Federal officials are conducting an unusual review to determine whether the government should pay for an expensive new vaccine for prostate cancer, renewing debate over whether some therapies are too costly.

The Centers for Medicare & Medicaid Services is running a “national coverage analysis” of Provenge, the first vaccine approved for treating any cancer. The treatment costs $93,000 per patient and has been shown to extend patients’ lives by about four months.

The decision to launch a formal examination has raised concerns among cancer experts, drug companies, lawmakers, prostate cancer patients and advocacy groups.

Provenge, which was approved for advanced prostate cancer in April, is the latest in a series of new high-priced cancer treatments that appear to eke out only a few more months of life, prompting alarm about their cost.

“This absolutely is the opening salvo in the drive to save money in the health-care system,” said Skip Lockwood, who heads Zero — the Project to End Prostate Cancer, a Washington-based lobbying group. “If the cost wasn’t a consideration, this wouldn’t even be under discussion.”