Treatment outcome and prognostic factors in PCNSL

Standard treatment with a thiotepa-based regimen in countries with a limited resource is less feasible. Aims of the study were to evaluate the treatment outcome, and identify the prognostic factors in patients with primary central nervous system lymphoma (PCNSL).

We conducted a retrospective study of 43 patients diagnosed with PCNSL, DLBCL subtype, who were treated with either HDMTX-based regimen, whole brain radiotherapy (WBRT), or both between 2010 and 2017.

There were 43 patients with a median age of 65 years (range 34-89 years). Protein expression of CD10, Bcl6, MUM1, Bcl2 and MYC were found in 19, 86, 91, 91 and 23%, respectively. Both germinal center B cell (GCB) and double-expressor (MYC+/Bcl2+) lymphomas were found in 21%. Multiple brain lesions and maximum tumor diameter (MTD) ≥5 cm were seen in 27 and 10 patients, respectively. Chemotherapy combined with WBRT, chemotherapy and WBRT were given to 20, 14 and 9 patients, respectively. Overall complete remission (CR) rate was 55.8%. Those receiving a combined-modality therapy had a higher CR rate than those treated with either chemotherapy (75% versus 36%, p = 0.036) or WBRT (75% versus 44%, p = 0.109). Median follow-up time was 17 months, and a 7-year overall survival (OS) was 40%. Features associated with a prolonged OS were an ECOG score ≤ 2 (p = 0.001), multiple brain lesions (p = 0.010), multiple area of brain involvement (p = 0.023), MTD < 5 cm (p = 0.004), GCB subtype (p = 0.003) and positive CD10 staining (p = 0.007). Expression of Bcl2 protein was associated with a significantly worse OS in the non-GCB DLBCL patients.

The factors affecting treatment outcomes in PCNSL were cell of origin of DLBCL, lesion characteristics, patients' status and treatment regimen.