Anti-cancer drugs administered before surgery and radiation treatment can substantially increase the survival rate for some breast cancer patients, researchers reported Friday.

"Ten years after diagnosis, 30 percent of the patients involved in the study are alive without evidence of disease - better results than treating similar patients with surgery and radiation alone," said Dr. Gabriel Hortobagyi, director of the study and a medical professor at M.D. Anderson Cancer Center."Breast cancer patients with locally advanced disease were once considered incurable because surgery and radiotherapy were not enough to treat them successfully," the doctor said.

The 10-year study, the results of which were published in the journal Cancer, involved 174 patients treated for primary breast tumors with no spread of the cancer. The patients were treated with a three-drug combination followed by surgery and radiotherapy.

Before development of the combination therapy, patients with such breast cancer were treated with high doses of radiation therapy, either preceded or followed by a simple mastectomy.

"Despite these attempts to destroy the locally advanced tumors, from 25 to 60 percent of these patients developed a local recurrence of the tumor in the area of radiation and-or surgery," Hortobagyi said. "More importantly, the survival rate 10 years after diagnosis was close to zero."

Dr. Charles Balch, co-author of the study, which was the largest and longest of its type, said the findings "suggest that there is a biological advantage to giving drug therapy before surgery."

The anti-cancer drugs - 5-fluorouracil, doxorubicin and cyclophosphamide - served to shrink the primary tumors, allowing for more conservative surgery, Hortobagyi said. The drugs also eliminated malignant cells that had broken away from the primary tumors, but had not yet formed secondary tumors, he said.