AbstractBackground and AimThe relationships between the X‐ray repair cross‐complementing 1 (XRCC1) Arg399Gln polymorphism (rs25487, G > A) and responses to platinum‐based chemotherapy of gastric and colorectal cancer patients are controversial. Therefore, we performed a meta‐analysis to assess the relationships.MethodsWe retrieved the relevant articles from MEDLINE and EMBASE databases. Fourteen studies with 1618 gastric and colorectal cancer patients were included. Primary outcomes included response rate (RR), progression‐free survival (PFS), and overall survival (OS). Odds ratio (OR) or hazard ratio with 95% confidence interval (CI) were estimated. All analyses were performed using the Stata software version 11.0 and Review Manager (v5.0).ResultsIn the dominant model, the A allele of XRCC1 Arg399Gln polymorphism was associated with reduced RR to platinum‐based chemotherapy in all gastric and colorectal cancer patients (A/G + A/A vs G/G OR, 0.73; 95% CI, 0.55–0.96) and in Asians (OR, 0.62; 95% CI, 0.44–0.89) but not in Caucasians (OR, 0.92; 95% CI, 0.60–1.42). In addition, stratified analysis for different types of cancers indicated a marginally significant decrease of RR in colorectal cancer patients (OR, 0.68; 95% CI, 0.46–1.00) but not in gastric cancer patients (OR, 0.78; 95% CI, 0.53–1.15). However, we did not observe a significant association between XRCC1 Arg399Gln polymorphism and hazard for PFS and OS for gastric and colorectal cancer patients in all tested models.ConclusionsXRCC1 Arg399Gln polymorphism may be a valuable genetic marker for platinum‐based chemotherapy of gastric and colorectal cancer patients, and more well‐designed studies with large samples are needed to confirm our findings.