The federal government’s insurance program for the elderly Thursday officially agreed to pay for Provenge, an expensive new “vaccine” to treat prostate cancer.

The Centers for Medicare & Medicaid Services (CMS) announced a final decision to immediately start covering Provenge, which costs $93,000 a patient. The announcement confirms what the agency had said it planned to do in March.

Although Medicare is not supposed to take cost into consideration when making such rulings, the decision by CMS to launch a formal examination of the question had raised concerns among cancer experts, drug companies, lawmakers, prostate cancer patients and advocacy groups.

“We are optimistic that innovative strategies may improve the experience of care for our beneficiaries who have cancer,” said CMS Administrator Donald M. Berwick in a statement. “CMS is dedicated to assuring that these patients can seek the treatments they need in accordance with their wishes.”

Prostate cancer is the most common cancer in men in the United States after skin cancer. More than 192,00 new cases are diagnosed each year and more than 27,000 men die from the disease each year.

Because men tend to be elderly when they receive diagnoses of advance prostate cancer, Medicare’s decision will have a major effect on Provenge’s accessibility.

Provenge, which received Food and Drug Administration approval in April, is the latest in a series of new, high-priced cancer treatments that appear to provide patients with a few extra months of life. The treatments have raised alarm about their costs.

Unlike standard vaccines, which are given before someone gets sick to stimulate the immune system to fight off infections, Provenge is a “therapeutic vaccine” that spurs the immune system to attack cancer cells.