There is already a body of scientific evidence demonstrating that obesity is linked to treatment failure after prostatectomy. However, there are no data on the effects of obesity on the effectiveness of radiation treatment for prostate cancer. Sara Strom, Ph.D. of the University of Texas M. D. Anderson Cancer Center in Houston and colleagues reviewed the medical records of 873 patients who received radiotherapy alone for prostate cancer. Among the group, 18 percent were mildly obese and 5 percent were moderately to severely obese.
After an average 96 months of follow-up, 295 of the men had three consecutive increases in blood PSA, indicating biochemical failure. Meanwhile, 127 of the men had clinical failure (local recurrence and/or distant metastasis) determined by radiologic studies, biopsy, or physical examination. On analysis, risk of biochemical and clinical failure were influenced by BMI. As BMI increased, the risk of disease progression following therapy also increased. For example, men who were moderately or severely obese were at double the risk for biochemical failure than other men who were not.
The authors conclude, "our findings validate the importance of obesity in prostate cancer progression and suggest a link to the biology of this tumour." To understand the influence of obesity on treatment and possibly exploit that understanding to improve treatment outcome, "future studies should evaluate the relationship of obesity with dietary factors, genetic modifiers of steroid androgen metabolism, insulin, and a detailed investigation of the insulin growth factor pathway to explore the underlying mechanisms of action in prostate carcinogenesis," suggest the authors.
MEDICA.de; Source: John Wiley & Sons, Inc.