In an analysis from the Childhood Cancer Survivor Study (CCSS) reported in the Journal of Clinical Oncology, Moskowitz et al found a significant increase in overall mortality among childhood cancer survivors who developed breast cancer vs matched controls. A numeric increase in breast cancer mortality was observed.
The analysis involved data from 274 female patients in the CCSS cohort of 5-year survivors who were first diagnosed with cancer between 1970 and 1986 before the age of 21, and were subsequently diagnosed with breast cancer. The median age at breast cancer diagnosis was 38 years. Patients were matched for age, race, and year of diagnosis with a control group of 1,095 women with de novo breast cancer.
Overall and Breast Cancer Mortality
The median follow-up after first breast cancer diagnosis among childhood cancer survivors still alive at last contact was 8 years (range = < 1–26 years). Overall, 92 childhood cancer survivors died, 49 due to breast cancer. Overall survival at 10 years after breast cancer diagnosis was 73%. Risk of death from any cause was higher among childhood cancer survivors (hazard ratio [HR] = 2.2, P < .001) and remained significantly higher after adjustment for breast cancer treatment (HR = 2.4, 95% confidence interval [CI] = 1.7–3.2).
Five- and 10-year rates of breast cancer–specific mortality were 12% and 20% among childhood cancer survivors vs 9% and 13% in the control group, yielding a nonsignificantly increased risk among survivors (HR = 1.3, 95% CI = 0.9–2.0). Survivors were five times more likely to die from other health-related causes, including other malignant neoplasms and cardiovascular or pulmonary disease (HR = 5.5, 95% CI = 3.4–9.0). The risk of a second asynchronous breast cancer was significantly higher among survivors (P < .001), with 5-year rates of 8.0% vs 2.7%.
The investigators concluded, “Mortality after breast cancer was higher in childhood cancer survivors than in women with de novo breast cancer. This increased mortality reflects the burden of comorbidity and highlights the need for risk-reducing interventions.”
Chaya S. Moskowitz, PhD, of the Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, is the corresponding author for the Journal of Clinical Oncology article.
Disclosure: The study was supported by grants from the National Cancer Institute, Meg Berté Owen Foundation, and American Lebanese Syrian Associated Charities. For full disclosures of the study authors, visit jco.ascopubs.org.
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