Ninety-two veterans were given incorrect radiation doses in a common surgical procedure to treat prostate cancer during a six-year period at the Veterans Affairs Medical Center in Philadelphia, according to newspaper reports Sunday.

A hospital team that performed the procedure botched it on 92 of 116 occasions and continued the treatment for a year even though monitoring equipment was broken, The New York Times said. The Philadelphia Inquirer said treatment errors occurred in 92 of 114 cases.

The cases involved brachytherapy, in which implanted radioactive seeds are used to kill cancer cells. Most veterans got significantly less than the prescribed dose while others received excessive radiation to nearby tissue and organs.

A federal commission announced last fall that an inspection at the hospital was under way partly because of the number of patients given incorrect radiation doses. The medical center suspended its prostate cancer treatment program as a result of the ongoing investigation.

Investigators found that 57 implants delivered too little radiation to the prostate and 35 cases involved overdoses to other parts of the body, according to a Nuclear Regulatory Commission report published in the Federal Register this month. An unspecified number of patients had both underdoses to the prostate and overdoses in other areas.

All of the affected veterans have received follow-up care, and eight got additional seed implants at a Seattle VA center, according to Dale Warman of the Philadelphia VA Medical Center. Warman said the hospital leadership "takes the ... situation very seriously and has taken every step possible to correct or mitigate the problem."

Four of the men have since died, but Warman said none of the deaths was connected to prostate cancer or the treatment.

Several staff members, including oncologist Gary Kao, who was under contract to the VA and was involved in nearly all of the cases, are no longer employed at the hospital. Kao's lawyer, Jack L. Gruenstein, told the Times its account of the doctor's role was "false" but declined to elaborate.

A team from the commission, which oversees such radiation therapy, is scheduled to be in Philadelphia this week to investigate.

"As we have done throughout this process, Philadelphia VA Medical Center staff are prepared to share whatever records and information are necessary to discover what happened, why it happened, and to take steps to prevent it from happening again," Warman said.