Obesity linked to prostate cancer aggressiveness, recurrence

Obesity increases the risk for higher grade prostate cancer and higher recurrence rates after radical prostatectomy, two research groups report. Both propose that obesity may at least partially explain the racial disparity in prostate cancer outcomes.

Epidemiologic studies have been inconsistent in showing a relationship between obesity and prostate cancer, the two teams note in a December 22 online release from the Journal of Clinical Oncology. In fact, obesity seems to be a stronger risk factor for prostate cancer mortality than incidence.Dr. Christopher L. Amling, at the Naval Medical Center in San Diego, and colleagues evaluated data for 3162 patients who underwent radical prostatectomy between 1987 and 2002, as documented in the Center for Prostate Disease Research database. Nineteen percent of the cohort was obese, as defined by a body mass index of 30 kg/m? or above. Obesity was associated with a median PSA of 6.3 versus 6.1 in the non-obese group (p = 0.027), higher Gleason score (p = 0.003), incidence of positive surgical margins (p = 0.007), and biochemical recurrence rate (p = 0.027).Compared with white men, black men presented with cancer at younger age and with tumors of higher grade and stage. They were also significantly more obese. In multivariate analysis, black race but not BMI remained a significant independent indicator of cancer recurrence.Meanwhile, the Shared Equal Access Regional Cancer Hospital (SEARCH) database Study Group, led by Dr. Stephen J. Freedland at Johns Hopkins School of Medicine in Baltimore, also reports that black men had significantly higher mean BMI than white men. Included in the analysis were 1752 patients treated with radical prostatectomy between 1988 and 2002. Of note, the incidence of obesity approximately doubled over the last decade of the study.Obese patients were younger and had higher biopsy and pathologic Gleason scores, Dr. Freedland and associates report. The risk for PSA failure was significantly increased for those with BMI of 35 kg/m? (p = 0.002). Multivariate analysis showed that obesity, but not race, was independently associated with disease recurrence.”Given the disproportionate burden of [prostate cancer] on black men, programs targeted to control obesity in the black community may be warranted,” they suggest.In an editorial, Dr. Alfred I. Neugut and colleagues at Columbia University in New York note that obesity, while not a consistent risk factor for prostate cancer incidence, is consistently associated with prostate cancer mortality.”In light of the increasing worldwide incidence of obesity, the identification of obesity as a risk factor for aggressive prostate cancer is important because it may be one of the few modifiable risk factors for prostate cancer,” they maintain.(Source: J Clin Oncol 2004;22: Reuters Health: December 22, 2003: Oncolink)