Breast Cancer Perspective
In this issue of Oncology Forum, there are several articles focussing on the screening, diagnosis, and treatment of breast cancer. Epidemiological studies show that the incidence of breast cancer has increased in various Asian countries, including Hong Kong, Singapore, the Philippines, and China, during the past 20 years. Data from the Hong Kong Cancer Registry indicate that breast cancer overtook lung cancer in 1994 to become the most frequent cancer among Hong Kong women. The crude incidence rate per 100,000 Hong Kong women increased from 31.5 in 1978 to 48.8 in 1997. This increase is paralleled by the rise in the age-standardised incidence rate, which indicates that the increase cannot be fully accounted for by population growth and an increasing ageing population.
Risk factors for the development of breast cancer include genetic (familial) factors, history of irradi-ation to the breast, pre-existing proliferative breast pathology, dietary factors and prolonged oestrogen stimulation such as hormonal replacement therapy, nulliparity, early menarche, late menopause, and older primigravida. There is an article from Taiwan discussing the relationship of hormonal replacement therapy and breast cancer in the current issue. Cancer statistics show that the greatest increase in age-specific incidence rates was in the 30 to 49 years age group. It was postulated that the increase is due to a westernised diet, which includes alcohol and a higher proportion of fat, as compared with a traditional Asian diet. The 30 to 49 years cohort was born after the Second War World, after which Hong Kong became more affluent and westernised.
Early diagnosis improves the outlook for patients with breast cancer. Randomised clinical trials in western countries demonstrate that a screening programme using mammography and clinical breast examination reduces the breast cancer mortality by approximately 80%. Unfortunately, Asian data on the role of screening mammogram is lacking. Despite the recent rise in incidence of breast cancer, the cumulative lifetime risk for Hong Kong females is 1 in 24; approximately one-third that of Caucasians. This factor may reduce the cost-effectiveness of population wide screening and there is a paper addressing this argument in the current issue.
Promotion of public awareness and widespread use of a screening programme will increase the proportion of patients presenting with non-palpable breast lesions. This calls for advanced surgical procedures for histological diagnosis. The clinical experience of performing these advanced surgical procedures in the Chinese population in a regional hospital in Hong Kong is published in this issue.
The mortality rate of breast cancer in the USA and in European countries has been declining since 1990. This is attributed to the widespread use of screening programmes and adjuvant treatment. The Early Breast Cancer Trialists Collaborative Group have shown that adjuvant local (postoperative locoregional irradiation) and systemic (hormonal and chemotherapy) treatment can reduce the odds of recurrence of breast cancer by up to 50%. However, the optimal adjuvant treatment for various disease stages is not yet defined. Clinical trials to evaluate the role of new predictive factors such as Her-2 overexpression and new chemotherapeutics/hormonal agents are in progress. This issue contains a review of the treatment of breast cancer by Dr Hortobagyi.
The proportion of locally advanced disease may represent as much as 50% of all newly diagnosed breast cancers in developing countries and therefore poses a significant health care problem. The outlook for this patient group is poor despite the advent of effective systemic treatment. Dr Hortobagyi has written a treatment algorithm for the management of locally advanced disease, which requires close collaboration between surgeons, diagnostic radiologists, radiation oncologists, and medical oncologists.
To achieve the success obtained in western countries, promotion of public awareness, early diagnosis, optimal surgery, and widespread use of appropriate adjuvant treatments are essential. Setting up specialised centres that provide multidisciplinary services to patients with breast cancer is necessary for improving treatment results.
Dr WH Kwan
Consultant
Department of Clinical Oncology
Prince of Wales Hospital
Shatin, NT, Hong Kong
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