Clinico-pathological Features and Treatment Patterns of Primary Breast Cancer in Older Women in Hong Kong, with Comparison to Their Younger Counterparts

Abstract

Introduction: Breast cancer in older women is frequently considered less aggressive when compared with that in younger women. Objectives: To compare the clinico-pathological features and treatment patterns in two age groups (age ≥70 and <70). Methods: As part of a UK-Hong Kong research program on the effect of age and ethnicity on biology and clinical outcome of breast cancer, we retrospectively reviewed a consecutive series of Chinese female patients, with available surgical tumor samples, T1-4N0-2M0 breast carcinoma treated with primary surgery, between 2000-2005, and referred for adjuvant treatment and follow up at the Departments of Clinical Oncology of two teaching hospitals (Queen Mary Hospital and Pamela Youde Nethersole Eastern Hospital) in Hong Kong. Results: Total 783 patients were included (20% aged ≥70; 80% <70) with a mean follow-up of 132 months. No differences were seen in T and N stages, ER/PR and HER-2 status in both age groups. More older patients underwent mastectomy (87.3% versus 80.4%, p=0.046), with no differences seen in the type of axillary surgery. Adjuvant chemotherapy (8.9% versus 58.2%, p<0.0001) and radiotherapy (30.0% versus 57.1%, p<0.0001) were less often used in the older age group. At 10 years, there remained no difference in local or distant recurrences between the two groups. Both of which had similar breast cancer specifi c survival (BCSS) (older versus younger: 76.8% versus 77.9%, p=0.285). The older group had a shorter overall survival (OS) (51.1% versus 75.6%, p<0.001). Conclusions: Some differences in treatment pattern have been observed between the two groups. The difference in OS in the older population may in part be explained by competing causes of death. The lack of differences in clinico-pathological features and BCSS compared to what is often seen in the Western literature, suggests there may be possible differences in tumor biology in Chinese breast cancer. Further work is ongoing to investigate this.