June 28 - 29, 2007 Advisory Committee Meeting
Dr. McTiernan reviewed issues surrounding cancer.
Because cancer is a common condition and only about 15% is familial,
lifestyle and environmental change are important factors. There most likely will
be significant overlap with other groups, even though other groups may not
realize it. Some mechanisms that may associate physical activity and cancer, if
there is an association, may be related to metabolic factors, hormones, and
Because there is a rich body of observational data on cancers the Committee
will have to realize up front that observational data in this area will be the
best source of data. Also, most of the data is on the most common cancers. For
other cancers it is important to understand there many not be much data at all.
For cancers where there may not be an effect of exercise or physical activity
on incidents of cancer, there still may be an important role in prognosis,
either the stage at which a cancer is developed, and one example would be
prostate cancer perhaps, or just once somebody gets the cancer, what's their
prognosis? While we are not talking about acute rehab for this issue, cancer
survivors of some type tend to be long-term cancer survivors with many years of
life left. Therefore, a recommendation for that group for lifestyle changes may
be of benefit.
Phase two of the literature review should include more mechanistic literature
searches, some of which will overlap with other groups. Mechanisms will be very
important to identify in order to come up with a potential prescription for
physical activity or exercise for cancer prevention or risk reduction.
A key question regarding cancer will be whether physical activity alone is
beneficial or whether weight control is an important part. Some of the data
suggest that for some cancers, physical activity may be most beneficial if the
individual keeps the weight down, but other studies may not find that.
Additionally, are there some subgroups that will benefit more from physical
activity than others?
In general, we should be looking at the associations for the main cancers as
well as what data exists on the less common cancers and try to come up with a
recommended prescription. Finally, we also need to address the cancer survivor