Relation between drug treatment and cancer in hypertensives in the SwedishTrial in Old Patients with Hypertension 2: a 5-year, prospective, randomised, controlled trial

Background Is cancer related to hypertension and blood pressure? Do anti hy pertensive drugs promote cancer? Do antihypertensive drugs protect against cancer? We previously analysed the frequency of cardiovascular mortality an d morbidity in elderly people who participated in the Swedish Trial in Old Patients with Hypertension 2 (STOP-Hypertension-2). We have also looked at the frequency of cancer in these patients. Methods We randomly assigned 6614 elderly patients with hypertension (mean age 76 years, median time of follow-up 5.3 years) to one of three treatment strategies: conventional drugs (diuretics or beta -blockers), calcium anta gonists, or ACE inhibitors. We matched the patients to the Swedish Cancer R egistry and compared our findings with expected values based on age, sex, a nd calendar-year-specific reference frequencies for the general Swedish pop ulation. We also compared the number of cancers between the three treatment groups. Findings At baseline, 607 (9%) patients had previous malignant disease. Dia gnoses were closely similar to the distribution of cancer types that might be seen in elderly patients. During follow-up, there were 625 new cases of cancer in 590 patients. The frequency of cancer did not differ significantl y between the treatment strategies, including all cancers and those at indi vidual sites. The standardised incidence ratios (SIRs) for all cancers were also close to unity: 0.92 (95% CI 0.80-1.06) for conventional drugs, 0.96 (0.83-1.10) for calcium antagonists, and 0.99 (0.86-1.13) for ACE inhibitor s. Interpretations No difference in cancer risk was seen between patients rand omly assigned to conventional drugs, calcium antagonists, or ACE inhibitors . Thus, the general message to the practising physician is that more attent ion should be given to getting the blood pressure down than to the risk of cancer.