When and how to perform surveillance imaging in patients with lymphoma, and is it worth it?

Abstract

Why, when and how to perform surveillance imaging in lymphoma patients has been a debated topic for a long time. More than 25 years after the introduction of computed tomography (CT) and more than 10 years after the introduction of positron emission tomography (PET)/CT, there is still no substantial evidence supporting the widespread use of routine imaging in patients who achieve a good remission after therapy. Even though routine scans detect some relapses prior to the development of symptoms, it has not yet been demonstrated that detecting the relapse at a subclinical stage will in fact improve the eventual outcome [1]. In this issue of Leukemia and Lymphoma , Abel and colleagues report their fi ndings gathered from a multiinstitutional survey of the patterns and signifi cance of surveillance imaging of patients in remission after treatment for diff use large B-cell lymphoma (DLBCL) [2]. With the participation and cooperation of seven diff erent academic lymphoma treatment centers, they identifi ed a cohort of 845 patients treated between 2000 and 2008 who were all in remission for at least 3 months post-therapy and had a minimum of least 2 years of follow-up. After the exclusion of 220 patients who had died, developed a second cancer or were lost to follow-up during the fi rst 2 years, they were fi nally left with a cohort of 625 patients. In the analysis of imaging frequency, the authors focused on the use of surveillance imaging during the fi rst 2 years post-treatment. Twenty-two patients who relapsed less than 6 months after therapy were excluded from this analysis in order to avoid the counting of frequent re-imaging of patients in questionable remission after therapy. Since the authors had also excluded patients with an unsatisfactory remission status and patients who died and/or relapsed very early after therapy, the remainder must be regarded as a “ good-risk “ group of patients. Nevertheless, among the remaining 603 patients, they found that the median number of imaging studies was 2.5 per year per patient. Th ere was wide variation between centers, with mean numbers of imaging studies per patient ranging from 0.5 to 3.5 per year. Th is supports the suspicion that surveillance imaging strategies are founded on local preferences and habits rather than evidence-based medicine. Just over 50% of the patients had PET or PET/CT performed at some stage during the fi rst 2 years of follow-up [2]. Fifty of the 625 patients relapsed during a median follow-up of 5 years, and no more than a quarter of those relapses were identifi ed by routine imaging of asymptomatic patients. Th is implies that more than 120 scans had in fact been performed