A failure of oversight and systemic problems in prostate-cancer care at the Philadelphia VA Medical Center caused 92 veterans to receive incorrect doses of radiation to treat their condition, triggering a federal investigation of the hospital's protocols.

Most of the vets got significantly less than the prescribed dose from brachytherapy - the use of implanted radioactive seeds to kill cancer cells. Other patients received excessive radiation to nearby tissue and organs.

Nearly all of the brachytherapy cases with incorrect doses were performed by a University of Pennsylvania doctor under contract to the VA. That radiation oncologist, Gary Kao, has not seen patients since the problem was discovered last year, said a Penn official.

In one case, the error may have contributed to rectal bleeding, concluded the U.S. Nuclear Regulatory Commission, which oversees such radiation therapy and is reviewing the matter. The substance of that review was reported on nytimes.com yesterday afternoon.

It took officials more than six years to catch the mistakes, investigators said. When they were discovered last year, all brachytherapy treatments at the hospital were halted, and remain so.

The delay and the number of missteps trouble Eric M. Horwitz, acting chairman of the radiation oncology department at the Fox Chase Cancer Center in Philadelphia.

"It is still surprising that some of these things happened," said Horwitz, who was recently elected president of the American Brachytherapy Society.

"Not only did all the systems not work, but in certain instances, it looks like they didn't put the seeds where they were supposed to go."

All of the affected veterans have since gotten follow-up care, and eight patients received additional seed implants at the VA Medical Center in Seattle, said Dale Warman of the Philadelphia VA Medical Center.

The hospital's "leadership takes the brachytherapy dosing situation very seriously and has taken every step possible to correct or mitigate the problem," Warman said.

An investigation is ongoing. This week, a team from the Nuclear Regulatory Commission is scheduled to be at the Philadelphia VA, delving into the brachytherapy cases.

"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.

Kao remains at Penn, performing laboratory work. He did not respond yesterday to an e-mail or a phone message left with a colleague.

Last summer, the Philadelphia VA said that it was examining brachytherapy cases involving 114 men, ages 50 to 87, who may have been underdosed during treatment for prostate cancer from February 2002 to May 2008. Most were from New Jersey, Pennsylvania, and Delaware.

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

The improper dosings were discovered in May 2008 by another physician, Richard Whittington, who heads radiation oncology at the Philadelphia VA. The hospital said he performed six of the 114 procedures in question, though it was unclear if any of his patients had received an improper dosage. Reached yesterday, he referred the matter to a VA spokesman.

"We share the [VA's] goal of assuring that veterans receive the best possible care and believe that a thorough review is critical to achieving this goal," said Susan E. Phillips, a Penn health system senior vice president, in a statement. "Because this is an ongoing investigation, we are unable to comment further at this time."

The prostate gland sits under the bladder and in front of the rectum, and so it is crucial to focus radiation onto the prostate to avoid serious side effects.

In brachytherapy, physicians insert 40 to 130 radioactive seeds, which are about the size of a grain of rice. They emit low-energy radiation, which is primarily absorbed in the treatment area around the seed.

Why did it take more than six years to catch the errors?

One reason could be a lack of independent oversight, said James P. Bagian, chief patient-safety officer for the VA health system.

Bagian, who cochaired a systemwide review of brachytherapy last fall, said his committee found that in Philadelphia and other VA medical centers, the quality-assurance aspects of the programs were conducted by the contracted doctors themselves and were not "independent enough to assure we are getting an unbiased report."

The ongoing NRC investigation has identified 57 of the vets who got less than 80 percent of the prescribed dose.

The radiation shortfalls were not small.

"We are not talking at 79 percent of what was delivered, or close to 80 percent," the NRC's Patricia Pelke told an NRC advisory committee last month. "We are talking about percentages dramatically lower than that."

In addition, 35 vets received excessive doses, including 25 who received too much radiation to their rectums, according to an NRC report published in the Federal Register this month.

The NRC probe cited several causes, including that no corrective action was taken when low doses were discovered following procedures. Often, however, no such post-implant checks were performed because of a computer glitch. There was also inadequate supervision of the physician involved in the procedures, the VA's root-cause analysis into the problems revealed.

The NRC identified other problems.

The doctor who performed most of the problem cases didn't use real-time X-rays to check the placement of the seeds.

"He refused to use fluoroscopy; said he didn't need it," NRC staffer Darrel Wiedeman told the advisory committee in May, referring to an X-ray procedure that allows doctors to see internal organs.

"We found that there was poor management oversight, or there was none," Wiedeman said.

And he added, "the radiation safety staff, they did quarterly audits, but their audits didn't pick up any of these problems."

The VA has taken some corrective actions.

Several of the key staff, including Kao, "are no longer employed" at the hospital. A physician and medical physics consultant who are expert in brachytherapy were hired to evaluate the program. And the program will remain closed until all the problems are fixed and safeguards put in place to prevent a recurrence.

"We have worked closely and advised every affected veteran about his right to seek compensation," Warman said.

Some have indicated their intent to sue, although Warman declined to say how many since "going into numbers serves no purpose as the process is ongoing."

Contact staff writer Josh Goldstein at 215-854-4733 or jgoldstein@phillynews.com.