| Abstract: | Background Infiltrative growth pattern at the tumor margin has been associated with shorter patient survival. However, little is known about the prognostic significance of tumor growth pattern, independent of tumoral molecular alterations and other histologic features. Methods Utilizing a database of 1139 colon and rectal cancer patients in two prospective cohort studies, histologic features including tumor growth pattern, tumor differentiation, lymphocytic reaction, mucinous component, and signet ring cell component were recorded by a single pathologist. Cox proportional hazard model was used to compute mortality hazard ratio, adjusting for clinical, pathologic, and tumor molecular features, including microsatellite instability, the CpG island methylator phenotype, long interspersed nucleotide element 1 (LINE-1) methylation, and KRAS, BRAF, and PIK3CA mutations. Results Among 1139 colorectal cancers, we observed expansile growth pattern in 372 tumors (33%), intermediate growth pattern in 610 tumors (54%), and infiltrative growth pattern in 157 tumors (14%). Compared to patients with expansile growth pattern, those with infiltrative growth pattern experienced shorter cancer-specific survival (log rank P?P?P interaction with stage?=?0.0001). Conclusions Infiltrative growth pattern was associated with worse prognosis among stage I?CIII colorectal cancer patients, independent of other clinical, pathologic, and molecular characteristics. |
