Abstract 6315: Are a subset of patients at higher risk for mortality in stage III colon cancer: An analysis of the SEER database

Abstract

Abstract Background: High-risk features (HRF) increase mortality for Stage II colon cancer (CC). These HRF include pathologic T4 disease, perineural invasion (PNI), lymphovascular invasion (LVI), an inadequate lymphadenectomy (less than 12 lymph nodes harvested) and poorly differentiated tumors. The presence of two or more HRF has an additive impact on survival for patients with Stage II CC. While T4 and disease greater than N1a raise the risk of mortality in Stage III CC, the effect of the other accepted HRF in patients with Stage III CC has not been studied. Materials and Methods: Surveillance, Epidemiology and End Results (SEER) (2010 - 2017) was used to identify patients with Stage III and IV CC. Patients with Stage III CC were then further classified by the presence of zero, 1, or 2 or more of the following HRF: pathologic T4, PNI, inadequate lymphadenectomy, or poor differentiation. Overall (OS) and cause-specific (CS) survival were calculated. Results: 57,640 patients with Stage III or IV CC were identified. 35,760 (62%) patients had Stage III disease and 21,880 (38%) had Stage IV disease. Among patients with Stage III disease, 16,733 (46.8%) had no HRF, 12,703 (35.5%) had 1 HRF and 6,324 (17.7%) had 2 or more HRF. For patients with 1 HRF, 4,610 (36.3%) had poor differentiation, 2,339 (18.4%) had PNI, 3,673 (28.9%) had T4 disease, and 2,078 (16.4%) had an inadequate nodal harvest. Patients with Stage III CC without HRF had the best OS (73.3%) and CS (81.4%,). This was followed by Stage III with 1 HRF (OS 63.7%, CS 71.6%) and Stage III with 2 or more HRF (OS 44%, CS 51%). Patients with Stage IV disease had the worst OS (18.1%) and CS (20.4%) (p<0.05). For patients with 1 HRF, pathologic T4 conferred worse OS (57.2%) and CS (63.2%), compared to PNI (OS 66.4%, CS 73.7%), inadequate lymphadenectomy (OS 64.6%, CS 74.9%) and poor differentiation (OS 66.6%, CS 75.4%) (p<0.01). Conclusion: HRF have a cumulative influence on OS and CS in patients with Stage III CC. The presence of multiple HRF should be considered higher risk for patients with Stage III disease. Citation Format: Luv N. Hajirawala, Yong Yi, Michelle A. Bergeron, Danielle A. Dooley, Guy R. Orangio, Elyse R. Bevier-Rawls, Kurt G. Davis, Jeffrey S. Barton. Are a subset of patients at higher risk for mortality in stage III colon cancer: An analysis of the SEER database [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 6315.