Purpose: To estimate the clinical benefits and cost effectiveness of computed tomography (CT) in the follow-up of patients with complete response (CR) after treatment for Hodgkin's disease (HD).
Patients and methods: We developed a decision-analytic model to evaluate follow-up strategies for two hypothetical cohorts of 25-year-old patients with stage I-II or stage III-IV HD, treated with doxorubicin, bleomycin, vinblastine, and dacarbazine-based chemotherapy with or without radiation therapy, respectively. We compared three strategies for observing asymptomatic patients after CR: routine annual CT for 10 years, annual CT for 5 years, or follow-up with non-CT modalities only. We used Markov models to calculate life expectancy, quality-adjusted life expectancy, and lifetime costs. Baseline probabilities, transition probabilities, and utilities were derived from published studies. Cost data were derived from the Medicare fee schedule and medical literature. We performed sensitivity analyses by varying baseline estimates.
Results: Annual CT follow-up is associated with minimal survival benefit. With adjustments for quality of life, we found a decrement in quality-adjusted life expectancy for early-stage patients followed with CT compared with non-CT modalities. Sensitivity analyses showed annual CT for 5 years becomes more effective than non-CT follow-up if the specificity of CT is 80% or more or if the disutility associated with a false-positive CT result is less than 0.01 quality-adjusted life years (QALYs). For advanced-stage patients, annual CT for 5 years is associated with a very small quality-adjusted survival gain over non-CT follow-up with an incremental cost-effectiveness ratio of 9,042,300 dollars/QALY.
Conclusion: Our analysis suggests that routine CT should not be used in the surveillance of asymptomatic patients in CR after treatment for HD.