Obesity Increases Prostate Cancer Recurrence
Obesity is known to predict prostate cancer progression in men who undergo radical prostatectomy, or complete surgical removal of the prostate gland, Dr. David Palma and colleagues from the British Columbia Cancer Agency, Vancouver, Canada, pointed out.The researchers therefore examined whether obesity is associated with outcome for patients who undergo external beam radiation therapy for prostate cancer.
Overweight men risk having their cancers overlooked by doctors who are analyzing PSA test results, as overweight men were found to have as much as 30 percent lower PSA levels at the same or higher risk of cancer. Because the size of the prostate gland is larger in obese men, prostate cancer can be 20 percent to 25 percent harder for doctors to detect. Because biopsies sample less of the total tissue in a larger prostate, it’s harder to spot hidden cancer.
Cancer, researchers found that moderately and severely obese patients had a 99 percent greater risk of developing biochemical failure (an early marker of cancer progression) than other patients. The study also reports that obese patients had a 66 percent increased risk of having a tumor that recurs or becomes metastatic than did non-obese patients.
The implication is that prostate cancer patients who are obese should probably be followed more closely than patients with similar cancer characteristics who are not obese. That could include regular digital rectal exams, more frequent prostate-specific antigen (PSA) testing, and perhaps setting a lower PSA cutoff point as an indication of recurrence. The greater risk associated with obesity may be related to technical issues. For example, it’s more difficult for surgeons to perform a radical prostatectomy in obese patients.
Recent studies have suggested that obesity is an adverse risk factor for recurrence of prostate cancer after prostatectomy. Obesity has been associated with higher-grade tumors, a trend toward increased risk of positive surgical margins, and higher biochemical failure rates. One study has also shown that earlier.
A connection to obesity may help explain a racial difference in prostate cancer that has long puzzled researchers: the disease tends to occur at a younger age in black men in the United States than in whites, and is more aggressive and twice as likely to be fatal. In the two studies, blacks had higher rates of obesity than whites, a finding that the researchers said might account for much of the racial disparity in the severity of the disease.
The positive effects of combining anti-androgen therapy to vaccine “may be because the vaccine acts to ‘prime’ the immune system, and when you add the hormone treatment, it allowed the vaccine to work even better,” “Our study indicates there may well be a synergy between immunotherapy with vaccines and hormone deprivation.”
