Until the mid-20th century, doctors could do little for children in cancer wards except try to comfort them. “There wasn’t much else you could do but care,” Audrey Evans recalled of the era when she began studying for a career as a pediatric oncologist.

The British-born doctor arrived in Boston in 1953 on a Fulbright scholarship to work at Boston Children’s Hospital with Sidney Farber, an oncologist who had begun to gain international recognition for his use of chemotherapy treatment. Children in his studies had managed to beat leukemia into remission – the first major victory over what had long been an almost universally fatal disease.

One of his most promising proteges, Dr. Evans went on to conduct groundbreaking cancer studies and establish the first protocol that accurately diagnosed neuroblastoma, a cancer of immature nerve cells that is the most common type of cancer in infants. Among other advances, the Evans staging system spared children who did not need chemotherapy and radiation their brutal and long-lasting side effects.

During Dr. Evans’s decades-long career, neuroblastoma deaths dropped by half; today about 80 percent of afflicted children survive the disease. “More than any other person during the last three decades, she has transformed our thinking about neuroblastoma,” the journal Cancer Research declared in 2000.

She also co-founded in 1974 the first Ronald McDonald House, which provides affordable lodging for families of gravely ill children.

Dr. Evans, 97, renowned as a scientist, as a medical administrator and as an advocate for children, died Sept. 29 in Philadelphia. Her death was announced by Ronald McDonald House Charities. The cause was not immediately available.

In Boston and later as chief of pediatric oncology at Children’s Hospital of Philadelphia, Dr. Evans embraced what is now called “total care” to address the physical and emotional needs of patients and their families. She allowed frightened children to bring pet parakeets, rabbits and hamsters into the oxygen tent or radiation chamber.

In her office, Dr. Evans kept photographs of the children she saved and those she could not.

“I have learned to be able to talk [to children] about what dying is like,” she told the Philadelphia Inquirer. “One of the best things you can do is to be there and to share.”

She assured one girl, for instance, that there would be flowers in heaven. She sat vigil with a boy until 4 a.m., granting his last wish for chocolate cake.

Meanwhile, she and Farber’s other trailblazing colleagues were testing new ways to treat pediatric cancer patients. A seminal 1948 study by Farber had demonstrated chemotherapy’s ability to fight cancers of the blood, and he hoped to prove that chemicals could eradicate solid tumors as well.

At Farber’s request, Dr. Evans and Giulio D’Angio, a colleague who later became her husband, co-wrote a 1959 study on the effects of radiation and a chemical antibiotic in children with a type of kidney cancer. Their study provided the first evidence that chemotherapy could combat solid metastatic tumors.

Their research also helped prove one of Farber’s key theories, a concept that forms the basis of modern cancer treatment for children and adults: Chemotherapy and radiation are more effective when combined.

Dr. Evans was head of the hematology-oncology unit at the University of Chicago when C. Everett Koop recruited her in 1968 to Children’s Hospital of Philadelphia. The future U.S. surgeon general was then head of surgery at the Philadelphia medical center and was intrigued by her research on neuroblastoma.

As Koop had hoped, Dr. Evans succeeded in standardizing treatment for neuroblastoma. Using index cards, she began recording data that would help doctors determine the extent of the disease: One small tumor classified a child as Stage 1, or low risk; many widespread tumors deemed a child Stage 4 and mandated aggressive treatment. She published her staging system in 1971.

Neuroblastoma was rarely studied before Dr. Evans took an interest in the disease, which in some cases spontaneously disappears without treatment. Today, doctors use an international staging system that retains key elements of Dr. Evans’s initial parameters taking into account the tumor’s size, location and spread.

The stratification system included survival rates, and allowed some children to skip chemotherapy entirely. Perhaps more important, it aided standardized clinical trials all over the world.

In her early years at the Children’s Hospital of Philadelphia, where she spent the bulk of her career, Dr. Evans installed a floor-to-ceiling bird cage stocked with finches to entertain her patients.

She “got away with things,” she told a publication of Ronald McDonald House Charities, because few hospital administrators were willing to visit the pediatric oncology ward, a depressing and increasingly crowded place.

“The families just ended up staying in the hospital – in the hallways and in the bedrooms,” Dr. Evans told the Associated Press in 1984. “There were people all over.”

She occasionally used her personal credit card to book hotel rooms for exhausted parents. She sent mothers to the YWCA and fathers to a hostel, but she “needed a house where I could send the moms and dads together,” she later told an interviewer.

Dr. Evans envisioned a bed-and-breakfast where families could retreat from the hospital and stay for months with other families in the same plight. A large Edwardian house near the hospital caught her eye.

At the time – the early 1970s – the 3-year-old daughter of Philadelphia Eagles tight end Fred Hill was being treated for leukemia at a nearby hospital. Hill’s teammates held a few fundraisers and then heard of Dr. Evans’s program. They presented her with a $100,000 check.

“I gratefully accepted but said, ‘What I really need is money for a house,’ ” she later told the Philadelphia Inquirer.

Jim Murray, the team’s general manager, had established a sponsorship relationship with McDonald’s and proposed promoting the fast-food chain’s “shamrock” mint milkshakes in exchange for the profits.

McDonald’s agreed in exchange for naming rights, and “Ronnie’s House” opened in 1974. More than 300 Ronald McDonald Houses exist today, charging modest fees – or nothing – for long-term rooms near hospitals.

Audrey Elizabeth Evans was born in York, England, on March 6, 1925. Determined at an early age to become a doctor, she assembled a homemade first-aid kit of bandages, cotton balls and a tiny bottle of antiseptic, which she toted around her Quaker school. Her parents “believed that girls should do as well as boys,” she once told an interviewer, and encouraged her in her education.

Hospitalized for a year with tuberculosis, she missed months of boarding school in Bristol but was nonetheless admitted to the medical school her older sister attended, the Royal College of Surgeons of Edinburgh, in Scotland.

As the only woman in the Royal Infirmary teaching hospital, she was barred from the men’s cafeteria and dormitory and slept in a bedroom in a tower. But she had to share the men’s lock-free bathroom, where she recalled singing loudly to ward off intruders.

Dr. Evans moved to Boston in 1953, landing a position in Farber’s inpatient ward, where she met D’Angio, a radiation oncologist known as “Dan.” She became godmother to his sons, and, in 2005, after his first wife died, they were married. She was a first-time bride at 79. D’Angio died in 2018. A complete list of survivors was not immediately available.

After Dr. Evans’s retirement in 2009, she kept busy riding horses, tending sheep and scuba diving. But she said “missed the kids” and felt depressed – until she found a new project.

Involving herself in her Episcopal church’s summer program at a shuttered house of worship in north Philadelphia, she helped raise money to reopen the church as a middle school. She and her pastor co-founded a private school, St. James, in 2011. She was a regular presence on campus, where she could be seen walking arm in arm with students.

“I’m taking care of children here, and I was taking care of children with cancer,” she said in a St. James School video. “These kids need help, too.”

For her 90th birthday party, Dr. Evans created a gift registry. On the list: money for the school’s library books, for heat, for science materials – and $250 for turkey meatloaf, her favorite meal, for the children.