Special CME Issue - West Virginia State Medical Association

vigorous activity could slow the
progression of prostate cancer and
might be recommended to reduce
mortality from prostate cancer.
A more recent report 18 reviewed
the results from 40 epidemiological
studies evaluating the effects of
physical activity/exercise on the
prevention of prostate cancer.
Fourteen of the studies showed no
relationship between exercise and
the development of prostate cancer,
while four showed an increased risk.
The remaining 22 studies showed that
exercise reduced the risk of prostate
cancer in study participants. Richman
et al studied the effect of vigorous
activity on disease progression. 19
In 1,455 patients diagnosed with
prostate cancer, men who walked
briskly for 3 hours or more per week
had a 57% lower progression rate
than those who walked at a lower
intensity (p = 0.03). They also report
that walking pace significantly
decreased progression regardless
of duration (p = 0.01). The authors
concluded that brisk walking after
the diagnosis of localized prostate
cancer may delay or inhibit the
risk of prostate cancer progression.
Similar results were observed in a
9-year prospective study conducted
by the American Cancer Society
Cancer Prevention Study II Nutrition
Cohort. Of the 72,174 men in the
cohort (all cancer-free at enrollment),
5,503 developed prostate cancer
during the course of the study. 20
Results indicated that there was a
reduced risk of aggressive prostate
cancer development in those
men most physically active.
The Impact of Exercise on Patients
Undergoing Androgen Deprivation
Therapy for Prostate Cancer
Androgen deprivation therapy
(ADT), a common treatment for
men with prostate cancer, reduces
testosterone production and causes
side effects that negatively impact
quality of life and reduce physical
functionality. 21 Fat gain and bone/
muscle loss are common physical
changes noticed during ADT. Studies
have shown that exercise may
improve treatment-related toxicities
of ADT in patients with prostate
cancer. 22 Galvao et al examined the
combination of resistance and aerobic
exercise for 12 weeks in 57 men with
prostate cancer that were undergoing
ADT. The study results indicated
that with exercise, lean mass and
muscle strength increased, physical
function and balance improved
when compared to patients that were
randomized to usual care. 23 Keogh
et al also evaluated the impact of
exercise on prostate cancer through
a systematic review of 12 training
studies. This study also suggested
that an exercise program may
improve muscle mass, strength, and
functional performance. Muscle and
aerobic endurance also improved
as did the overall quality of life. 12 In
addition to the reported literature
above, Galvao et al investigated the
effect of exercise on acute and chronic
exposure to ADT in 50 men for nonbone
metastatic prostate cancer. The
investigators concluded that during
acute exposure of ADT of less than
6 months, an increase in total body
fat and triglycerides were observed;
however, the benefits of exercise of
improved muscle strength, muscle
function and cardiorespiratory
function were similar regardless of
the duration of ADT exposure. 24
Effects of Exercise in Patients
Receiving Radiotherapy
for Prostate Cancer
Fatigue is one of the most common
side effects associated with radiation
therapy for the treatment of prostate
cancer. Other common short-term
side effects include nausea, diarrhea,
urinary frequency due to bladder
inflammation, painful urination, and
skin soreness at the site of treatment.
Many patients who receive radiation
therapy will also develop erectile
dysfunction. Erectile dysfunction
usually occurs 6 to 12 months after
treatment and is due to blockage of
the penile arteries and decreased
circulation of blood to the penis.
The effects of exercise training
on acute radiation toxicity were
evaluated in 66 patients undergoing
external beam radiotherapy for
cancer of the prostate. 25 Participants
were randomized to a control group
or to an exercise group which was
asked to walk for thirty minutes,
three times a week. After four weeks
of external beam radiotherapy,
the investigators observed a trend
towards lower rectal toxicity in the
exercise group and a significant
decrease in overall toxicity scores
during therapy (p =0.004). Exercise
has also been reported to reduce
the fatigue associated with external
beam radiotherapy for localized
prostate cancer. 26 After 4 weeks of
radiotherapy, patients in the control
group experienced significant
Table 1. Possible Mechanisms
for Exercise to Benefit Prostate
Cancer Patients
• Improve immune function
• Reduce obesity
• Regulate body weight
• Improve cardiovascular function
• Reduce inflammation
• Reduction of fatigue
• Possible reduction of side effects
from prostate cancer therapies
increases in reported fatigue scores
(p = 0.013), while patients in the
exercise groups exhibited no such
increase. The Prostate Cancer
Radiotherapy and Exercise Versus
Normal Treatment Study examined
the effects of 24 weeks of resistance
training or aerobic training compared
to standard care. 27 After 24 weeks of
training, both resistance (p = 0.01)
44 West Virginia Medical Journal