ENDO 2012: Patients with Colorectal Cancer Exposed to Beta Blockers, ACE Inhibitors, ARBs Have Better Outcomes
(ChemotherapyAdvisor) – Patients with advanced colorectal cancer exposed to a combination of a beta blocker and an angiotensin converting enzyme inhibitor/angiotensin receptor blocker (ACE/ARB) gain weight and have better survival outcomes, a study presented June 24 at The Endocrine Society's 94th Annual Meeting in Houston, TX, has found.
Noting that recent in vitro studies have suggested angiotensin and beta-adrenergic blockade may decrease progression of colon cancer, Diana R. Engineer, MD, of the Michael E. DeBakey Veterans Affairs Medical Center, Houston, TX, and colleagues conducted a retrospective chart view to determine whether exposure to beta blockers, ACE inhibitors, or ARBs was associated with a decrease in mortality, weight loss, or number of hospitalizations in patients diagnosed with advanced colorectal cancer at their institution between January 2000 and July 2009.
Patients with hypertension and diabetes were included; excluded were those with other conditions that may benefit from angiotensin blockade or from beta blockers, such as NYHA Class III or IV congestive heart failure, end-stage chronic obstructive pulmonary disease, and hyperthyroidism.
Data on survival, hospitalization, gender, cancer progression, cancer treatment, body weight (6-12 months prediagnosis, baseline, and every 6 months postdiagnosis), albumin, creatinine, medications, and disease stage were collected.
Of 425 patients with new diagnoses of stage III-IV colon cancer identified, 262 met the inclusion criteria. Patients exposed to ACE inhibitors/ARBs, beta blockers, or both were most likely to have diabetes, hypertension, have stage III disease.
No difference in age, gender, chemotherapy regimen, or radiation was observed between those with colorectal cancer and a control group not exposed to ACE inhibitors/ARBs and beta blockers. However, the combination of ACE inhibitors/ARBs and beta blocker was associated with decreased mortality vs unexposed individuals even after adjusting for age and stage. Median survival was 1,341 vs 695 days, respectively (Cox regression P<0.03).
“Body weight changes between 6 and 18 months after diagnosis also predicted survival after adjusting for stage and exposure,” they found. Exposure to ACE inhibitors/ARBs and beta blockers in combination was associated with more weight gain vs unexposed subjects (P<0.02), “and predicted weight loss, even after adjusting for stage.” They also noted a tendency towards increased cancer progression (P=0.085) in unexposed patients. Number of hospitalizations was similar between groups.
“Future studies to determine the causality of this association are warranted,” they concluded.