Breast conserving surgery versus mastectomy: the influence of comorbidities on choice of surgical operation in the Department of Defense health care system.

BACKGROUND Studies on the effect of comorbidities on breast cancer operation have been limited and inconsistent. This study investigated whether pre-existing comorbidities influenced breast cancer surgical operation in an equal access health care system. METHODS This study was based on linked Department of Defense cancer registry and medical claims data. The study subjects were patients diagnosed with stage I to III breast cancer during 2001 to 2007. Logistic regression was used to determine if comorbidity was associated with operation type and time between diagnosis and operation. RESULTS Breast cancer patients with comorbidities were more likely to receive mastectomy (odds ratio [OR] = 1.27; 95% confidence interval [CI], 1.14 to 1.42) than breast conserving surgery plus radiation. Patients with comorbidities were also more likely to delay having operation than those without comorbidities (OR = 1.27; 95% CI, 1.14 to 1.41). CONCLUSIONS In an equal access health care system, comorbidity was associated with having a mastectomy and with a delay in undergoing operation.