Androgen deprivation therapy and acute kidney injury in patients with prostate cancer undergoing definitive radiotherapy

Background Androgen deprivation therapy (ADT) is frequently utilized in conjunction with radiotherapy (RT) in the definitive management of prostate cancer. Prior studies have suggested an association between ADT use and acute kidney injury (AKI), however, these included heterogeneous populations undergoing a variety of treatments and relied on billing codes to ascertain the incidence of AKI. Methods We analyzed a cohort of 27,868 veterans undergoing definitive RT + /- ADT for prostate cancer between 2001 and 2015 using the Veterans Affairs Informatics and Computing Infrastructure (VINCI). Exposure was defined as use of ADT within one year of diagnosis. The primary outcome was AKI, defined by an increase in serum creatinine to at least 1.5 times the baseline value. AKIs were classified as mild, moderate, or severe in accordance with international guidelines. A multivariate competing risks model was used to account for demographic and oncologic factors as well as medications and procedures known to influence the risk of AKI. Results Most (n = 18,754) men received RT alone; 9,114 men received RT + ADT. The incidence of AKI at two years after diagnosis was 10.5% in the RT + ADT group and 7.9% in the RT group (Gray's test p < 0.01). Multivariate analysis confirmed ADT usage was associated with an increased risk for any AKI (SHR = 1.24, 95% CI = 1.14-1.36, p < 0.01). ADT was also associated with an increased risk of mild AKI (SHR = 1.13, 95% CI = 1.01-1.27, p = 0.04) and moderate AKI (SHR = 1.45, 95% CI = 1.20-1.76, p < 0.01), though not severe AKI (SHR = 1.33, 95% CI = 0.93-1.91, p = 0.11). Conclusions Our findings confirm that use of ADT is associated with an increased risk of AKI in patients undergoing definitive RT for prostate cancer. Clinicians should be alert to the potential for renal dysfunction in this population.