The Role of Radiotherapy in the Treatment of Primary Central Nervous System Lymphomas

Primary central nervous system (PCNS) lymphomas are rare disease entities, though the incidence is increasing due to various immunosuppressive situations. The brain, eyes, and the spinal cord could be affected without any systemic disease involvement. Untreated PCNS lymphoma has been a rapidly fatal course. However, combined modality treatments have positive impact on overall survival. Pretreatment plan is formed by evaluating the treatment options to be used, disease involvement, and individual comorbidity. The PCNS lymphomas are known to be very sensitive to irradiation and chemotherapy treatments. The treatment plan is also generated according to the neurological condition and functional status of patients. The mainstay of induction therapy has been high dose methotrexate administration for most patients. The addition of radiotherapy as a consolidation treatment increases progression-free survival. The use of reduced irradiation dose and different fractionation schemes has been investigated in different studies to avoid the increased toxicity of high-dose whole-brain radiotherapy. High-dose chemotherapy, autologous hematopoietic cell transplantation, and whole-brain radiotherapy are alternative applications in patients with insufficient response to induction therapy. Stereotactic radiotherapy is another option in case of relapsed or refractory disease. Age and performance are also important indicators of survival and tumor progression. study of MTX, Rituximab and Temozolomide, plus hyperfractionated WBRT (36 Gy in twice daily 1.2 Gy fractions) in 66 patients with PCNSL was associated with an objective response rate of 85.7%. This study demonstrated that OS and PFS were improved compared with historical controls from RTOG-9310. Among patients, 66% had grade 3 and 4 toxicities before hWBRT, and 45% of patients experienced grade 3 and 4 toxicities attributable to post hWBRT chemotherapy.