The faces of Dr. Martin Brecher through the years flashed by in a slide show Wednesday evening underneath a tent in Kaminski Park and Gardens at Roswell Park Cancer Institute as hundreds of patients, families and colleagues lined up to shake his hand, hug him and take photos with him at his retirement celebration.

In a photo from the 1970s with young patients surrounding wrestler Hulk Hogan, Brecher looked like a cast member from the TV series “M*A*S*H.” In a recent one, with jubilant patients pushing Brecher in a wheelchair, he could be a doctor in a Norman Rockwell illustration.

There he was at a holiday party, sitting on Santa’s lap. At another holiday party, he actually was Santa. If, he said later, “you can imagine a skinny, dark-haired Jewish Santa.”

“I had to see him. He was excellent, the best doctor ever,” said Lindsay Tobin, who drove from the other side of Rochester and waited in line with her sons, Aiden, 7, and Caleb, 5, and her father, Gary Mannix, of the Town of Tonawanda.

“Dr. Brecher treated me when I had leukemia when I was 5,” she explained. “I went into remission when I was 8, and I’ve been cancer-free ever since.”

Other patients, including Kathy Curatolo, of Clarence, Roswell Park’s longest-lived pediatric cancer survivor, praised his care and compassion during the formal part of the program.

A current patient, Zach Nosbisch, 13, told about how he was diagnosed with lymphoma in 2012.

“I was terrified,” he said, “but he made me feel controlled and calm. He said how he was always going to be there for me.”

A former patient, Mary Flanagan, related how Brecher, through monitoring and adjustments to her treatments, made it possible for her to go to her high school prom during her second bout with leukemia at age 16.

“He gave me the options,” she said. “He said, ‘Let’s work with you, let’s get you to the prom.’ I wanted to not wear a wig, but I did, and my prom date wore it half the night.”

The same qualities were cited by his colleagues.

“He has had an impact on countless lives of children who now are adults,” said Dr. Donald Trump, Roswell Park president and chief executive officer, “and, through his clinical trials, on children throughout the nation. The people wearing leis, the families and patients tonight, they’re all a tribute to the work that Dr. Brecher did.”

Dr. Teresa Quattrin, pediatrician in chief at Women & Children’s Hospital, told how he encouraged and supported her when she came to Buffalo for pediatric training. “I was very apprehensive,” she said. “He took me aside and said, ‘Don’t worry. Everything will be fine and I’ll be there for you.’ It was the worst possible time for a resident and he made it very easy. He would be there at all times, evenings, nights, it didn’t matter.”

“When he became chief, I became head of the diabetes center. That’s another great virtue of Marty, being able to cooperate with the program and make everything work in harmony.”

“I came to Buffalo originally to go to medical school,” Brecher noted in his remarks. “Four years in and out.”

But, he added, after doing a pediatric residency at Roswell Park and Children’s Hospital, he decided “hematology-oncology was the thing to do.”

“This has been an incredibly exciting time to be in this field,” he said. “The disease was a death sentence when I started. People are now cured to a remarkable degree. It’s really been amazing.”

Brecher began treating children and adolescents with cancer at Roswell Park in 1975. He was appointed acting chief of pediatrics at the hospital in 1987 and chairman in 1990, as well as division chief of pediatric hematology-oncology at Women & Children’s Hospital.

Although he is retiring from active clinical practice July 1, he has promised to stay on as chief until they find a successor. And if someone needs to consult with him, he won’t be far away.

“If the next winter is like last winter, I may go away for a couple weeks,” he said after greeting dozens more well-wishers and former patients at the end the program, “but I plan on staying here for a while.”