Real-world evaluation of effectiveness and tolerance of chemotherapy for early-stage breast cancer in older women

Purpose: Older patients with early-stage breast cancer (ESBC) tend to receive less aggressive treatment, have higher mortality rates, and are underrepresented in clinical trials. Outcomes, tolerance and toxicity of chemotherapy are underreported. Thus, we assessed the outcomes of chemotherapy in the real-world in a community oncology setting. Methods: We retrospectively chart reviewed consecutive older patients (≥ 70 years) with ESBC diagnosed between January 1, 2010, and December 31, 2016, who received chemotherapy at our institution. Study outcomes were survival estimates. Logistic regression determined associations with measures of intolerance. Results: Of 1296 patients, 229 received chemotherapy. Overall, 24% had early chemotherapy cessation; 18% had dose reductions; and 27% had dose delays. Severe, life threatening and lethal toxicities occurred in 38%, 1.3%, and 2.2%, respectively; constitutional toxicity (37%) was the most common. The 1- and 3-year overall survivals were 94% and 79%; 1- and 3-year breast-specific survivals were 96% and 89%, while 1- and 3-year disease-free survivals were 95% and 82%, respectively. Anthracyclines were the most poorly tolerated regimen having associations with hospital visits (OR 10.97, 95% CI 2.10–57.23) and severe toxicities (OR 5.28, 95% CI 1.27–21.89). Anti-HER2 therapies (OR 3.03, 95% CI 1.18–7.78) and poorer performance status (PS) (OR 7.48, 95% CI 1.75–31.98) were associated with severe toxicities. Older age (> 80 years) was associated with early cessation of therapy (OR 3.64, 95% CI 1.34–9.83). Conclusions: Chemotherapy can be effectively delivered to older patients with ESBC and is reasonably well tolerated. The high rate of anthracycline intolerability, poorer PS, and advanced age should be considered when tailoring treatment regimens.