CHICAGO >> A cheap, decades-old chemotherapy drug extended life by more than a year when added to standard hormone therapy for men whose prostate cancer has widely spread, doctors reported Sunday.

Men who received docetaxel, sold as Taxotere and in generic form, lived nearly 58 months versus 44 months for those not given the drug, a major study found.

“This is one of the biggest improvements we’ve seen in survival in adults” with any type of cancer that has widely spread from its original site, said Dr. Christopher Sweeney of Dana-Farber Cancer Institute in Boston. He led the study and shared the results Sunday at the American Society of Clinical Oncology’s annual conference in Chicago.

Prostate cancer is the most common cancer in men. In the United States, about 240,000 new cases are diagnosed each year. About 30,000 annually are like the men in this study, with disease that has spread to bones or other organs.

In the study, all 790 men received drugs to block testosterone, a hormone that fuels prostate cancer’s growth, and half also were given six infusions of docetaxel, one every three weeks.

About 2 1/2 years later, 101 of the men given docetaxel had died versus 136 of the men who did not receive it. One man died from the treatment, and about 6 percent had fevers from low blood counts, but most were able to tolerate treatment well, Sweeney said.

The National Cancer Institute paid for the study, which took nearly a decade to do. The result shows the importance of federal funding for research that otherwise might not get done, said Dr. Clifford Hudis, who works at Memorial Sloan Kettering Cancer Center in New York and also is the president of the oncology society.

“These are often studies that industry is less interested in funding, such as a new use for an old drug” that lost patent protection long ago, he said.

Generic docetaxel costs about $1,500 or less per infusion. That’s far less than some other cancer drugs, which can exceed $100,000 for a course of treatment.