Young Women with Breast Cancer in the United States and South Korea: Comparison of Demographics, Pathology and Management

Background: Breast cancer diagnosed in young women may be more aggressive, with higher rates of local and distant recurrence compared to the disease in older women. Epidemiologic evidence suggests that Korean women have a lower incidence of breast cancer than women in the United States, but that they present at a younger age than their American counterparts. We sought to compare risk factors and management of young women with breast cancer in Boston, Massachusetts (US) with those in Seoul, South Korea (KR). Materials and Methods: A retrospective review was performed of consecutive patients less than 35 years old with a diagnosis of breast cancer at academic cancer centers in the US and KR from 2000-2005. Patient data were obtained by chart review. Demographic, tumor and treatment characteristics were compared utilizing Pearson's chisquare or Wilcoxon rank-sum tests where appropriate. All differences were assessed as significant at the 0.05 level. Results: 205 patients from the US and 309 from KR were analyzed. Patients in US were more likely to have hormone receptor positive breast cancer, while patients in KR had a higher rate of triple negative lesions. Patients in US had a higher mean body mass index and more often reported use of birth control pills, while those in the KR were less likely to have a sentinel node procedure performed or to receive post mastectomy radiation. Conclusions: Patients under 35 diagnosed with breast cancer in the US and KR differ with respect to demographics, tumor characteristics and management. Although rates of breast conservation and mastectomy were similar, US patients were more likely to receive post mastectomy radiation. The lower use of sentinel node biopsy is explained by the later adoption of the technique in KR. Further evaluation is necessary to evaluate recurrence rates and survival in the setting of differing disease subtypes in these patients.