/PRNewswire/ -- For the first time ever, surgeons who operate on men with prostate cancer have results from a large study to backup what many suspected all along: minimally-invasive methods to remove the prostate pose fewer post-surgical complications, present less need for blood transfusion and allow men to leave the hospital sooner. More importantly, given the large sample of more than 78,000 men, researchers also were able to determine a statistically lower chance of postoperative death within 30 days after minimally invasive surgery compared to open surgery.

But researchers also found something they didn't expect: complications increased over time for the traditional open procedure.

The study is published in the April 2012 issue of European Urology.

"This study is noteworthy because we looked at data from 100% of Medicare patients in the United States, not in just one hospital or one geographic area," said study first author Keith Kowalczyk, M.D. of MedStar Georgetown University Hospital, who performed the study with Jim C. Hu, M.D., MPH of the Department of Urology at the David Geffen School of Medicine at UCLA. "So these results reflect what's really happening in communities across America today, not just in high volume academic centers where most of our data comes from. Also, since the numbers were provided by the Center for Medicare Services, we were able to look at a larger number of patients than previous studies. That enabled us to detect statistically significant differences in outcomes between the two methods that earlier studies might not have captured," said Dr. Kowalczyk.

Complications included respiratory, cardiac, surgical and genitourinary, including urinary tract infections, kidney infections, kidney obstructions and bladder problems.

The study looked at 78,232 men over the age of 65 who had their prostate removed due to prostate cancer between 2003 and 2007. Minimally invasive radical prostatectomy (MIRP) was performed on 19,594 men using either laparoscopy or robotic technology like the da Vinci robotic system; open retropubic radical prostatectomy (RRP) was used in 58,638 men.

At the beginning of the time period studied, minimally invasive techniques were performed in fewer than 5-percent of cases but rose to being used 44.5-percent of the time.

By contrast, use of the standard procedure decreased from 89.4-percent in 2003 to 52.9- percent by 2007.

"In the minimally invasive (MIRP) group over time, genitourinary complications and the need for blood transfusions decreased, perhaps signaling that surgeons were becoming more comfortable and increasingly successful with new robotic procedures," said Dr. Kowalczyk.

While complications decreased with the minimally invasive procedure over time, in the group having traditional open surgery complication risks increased from 27.4 percent to 32 percent and included a significant increase in post-surgical death from 0.5 percent to 0.8 percent. Overall, men undergoing the minimally invasive procedure had a 0.2 percent risk of post-surgical death vs. a 0.6% risk in men undergoing the open procedure. Although the risk of death in both groups was quite small, this was still a statistically and potentially clinically significant difference between the two groups.

"We expected to see fewer complications as surgeons got more comfortable with minimally invasive procedures like robotics, but it remains somewhat of a mystery why the complication rates rose in the open surgery group. We statistically controlled for factors such as patient age and medical history, however men undergoing the open procedure were still more likely to experience more postoperative complications and mortality compared to the minimally invasive procedure. We think this warrants more study," said Dr. Kowalczyk.

"The bottom line is that seeing an experienced surgeon is probably the most important variable when planning a safe and effective strategy to treat prostate cancer," Dr. Kowalczyk said.