Abstract

A mini-symposium was held in Montreal, Canada, at the International Surgical Week for the Breast Surgical International in 2007 addressing the question whether breast cancer is the same disease in Asian and Western countries. Numerous investigators from Asian and Western countries presented the epidemiologic and clinical outcome data of women with breast cancer. Although there are significant similarities, the striking difference is that the peak age for breast cancer is between 40 and 50 years in the Asian countries, whereas the peak age in the Western countries is between 60 and 70 years. Also, the incidence of breast cancer in Asia is rising and is associated with increased mortality. In the West, although the incidence is increasing, the mortality rate is definitely decreasing. Future prospective data collection from Asian and Western countries may provide further interesting epidemiologic and outcome data regarding the outcome of women with breast cancer from Asian and Western countries.

Background

Whether breast cancer is the same disease in Asian and Western countries was the topic of a 2007 Breast Surgery International symposium at International Surgical Week.

Methods

Participating investigators from China, Taiwan, India, Japan, South Korea, Sweden, Canada, and the United States were asked beforehand to provide data on the epidemiology and treatment outcome of women in their countries.

Results

Comparisons of the epidemiologic and clinical outcome data of women with breast cancer showed significant similarities, but the striking difference is that the peak age is between 40 and 50 years in Asian countries, but is between 60 and 70 years in Western countries. The incidence of breast cancer in Asia is rising and is associated with increased mortality. In the West, although the incidence is also increasing, the mortality rate is definitely decreasing.

Discussion

Future prospective data collection from Asian and Western countries may provide further interesting epidemiologic and outcome data regarding the outcome of women with breast cancer from Asian and Western countries.

Introduction

Adjuvant breast cancer therapy significantly improves survival, but overtreatment and undertreatment are major problems. Breast cancer expression profiling has so far mainly been used to identify women with a poor prognosis as candidates for adjuvant therapy but without demonstrated value for therapy prediction.

Methods

We obtained the gene expression profiles of 159 population-derived breast cancer patients, and used hierarchical clustering to identify the signature associated with prognosis and impact of adjuvant therapies, defined as distant metastasis or death within 5 years. Independent datasets of 76 treated population-derived Swedish patients, 135 untreated population-derived Swedish patients and 78 Dutch patients were used for validation. The inclusion and exclusion criteria for the studies of population-derived Swedish patients were defined.

Results

Among the 159 patients, a subset of 64 genes was found to give an optimal separation of patients with good and poor outcomes. Hierarchical clustering revealed three subgroups: patients who did well with therapy, patients who did well without therapy, and patients that failed to benefit from given therapy. The expression profile gave significantly better prognostication (odds ratio, 4.19; P = 0.007) (breast cancer end-points odds ratio, 10.64) compared with the Elston–Ellis histological grading (odds ratio of grade 2 vs 1 and grade 3 vs 1, 2.81 and 3.32 respectively; P = 0.24 and 0.16), tumor stage (odds ratio of stage 2 vs 1 and stage 3 vs 1, 1.11 and 1.28; P = 0.83 and 0.68) and age (odds ratio, 0.11; P = 0.55). The risk groups were consistent and validated in the independent Swedish and Dutch data sets used with 211 and 78 patients, respectively.

Conclusion

We have identified discriminatory gene expression signatures working both on untreated and systematically treated primary breast cancer patients with the potential to spare them from adjuvant therapy.