Cancer Epidemiology and Large Randomised Trials
Previous and current research
One of the major research interest of our group is the
assessment of some of the widely practicable treatments for
cancer, by obtaining large-scale randomised evidence either
through overviews of previous trials or by conducting large
randomised trial, involving many hundred hospitals. A number
of large cancer trials are under way in China, including one
with 7 days of portal-vein infusion with 5-FU among 11,000
colorectal cancer patients and one with ovarian ablation among
3500 early breast cancer patients.
Another main research area is large epidemiological studies
in China assessing the health effects of smoking, alcohol
drinking, tea drinking, indoor air pollution, blood pressure,
lung function and blood lipids on cancer and various other
chronic diseases. These include a large nationwide retrospective
study of one million Chinese deaths in 1986-88 and the nationwide
prospective study of 250,000 Chinese adults that began in
1991. These studies indicated that although the pattern of
disease produced by tobacco is very different from that in
countries such as the United States and the United Kingdom
(the chief risks produced in Chinese smokers being death from
cancer, respiratory disease rather than vascular), the overall
magnitude of the hazard is already substantial even at an
early stage of tobacco epidemic.
Future projects
All patients entered into two large trials will be followed
up for at least five years for the assessment of long-term
survival. In colorectal cancer trial with portal-vein infusion,
1000 pairs of normal and cancer tissue samples have been collected.
This will provide a unique opportunity to evaluate the value
of the known molecular features as prognostic markers (such
as p53, K-ras and HNPCC mutation, etc). We intend to
examine if, in China where the incidence of colorectal cancer
is still very low, the frequencies of those mutations are
similar to that reported in Western populations. We also intend
to explore the relationship between certain types of mutation
and long-term survival.
On epidemiological side, further detailed
analyses will be undertaken to examine the relationship of
smoking, alcohol drinking, indoor air-pollution and various
other factors with total and cause specific mortality. Deaths
in the large prospective study will be actively monitored
for the next 5, 10 and 15 years to assess the evolution of
tobacco epidemic.
