Practice matters for doctors, too: A 15-year study found men whose cancerous prostates were removed by a more experienced surgeon were less likely to relapse.

Specialists have long advised people who need surgery for whatever reason to pick an experienced surgeon. But how experienced? For prostate cancer, surgeons seemed to improve until they'd done 250 of the operations, concludes the study published Tuesday by the Journal of the National Cancer Institute.

Researchers fromMemorial Sloan-Kettering Cancer Center tracked the outcomes of more than 7,700 men who had their cancerous prostates removed between 1987 and 2003 by 72 surgeons at that hospital and three other respected university-based hospitals.

Within five years of their prostate removal, 17.9 percent of men treated by inexperienced surgeons — those who had done just 10 prior operations — had evidence that their cancer was back.

Among men treated by experienced surgeons — 250 prior operations — 10.7 percent relapsed.