With more than 70% of childhood cancers now curable, there is an increasing need for physicians to monitor survivors to minimize their problems from treatment, and to help fine-tune therapies, say researchers in a recent issue of the British Medical Journal (Vol. 323, No. 7307: 271-274).

“We have a responsibility to monitor our long-term survivors, because they are at risk,” says Hamish B. Wallace, MD, lead author of the BMJ study and a consulting pediatric oncologist at the Royal Hospital for Sick Children in Edinburgh, Scotland.

“For example, if childhood treatment with chemotherapy drugs known as anthracyclines has left you at risk for heart failure, you really do not want to be training hard in the gym with weights,” Wallace tells ACS News Today. “And your obstetrician, if you get pregnant, needs to know about that risk.”

Wallace and colleagues at several institutions in Britain reviewed the medical literature from recent decades on survival and complications of childhood cancer treatment and summarized their findings.

The researchers note that within 25 years of a childhood cancer diagnosis, a second primary cancer (a new cancer, rather than a recurrence of the original cancer), developed in about 4% of the British childhood cancer survivors, six times the cancer risk of children who did not have cancer during childhood.

The increased risk occurs partly because some treatments — such as radiation and some chemotherapy drugs — can cause cancer, and partly because some of the children diagnosed had a genetic predisposition to cancer.

Bone cancer and leukemia were the most common second primary cancers.

The researchers note that radiotherapy and chemotherapy — especially drugs known as anthracyclines — can damage heart muscle and large blood vessels.

They found some treatments affected male potency or female fertility. Females whose ovaries are harmed should have hormone replacement therapy from puberty until they are in their 50s, to help preserve bone density and protect the heart, the authors said.

Some chemotherapy drugs, radiotherapy to the central nervous system, and absence from school during treatment put children’s performance in school at risk. Some treatments may slow physical growth, and others affect bone density, the authors noted.

The authors suggest that because the likelihood of complications varies with the type of treatment, lifetime follow-up could be done by phone or mail every year or two for many low-risk patients. For patients who received more intensive therapy, once they reach a five-year cancer-free milepost, their follow-up could be done by a primary care physician or nurse practitioner every one or two years.

A childhood cancer expert affiliated with the American Cancer Society (ACS) tells ACS News Today that attempts at follow-up by mail and phone directed solely by doctors’ offices might not work as well in the US as it has in Europe.

“We live in a mobile society,” says Teresa J. Vietti, MD, professor emeritus at Washington University School of Medicine, and a member of the ACS editorial advisory board.

“Yet, follow-up of childhood cancer survivors — at least once a year after more intense follow-up is completed — is vital to their well-being and survival,” Vietti says.

“So, parents need to make sure at the end of treatment that they obtain from the child’s doctors a list of treatments the child had, and possible long-term effects of those therapies,” notes Vietti.

“The child should understand those risks, too, as soon as appropriate, and that information should also be relayed to any doctors helping provide medical care to the survivor later,” Vietti adds.

“That way, former patients can enjoy the long-term survival that medical advances have provided, and still maintain as much control as possible over any problems that might arise,” Vietti concludes. “That’s the balance sought in — and necessary for — successful survivorship.”