Surveillance computed tomography imaging and detection of relapse in intermediate- and advanced-stage pediatric Hodgkin's lymphoma: a report from the Children's Oncology Group

Abstract

PURPOSE Children with Hodgkin's lymphoma (HL) routinely undergo surveillance computed tomography (CT) imaging for up to 5 years after therapy, resulting in cost and radiation exposure, without clear benefit. The objective of this study was to determine the contribution of surveillance CT, as compared with clinical findings, to detection of disease recurrence. PATIENTS AND METHODS Two hundred sixteen patients, age ≤ 21 years old, were treated on the multicenter Pediatric Oncology Group 9425 trial. Data for patients who experienced relapse were retrospectively reviewed to determine whether imaging or clinical events prompted suspicion of disease recurrence. Correlation was made to disease stage, time to recurrence, relapse site, and overall survival (OS). Results With a median follow-up time of 7.4 years, 25 (11.6%) of 216 patients had experienced a relapse, of whom 23 experienced local relapse. Median time to relapse was 7.6 months (range, 0.2 to 48.9 months). Nineteen relapses (76%) were detected based on symptoms, laboratory or physical examination findings, and two relapses (8%) were detected by imaging within the first year after therapy. Only four patients (16%) had their recurrence detected exclusively by surveillance imaging after the first year. Six deaths occurred, all in patients who experienced relapse within the first year after therapy. No patient with a recurrence after 1 year off treatment has died, regardless of how the recurrence was detected. CONCLUSION The majority of pediatric HL relapses occurred within the first year after therapy or were detected based on change in clinical status. Detecting late relapse, whether by imaging or clinical change, did not affect OS. These findings indicate that CT is overused for routine surveillance of patients with HL.

Conflict of interest statement

Authors' disclosures of potential conflicts of interest and author contributions are found at the end of this article.

Figures

Fig 1.

(A) Overall survival (OS) for patients with a reported relapse (n = 25). Patients were grouped as follows based on method of relapse detection: group 1 (relapse within the first 12 months, detected either by imaging, symptoms [Sx], or clinical findings); group 2 (relapse after 12 months, detected by Sx or clinical findings); and group 3 (relapse after 12 months, detected by imaging only, no Sx or clinical findings). Six patients died, all of them from group 1. The differences in postrelapse OS curves between group 1 and group 2 and between group 1 and group 3 are not statistically significant (P = .12 and P = .16, respectively) because of the small sample size. Combining groups 2 and 3, the difference between group 1 (relapse < 12 months) and groups 2 and 3 (relapse > 12 months) resulted in P = .04. (B) OS for patients with a relapse (n = 25) versus the remaining study cohort (n = 191). Six deaths were reported among the 25 patients with a relapse, and six deaths were reported among the remaining patients. The difference is statistically significant (P < .001).

Fig 2.

Proposed surveillance scheme for routine post-therapy monitoring in Hodgkin's lymphoma. (*) CT or MRI, provided the treating institution has demonstrated feasibility and efficacy of MRI at detecting known sites of disease at diagnosis or on interim early response assessment. Off-therapy computed tomography (CT) or magnetic resonance imaging (MRI) should be limited to initial sites of involvement (ie, stage IIA patients with disease limited to the mediastinum would have routine surveillance imaging limited to the thorax). (†) Fluorodeoxyglucose (FDG) positron emission tomography (PET) or PET/CT should only be obtained off therapy if still positive during on-therapy monitoring. Patients with persistent FDG-avid disease after completion of therapy should be considered for retrieval therapy rather than further routine surveillance. CXR, chest x-ray; Rx, therapy.