Studies of nearly 29,000 breast-cancer patients leave no doubt that drug and hormone therapies improve chances of surviving the disease, the second-leading cancer killer of American women, researchers say.

Analysis of 61 studies showed that the synthetic hormone tamoxifen improves the survival of breast cancer victims over age 50, while chemotherapy helps younger women.During the first five years after treatment, tamoxifen reduced the odds of death among older women by about one-fifth, the analysis revealed, while a combination of chemotherapy drugs reduced the odds by about one-quarter for younger victims.

The studies were started as far back as 20 years ago.