Cancer Survivors Lack Ideal Screening (Radiation therapy has long term risks.)

Family Practice News ^ | 15 June 2009 | DAMIAN MCNAMARA

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ORLANDO — Fewer than half of childhood cancer survivors who are deemed to be at high risk of secondary breast, colon, and skin malignancies follow cancer-screening and surveillance recommendations as adults, according to a new analysis of the large, longitudinal Childhood Cancer Survivors Study.

High-risk survivors were the least compliant with colonoscopy recommendations: Only 11.5% of 794 survivors who were considered vulnerable for colorectal cancer had a colonoscopy during the 5 years before they were surveyed, Dr. Paul Nathan reported at the annual meeting of the American Society of Clinical Oncology.

Skin cancer is the most common radiation-associated second malignancy in survivors, but just 26.7% of 4,833 survivors at high risk had ever had a complete skin exam, said Dr. Nathan, who is an oncologist at the Hospital for Sick Children in Toronto.

Women at high risk for breast cancer were more compliant with recommendations, he added; even so, only 46.3% of 521 in this group had a mammogram performed during the 2 years before they were asked about screening.

Most of the 8,318 survivors surveyed in this phase of the National Cancer Institute-funded study were in the care of family physicians, according to Dr. Nathan. About 12.5% had been seen at a cancer center or within a long-term follow-up program in the previous 2 years. Another 12% reported no medical care during this time. The remaining patients were “predominantly seen by their primary care physician in their community,” he said.

Cancer survivors and their primary care physicians need to be more vigilant, Dr. Nathan said, calling for oncologists to take the lead in educating their primary care colleagues about recommendations for long-term follow-up. Individual primary care physicians may have only a few childhood cancer survivors in their practice, he said, but they should be made aware of these patients' special requirements.

“There is broad consensus that survivors of childhood cancer need regular surveillance and screening in the hope that if we pick up these cancers early, we can change the mortality [and morbidity],” Dr. Nathan said.

Dr. Charles L. Bennett, professor of geriatrics, economics, and oncology at Northwestern University in Chicago, said he was unsure whether survivorship care was the responsibility of the oncologist or the primary care provider, but suggested that it is most likely a shared responsibility. This study is important because “surveillance is essential, yet empirical data are lacking,” he added.

With a 5-year survival rate of 80% for pediatric cancers, most patients survive long term (J. Clin. Oncol. 2009;27:2308–18). Dr. Nathan estimated that about 9% of 325,000 survivors of childhood cancer who are alive in the United States will develop a new malignancy within 30 years of their original diagnosis. In addition, secondary malignancies are the leading cause of death among survivors who live at least 20 years beyond initial diagnosis.

The Childhood Cancer Survivors Study enrolled 20,602 people who were initially diagnosed with cancer in 1970–1986 and had survived at least 5 years. Of these original participants, 3,305 had been lost to follow-up and 1,541 had died by the time of the 2003 follow-up survey, on which the new study is based. Another 3,197 declined to participate in the survey and 990 were excluded from the analysis (among them, 960 survivors who had already developed a secondary malignancy). The average age of survivors interviewed was 31.2 years. A matched group of 2,661 siblings and 8,318 population controls was also assessed.

The study's primary aim was to determine adherence to the Children's Oncology Group's guidelines for following cancer survivors (www.survivorshipguidelines.org). Survivors were considered at high risk for the following:

▸ Breast cancer, if they received 20 Gy or more of radiation therapy to the breast during childhood. Mammography is recommended every 1–2 years beginning at age 25 years, or 8 years after the initial cancer diagnosis for these patients.

▸ Colorectal cancer, if they received 30 Gy or more of radiation to the abdomen, pelvis, or spine. Screening colonoscopy is recommended every 5 years starting at age 35 years.

▸ Skin cancer, if they were exposed to any radiation during childhood. An annual skin examination of treated areas is recommended. “We know the rate of nonmelanoma skin cancers in irradiated areas is approaching 7% for survivors over 30 years,” Dr. Nathan noted.

The investigation was limited by the fact that the cancer diagnoses occurred from 1970 to 1986 “and clearly therapy has changed,” said Dr. Nathan, who reported having no conflicts of interest.

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Life itself is a long term risk... For the fortunate.