The Treatment of Primary Breast Cancer in Older Women With Adjuvant Therapy: A Retrospective Analysis of Data From Over 3000 Patients From the PATH Biobank, With Two-Year Follow-up.

BACKGROUND: Breast cancer is the most common cancer in women in Germany. Mortality from breast cancer has declined over the past 15 years, but less so in women aged 70 or older than in younger women. The discrepancy might be explained by age-related differences in treatment.
METHODS: Data from the Patients' Tumor Bank of Hope (PATH) database of women who underwent adjuvant treatment for the treatment of an invasive primary tumor without distant metastases (year of diagnosis, 2006-2011) were retrospectively analyzed. The clinical and tumor-biological findings and treatment data over two years of follow-up were compared across three age groups (under age 50, ages 50 to 69, and ages 70 and up). Chi-square tests were carried out to reveal significant differences, and post-hoc multiple comparisons were performed with and without Bonferroni correction. Treatment data were adjusted for staging and grading and tested for age-dependence with logistic regression.
RESULTS: Follow-up data were available for 3257 (65% ) of 4981 women, of whom 61% were in the middle age group and 22% in the oldest. Compared to women aged 50 to 69, those aged 70 and up less commonly received breast-conserving treatment (68.8% vs. 86.4% ), chemotherapy (27.5% vs. 44.1% ), radiotherapy (81.8% vs. 92.4% ), and trastuzumab (52.9% vs. 79.3% ; p<0.001 for all differences). All differences remained significant after stastistical adjustment.
CONCLUSION: The cause of these age-related differences is unclear. It cannot be determined from these data whether concomitant disease, the older patients' individual decisions, or other factors were responsible for their not receiving treatment as often as the younger patients did.