Meta-analysis of clinical trials on concordance of mutational stauts of primary tumour and distant metastases of colorectal cancer

Abstract

Background . During the last years several trials emerged demonstrating high tumour heterogeneity, including those on colorectal cancer. Objective. These findings made us initiate a meta-analysis of trials dedicated to this question. Materials and methods. We searched PubMed database, ASCO and ESMO abstracts for publications presented until August 2016. Studies which compared concordance of KRAS, NRAS, BRAF and PIK3CA mutations between primary tumour and metastases of colorectal cancer and which included more than 10 patients were included in meta-analysis. Meta-analysis was performed using Review Manager (RevMan), version 5.3. Results. Statistically significant differences were observed in KRAS (5 %; RR 0.95; 95 % CI 0.92–0.98; р = 0.003), PIK3CA (7 %; RR 0.93; 95 % CI 0.86–0.99; р = 0.04) mutational status, but not BRAF and NRAS. We observed no significant publication-associated systematic errors. KRAS discordance was significantly higher between primary tumour and lymph node metastases – 13.2 % (р = 0.036). Conclusions. A possibility of KRAS discordance between primary tumour and colorectal cancer metastases was demonstrated. Considering a small number of patients with discordance it is necessary to distinguish a high-risk discordance group, which will require an additional mutational analysis of metastatic nodes tissue.