Weight History Sheds Light on Prostate Cancer

Obesity a Factor in Predicting Disease Progression

A man's weight at the time he is diagnosed with prostate cancer, as well as his history of weight gain, appear to play significant roles in whether his cancer will return or progress, according to a new study.

A link between weight and initial development of prostate cancer has been made previously. However, this report by M. D. Anderson researchers, published in the Oct. 1 issue of Clinical Cancer Research, is the first to associate weight at different ages and adult weight gain with the risk of progression after prostatectomy (surgical removal of part or all of the prostate gland).

"After surgery, a patient's PSA (prostate specific antigen) level, should go back to being undetectable, but if it begins to rise, that is 'biochemical failure', an indicator of progression," says the study's lead researcher Sara Strom, Ph.D., an associate professor in the Department of Epidemiology at M. D. Anderson. "Thirty percent of men who have biochemical failure will develop a life-threatening cancer metastasis (spreading of the disease), and PSA is the only marker we have as yet to predict whose cancer will spread."

Weight and age influence timing of biochemical failure

In the study, researchers monitored 526 M. D. Anderson prostate cancer patients for an average of 4 years after prostatectomy, and found that 18% of the patients experienced biochemical failure. Researchers then correlated an individual's risk of experiencing that failure with his weight history.

They looked at:

Obesity at diagnosis- Patients with a body mass index (BMI) of 30 or more when they were diagnosed with prostate cancer were more likely to experience biochemical failure than those who were not obese.

BMI is a measure of total body fat based on weight relative to height, according to the National Institutes of Health (NIH). A person with a BMI of at least 30 (about 30 pounds kg/m2) is considered obese.

Obesity at 40- Patients who were obese at age 40 had an even greater rate of biochemical failure.

Weight gain from age 25 to diagnosis- Patients who gained weight at the greatest rate between age 25 and the time of their diagnosis experienced disease progression significantly sooner (an average of 17 months) than those who gained weight more slowly (an average of 39 months).

Strom says it is unclear how obesity contributes to prostate cancer progression, although theories include links to hormone changes or poor lifestyle behaviors such as poor diet and inadequate physical activity. She adds that additional studies could lead to the creation of preventive strategies.

Given further validation of the results, Strom also suggests the possibility of:

New treatment plans- Oncologists may consider a man's weight when designing treatment plans for newly diagnosed patients.

Risk reduction strategies- Interventions such as diet and exercise could be used to help reduce the risk of prostate cancer progression.