Purpose: To determine patterns and predictors of concordance with institutional treatment guidelines among older women with breast cancer.
Methods: The study population included 1,568 patients aged 55 years and older who were treated at M.D. Anderson Cancer Center between July 1997 and January 2002 for stage I to IIIA invasive ductal and lobular breast cancer. Concordance with institutional guidelines was determined for definitive surgical therapy, radiotherapy after breast-conserving surgery, radiation therapy after mastectomy, adjuvant chemotherapy use, and adjuvant hormonal therapy use. The following variables were considered as possible modifiers of concordance: patient age, marital status, race, educational level, Eastern Cooperative Oncology Group performance status, comorbidity score, clinical stage, hormone receptor status, HER2-neu status, tumor grade, pathologic tumor size, lymphatic invasion, and number of lymph nodes involved. Logistic regression modeling was performed to determine the independent effect of each variable on guideline concordance.
Results: Older women were less likely to receive treatment in concordance with guidelines for definitive surgical therapy (P < .001), postlumpectomy radiation (P = .03), adjuvant chemotherapy (P < .001), and adjuvant hormonal therapy (P < .001). In multivariate analysis, age > or = 75 years predicted a deviation from guidelines for definitive surgical therapy, adjuvant chemotherapy, and adjuvant hormonal therapy. Nonwhite race was associated with decreased likelihood of adjuvant radiation therapy after breast conservation.
Conclusion: After adjustment for comorbidity score, race, marital status, educational status, clinical stage, and tumor characteristics, increasing patient age was independently associated with decreased guideline concordance for definitive surgery, adjuvant chemotherapy, and adjuvant hormonal therapy. Future research should focus on delineating the possible reasons for guideline discordance.