Primary Central Nervous System Lymphoma: Long-Term Treatment Outcomes and Cost-Analysis from a Retrospective Study of High-Dose Methotrexate Based Chemoimmunotherapy and Reduced Dose Radiation Therapy Approach

Standard treatment of primary central nervous system lymphoma (PCNSL) in countries with limited resources remains conventional chemotherapy, with or without whole brain radiotherapy (WBRT). To evaluate the treatment outcomes, prognostic factors and costs in patients with PCNSL treated with high-dose Methotrexate, vincristine and procarbazine, plus Rituximab (MVP-R) followed by consolidation with reduced dose (rd) WBRT and Cytarabine chemotherapy. We conducted an institutional audit of the first line treatment of patients with PCNSL, who were treated with MVP-R regimen, WBRT, or both between September 2011 and January 2020. Long term neuro-cognitive toxicity was recorded on follow up. The 5-year overall survival (OS) was the primary end point. Of 54 patients, 42 were evaluable [median age: 54 years (19-73 years)]. The commonest subtype was activated B-cell subtype (90%). At presentation, multiple and deep brain lesions were reported in 38 and 73% patients, respectively. Combined chemoimmunotherapy was given to 41 patients and WBRT to 29 patients. 27 patients (65%) achieved a complete response, and 22 received rdWBRT. 7 patients with partial response received conventional dose WBRT. Among tested prognostic factors, response to treatment was the single most significant determinant. At a median follow-up of 58 months, the 5-year progression free survival was 42%, and 5-year OS was 60%. The median direct hospital costs incurred by most patients for investigations and treatment were $1976.45 and $12,078.49, respectively. MVP-R is a well-tolerated regimen with substantial long term outcomes. Among all prognostic factors, response to therapy is the most significant.

How I treat primary CNS lymphoma

Primary CNS lymphoma (PCNSL) is a rare malignancy with peculiar clinical and biologic features, aggressive course, and unsatisfactory outcome. It represents a challenge for multidisciplinary clinicians and scientists as therapeutic progress is inhibited by several issues. Molecular and biologic knowledge is incomplete, limiting the identification of new therapeutic targets, and the particular microenvironment of this malignancy, and sanctuary sites where tumor cells grow undisturbed, strongly affects treatment efficacy. Moreover, active treatments are known to be associated with disabling neurotoxicity, posing the dilemma of whether to intensify therapy to improve the cure rate or to de-escalate treatment to avoid sequels. The execution of prospective trials is also difficult because of the rarity of the tumor and the impaired general condition and poor performance status of patients. Thus, level of evidence is low, with consequent uncertainties in therapeutic decisions and lack of consensus on primary endpoints for future trials. Despite this unfavorable background, laboratory and clinical researchers are coordinating efforts to develop new ideas, resulting in the recent publication of studies on PCNSL's biology and molecular mechanisms and of the first international randomized trials. Herein, these important contributions are analyzed to provide recommendations for everyday practice and the rationale for future trials.