AMSTERDAM — A large mural painted on the wall of one of the radiation scanning rooms at New York Oncology Hematology commemorates the life of Maggie McNamara, cut short at age 28 by breast cancer.

Kelly Diamond was McNamara’s best friend and, as a laboratory nurse in the radiation unit of NYOH, she was by her side through every minute of her treatment and therapy.

The mural invokes feelings of calm, with Adirondack chairs overlooking mountains and a river, a hot air balloon in the sky and geese flying into the sunset.

“Maggie loved geese and every time we went walking we’d see them,” Diamond said.

NYOH is celebrating its 25th anniversary of treating patients like McNamara, and Diamond has been there through it all.

Over 25 years ago, Diamond was the only nurse in a fledgling operation at St. Mary’s Hospital, which saw about four cancer patients per week. Diamond and one physician would provide treatments to the inpatients at St. Mary’s and a few of the outpatients.

“I mixed the chemotherapy treatments myself,” Diamond said. “We didn’t have a pharmacist to do that.”

The practice grew quickly and within a year, NYOH opened its first office, across the street from St. Mary’s Hospital, in November 1984. That’s when Karen Jurcsak, a laboratory manager, joined the team.

“We were only open two full days and two half-days,” Jurcsak said. “We had five people working there, four full-time and one part-time.”

After 25 years, NYOH sees more than 6,500 patients per year at its Riverfront Center location alone. About 400 people work for the company, which has nine locations throughout the Capital Region offering an array of services from diagnosis to treatment.

“I think that the community setting has contributed to the success of NYOH,” Diamond said. “We know our patients, we see them at football games and in the grocery store and we know their life stories.” Jurcsak, who is not only an employee but a cancer survivor since 2004, said she received the best care she could within five minutes of her home.

Before cancer care was available in Amsterdam, patients had to travel at least as far as Albany for treatments. Often that meant traveling over an hour round-trip five days per week.

“We had one woman who would travel to our Albany office from Hagaman with a wastebasket in case she got sick on the ride,” Diamond said.

Advancements in cancer care have nearly eliminated some of the side effects associated with cancer treatments, including nausea and vomiting, Diamond said.

Through its affiliation with the U.S. Oncology Network, NYOH provides services that generally are available only in large cities, such as clinical trials and new technology.

“You can go to Boston or New York if you want to, but you can have all of that here too,” Diamond said.

NYOH has five fully equipped cancer centers. Its administrative offices are in Clifton Park, but management travels from site to site, so there is no headquarters.

Executive Director Kevin Wilson said NYOH will stay on top of technological advances in treatment and patient care but will basically be in the same place in 25 years that it is now.

“We have very talented and experienced people and we just need to make sure they have the tools to continue the world-class research and patient care that we offer,” Wilson said.

Specifically, the company has implemented an electronic records system, and through U.S. Oncology has a tracking system for drugs.

“It’s very detailed to where it ensures that what you’re getting is exactly what you’re supposed to get,” Wilson said.

While dealing with cancer patients every day may seem like daunting and at times heartbreaking work, both Diamond and Jurcsak don’t see it that way.

“Yes, we see the suffering, but we also see the survivors, like me,” Jurcsak said. “We get to see all the good that we’ve done.”

“Wow, 25 years,” Diamond said. “I can’t believe how it’s gone by.”