Cardiovascular drugs and cancer: of competing risk, smallpox, Bernoulli, and d'Alembert

At a first glance cardiovascular disease and cancer have little in common. However, even a cursory review of the literature reveals a myriad of articles documenting an association between the two. This would indicate that either cardiovascular disease and/or its treatment affect cancer, or that cancer and/or its treatment affect cardiovascular disease, or still that both cancer and cardiovascular disease are affected by a common underlying mechanism. Among the various possible interactions, the most concerning one is that cardiovascular drug therapy when given over decades could possibly increase the risk of incident cancer, i.e. that cardiovascular drugs could prove to be carcinogenic.The article by Sipahi et al .1 reporting a small but significant risk of cancer associated with angiotensin receptor inhibitors was widely covered by news media and created anxiety among patients and uncertainty among physicians. Reassuringly, thorough and comprehensive re-analyses of the data2,3 and a cohort study4 found this issue to be ‘much ado about nothing’.5 Also, a Food and Drug Administration review6 launched in the wake of the controversial Sipahi study recently came to the conclusion that angiotensin receptor blockers do not pose a cancer risk to patients.One problem with the analyses of cardiovascular drugs and cancer, which in general is overlooked, is that life per se is a game of multiple competing risks. Throughout life, every person continues to be exposed to multiple risks of death, such as cardiovascular diseases, cancers, accidents, and infections. Because death is not (at least not usually) a repetitive event and most often can be blamed on a single cause, these death risks compete with one another for the life of a person. If one regularly takes an antihypertensive drug or a statin and therefore does not die of a myocardial infarction, stroke, …