BY DOUGLAS SCHERR M.D.
Obesity is becoming an increasing concern with regard to prostate cancer treatment decisions as the number of patients with a Body Mass Index (BMI) of greater than 30 grows. While there hasn’t been conclusive study into the area, it has been generally found that obesity is a negative risk factor for prostate cancer.
Along with an increased risk of disease-related death, obesity has been linked to aggressive prostate cancer (NEngl J Med. 2003;348: 1625-1638). Increased BMI has also shown a positive correlation to Gleason score and positive surgical margins (e.g., JClin Oncol. 2004;22: 439-445; J Urol. 2005;174:919-922; and Urology.2005;66:1060-1065). This increase of positive surgical margins is critical as it can be an indicator for recurrence of the disease.
As a urologist, treatment options for obese patients are a crucial question. Prostate-specific antigen tests have been shown to be less effective and patients with high BMI’s receive nonsurgical therapies more frequently. If this is a result of physician bias or patient choice is unclear, but shows how obesity can affect both screening and treatment decisions.
It is important to note that this area of research suffers from a lack of data. Firstly, the studies from which these findings were drawn were done retrospectively and weren’t initially intended to compare obese and non-obese patient groups. Secondly, there hasn’t been a study comparing robotic prostatectomy and robotic-assisted laparoscopic prostatectomy across various BMI segments so the implication of high BMI on certain treatment options is mostly theoretical. Thirdly, the data on robotic prostatectomy must consider the physician experience with the procedure since there is a steep learning curve involved in the metrics used to evaluate its effectiveness.
Robotic prostatectomy as a treatment for prostate cancer has grown in popularity in the past eight years because of its minimally invasive nature. About half of all prostatectomies performed are robotically assisted and this number is expected to grow as doctors gain experience and familiarity with the procedure. In relation to obese patients, it is thought that with increased physician experience the differences in operating time, blood loss, and complication rate as compared with non-obese patients will diminish.
Even with the lack of research on the topic, physicians have to prepare to treat an increasing amount of patients with BMI’s meeting the World Health Organization standards for obesity. While findings are not fully conclusive it is clear that obese patients offer a different set of challenges as doctors try to tailor more effective treatment options.
Dr. Douglas Scherr works as the Clinical Director of Urological Oncology at the Weill Medical College of Cornell University in New York City. His work has been on urologic malignancies with specific focus on bladder and prostate cancer. Since 2002, Dr. Scherr has preformed over 500 robotic prostatectomies with the Da Vinci robotic system. For more information on robotic prostatectomies, visit www.robotic-prostatectomy.com.