Urothelial cell carcinoma after BK polyomavirus infection in kidney transplant recipients: A cohort study of veterans.

BACKGROUND

BK polyomavirus (BKPyV) reactivation is a common clinical occurrence in kidney transplant recipients (KTR). Several other polyomaviruses have been implicated as pathogens with a direct role in the development of malignancies, raising the question of whether BKPyV might also be oncogenic.

METHODS

This study is the first retrospective, multicenter cohort study evaluating the relative risk for urothelial cell carcinoma (UCC) associated with BKPyV infection among KTR, and was conducted among veterans who underwent transplantation between 2000 and 2009. BKPyV cases were defined as those veterans with any clinical evidence of BKPyV infection, including positive polymerase chain reaction testing of urine and/or serum for BKPyV or kidney biopsy showing BKPyV-associated nephropathy.

RESULTS

Among the 646 veterans who met inclusion criteria for the study, 103 had clinical evidence of BKPyV infection (16%). The overall relative risk for developing any malignancy after BKPyV infection was 1.13 (95% confidence interval [CI] 0.89-1.44). The adjusted relative risk for malignancy after BKPyV infection was greatest with UCC (8.21, 95% CI 0.75-89.7) and with metastatic disease of unknown etiology (8.21, 95% CI 0.75-89.7). The screening prevalence for BKPyV infection increased from 18% for those veterans who underwent transplantation in 2000 to 86% for those veterans who underwent transplantation in 2009, during which time the measured prevalence of BKPyV infection increased from 7% to 24%.

CONCLUSION

In this cohort of KTR veterans, no overall increased or decreased relative risk for malignancy was associated with evidence of prior BKPyV infection. A >8-fold increased risk of developing UCC after BKPyV infection was seen, although this risk was not found to be statistically significant.