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Value of surveillance studies for patients (pts) with stage I-II diffuse large B-cell lymphoma (DLBCL) in the rituximab (R) era.
Abstracts that were granted an exception in accordance with ASCO's Conflict of Interest Policy are designated with a caret symbol (^).
Background: The role of surveillance studies in early-stage DLBCL in the R era has not been well defined. The goal of this study is to evaluate the use of imaging (CT and PET-CT) scans and LDH in surveillance of patients with stage I-II DLBCL. Methods: A retrospective analysis was performed of pts who received definitive treatment (Rx) at Stanford from 2000-2013, using Kaplan-Meier analysis to compute estimates of overall survival (OS) and freedom from progression (FFP). Results: 162 pts with stage I-II DLBCL were treated with R-chemotherapy, radiation (RT), or combined modality therapy (CMT). 5-year OS and FFP were 80.7% and 81.5% respectively. 94/162 pts (58%) achieved a complete metabolic response on PET scan after completion of chemotherapy, and this was associated with superior FFP (HR 3.06, p=0.003). 128/162 pts (79%) were followed with at least one surveillance PET scan beyond end-of-treatment scans. 18/162 pts relapsed after initial response to Rx. Of these, 9 relapses were detected initially by surveillance imaging studies (8 PET, 1 CT), and 9 were detected clinically (5 by pt-reported symptoms, and 4 by both symptoms and physical exam). No relapses were detected by surveillance LDH. At the time of relapse, LDH was found to be elevated in 3/13 pts, all of whom had relapse detected clinically. Median duration from initiation of Rx to relapse was 14.3 mos (range 7.8 – 121.1 mos) among pts with relapses detected by imaging, and 59.8 mos (9.3 – 123.3 mos) among pts with relapses detected clinically (p=0.077). There was no significant difference in OS from date of first Rx or OS following relapse between pts whose relapse was diagnosed by imaging vs clinically. 13/18 pts were successfully salvaged; salvage Rx included chemotherapy alone (10 pts), hematopoietic cell transplant (4 pts), CMT (3 pts) and RT alone (1 pt). Conclusions: A complete response on PET scan immediately after initial chemotherapy is associated with superior FFP in stage I-II DLBCL. Use of PET scans as post-treatment surveillance imaging is associated with earlier diagnosis of relapse, but no OS advantage. LDH is not a sensitive marker for relapse. Our results argue for limiting the use of post-Rx surveillance studies in asymptomatic pts.