Is guideline-adherent adjuvant treatment an equal alternative for patients aged >65 who cannot participate in adjuvant clinical breast cancer trials? A retrospective multi-center cohort study of 4,142 patients.

Introduction: It is well accepted that innovation in oncology is transported through randomized clinical trials (CT), furthermore there is some evidence that patients profit from participation in CT. However, especially elderly patients aged >65 usually do not have access to clinical trials; we therefore used an unselected patient cohort to investigate the following questions: (1) Is there a difference in survival parameters between study participants <65 and elderly 65-80 non-participants? (2) Is guideline-adherent adjuvant treatment an equal alternative for elderly patients aged 65-80?
Materials and Methods: This German retrospective multi-center cohort study included 4,142 patients (study participants <65 and elderly breast cancer patients 65-80) with primary breast cancer recruited from 1992 to 2008 in 17 participating breast cancer centers.
Results: Applying the exclusion criteria, we included 960 (23.2%) study participants (PA) <65 and 3,182 (76.8%) elderly >65. Elderly non-participants (NPA) >65 demonstrate a significantly inferior RFS [RFS: HR = 1.67; p < 0.001] and OS [OS: HR = 1.98; p < 0.001] compared to PA <65. Within the elderly group, 1,868 (58.7%) patients received guideline-adherent adjuvant treatment. When comparing guideline conform elderly >65 versus PA <65, we found no significant difference in RFS [RFS: HR = 1.17; p = 0.218] and OS [OS: HR = 1.34; p = 0.054]. In contrast, non-guideline-adherent elderly demonstrated significantly inferior survival parameters [RFS: HR = 2.06; p < 0.001] [OS: HR = 2.50; p < 0.001] compared to <65 PA.
Conclusion: Guideline-adherent adjuvant treatment seems to be an equivalent option for elderly breast cancer patients. There is a strong association between guideline adherence and improved outcome parameters in elderly breast cancer patients.