Detection of breast cancer improves
Government urged to introduce screenings
Breast screening in Hong Kong has become acceptable and comparable to international standards, and it might be time for the government to consider population-based screening, initially for high-risk women, doctors say.
Based on some 46,000 mammograms from 1998-2002, the detection of cancer, the ability to detect cancer early and cancer detection in the high-risk group were 'all considerably better' than the previous 10 years, said radiologists at the Kwong Wah Hospital-based mammogram programme, the largest in the city.
The screening programme was launched in 1991 at three well-woman clinics in Kwong Wah and Tung Wah Eastern hospitals, in which women in the appropriate age groups can pay HK$700 to undergo a mammogram. Hong Kong does not have population-based screening, in which women in target groups are invited to have checks.
Experts are divided over the cost-effectiveness of mammography because the incidence of breast cancer is relatively low compared to the rate in the west. But breast cancer remains the No1 cancer affecting women, and its incidence has been increasing since 1995.
There were 2,273 new cases and 454 deaths in 2004, the latest Cancer Registry figures show. One in 22 women has a cumulative lifetime risk of getting it, with the median age of new cases standing at 52.
In what is arguably the first study of the beneficial effects of mammography, Kwong Wah radiologists said the test was well-accepted and their programme could be a model for breast screening in Hong Kong, while serving as a training ground for breast radiologists and mammographers.
'All these are essential prerequisites for the introduction of population screening,' the doctors wrote in last month's issue of the Hong Kong Medical Journal.
The Kwong Wah experience 'confirms that screening of high-risk women is definitely warranted', the authors said.
A total of 46,637 mammograms were conducted at the three well-woman clinics at Kwong Wah and Tung Wah Eastern hospitals from 1998-2002.
The study found that five in 1,000 women had breast cancer, compared to the international standard of two to 10 per 1,000, said Lui Chun-ying, associate consultant at Kwong Wah Hospital's radiology department. It also found that 45 per cent of those detected were 'minimal cancers'.
'The invasive component of the cancer is less than 1cm,' Dr Lui said. 'That is important because the patient has better prognosis. There are many more treatment choices with less trauma and less morbidity.'
The study is continuing, with the team collecting mammogram data - from 2002 up to the end of the year - of women who had undergone the checks every two years, and will comprise previously screened and newly screened women, said Lam Hon-shing, radiology chief of the Hospital Authority's Kowloon West Cluster.
Dr Lam said the study showed 'the mammography programme is well-accepted by oriental women'.
'That means they are willing to screen despite the discomfort of mammography. This is reflected in our long waiting time of one to two years,' Dr Lam said.
'Secondly, we do detect some cancer early, which is good for those women,' he said. 'Detection of large cancers may not be beneficial, but detection of very small cancers will be very beneficial.'
He added it would be up to the government and the authority to decide how screening should proceed.
Experts have argued that because the breasts of Asian women are dense - as opposed to westerners' fatty breast tissue - mammography might not be as sensitive, said Dr Lam. 'But we find the detection rate is comparable to international standards.'