One in every 640 young adults in the United States survived cancer as a child, and approximately two-thirds of them have at least one chronic health problem.
Better cancer treatments in recent decades increased pediatric cancer survivor rates from below 50% to today's average of 80%, and as a result there is more focus on the long-term medical needs of survivors. Depending on their disease and the treatment they received, these patients are at higher risk for secondary cancers, cardiovascular and lung diseases, learning disabilities and memory difficulties, vision and hearing problems, or infertility.
Long-term follow-up programs for childhood cancer survivors have proliferated in the past 5 years, but too often these patients aren't recognized or adequately cared for, Dr. Anna T. Meadows said in an interview.
“There aren't enough primary care doctors who want to undertake follow-up of pediatric cancer survivors,” said Dr. Meadows, director of the Cancer Survivorship Project and the Living Well After Childhood Cancer program at the Children's Hospital of Philadelphia. “People are not really thinking that the kids grow up, when the average age of our survivors is now in the 40s.”
Dr. Meadows and her associates reviewed reports of subsequent neoplasms in 14,358 participants in the National Cancer Institute's Childhood Cancer Survivor Study. They estimated 30-year cumulative incidences of 9% for second malignant neoplasms and 7% for nonmelanoma skin cancers (J. Clin. Oncol. 2009;27:2356-62).
Although only 13% of the cohort were survivors of Hodgkin's lymphoma, these patients accounted for 34% of the second malignant neoplasms, mainly because of an increased risk for breast cancer; among 157 second breast cancers, 60% were Hodgkin's survivors. The largest proportions of nonmelanoma skin cancers occurred in survivors of Hodgkin's lymphoma (38%), leukemia (32%), and CNS tumors (9%).
A separate systematic review by Dr. Tara Henderson, which is slated to be published in the April issue of the Annals of Internal Medicine, found a 12%-21% risk for breast cancer in female survivors of Hodgkin's lymphoma who were treated with radiation.
“It's the same incidence as in women who have a BRCA mutation, so it's very high risk,” said Dr. Henderson, a pediatric oncologist and director of the Childhood Cancer Survivors Center at the University of Chicago, in an interview.
Like breast cancers in the general population, breast cancer in childhood cancer survivors is curable if diagnosed early, Dr. Henderson noted, so she recommends earlier screening for breast cancer in Hodgkin's lymphoma patients—starting mammography and MRI screening 8 years after treatment or at age 25 years, whichever comes last.
Radiation therapy also commonly increases later risk for skin cancers, sarcomas, and thyroid cancer. “We just have to make clinicians aware that the risk is there,” she said.
Dr. Paul Nathan agreed. If “an adult shows up in your practice for a particular problem who has had cancer as a child, you need to pay close attention,” he said in an interview. “Lumps or bumps that you may otherwise think are fairly innocent in a 20- or 30-year-old may not be” innocuous in cancer survivors, said Dr. Nathan, a hematologist/oncologist at the Hospital for Sick Children, Toronto.
He recommends that physicians consult guidelines for long-term follow-up of childhood cancer survivors, which are updated every 2 years by the Children's Oncology Group and are available at www.survivorshipguidelines.org
It's not uncommon, however, for adult patients to know little about their childhood cancer diagnosis or treatment. A grant from the Agency for Healthcare Research and Quality is helping Dr. Karen J. Wasilewski-Masker and her associates at Children's Healthcare of Atlanta to develop SurvivorLink, a computerized network. In what may be the first project of its kind in the country, SurvivorLink would give primary care physicians, surgeons, and other specialists throughout Georgia access to medical summaries and information on any patient seen in her institution's Childhood Cancer Survivorship Program, she said in an interview.
Not only do survivors need to be educated, so does the medical community. “These patients are out there and have health risks and need to be followed,” Dr. Daniel A. Mulrooney said in a separate interview. Today's physicians learned next to nothing about childhood cancer survivors in their medical training, and it's unlikely that current medical school curricula cover the topic either, he suggested.
“The cumulative incidence curves for secondary cancers [in childhood cancer survivors] have not yet plateaued—we haven't seen any type of downturn,” said Dr. Mulrooney, a pediatric hematologist/oncologist at the University of Minnesota, Minneapolis. “These cancers develop earlier than expected and are likely to increase over time.” It will be challenging, because these patients will grow to the age when cancers are more common.