Objectives: Renal cell cancer has been associated with hypertension or with drugs to treat it in several studies. We assessed whether the association is explained by more frequent detection of early renal cell cancer among persons being treated for hypertension.
Methods: The data were collected in our Case-Control Surveillance Study, in which patients aged 20 to 69 years were interviewed in hospitals in Baltimore, Boston, New York, and Philadelphia during 1976-1996. We compared 134 incident cases of renal cell cancer who were being treated with drugs for hypertension to 193 untreated cases with respect to the route to diagnosis and the stage.
Results: The relative risk estimate for having been diagnosed incidentally during a routine examination or workup for another condition, relative to having been diagnosed because of symptoms of renal cell cancer, was 1.3 (95 percent confidence interval, 0.7-2.5). The estimate for diagnosis at stage I or II relative to stage III or IV was 1.2 (0.7-2.1).
Conclusion: In Case-Control Surveillance Study data, the relative risk estimate for renal cancer among users of various classes of antihypertensive drugs is 1.8 or 1.9. The present results suggest that this association can, at most, be explained only partially by the selective diagnosis of renal cell cancer among persons being treated for hypertension.