How effective is non-myeloablative chemotherapy after high-dose methotrexate-based treatment in patients with primary central nervous system lymphoma?

This study evaluated the outcomes of patients with primary central nervous system lymphoma (PCNSL) on high-dose methotrexate (HD-MTX; Otrexup)-based chemotherapy followed by non-myeloablative consolidation therapy. The study showed that HD-MTX-based chemotherapy with non-myeloablative consolidation therapy is an alternative and good treatment option for these patients.

PCNSL is a rare and aggressive type of non-Hodgkin’s lymphoma (NHL). PCNSL affects the brain and spinal cord, associated nerves, and tissue layers that enclose the brain and spinal cord, and the eyes. These organs and tissues are protected by the blood-brain barrier (BBB). It is difficult for many medications to effectively cross the BBB.

HD-MTX-based chemotherapy is currently used in the treatment of newly developed PCNSL. HD-MTX has been explored in combination with other therapies, however, this may not be suitable for patients such as the elderly. After initial (induction) treatment, consolidation treatment is given to kill any remaining cancer cells left and prevent relapse. It is important to consider alternative treatment approaches like non-myeloablative sequential chemotherapy since the best treatment option for PCNSL is still unclear.

This study analyzed the clinical data of 243 patients with PCNSL. 94.7% of these patients were given HD-MTX combination treatments. 59.3% of patients received rituximab (RTX; Rituxan), an immunotherapy, with increased use over time. 95 patients completed consolidation chemotherapy with pemetrexed (Alimta) or etoposide (Vepesid) with cytarabine (Cytosar-U). The average follow-up time was 27 months.

After induction treatment, 72.8% of patients responded and 58.8% had a complete response (complete disappearance of cancer). The average survival without cancer worsening was 14 months. After 2 years, 33.2% of patients were alive without cancer worsening. After 4 years, it was estimated that 61.6% of patients were alive.

The average survival without cancer worsening was 28 months for the patients that completed consolidation treatment. 78.7% of these patients were estimated to be alive at 4 years. The overall survival for patients who completed consolidation therapy was not reached (extended the study follow-up period) and was 55 months for those who did not receive consolidation treatment. 

A better early response was associated with longer survival without cancer worsening.

The study found that HD-MTX-based induction chemotherapy with non-myeloablative consolidation chemotherapy was a good treatment option for patients with PCNSL.

The study had lost several patients to follow-up. The study design increased the chance of occurrence of biased results. Further studies are needed with an emphasis on the quality of life of patients.