ORLANDO — Fewer than half of childhood cancer survivors who are deemed to be at high risk of secondary breast, colon, and skin malignancies receive recommended cancer screening and surveillance as adults, according to a new analysis of the large, longitudinal Childhood Cancer Survivors Study.
The deficiency was most notable for colonoscopy: Only 11.5% of 794 survivors who were considered vulnerable to 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, an oncologist at the Hospital for Sick Children in Toronto.
Women at high risk for breast cancer were more likely to undergo recommended screening, he added, yet only 46.3% of 521 women in this group had a mammogram performed during the 2 years before being asked about screening.
Of the 8,318 survivors surveyed in this phase of the National Cancer Institute–funded study, 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.” Most of the survivors were in the care of family physicians, he said.
Cancer survivors and their primary care physicians need to be more vigilant, Dr. Nathan said. Individual primary care physicians may have only a few childhood cancer survivors in their practice, but they should consider 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],” he said.
The study discussant, 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,” Dr. Bennett said, adding that “these are real issues. These are lifelong concerns.”
The 5-year survival rate is 80% for pediatric cancers, and 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. 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 the original participants, 3,305 had been lost to follow-up and 1,541 had died by the time of the 2003 follow-up survey that was used for the new study. 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 years. A matched group of 2,661 siblings and 8,318 population controls also was assessed.
The study's primary aim was to determine adherence to the Children's Oncology Group's guidelines for following survivors of childhood cancers (www.survivorshipguidelines.org
▸ Breast cancer. For those who received 20 Gy or more of radiation therapy to the breast during childhood, mammography is recommended every 1-2 years starting at age 25 years, or 8 years after the initial cancer diagnosis.
▸ Colorectal cancer. For those who 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. For those who 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.
In a secondary analysis, the researchers compared survivors who were not at high risk of secondary cancers with matched controls from the National Health Interview Survey of the general population to determine adherence to U.S. Preventive Services Task Force cancer screening guidelines for breast, colon, and cervical cancer.
This analysis showed that these survivors were more likely than controls to undergo recommended mammography (67%, vs. 58% of controls), were more compliant with Pap smear recommendations (82% vs. 70%), and had a comparable—albeit low—rate of recommended colonoscopy (24% in both groups). However, the number of survivors who reached the minimum age for the colonoscopy recommendation (50 years) was small, Dr. Nathan noted.