Overall health at diagnosis predicts the risk of complications within the first year after breast cancer diagnosis.

PURPOSE Breast cancer patients with overall poor health are at a greater risk of both complications during treatment and mortality from competing causes. We sought to determine the association of pre-existing comorbidities on treatment-related complications and overall survival. METHODS We identified women ages 40-90 years old from our institutional registry with stage I-II invasive breast cancer from 2005 to 2014. Recursive partitioning was used to stratify women based on pre-existing comorbidities as low, moderate, or high risk of treatment-associated complications. Cox proportional hazards model was constructed to estimate the association of risk with overall survival. RESULTS 2077 women were studied. Mean age was 60 (IQR 51-68). Over half (54%) had ≥ 1 comorbid condition, and 29% experienced at least one adverse medical event within 1 year of diagnosis. Risk categories included low (no comorbidities or hypertension), moderate (combinations of comorbidities excluding congestive heart failure), and high (congestive heart failure in isolation or in combination with other conditions). High-risk women had a lower 10-year OS compared to moderate- or low-risk women (89% vs 90% vs 96%, log-rank p < 0.001). After adjustment, being at moderate (HR 2.20, 95% CI 1.30-3.72, p = 0.003) or high risk (HR 5.07, 95% CI 1.66-15.52, p = 0.004) of adverse sequelae was associated with reduced OS compared to those at low risk of these adverse medical events. CONCLUSIONS Following breast cancer diagnosis, overall poor health was associated with a greater risk of mortality and complications within the first year of treatment, which was driven by a pre-existing diagnosis of congestive heart failure.