Systemic relapses of primary CNS lymphomas (PCNSL): a LOC network study

Area of Science:

• Neurology
• Oncology
• Pathology

Background:

• Primary CNS lymphomas (PCNSL) typically remain confined to the central nervous system.
• The behavior and characteristics of extracerebral relapses in PCNSL are not well understood.

Purpose of the Study:

• To analyze the incidence, characteristics, and outcomes of rare extracerebral relapses in PCNSL.
• To identify factors associated with survival in patients experiencing systemic relapse.

Main Methods:

• Retrospective nationwide population-based study using the French LOC database.
• Inclusion of 1968 PCNSL patients diagnosed from 2011 onwards.
• Analysis of 30 patients (1.5%) with confirmed extracerebral relapse, including histological confirmation in 20 cases.

Main Results:

• Extracerebral relapse occurred in 1.5% of PCNSL patients, with a median delay of 15.5 months.
• Common sites of relapse included visceral organs (77%), lymph nodes (40%), and peripheral nervous system (23%), with notable involvement of testis and breast.
• Median progression-free survival was 7 months and overall survival was 12 months post-relapse; higher KPS and pure systemic relapses correlated with better OS.

Conclusions:

• Extracerebral PCNSL relapses are uncommon, predominantly extranodal, and frequently involve specific organs like the testis, breast, and PNS.
• Mixed CNS and systemic relapses indicate a worse prognosis.
• Systematic PET-CT screening at diagnosis is recommended to detect potential occult extracerebral disease.