Missed opportunities: racial disparities in adjuvant breast cancer treatment.

PURPOSE: Underuse of adjuvant therapy is a potentially important and remediable explanation for the inferior survival of minority women with breast cancer. We sought to measure a racial disparity in the underuse of adjuvant treatments for early-stage breast cancer and to identify associated factors.
METHODS: Cross-sectional study with review of all inpatient and outpatient medical records of 677 women treated surgically for a primary American Joint Committee on Cancer stage I or II breast cancer in 1999 to 2000. Underuse was defined as omissions of radiation therapy after breast-conserving surgery, adjuvant chemotherapy after resection of hormone-receptor-negative tumors > or = 1 cm, or hormonal therapy for receptor-positive tumors > or = 1 cm.
RESULTS: One hundred forty-five (21%) of 677 women experienced underuse of appropriate adjuvant therapy: 16% in whites, 34% in blacks, and 23% in Hispanics (P < .001). Women referred to medical oncologists were less likely to experience underuse of necessary adjuvant treatments (relative risk [RR] for underuse = 0.2; 95% CI, 0.1 to 0.3). Women who were minorities (RR = 2.0; 95% CI, 1.3 to 3.1), had higher levels of comorbidity (RR = 1.4; 95% CI, 1.1 to 1.8) and lacked insurance (RR = 1.9; 95% CI, 0.9 to 4.0) were at greater risk for underuse.
CONCLUSION: Minority women with early-stage breast cancer have double the risk of white women for failing to receive necessary adjuvant treatments despite rates of oncologic consultation similar to those for white women. Oncology referrals are necessary to reduce treatment disparities but are not sufficient to ensure patients' receipt of efficacious adjuvant treatment.