Oded and Meital Grinstein never expected to raise their family outside their native Israel.

But that changed when their firstborn child, now 14½, developed a rare, aggressive form of sarcoma soft-tissue cancer when she was six months old.

Although Israel offers excellent medical care, and its doctors are expert at treating most forms of cancer, it soon became apparent that there were no oncologists with expertise in their daughter’s condition. The country is too small for its doctors to have experience in treating some rare cancers.

After a worldwide search, the Grinsteins found the right specialist, a pediatric hematologist-oncologist at Memorial Sloan Kettering Cancer Center in Manhattan. So off they went in 2010, when Meital was pregnant with their second daughter, to start the grueling but ultimately lifesaving treatment in a foreign country.

Eventually, the Grinsteins settled in Fair Lawn. They wanted to be fairly close to Sloan Kettering in case their daughter’s cancer recurred.

But from Fair Lawn, Mr. Grinstein has helped about a thousand families like his — mostly from Israel — to find the best information and practitioners for their children with cancer through his nonprofit organization, My Child’s Cancer (www.mychildscancer.org).

One of many pieces of information Mr. Grinstein has amassed over the years is that brain tumors are the most common types of tumors in pediatric cancer.

On June 19, the organization’s nearly three-year-old Israeli branch, Hayeled Sheli (My Child), will host a conference for neuro-oncologists on adolescents and young adults with brain tumors.

Sessions will be led by two world-renowned experts from My Child’s Cancer’s advisory committee on brain tumors: Dr. Jonathan Finlay, professor emeritus of pediatrics and radiation oncology at Ohio State University College of Medicine; and Dr. Eric Bouffet, director of pediatric neuro-oncology at the Hospital for Sick Children in Toronto.

“When it all started 13 years ago, I documented what I knew about my daughter’s cancer and uploaded it to a website,” Mr. Grinstein said. “I invited a few other parents to do the same for the cancers they were dealing with. Soon, other parents started approaching us for more information, tips, connections, and introductions, and we built a parents’ network.

“I thought that it would be a total waste to let all this information just stay in our heads, so I decided to document our journey, and the journeys of the other people who were willing to share it,” he continued.

“Today it’s a whole different ballgame. We have international expert committees for groups of cancers. We have committees for soft-tissue cancer, bone cancer, neuroblastoma, and brain cancer, and we’ll create more.” The advisory committee on brain tumors includes about a dozen experts from several countries.

“Whenever a complicated case arises — a kid who doesn’t respond to treatment or has a combination of two rare types of cancer or one ultra-rare type — their parents approach us, and we translate everything and send the information to one of our experts to review,” Mr. Grinstein said.

“That expert then pulls in other experts as needed from the committee. They all review the case, and then we organize a telehealth session with the expert and the parents and the local doctor, usually Israeli.”

Mr. Grinstein describes these Zoom sessions as “mind-blowing in the amount of information shared, including unpublished clinical trials and new discoveries and developments.”

“The organization’s committees have an amazing impact on everyone involved,” he said. “Parents see there is no stone unturned to help their children. The local doctor benefits by working with the best of the best. So far, in 100 percent of cases handled by our committees, the treatment was changed, altered, or impacted in some way by that conversation.

“We are a small nonprofit with a big impact, as the information we found over the years has helped save kids’ limbs and organs, eyesight, the ability to walk — and of course, their lives.”

It took time for Israeli oncologists to accept what Hayeled Sheli was doing.

“At first, when we approached Israeli doctors, we got the cold shoulder. They’d tell us, ‘We don’t really need you guys; we can contact these experts ourselves.’

“Now, a significant number of Israeli pediatric oncologists refer cases to us because we find the best expert for each case,” Mr. Grinstein said. The June conference was planned with the full cooperation of Israeli hospital oncology department chiefs, he added.

Among the latest research in brain tumors the two experts will discuss are pediatric-type brain tumors that attack adults. Mr. Grinstein said pediatric cancers can appear in much older people.

In fact, he said, the oldest patient helped by My Child’s Cancer was a 73-year-old man with a type of soft-tissue cancer that usually affects children or young adults.

Although users pay nothing for the organization’s assistance, it is not free.

“We pay the experts generously for their time,” Mr. Grinstein said. “It costs me about $2,500 for each case, and we help about 100 kids per year.”

My Child’s Cancer is totally donor-supported by individuals, funds, and corporations.

“Last year we did a campaign with the support of a pharma company, and at the end we were able to introduce a new pediatric cancer drug to the Israeli basket” — that is, the range of products and services covered by Israel’s national healthcare system. “Dozens of kids had been traveling to New York to get this drug until finally our campaign succeeded.”

Also last year, a new donor came aboard: The Good People Fund, a targeted tzedakah project based in Millburn.

“The Good People Fund discovered My Child’s Cancer over a year ago and knew immediately that it was an important resource for families with a child facing a cancer diagnosis,” Naomi Eisenberger, Good People’s executive director, said.

“Oded Grinstein knew firsthand that the complexities of finding the right doctors and treatments add significant tension and concern to an already extraordinarily difficult situation. MCC’s medical expertise, coupled with compassionate volunteers who are committed to making the journey as comfortable as possible, are irreplaceable.

“We are excited about their work and dedicated to helping make it possible.”

As of January, Mr. Grinstein has made My Child’s Cancer his fulltime job. Until then, he worked in business development for Israel’s high-tech industry.

“I led My Child’s Cancer voluntarily for 12 years in my spare time, but demand is growing and the team is growing, so I had to commit myself fully to managing and raising funds for the two organizations,” My Child’s Cancer and Hayeled Sheli, he said.

The June conference will be followed the next day by a get-together where My Child families can meet the two North American physicians.

“Some families have been working with these experts for months or years and have never met them in person,” Mr. Grinstein said. “They just want to thank them, to hug them, for what they did for their children and their families. We know for a fact we changed the course for some of these kids.”

One girl, he related, was scheduled to undergo risky spinal surgery in Israel until My Child’s Cancer found a noninvasive treatment for her in the United States.

“She went back to Israel a few months later, cancer-free, without surgery,” Mr. Grinstein said. “We have this kind of impact on a monthly basis.”

Recently, an oncologist from Austria told a child’s Israeli doctor about a new clinical trial, but he didn’t stop there.

“He introduced the Israeli doctor to the lead researcher and made sure the kid got the drug free of charge, in Israel,” Mr. Grinstein said. “That Austrian expert de facto opened a clinical site in Israel, making it available to other kids who needed that drug.”

In at least one case, My Child’s Cancer was able to help two children in the same family. The family’s oldest child already had died of a brain tumor when another daughter, Lilly, was diagnosed with a similar tumor. The youngest child, Adam, was found to have the same cancer-risk gene as his sisters.

My Child’s Cancer translated Lilly’s medical records to English for review by Dr. Finlay, who altered Lilly’s treatment plan to a less radical procedure. It was done successfully. Dr. Boufett suggested some preventative measures for Adam. Everything was coordinated long distance between Lilly’s parents, the advisory committee, Lilly’s Israeli oncologist, and a representative from My Child’s Cancer.

My Child’s Cancer also hosts the WikiCancer website (www.MyWikiCancer.org) where parents and caregivers across the globe can learn from the experiences of others.

Today, Oded and Meital Grinstein are the parents of three daughters, who now are 14 1/2, 13, and 3 1/2 years old “Our oldest daughter was diagnosed at six months old. Our second daughter was born in the midst of her sister’s treatment in New York,” Mr. Grinstein said. “That meant we didn’t get to enjoy either child’s infancy.

“After 10 years we were back on track and decided to have another one.”