Cancer survivors in childhood are at high risk for second cancers in their forties and beyond, according to a new study.
Several studies have documented the increased risk of cancer survivors in childhood from having a second cancer, but this new study is among the first to assess this risk in its fifth or sixth decade of life. Although the risk of cancer increases with age, the study showed that cancer survivors in childhood over 40 years of age were more than twice as likely to have a second cancer than would be expected in the general population.
The results were published Aug. 10 in the Journal of Clinical Oncology:
The study, which was conducted by Dr. Lucie Turcotte of the University Of Minnesota Medical Center, used data from more than 14,000 participants from the NCI Childhood Cancer Survivor Study (CCSS) who were initially diagnosed between 1970 and 1986.
Almost 3200 participants in this CCSS cohort were 40 years or older when the last survey of study participants was conducted. In these individuals, 615 cancers were diagnosed, of which more than two-thirds (419) were nonmelanoma skin cancers.
Participants also had an increased risk of breast cancer, followed by kidney cancer, sarcoma, and thyroid cancer. Long-term survivors also had an increased risk of benign tumors.
Overall, approximately 16% of survivors in this analysis had subsequent cancer between the ages of 40 and 55. The incidence of cancer in these survivors was similar regardless of whether they had been diagnosed with a second (benign or malignant) tumor before age 40, the authors reported.
Second cancers in survivors are often related to previous treatments, and in this study both radiation therapy and treatment with a platinum-containing chemotherapy drug were significantly associated with substantially greater risks of subsequent cancer after age 40.
Many of the survivors included in the study had Hodgkin’s lymphoma as children (30%), partly because this cancer is usually diagnosed at a higher age than the other common cancers of childhood, so they were more likely to have arrived to its fifth and sixth decade of life.
High dose, chest radiation therapy was a standard treatment for Hodgkin lymphoma during the study period. This had “a clear influence” on the second malignant cancers seen in the study, wrote Doctors Mark Applebaum and Susana Cohn, in an accompanying editorial Notification of Exit at JCO.
Nearly 60% of Hodgkin lymphoma survivors were diagnosed with a malignant or benign tumor after age 40, they continued, largely because these survivors had a high incidence of breast cancer.
Excessive representation of Hodgkin lymphoma survivors in the study is a limitation, according to Dr. Julia Rowland, director of NCI’s Office of Cancer Survival.
“But the results also show that those who were diagnosed with specific cancer classes as children, their risk of a second cancer does not go away,” said Dr. Rowland.
Dr. Turcotte agrees. “Our results are likely to be the most important for Hodgkin lymphoma survivors,” she said. “They tell us that anyone who has received high dose radiation should continue to undergo constant observation as they age.”
Although closer outcome studies in childhood cancer survivors have shown an increased risk of lung, colon and rectal and head and neck cancer, the risk of such cancers was no longer in the long term in this study. JCO. It may be, said Dr. Turcotte, because the rates of these particular cancers are higher in the general population in people of this same age range, which obscures any potential risk of excess in long-term survivors.
The results of the study state that the general method of monitoring health needs to be different for childhood cancers survivors, Dr. Rowland emphasized.
She mentioned a recent conversation she had with a long-time survivor of childhood cancer. “And she said, ‘Childhood cancer is no longer necessarily a death sentence,’ Dr. Rowland recalled.”But it’s a lifelong sentence.” That’s an important point to remember for our younger cancer survivors. “