Utility of post-therapy brain surveillance imaging in the detection of primary central nervous system lymphoma relapse.

BACKGROUND: The optimal follow-up strategy for primary central nervous system lymphoma (PCNSL) patients after first-line therapy is unclear. The goal of this study is to determine the utility of planned brain surveillance imaging in the detection of relapse in a retrospective cohort of PCNSL patients.

METHODS: Patients were consecutive PCNSL cases treated in Leon Berard Cancer Centre, Lyon, France, from 1985 to 2011. Histology was diffuse large B-cell lymphoma in 94%. Patients were treated by methotrexate (92%) and cytarabine (63%) based-chemotherapy followed by radiotherapy for 108 patients (51%). Clinical records were reviewed for details at relapse and relationship to planned imaging. The imaging follow-up strategy was performed according to each treating physicians.

RESULTS: Among 209 PCNSL patients, 127 complete response patients entered in post-treatment observation and 63 (50%) subsequently relapsed. Among the 125 evaluable patients, the majority of relapses (N = 49, 80%) was asymptomatic and identified before the planned brain imaging. Surveillance imaging detected relapses before symptoms in 12 patients who entered in post-therapy observation (10%). The median number of brain imaging during the follow-up was 7 (0-13). A total of 819 MRI/CT-scan were performed leading to the detection of 12 asymptomatic relapses. The one year OS rates were 41% and 58% for symptomatic and non-symptomatic relapses, respectively (P = 0.21).

CONCLUSION: The majority of PCNSL relapses occurred outside planned follow-up with no difference in patient outcome between symptomatic and asymptomatic relapses. The role of brain imaging for the detection of relapses in the follow-up of PCNSL patients remains to be clarified.