seven expert centers were retrospectively studied. Pathological samples were centrally reviewed, and radiological data were locally reviewed. We analyzed RECIST-defined objective response (OR), tumor growth rate (TGR) and progression-free survival (PFS) obtained with first- (L1) or second-line (L2) treatments. We included 74 patients with advanced G3 NETs, mostly from the duodenal or pancreatic origin (71.6%), with median Ki-67 of 30%. The 126 treatments (L1 = 74; L2 = 52) included alkylating-based (n = 32), etoposide-platinum (n = 22) or adenocarcinoma-like (n = 20) chemotherapy, somatostatin analogs (n = 21), targeted therapies (n = 22) and liver-directed therapies (n = 7). Alkylating-based chemotherapy achieved the highest OR rate (37.9%) compared to other treatments (multivariable OR 4.22, 95% CI (1.5–12.2); P = 0.008). Adenocarcinoma-like and alkylating-based chemotherapies showed the highest reductions in 3-month TGR (P < 0.001 and P = 0.008, respectively). The longest median PFS was obtained with adenocarcinoma-like chemotherapy (16.5 months (9.0–24.0)) and targeted therapies (12.0 months (8.2–15.8)), while the shortest PFS was observed with somatostatin analogs (6.2 months (3.8–8.5)) and etoposide-platinum chemotherapy (7.2 months (5.2–9.1)). Etoposide-platinum CT achieved shorter PFS than adenocarcinoma-like (multivariable HR 3.69 (1.61–8.44), P = 0.002) and alkylating-based chemotherapies (multivariable HR 1.95 (1.01–3.78), P = 0.049). Overall, adenocarcinoma-like and alkylating-based chemotherapies may be the most effective treatments for patients with advanced G3 NETs regarding OR and PFS. Etoposide-platinum chemotherapy has poor efficacy in this setting.