Purpose: Because it is unknown whether adjusting the dose of sunitinib can benefit patients with pancreatic neuroendocrine neoplasms (Pan-NENs), this retrospective study examined maximum tumor shrinkage rates and prognoses in patients with and without low doses of sunitinib administration.
Methods: Eighty-seven patients with metastatic and unresectable neoplasms, treated with sunitinib for > 1 month, were divided into a low-dose (LD) or high-dose (HD) group. The tumor response rates were investigated over time using computed tomography according to the response evaluation criteria in solid tumors criteria.
Results: The LD and HD groups included 42 and 45 patients, respectively. There were no differences in baseline characteristics (tumor size, Ki-67 index, mitosis, and differentiation) between the two groups. Progressive disease (PD), stable disease (SD), and partial response (PR) were observed in 16.7, 54.8, and 28.6% of patients in the LD group, respectively, and in 13.3, 60, and 26.7% of patients in the HD group, respectively. There were no differences in tumor shrinkage rates between the two groups (p = 0.87). The 3-year progression-free survival rates for the LD and HD groups were 2.4% and 2.3%, respectively (p = 0.67), and the 3-year overall survival rates were 57.9% and 70.5%, respectively (p = 0.76). The occurrence of adverse events was similar between the two groups (61.9% vs. 60.0%, p > 0.95).
Conclusions: Dose reduction of sunitinib did not alter tumor shrinkage rates or prognoses for patients with advanced Pan-NENs.
Keywords: Liver metastasis; Low dose; Neuroendocrine tumor; Sunitinib; Unresectable.