1. The efficacy of anti-EGFR therapy in treating metastatic colorectal cancer differs between the middle/low rectum and the left-sided colon
- Author
-
Yee Chao, Kun Han Lee, Chun Chi Lin, Hao Wei Teng, Hung Hsin Lin, Jeng Kai Jiang, Shih Ching Chang, Wei Shone Chen, Sheng Chieh Huang, Shung Haur Yang, Huann Sheng Wang, Hou Hsuan Cheng, and Yuan Tzu Lan
- Subjects
Oncology ,0303 health sciences ,Cancer Research ,medicine.medical_specialty ,business.industry ,Genetic heterogeneity ,Colorectal cancer ,Metastatic rectal cancer ,Rectum ,medicine.disease ,Left sided ,03 medical and health sciences ,0302 clinical medicine ,medicine.anatomical_structure ,Growth factor receptor ,030220 oncology & carcinogenesis ,Internal medicine ,Cancer genome ,Overall survival ,Medicine ,business ,030304 developmental biology - Abstract
Background Clinically, metastatic rectal cancer has been considered a subset of left-sided colon cancer. However, heterogeneity has been proposed to exist between high and middle/low rectal cancers. We aimed to examine the efficacy of anti-epidermal growth factor receptor (EGFR) treatment for middle/low rectal and left-sided colon cancers. Methods This study enrolled 609 patients with metastatic colorectal cancer who were treated with anti-EGFR therapy. They were divided into groups based on primary tumour locations: the right-sided colon, the left-sided colon or the middle/low rectum. The efficacy of first-line and non-first-line anti-EGFR treatment was analysed. Genomic differences in colorectal cancer data from The Cancer Genome Atlas (TCGA) were investigated and visualised with OncoPrint and a clustered heatmap. Results On first-line anti-EGFR treatment, patients with middle/low rectal tumours had significantly lower progression-free survival, overall survival, and overall response rates (6.8 months, 27.8 months and 43%, respectively) than those with left-sided colon cancer (10.1 months, 38.3 months and 66%, respectively). Similar outcomes were also identified on non-first-line anti-EGFR treatment. In TCGA analysis, rectal tumours displayed genetic heterogeneity and shared features with both left- and right-sided colon cancer. Conclusions Anti-EGFR treatment has lower efficacy in metastatic middle/low rectal cancer than in left-sided colon cancer.
- Published
- 2021