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Additional CT scans increased risk for second primary malignancy in patients with non-Hodgkin's lymphoma
Patients with non-Hodgkin’s lymphoma who underwent more frequent surveillance CT scans demonstrated an increased risk for a secondary primary malignancy, according to a results of a nationwide population-based study conducted in Taiwan.
Use of CT scans for patients with lymphoma undergoing curative-intent treatment has become more common, and development of radiation-associated second primary malignancies in long-term survivors has emerged as an increasing concern, according to study background.
Jyh-Pyng Gau, MD, of the division of hematology and oncology at Taipei Veterans General Hospital in Taiwan, and colleagues analyzed patients with non-Hodgkin’s lymphoma who received curative-intent treatment from 1997 through 2010.
Researchers divided patients into two groups based on the median number of CT scans performed (≤8 or ≥9).
Gau and colleagues used the Kaplan-Meier method to compare cumulative incidence of second primary malignancies in these groups, and they used propensity score matching to eliminate potential confounders. Cox proportional hazard models that used competing-risk analyses adjusted for mortality identified independent predictors for development of secondary primary malignancies.
Researchers identified 180 secondary primary malignancies in the study population.
Results showed patients who received nine or more CT scans had a significantly greater risk for secondary primary malignancy (HR=2.25; 95% CI, 1.61-3.13) than those who received ≤8 scans. The difference remained significant after correction with propensity score matching, researchers said.
Patients who received ≥9 CT scans demonstrated significantly higher incidence of secondary primary malignancies in the breast (HR=11.22), stomach (HR=5.22), and liver and biliary tract (HR=2.18) than those who underwent ≤8 scans.
Each additional CT scan increased risk for secondary primary malignancy by an estimated 3%, researchers wrote.
Disclosure: See the study for a list of the researchers’ relevant financial disclosures.