On-treatment markers as predictors to guide anti-EGFR MoAb treatment in metastatic colorectal cancer: a systematic review with meta-analysis.

Abstract

Skin toxicity (ST) and early tumor shrinkage (ETS) are early phenomenon during the anti-epidermal growth factor receptor (EGFR) monoclonal antibody (MoAb) treatment. We conducted a meta-analysis and included relevant studies that reported the impact of ST and ETS on survival- and life quality-based outcome of metastatic colorectal cancer (mCRC) patients treated with anti-EGFR MoAb. Relevant studies were identified from PubMed and Embase reporting the correlation of ST and ETS with the clinical outcome of mCRC patients treated with anti-EGFR MoAb. We also collected evidences on the impact of ST and ETS on absolute benefit acquired from additional anti-EGFR treatment and quality of life (ST only). Pooled hazard ratio and rate difference were all estimated by using random-effects model. Pooled data revealed that the occurrence of ST and ETS ≥20% (v<20%) during anti-EGFR MoAb treatment were both associated with better OS, PFS and ORR. This association could not be disturbed by KRAS status. Mean changes in safety follow-up life health state from baseline appeared unaffected by ST. Only mCRC patients with wild-type KRAS tumor who suffered grade 2+ ST could benefit from additional anti-EGFR treatment to chemotherapy or best supportive care (BSC) alone. ETS was also a predictor for absolute survival benefit acquired from additional anti-EGFR treatment for patients with wild-type KRAS tumors, and the more early shrinkage the tumor was, the much benefit was observed. ST and ETS are predictive of absolute benefit acquired from anti-EGFR treatment in mCRC patients with wild-type KRAS tumors. These two on-treatment markers can be used for clinical decision-making if no adequate biological markers from tissues are provided.