TORONTO - Children diagnosed with cancer in Canada have a far better chance of survival than in the past, but also will likely suffer from health problems in the future, the Canadian Cancer Society said Thursday.

Based on the success of earlier detection and improvements in treatment, the survival rate from childhood cancer has increased from 71 per cent to 82 per cent, an improvement of 11 per cent in the past 15 years, said Heather Logan, director of Cancer Control Policy. That means for every 100 children under the age of 14 who are diagnosed with cancer, 11 more are surviving at least five years past the date of remission.

“That’s 11 more faces that are alive now that wouldn’t have survived the disease nearly 15 years ago,” Logan said Wednesday while releasing a 108-page annual report titled Canadian Cancer Statistics 2008. “We need to know more about what causes childhood cancer so we can implement programs to prevent disease from occurring in the first place.”

Doctors, however, say those children who do survive should expect to suffer some form of delayed side effect, caused either by the original cancer or the treatment for it. While more are surviving, health repercussions still linger and are, in fact, more prevalent because of the higher survival rate. About two-thirds of all children who survive cancer will suffer at least one late effect from their treatment, and about one-third will suffer serious effects.

Those effects can appear anywhere between one week and 20 years down the road, and come in the form of neuropsychological changes that may appear as learning disabilities, secondary cancers caused by the chemotherapy, damages to organ systems and infertility.

“We need to know precisely how current therapy causes late onset side effects, to know how we need to modify current therapy even when that therapy is effective in curing the cancer,” said Dr. Paul Grundy, director of Alberta’s Children Cancer Program.

While little is known about what causes childhood cancer, doctors say environmental concerns that often cause cancer in adults have not had the same chance to harm children. Grundy said therapy for childhood cancer tends to be very intense and long, and its impact can be very severe.

“If we don’t treat their cancer, they’re going to die,” he said. “There isn’t a choice. It’s an area we need to study, but at the moment it’s not usually a choice that we can make at the point of our initial therapy.” Grundy added that few studies or tests have been done on the long-term effects of cancer treatment on children because of the lower survival rate in the past, which has limited the cases researchers can observe.

“We don’t know what the late effects or the possible late effects may be 30, 40 or 50 years after cancer chemotherapy because we don’t have a significant number of children who survived cancer,” he said.

While the numbers indicated that the childhood survival rate increased, the incidence of childhood cancer remained relatively constant over the same period. About 850 children below the age of 14 are diagnosed with some form of cancer each year. The number is relatively low compared to adult cases.

The overall statistics suggested that 166,400 people will be diagnosed with some form of cancer in 2008, an increase of 6,500 over last year. There also will be an estimated 73,800 deaths, 1,100 more than in 2007. The report attributes the increases to a growing and aging population.

Prostate cancer was the most common form among men, with 24,700 expected new cases, while 22,400 women are expected to be diagnosed with breast cancer. Lung cancer remains the highest killer for both men and women, with 11,000 and 9,200 respectively. Almost 40 per cent of women and 45 per cent of men will develop cancer in their lifetime, and approximately 25 per cent of Canadians will die from the disease.

National Post
Canada.com, Canada