Discussion on the benefits of different treatment strategies in elderly and non-elderly patients with appendix MiNEN: a retrospective study based on SEER database

Purpose To investigate the benefits of surgery alone and postoperative chemotherapy in elderly and non-elderly patients with appendiceal mixed neuroendocrine non-neuroendocrine neoplasms (MiNENs) and analyze the factors affecting the prognosis of patients with MiNEN of the appendix. Methods Based on the Surveillance, Epidemiology, and End Results database (SEER) of the National Cancer Institute of the USA, 389 patients with appendiceal MiNENs from 2000 to 2016 were collected. All patients were distributed in the elderly group (≥ 60 years old) and the non-elderly group (< 60 years old) according to their age. The prognosis of the two groups of patients who received simple surgery and postoperative chemotherapy was analyzed and compared. The two treatment methods of the two tranches were matched by propensity score matching method. The effect of different treatment ways on the prognosis of sick persons was compared. The survivorship curves were painted by the Kaplan Meier method, log rank test was used to analyze the subsistence discrepancy of each group, and COX proportional risk model was used to analyze the factors affecting the prognosis of patients with appendiceal MiNENs. Results No matter the overall survival rate (OS) or cancer-specific mortality (CSM) of the two treatment schemes, the prognosis of patients in the only surgery group was meaningfully higher than that in the postoperative chemotherapy group, with statistically significant difference in component comparison (χ 2 = 16.496, χ 2 = 16.860, P < 0.001). After propensity score matching of patients in each group, there was no striking discrepancy in the OS of patients in the only surgery group compared with those in the postoperative chemotherapy group, regardless of whether they were elderly patients or non-elderly patients (χ 2 = 3.205, χ 2 = 1.521, all P > 0.05), the CSM consequences are fitting in with the OS. The consequences of the multivariate COX regression model showed that age (≥ 60 years old), sex (female), high histological grade, and lymph node positive were all the influencing factors for the poor OS of patients with MiNEN; the CSM results are consistent with the OS. Conclusion For patients with appendix MiNEN, whether elderly or non-elderly patients (especially for non-elderly patients), surgical treatment may be a better choice.