Cytomegalovirus‐negative kidney transplant recipients are at an increased risk for malignancy after kidney transplantation

Background The effect of cytomegalovirus ( CMV ) serology status on malignancy risk in kidney transplanted patients is not clear yet. Methods In a nested case–control study, CMV serology status was compared between patients with a malignancy and 2:1 matched control patients without a malignancy. In a cohort study, the hazard of malignancy was compared between patients that were CMV ‐negative but had a CMV ‐positive donor and other patients, using Cox analysis. Results Fifty‐two of 599 patients transplanted in our center between 2001 and 2014 developed a malignancy. Nine (17.3%) of the 52 patients that developed cancer were CMV ‐negative but had a‐ CMV ‐positive donor compared with 6 (5.8%) of the 104 matched control patients (odd ratio 3.42, 95% confidence interval [ CI ] 1.15–10.2, P =.021). By univariate Cox model, there was a trend toward increased cancer risk in CMV ‐negative patients with a positive donor (hazard ratio [ HR ] 1.95, 95% CI 0.95–4.0, P =.07), but after adjusting for multiple covariates, CMV ‐negative status was significantly associated with increased risk of cancer ( HR 2.55, 95% CI 1.23–5.26; P =.012). Conclusions CMV‐negative patients that had a CMV ‐positive donor were found to have a higher risk of malignancy after kidney transplantation.