McMaster University

McMaster University

Cure rate for childhood cancers can come at a price

The Canadian Press
May 4, 2010
Sheryl Ubelacker

Vikram Bubber was just 5 when he began treatment for a tumour in his middle ear, but the memories of multiple bouts of chemotherapy and lying on a cold steel table beneath a radiation beam have barely dimmed with time.

It took two years of bombarding the tumour with every tool they had before doctors pronounced him cured. True, the hearing in one ear was destroyed, nerve damage had left him with a lopsided smile, and his once-thick hair had grown back fine and sparse.

But he was alive and done with cancer — or so he thought.

Twenty years later, Bubber was diagnosed with a tumour in his cheekbone, an entirely different cancer that resulted from his earlier radiation. Such secondary malignancies and other health conditions are known as "late effects," and they can arise decades after treatment in survivors of childhood or adolescent cancer.

Besides spawning a new cancer, chemo and radiation can lead to learning disabilities, retarded growth, heart disease, infertility and a range of psychosocial problems, including reduced self-esteem.

"Going through the second cancer, it brought back the realization of how cancer has affected me, the way I looked and the identity that I had because of the cancer," says Bubber, 31, of Surrey, B.C., who had his cheekbone removed and is slated for a second reconstructive surgery this fall.

Dr. Ronald Barr, a pediatric oncologist at McMaster University in Hamilton, says more than 80 per cent of children and adolescents diagnosed with cancer today can expect to be cured.

"In my working lifetime we've approximately doubled the cure rate for these young people," says Barr. "Terrific. Sound it out from the rooftops. Huge achievement."

But the downside of boosting those cure rates — often obtained by intensifying the amount and duration of treatment — can create a "terrible legacy" for many young cancer survivors, he says.

"These people who are surviving their original disease are facing a litany of the long-term adverse consequences of that earlier treatment ... The question becomes: what lies beyond cure for these young folks? And the whole issue of survivorship has come under the microscope."

Perhaps the most well-known project is the multicentre Childhood Cancer Survivor Study, led by researchers at Memorial Sloan-Kettering Cancer Center in New York City, which has followed thousands of young cancer patients who were treated between 1970 and 1986. The ongoing study found that almost three-quarters of those cured of an original malignancy will go on to develop a chronic health problem within 30 years of diagnosis.

The Canadian Cancer Society is among the agencies funding research in this country into the delayed effects of early cancer treatment.

"The reason people are focusing — and appropriately so — on pediatrics is because with kids, young adults, adolescents, we have probably two additional complexities that factor in over and above the general case," says Dr. Michael Wosnick, scientific director of the Canadian Cancer Society Research Institute.

"Young kids are still growing . . . their bones haven't grown, their brains haven't grown, their organs haven't grown to adult stature," Wosnick says. "And so there's a lot more active biological processes, so the opportunity for more damage."

"And the other is that, thankfully, we're creating more and more survivors. But the horizon for a 15-year-old surviving cancer is a lot longer than the horizon for a 60-year-old surviving cancer. If a late effect is going to show up 20 years from now, we're going to see it in the 15-year-old, whereas you're not necessarily going to see it in every 60-year-old."

Some fallout from treatment can come sooner than later, says Dr. David Malkin, an oncologist at the Hospital for Sick Children, pointing to youngsters treated for brain tumours.

A study published in the latest issue of the journal Pediatrics, part of the Childhood Cancer Survivor Study, found that young adult survivors are four times more likely to develop post-traumatic stress disorder than siblings who did not have cancer.

As well, research has shown that young cancer survivors face issues of isolation and socialization difficulties at a time when they are developing social skills needed to live successful, independent lives.

"I do feel isolated," concedes Bubber, an office manager for a Vancouver-area grocery chain, who is still trying to figure out what career path he wants to pursue.

"I see a lot of my friends from high school have started families and have found someone to share their life with," says Bubber, who is undergoing treatment for infertility, another treatment-related side-effect all too common among childhood cancer survivors.

"I would like to move forward, find someone and start a family and move on with my life," he says.

"I'm 31 now. Everybody keeps telling me I'm really young, but in my mind I'm thinking, ‘No, how much more time do I have to do what I want to do and have a family and be able to enjoy . . . the things that everybody else is doing right now?' "

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