Is It Time to Remove Radiotherapy in the Management of Primary Central Nervous System Lymphoma? Population-based Study, Pool-Analysis and Retrospective Study of Recurrence Pattern.

Abstract BackgroundBefore the introduction of the chemotherapeutic agent methotrexate, radiotherapy (RT) and steroids have been the sole, first-line treatment of primary central nervous system lymphoma (PCNSL). With the application of methotrexate, the role of RT in the treatment of PCNSL has been challenged. MethodsWe performed observation analysis on 2,486 PCNSL patients between 1988 and 2016 from the Surveillance, Epidemiology and End Results (SEER) database. Propensity score matching (PSM) was employed to ensure well-balanced characteristics of two groups of patients who received RT and those who did not receive it. Two randomized controlled trials (RCTs) were pooled to further evaluate the role of consolidation whole-brain radiotherapy (WBRT) in PCNSL. To clarify whether WBRT is necessary for PCNSL, 27 relapsed patients who attained complete response (CR), partial response (PR) or stable disease (SD) during or after first-line treatment without WBRT for newly diagnosed PCNSL in our institution was retrospectively analyzed; the pattern and location of relapse was identified. ResultsAfter matching, there was no statistical difference on survival between the two groups. In patients did not received chemotherapy, RT significantly improved the survival of patients who undergone biopsy (All P < .0001) or subtotal resection (All P < .0001). In particular, RT helped improve survival for patients with other infectious and parasitic diseases including HIV (OIPDH). Pool-analysis shown the better progression free survival (PFS) of patients with WBRT arm compared with no WBRT arm in per-protocol (PP) population (HR 0.71, 95% CI 0.52 to 0.98). In the 27 relapse patients, 17 (63%) had new measurable enhancing lesions at relapse at a spatially distinct site, the remote recurrence after CR was 9/11 (82%), and after PR was 8/15 (53%). Single lesion occurred remote recurrence was 11/13 (85%), while multiple lesions were 7/14 (50%). We also established a novel prediction model with excellent performance to estimate the potential benefit from RT with respect to the end point of overall survival. ConclusionsRT is still an important method in the treatment of PCNSL, which cannot be removed. More precise studies should be carried out to perfect the treatment strategies of the disease.