Role of Surveillance CT in Detection of Pre-Clinical Relapse in Patients with B-Cell Lymphoma : A Retrospective Study

Abstract

Background: with the evolution of curative treatment regimen, the rate of complete remission achieved in patients with diffuse aggressive non-Hodgkin lymphoma is continuously rising. It is achievable at the end of primary treatment in about 60-80%. On the other hand relapse is very common in the 1st two years after end of primary treatment in diffuse large B-cell lymphoma (DLBCL) and follicular lymphoma, that is to say, about 20-25% of patients relapse after complete response. Use of routine surveillance imaging for relapse detection is still an area of controversy. Evidence is still lacking to support the utility of routine imaging (namely CT scan) in detection of pre-clinical relapse in diffuse aggressive non-Hodgkin lymphoma (NHL). This work aims at adding further evidence to the pool of studies available in the literature which might encourage, or disapprove the rule of CT as a routine imaging procedures in lymphoma patients who achieved CR. Objectives: I. To clarify whether surveillance CT scan has a significant role in early detection of asymptomatic relapse in B-Cell lymphoma patients. II. To assess the contribution of image-based relapse detection to the overall survival of B-Cell lymphoma patients. Design: this is a retrospective cohort study in which 50 Patients with B-Cell lymphoma diagnosed between 2014 and 2016 were selected from the PACS of Radiology Department at Ain Shams University Hospitals. Age ranges between 20 and 70 year-old. All diagnoses were confirmed by histopathology studies. All patients underwent treatment and follow-up strategy as planned by their treating oncologist/hematologist, after which they entered CR or SD according to IWG Cheson criteria of treatment response. Disease progression was retrospectively reviewed over a period of 6 months up to 2 years. Surveillance CT scan was performed on the neck, chest, abdomen and pelvis on each of the planned follow-up visits. Relapses were defined as “asymptomatic” if there were no reported symptoms and a normal examination was recorded. Results: the most common cause of relapse detection was patient-reported symptoms alone (41%) or in combination with abnormal blood tests and/or physical examination (23%). Routine imaging was responsible for relapse detection in 27% of the patients. The unadjusted median OS for patients with imaging-detected relapse was 90 months versus 38 months for patients non imaging-detected relapse (P = 0.0008). Although surveillance imaging proved no significance in detection of pre-clinical relapse, our regression analysis showed that it remained significantly associated with reduced risk of death. Conclusion: clinical symptoms remain the leading factor in diagnosing recurrent lymphoma in the era of modern imaging, and this study questions the clinical relevance of current practice. A possible survival advantage was seen for patients with image-detected relapse.