Surgeons who perform the highest number of prostatectomies -- prostate removal to help stop cancer -- tend to have the best patient outcomes, a new study confirms.

In fact, it takes at least 250 operations before a surgeon becomes proficient in the procedure, researchers found. With more experience, the odds that the patient's cancer will come back declines, according to the report in the July 24 issue of the Journal of the National Cancer Institute.

"Your chance of being cancer-free after surgery for prostate cancer are strongly influenced by the amount of experience that your surgeon has," said lead researcher Andrew Vickers, from Memorial Sloan-Kettering Cancer Center in New York City.

Patients with prostate cancer need to be seen by an experienced surgeon, Vickers advised. In reality, "many patients are seen by surgeons with very low levels of experience," he said. "Many surgeons do as few as one prostatectomy a year -- they are never going to get experienced," he said.

Vickers noted that, at Sloan-Kettering, some surgeons only perform prostatectomies. This often means that "the only patients they see are the ones that are candidates for prostatectomy," he said.

In the study, Vickers and colleagues looked at data from 72 surgeons drawn from four major U.S. academic cancer centers. The researchers included almost 7,800 prostate cancer patients who underwent radical prostatectomies between 1987 and 2003.

Vickers's team found that more experience was linked with a greater likelihood that the patient's cancer would not return. In addition, they found that the learning curve was steep. Improvement in patient outcome dramatically increased for doctors once they had done at least 250 operations.

For example, patients whose doctor had done only 10 operations had a 70 percent increase in having their cancer return within five years compared with surgeons who had performed 250 or more prostatectomies. With inexperienced surgeons, 17.9 percent of patients had a recurrence of cancer, compared with 10.7 percent of patients whose surgeons had performed 250 or more prostatectomies, the researchers found.

Patients who need a prostatectomy should have it done at a teaching hospital or specialized cancer center, Vickers said. "In general, patients do better seeing surgeons who see a lot of these cases and in hospitals who do a lot of these cases," he said.

Hospitals that do a lot of prostatectomies usually have the most experienced surgeons on staff, Vickers said. "Patients are much more likely to find experienced surgeons at institutions that do a lot of prostatectomies," he said.

One expert believes teaching hospitals' emphasis on quality improvement helps improve surgeons' performance.

"In an academic setting, if they have a bad outcome or something doesn't go as they would have hoped, there is a mechanism to assess outcomes and have feedback and improvement," explained Dr. Anthony D'Amico, the chief of radiation oncology at Brigham and Women's Hospital, Boston.

In community hospitals, mechanisms to assess problems and improve quality are not always available, D'Amico said. "One of the reasons that higher volume in academic centers are correlated with better outcomes is because there is feedback and quality assurance mechanisms in place to help people to do better," he said.

In addition, D'Amico believes academic centers attract people interested in outcomes and in correcting their errors and improving their techniques. "It's not surprising that as they do more prostatectomies, they get better," he said.

Patients facing prostatectomy should ask their prospective surgeon two questions, D'Amico said. First, "What's your experience -- how many cases have you done or do in a week?" and, "Second, what mechanisms are in place for you to improve outcomes if you find a problem?"