Due to minimal rates of radiation-induced cancer deaths resulting from CT surveillance, even modest benefits experienced by patients with Hodgkin Lymphoma (HL) is enough to justify its use, according to results of a study published in the June issue of the American Journal of Roentgenology.
Despite imaging’s role in the surveillance of HL patients, ambiguity remains regarding the appropriate frequencies and timeframe of follow-up CT examinations, according to lead author Kathryn Lowry, MD, and her colleagues at Massachussets General Hospital in Boston. “The most recent National Comprehensive Cancer Network (NCCN) guidelines recommend surveillance CT examinations of patients who achieve remission every 6–12 months for 2–3 years after completion of therapy,” wrote Lowry et al. “However, given the young age and favorable prognosis of most HL patients, it is important to consider whether potential benefits of CT surveillance outweigh the potential risks of secondary malignancies associated with radiation exposures from multiple CT examinations.”
Lowry and her team of researchers set out to analyze radiation-induced cancer risks and competing risks resulting from HL. To do so, they projected HL lifetime mortality risks and life expectancy losses and compared them to radiation-induced cancers in HL patients undergoing surveillance CT using and adapted Markov model. They modeled men and women aged 35 years undergoing seven CT examinations of the chest, abdomen, and pelvis over a span of 5 years and projected radiation-induced cancer risks and deaths for 17 organ systems. They also performed a secondary analysis on cohorts of 20-, 50-, and 65-year-old men and women to determine relative risk projections.
They found that in the case of the model based on 35-year-old adults, projected deaths from HL were 3,324/100,000 for men and 3,345/100,000 for women, while deaths from radiation-induced cancers were estimated at 245/100,000 for men and 317/100,000 for women. Younger cohorts showed the highest rates of deaths and life expectancy losses from radiation-induced cancers.
“Our results highlight the need for additional information regarding the incremental mortality benefit of CT surveillance in these patients,” the authors wrote. “Modeling techniques such as those used in our analysis are important for more comprehensively understanding the nature of radiation-induced cancer risks and for informing health decisions at institutional and policy levels regarding the use of CT and other imaging modalities that involve ionizing radiation.”