Hypertension, use of antihypertensive medication, and breast cancer survival in the Black Women’s Health Study

Analysis of 2474 participants of the Black Women’s Health Study (BWHS) with invasive breast cancer investigated associations between hypertension and use of antihypertensive medication with breast cancer survival after adjustment for clinical and lifestyle factors and cancer treatment. In the full study population, the breast cancer-specific survival HR for untreated hypertension versus no hypertension was 1.17 (95% CI 0.75-1.82) while the HR for treated hypertension versus no hypertension was 0.81 (0.60-1.10). Among ER+ cases, there was no association between untreated hypertension and breast cancer-specific death (HR 0.96; 95% CI 0.50-1.82) but a strong inverse association between treated hypertension and breast cancer-specific death (0.53; 0.34-0.83). In contrast, for ER- cases, there was an increased risk of breast cancer-specific death among those with untreated hypertension (HR 2.19; 95% CI 1.09-4.39), but little evidence of an association with treated hypertension (1.32; 0.80-2.19). The authors conclude that Black ER+ breast cancer patients with hypertension have better survival when their hypertension is treated, possibly due to regular health care engagement or the tumor suppressing activity of antihypertensive medications. Randomized trials are needed to establish causality.