Durham, N.C. — A vaccine that Duke University researchers have been studying in clinical trials for several years is helping some brain tumor patients live longer.

In a report published in the Journal of Clinical Oncology, the Duke researchers say their brain tumor vaccine merits further investigation because the growth factor they've identified is also found in other kinds of cancer cells.

Lee Sullivan, 65, was diagnosed with brain cancer a year ago. A glioblastoma tumor caused a seizure while he was golfing in Durham.

"During my back-swing on the Hope Valley (Country Club) golf course, the lights went out," Sullivan said.

The tumor was surgically removed, and chemotherapy and radiation followed. He also began receiving a monthly vaccine designed to knock out a genetic growth factor found in the tumors of about one-third of patients.

"My hope is that this will extend my life considerably compared to what the normal diagnosis is," Sullivan said.

Duke neurosurgeon Dr. John Sampson said the vaccine also extended the progression-free survival period of patients, from a median of 15 months to a median of 26 months.

"We really need to test this in more rigorous ways to be certain, but in study after study that we've done, we seem to be having the same results," Sampson said. "Immune responses that we monitor actually can help us predict which patients will do well on the vaccine and which ones might not."

Sullivan said he's feeling great almost 12 months into his vaccine treatments, and he plans to continue the monthly vaccine as long as it appears to be working.