From the Journals

Comorbidities drive excess mortality after breast cancer diagnosis in childhood cancer survivors



Among women with breast cancer, risk of death is more than twice as high for those who are childhood cancer survivors than for those in whom this cancer is their first, found a retrospective cohort study. However, the excess deaths are mainly from comorbidities related to previous therapies.

Breast cancer is among the leading subsequent malignancies in adult survivors of pediatric cancers, note the investigators, who were led by Chaya S. Moskowitz, PhD, of the department of epidemiology and biostatistics at Memorial Sloan Kettering Cancer Center in New York. But outcomes after this diagnosis are not well characterized.

The investigators used the Childhood Cancer Survivor Study to identify 274 female 5-year survivors of cancer diagnosed before age 21 years who received a subsequent breast cancer diagnosis at a median age of 38 years. They then used Surveillance, Epidemiology, and End Results data to identify a control group of 1,095 female patients with de novo breast cancer matched on age, race, stage, and year of breast cancer diagnosis.

The 10-year overall survival was 73% among the childhood cancer survivors, investigators reported in the Journal of Clinical Oncology.

Compared with the control women whose breast cancer was their first cancer, the women with breast cancer who were childhood cancer survivors had an elevated risk of death from any cause (hazard ratio, 2.2) that persisted after analyses were adjusted for receipt of chemotherapy and radiation therapy (HR, 2.4). In addition, findings were similar in analyses restricted to women with ductal carcinoma in situ and women with stage 1-3 breast cancer.

The childhood cancer survivors had a modestly elevated risk of dying from breast cancer (HR, 1.3) but a sharply elevated risk of dying from other health-related causes, including other subsequent malignancies and cardiovascular or pulmonary disease often related to previous therapies (HR, 5.5).

In addition, the childhood cancer survivors had a higher cumulative incidence of diagnosis of second asynchronous breast cancers a year or more later, relative to the women in whom breast cancer was their first cancer (P less than .001). The 5-year cumulative incidence was 8.0% among the childhood cancer survivors and just 2.7% among the control women.

“Although BC [breast cancer]-specific mortality was modestly higher in childhood cancer survivors, deaths attributable to health conditions other than BC seem to be the driving force in the elevated all-cause mortality,” Dr. Moskowitz and colleagues wrote.

“To change the dismal outcomes of these women, our results suggest that it is imperative that at the time of a secondary BC diagnosis, they have a comprehensive evaluation that extends beyond a singular focus of the BC,” they concluded. “This should include an assessment of existing cardiopulmonary disease and a plan for future cancer screening to optimize the management of comorbidities and cardiopulmonary disease and prolong the lifespan of these survivors.”

Dr. Moskowitz reported that she has a consulting or advisory role with Bioclinica. The study was supported by the National Cancer Institute, a Memorial Sloan Kettering Cancer Center Core grant, the Meg Berté Owen Foundation, and the American Lebanese Syrian Associated Charities.

SOURCE: Moskowitz CS et al. J Clin Oncol. 2019 Jul 1. doi: 10.1200/JCO.18.02219.

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