Abstract
Objective: To assess predictors of delayed radiotherapy (RT) and the potential impact of RT delay on breast cancer outcomes in older women with early-stage breast cancer.
Methods: We studied 616 women, ages 65 years or older, who were diagnosed with early-stage breast cancer from 1990–1994 at six HMOs. These women were a subset of the Cancer Research Network’s Breast Cancer Treatment Effectiveness in Older Women (BOW) cohort. All women included underwent breast conserving surgery and radiotherapy, but no chemotherapy. We examined whether race, age, estrogen receptor (ER) or progesterone receptor (PR) status, Charlson comorbidity index at diagnosis, tamoxifen use, tumor size, histology, and lymph-node positivity were associated with RT delays of more than 8 weeks post-surgery using chi-square tests and multivariate logistic regression. We applied Cox proportional hazards models to assess whether RT delay and demographic and clinical variables were associated with 10-year breast cancer recurrence rates.
Results: Of the 82 women with delayed RT, 17 (21%) recurred, whereas only 73 of 534 (14%) without delay recurred (P=0.09). Of those with delays >8 weeks, mean delay was 114 days (16 weeks) and median was 69.5 days (10 weeks). African American race compared to White race was associated with delayed RT (OR, 3.1; 95% CI, 1.5–6.6) in multivariate analyses that controlled for demographic and clinical variables and HMO site. Breast cancer tumors larger than 2 cm were associated significantly with higher recurrence rates (HR=4.2; 95% CI, 2.2–8.1), as were subjects with more than 4 positive lymph nodes (HR=6.6; 95% CI, 1.9–22.7). There was a trend towards higher recurrence rates for subjects with RT delay (HR=1.7; 95% CI, 0.91–3.0).
Conclusions: Although African American race was associated with RT delay, RT delay itself was not strongly associated with recurrence rates. Tumor characteristics are the major predictors of recurrence in this population of breast cancer patients.
- Received September 11, 2008.
