Abstract: PD52-07
Sources of Funding: This research was supported in part by the CUA-Pfizer Urology Resident Research Grant and the Canadian Drug Safety and Effectiveness Network.

Introduction

Exposure to commonly-prescribed medications may be associated with cancer risk. However, there is limited data in kidney cancer. Furthermore, methods of classifying cumulative medication exposure in previous studies may be prone to bias.

Methods

We conducted a population-based case-control study utilizing health care databases in Ontario, Canada. Individuals enrolled as cases were aged ≥66 with an incident diagnosis of kidney cancer. For each individual enrolled as a case, we identified up to four individuals without kidney cancer as controls matched on age, sex, history of hypertension, comorbidity score, and geographic location. Cumulative exposure to commonly prescribed medications hypothesized to modulate cancer risk were obtained using prescription claims data. We modelled exposure in four different fashions: 1) as continuous exposures using a) fractional polynomials (which allow for non-linear relationship between a continuous exposure and outcome) or b) a linear relationship; and 2) as dichotomous exposures denoting a) 3 years or greater vs. less than 3 years of cumulative exposure; or b) &[prime]ever&[prime] vs. &[prime]never&[prime] exposure. We used conditional logistic regression to estimate the association of medication exposure on incident kidney cancer.

Results

We identified 10,377 incident cases of kidney cancer and 35,939 matched controls. When utilizing fractional polynomials, increasing cumulative exposure to aspirin, selective serotonin reuptake inhibitors, and proton-pump inhibitors were associated with significantly reduced risk of developing kidney cancer, while increasing exposure to anti-hypertensive drugs was associated with significantly increased risk (Table 1). The directions of association were relatively consistent across analyses; however, the magnitudes were sensitive to the method of analysis (Table 2).

Conclusions

Our study provides impetus to further explore the effect of commonly-prescribed medications on carcinogenesis to identify modifiable pharmacological interventions to reduce the risk of kidney cancer.

Funding

This research was supported in part by the CUA-Pfizer Urology Resident Research Grant and the Canadian Drug Safety and Effectiveness Network.