Older women with breast carcinoma are less likely to receive adjuvant chemotherapy: evidence of possible age bias?

Background: Older women with breast carcinoma are less likely than younger women to receive adjuvant chemotherapy. The authors hypothesized that after controlling for confounders (i.e., variables related to both age and chemotherapy use) and effect modifiers (i.e., variables that have a significant interaction with age), age would become a less significant factor for predicting adjuvant chemotherapy use.

Methods: Data on 480 women with localized breast carcinoma were entered into the National Comprehensive Cancer Network database at The Ohio State University Medical Center. Women were divided into 3 groups: women age < 50 years (n = 143 [30%]), women ages 50-65 years (n = 216 [45%]), and women age > 65 years (n = 121 [25%]). Chi-square and Wilcoxon rank sum tests were used for univariate analyses of the variables of interest, and logistic regression was used for multivariate analyses.

Results: After adjustment for confounders (stage, tumor size, progesterone receptor status, and lymph node involvement) and effect modifiers (namely, estrogen receptor [ER] status), the odds of not receiving chemotherapy for women ages 50-65 years and women age > 65 years with ER-positive breast carcinoma were approximately 6 (odds ratio [OR], 6.4; 95% confidence interval [CI], 3.1-13.3; P < 0.001) and 62 (OR, 62.4; 95% CI, 21.8-178.7; P < 0.001) times greater, respectively, than the odds for women age < 50 years. Women ages 50-65 years with ER-negative breast carcinoma were not significantly different from women age < 50 years with respect to chemotherapy use (OR, 1.9; 95% CI, 0.5-7.3; P = 0.374). However, the odds of not receiving chemotherapy for women age > 65 years with ER-negative breast carcinoma were 7 times (OR, 6.7; 95% CI, 1.5-30.6; P = 0.013) greater than the odds for women age < 50 years.

Conclusions: The results of the current study indicate that based on older age alone, women are less likely to receive adjuvant chemotherapy. In addition, the results suggest that age bias may contribute to undertreatment and lack of accrual of older women into clinical trials.