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Gabriel M Leung, MD, MPH, Tai-Hing Lam, MD, MSc, Thuan Q. Thach, PhD and Anthony J. Hedley, MD

The authors are with the Department of Community Medicine, University of Hong Kong Medical Centre, Hong Kong, China.

Correspondence: Requests for reprints should be sent to Gabriel M Leung, MD, MPH, Department of Community Medicine, Faculty of Medicine Bldg, University of Hong Kong, 21 Sassoon Rd, Pokfulam, Hong Kong, China (e-mail: gmleung{at}hku.hk).

We agree with Tseng and Fang’s extrapolation of our calculations to Asian Americans but differ on their interpretation of the results. First, while Asian Americans suffered fewer breast cancer–related deaths, their mortality rates relative to incidence for women aged 50 years and older in 1996 (32.7/126.4 per 100 000 = 0.26) were in fact higher than those reported for Whites (78.2/367.4 per 100 000 = 0.21).¹

Second, their assertion that "any cancer death resulting from late detection is one that should have been prevented" is misleading. There are 2 kinds of early detection in cancer control. Screening of asymptomatic individuals is one strategy. There is evidence that shows breast self-examination in well women does not reduce mortality,² and the literature is controversial regarding whether mass mammography screening benefits White populations.³ The other type of early detection—prompt recognition of symptoms, quick access to health care, and early diagnosis—followed by optimal treatment⁴ may hold much greater promise in reducing breast cancer mortality.

Third, we concur that the effects of Westernization have led to increased breast cancer incidence in Asian populations,⁵ but the absolute rates remain less than one half to one third the corresponding rates for White Americans. Ethnicity and place of origin of Asian Americans therefore need to be taken into account in the overall assessment of risk for breast cancer, just as age, family history, and past history of breast pathology are included. While a "wholesale relaxation of guidelines" for Asian Americans may be unwarranted, disregarding both lack of benefit and harm from screening mammography is unethical. However, we agree that we must remain vigilant in monitoring breast cancer trends and be prepared to reevaluate the current recommendations if and when significant changes occur.

We agree that research should be directed at identifying factors responsible for the different risks in Western versus Asian women. Preliminary data⁶ support the hypothesis that hormone-dependent malignancies have their origin in intrauterine life, where higher levels of pregnancy hormones favor the generation of more susceptible stem cells with compromised genomic stability. This may be linked to the observation that it takes more than 2 generations for the incidence of breast cancer in Asian immigrants to the West to reach the higher rates prevailing in the host population. Future research should focus on lifestyle or other environmental determinants of pregnancy hormone levels and possible mechanisms by which they may influence carcinogenesis.

All screening potentially causes harm. Indiscriminate mass screening of well people at low risk for the disease can cause large-scale harm. Clinicians and public health providers must heed Hippocrates’ dictum—Primum non nocere.

References

1. National Cancer Institute. SEER incidence and US mortality statistics. Available at: http://seer.cancer.gov/canques. Accessed December 17, 2002.

2. Thomas DB, Gao DL, Ray RM, et al. Randomized trial of breast self-examination in Shanghai: final results. J Natl Cancer Inst. 2002;94:1445–1457.[Abstract/Free Full Text]

3. National Cancer Institute. PDQ cancer information summaries: screening/detection for breast cancer. Available at: http://www.nci.nih.gov/cancer_information/doc_pdq.aspx?version=1&summaryid=208_04723. Accessed December 17, 2002.

4. Gillis CR, Hole DJ. Survival outcome of care by specialist surgeons in breast cancer: a study of 3786 patients in the west of Scotland. BMJ. 1996;312:145–148.[Abstract/Free Full Text]

5. Leung GM, Thach TQ, Lam TH, et al. Trends in breast cancer incidence in Hong Kong between 1973 and 1999: an age-period-cohort analysis. Br J Cancer. 2002;87:982–988.[ISI][Medline]

6. Lipworth L, Hsieh CC, Wide L, et al. Maternal pregnancy hormone levels in an area with a high incidence (Boston, USA) and in an area with a low incidence (Shanghai, China) of breast cancer. Br J Cancer. 1999;79:7–12.[ISI][Medline]

This Article Extract Full Text (PDF) Submit a response Purchase Article View Shopping Cart Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services Similar articles in this journal Similar articles in ISI Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Leung, G. M Articles by Hedley, A. J. Search for Related Content PubMed Articles by Leung, G. M Articles by Hedley, A. J. Related Collections Cancer Asians Screening Immigration Women's Health