But even at these elite centers, IP treatment did not take off as much as experts thought it should. From 2003 to 2006, as research began showing it had benefits, overall use of the treatment rose from zero to 33 percent of patients. From 2007 to 2008 — after the major, landmark study and the alert from the cancer institute — the use rose to 50 percent of eligible patients.

But then it reached a plateau. Rates varied from one hospital to the next, with 4 percent to 67 percent of patients receiving IP treatment. Researchers say that at smaller, less prestigious hospitals, the rates are even worse.

The hospitals that participated in the study were named in the journal article, but their individual rates were not disclosed.

“We suspected that even at the best centers there would be low integration of IP chemotherapy, but we were surprised to see how low it was across academic centers, and also to see how much variation there was between centers,” said Dr. Alexi A. Wright, the first author of the study and a medical oncologist at the Dana-Farber/Brigham and Women’s Cancer Center in Boston. “It’s the best data we have for improving survival among patients with this cancer.”

Deborah Dennehy, 58, a second-grade teacher from Amesbury, Mass., had IP treatment two years ago at Dana-Farber. She said she gained as much as 10 pounds with each treatment from all the fluid infused, and felt like a “beached whale” for a few days afterward. She lost her hair and temporarily had some numbing in her fingertips from the chemotherapy, but medication prevented nausea. Now, she said, “I feel great.” And given the data on the treatment, she said, “I felt it was totally worth the inconvenience.”

The new study confirmed earlier findings that IP treatment helps women live longer. Among women who had IP treatment, 81 percent were still alive three years later, compared with 71 percent in women who had only intravenous chemotherapy. The findings are based on the records of about 500 women.

Another study, also published in The Journal of Clinical Oncology, in May, found that the benefits of IP therapy are long-lasting: among women followed for 10 years, the risk of death was 23 percent less in those who had IP therapy.