In sum, the SNPs CNTN6 rs6764623 (CC/CA vs. AA; aHR = 0.44; P = 0.040), PTGS2 rs20417 (GG vs. CC/CG; aHR = 2.88; P = 0.031) and RGS7 rs2502448 (TT vs. CT/CC; aHR = 2.35; P = 0.013) were associated with the five-year risk of cancer recurrence, while ITGB3 rs5918 was a predictor of the risk of death due to all causes, particularly among male patients (TT vs. CT/CC; aHR = 2.05; P = 0.019). This evidence concerns the gene CNTN6 and cancer.