A new study, led by an Indian-origin scientist, has shown that obesity increases risk of prostate cancer recurrence for both blacks and whites.
Study's lead author Jayakrishnan Jayachandran, M.D. a urologic oncology fellow at Prostate Medical Center, and colleagues examined the records of 1,415 men enrolled in the Shared Equal Access Regional Cancer Hospital (SEARCH) database who had undergone a radical prostatectomy. Black men comprised almost half (47 percent) of the sample.
After adjusting for various preoperative characteristics, researchers analyzed the relationship between body mass index (BMI) and the aggressiveness of the cancer, as measured by the risk of recurrence.
As compared to other studies, investigators found no association between race and obesity.
Almost a third of the men were obese, regardless of race.
"We found that higher BMI was associated with significantly increased risk of cancer recurrence for both blacks and whites," Jayachandran said.
"Though prior SEARCH-based studies from our group found that obesity was associated with a higher risk of disease progression as measured by a rising PSA after surgery, it now appears that being obese just means a poorer prognosis, period, regardless of race," Jayachandran added.
As for why that might be, Jayachandran says he's not sure, but he says it may have something to do with altered hormone levels.
"Obesity is associated with more estrogen and less testosterone, and it may be that lower testosterone promotes more aggressive tumours as recent studies have suggested," Jayachandran said.
Also, Jayachandran says alteration in the production of other hormones, like insulin, insulin-like growth factor or leptin, which occur in obese men, may also be involved in the development of more aggressive tumours.
"This is something we simply do not understand, but we are actively studying all of these factors," Jayachandran said.