When it comes to breast-cancer surgery, a new study suggests that experience is crucial — far fewer patients die at hospitals that perform more surgeries.

So you should go to a hospital that performs a lot of surgeries? Not necessarily. While researchers see a connection between a high number of surgeries and lower death rates, they are not entirely sure what it means.

"We're not ready to say, 'You need to go see a surgeon who has done this many operations, or to a hospital that's done this many operations," says study lead author Mary Ann Gilligan, M.D, associate professor of medicine at the Medical College of Wisconsin. "Really, what [the study] is doing is raising some issues that need to be further evaluated."

Gilligan and the rest of her team looked at 11,225 Medicare patients who were treated for early-stage breast cancer between 1994 and 1996. The patients were treated at 457 hospitals.

The risk of dying from breast cancer was 20 percent lower in hospitals that performed a high number of breast-cancer surgeries. The risk of dying from all causes was 17 percent lower for patients treated in those hospitals.

The study appears in the March 2007 issue of the American Journal of Public Health.

Other studies have shown that more experienced surgeons do a better job with the most technically demanding cancer surgeries, such as those for esophageal or pancreatic cancer, Gilligan said. But the breast cancer numbers leave plenty of room for speculation. "It may not be the surgical expertise at all. It may be that hospitals with higher volumes have systems in place [with] better follow-through, making sure the patients are getting the follow-up they need."

It makes sense that hospitals with the most practice would have the best survival rates, said Pushpendu Banerjee, M.D., an oncologist at Scripps Memorial Hospital La Jolla, in California.

"If you tend to do something on a repetitive basis and you do higher numbers, you're more likely to be better at it," he said.

On the other hand, smaller hospitals might be home to a single surgeon with an excellent record, Banerjee said. And a busy hospital could be an exception to the rule. "You can't jump to conclusions that a high-volume place will definitely be better for you," he said.