Robotic laparoscopic radical prostatectomy found viable in obese men

February 1, 2012

Obesity should not preclude a patient from undergoing robot-assisted laparoscopic prostatectomy (RALP), but these men may require more time for the procedure.

Key Points

Instead of avoiding obese patients, the authors of a recent study explain, surgeons can tailor the procedure and achieve the same results they see in normal-weight patients.

"It is no secret that in the United States, obesity is quite prevalent," said co-author Carson Wong, MD, who was associate professor of urology at Oklahoma University Health Sciences Center, Oklahoma City, when the study was conducted.

Obesity may not be an exclusion criterion, but obese patients do pose special challenges, Dr. Wong cautioned during a surgical forum at the 2011 American College of Surgeons Clinical Congress in San Francisco. Excessive fat is a surgical obstacle, one that can be removed to achieve a successful prostatectomy.

The investigators divided their patients into three groups based on BMI. Normal-weight patients had a BMI of less than 25 kg/m2 , overweight patients had a BMI of 25 kg/m2 to less than 30 kg/m2 , and obese patients had a BMI of 30 kg/m2 and higher. BMI was the only statistically significant parameter that was different among the three patient groups, Dr. Wong said. Patient age, serum PSA, prostate volume, quality of life scores, clinical stage, Gleason score, and other factors were similar.

Higher BMI linked with longer OR time

Intraoperative parameters were also similar among the three groups with one exception: Higher BMI was associated with longer operative times. The normal-weight group had a mean operative time of 185 minutes compared to 197 minutes for the overweight group and 215 minutes for the obese group. Pathologic stage, Gleason score (including upgrading or downgrading), positive margin rate, prostate volume, and other parameters were similar.

Clinical outcomes were also similar among the three groups, including length of hospital stay (1 day), urethral catheter duration (5 to 6 days), pad use per day at 6 weeks (about 1.2), time to urinary continence (10 weeks), and potency at 12 months (51%-60%).

"We are very aggressive on penile rehabilitation," Dr. Wong said. "We provide every man a vacuum erection device daily and a PDE-5 inhibitor three times a week."

There were few adverse events in any of the groups and no serious events in the cohort.

The published literature on RALP in overweight and obese men is conflicting, Dr. Wong noted. Most studies report longer operative time and greater blood loss, although his group did not see any difference in blood loss. A problem, he said, is that obese patients have excessive intraperitoneal and pelvic fat. Excess fat can result in difficult visualization of the operative field, reduced space for instrument manipulation, and difficulties in surgical dissection.

Excess fat can be managed with careful port placement and longer trocars, Dr. Wong said. A key to successful RALP in obese patients is similar to that for open prostatectomy in obese patients: complete dissection and removal of the peripostatic fat.

"Defatting the prostate is key," he said. "You start near the bone where the dissection plain is clear and simply peel the fat away. Once the fat around the prostate is removed, you can visualize the anatomic landmarks, manipulate the robot instruments, and dissect the surgical planes."