The possibility that blood pressure-lowering drugs might influence cancer was first raised a few years ago when it was suggested that patients who took calcium channel blockers were at increased risk of developing cancer. This finding has not been confirmed in other analyses but has prompted a look at the effects of other agents. The results of a new analysis were announced at the International Society of Hypertension meeting in Amsterdam in June, 1998. The Hypertension Clinic in Glasgow, Scotland, has kept detailed records of patients' medications and causes of death over the past 20 years. The records of 1,559 patients who were treated with ACE (angiotensin converting enzyme) inhibitors (mostly captopril and enalapril) were compared with 3,648 who were treated with other blood pressure lowering drugs. The findings were:
- the risk of developing cancer was 25% lower in the patients given ACE inhibitor than in the others;
- patients who were treated with ACE inhibitors for more than three years were at even lower risk of developing cancer;
- the number of cancer cases in the clinic patients treated with non-ACE inhibitor drugs was exactly the same as in the general population;
- there was no increase of cancer cases in patients treated with calcium channel blockers.
Since this was a retrospective analysis, the findings do not prove that ACE inhibitors protect against cancer, but they certainly raise the possibility. It could be linked to the recent discovery that cancers in mice can be prevented by drugs which stop the growth of the tumor's blood supply, since angiotensin (the formation of which is blocked by ACE inhibitors) stimulates the growth of new blood vessels.
