Increasing Mortality in Korean Patients With Breast Cancer: High Mortality Rate in Elderly Breast Cancer Population Due to Suboptimal Treatment and Other Diseases.

Background: The incidence of breast cancer in Asia, including Korea, has rapidly increased. Each country has shown different clinical features. This study presents a comprehensive understanding of breast cancer in different age groups in Korea and determines potential measures for improving patient survival.

Methods: Patients diagnosed with invasive breast cancer stages I to III with available clinicopathologic and follow-up data were included in the study. Kaplan-Meier survival graphs were generated for each group and compared using log-rank test. The hazard ratio for each risk factor was calculated using the Cox regression model and the 95% confidence interval.

Results: The final cohort included 833 patients with a mean age of 51.3±11.3 years (range, 22-89 years), and 191 (22.9%) of them were aged >60 years. Patients aged ≥60 years had worse overall survival (OS) and distant disease-free survival than those aged <60 years. Although no difference was observed in the tumor biology, elderly patients showed significant differences in practice patterns: they tended to undergo mastectomy (40.2% vs 62.8%, <0.001), did not receive the standard chemotherapy (88.4% vs 69.3%, < 0.001), and had a higher risk of developing second primary cancer or diseases other than breast cancer (1.2% vs 6.8%, < 0.001), which significantly correlated with poor survival in elderly patients.

Conclusion: Less-than-the-standard treatment of care or development of a second primary disease resulted in poor prognosis in elderly patients in Korea. A multi-institutional and multinational study is warranted to elucidate the clinical features of breast cancer in Asian patients.