2018 Volume 27 Issue 1 Pages 29-36
Combination of systemic administration of high dose methotrexate (HD-MTX) and whole brain radiation therapy (WBRT) has widely been used as the standard treatment modality for primary CNS lymphoma (PCNSL). In this study, we retrospectively analyzed newly diagnosed PCNSL cases treated with different regimens at our institute. First, by comparing the results of our historical data of DeVIC (dexamethasone, etoposide, ifosfamide, carboplatin)/WBRT and HD-MTX/WBRT, we evaluated their strengths and limitations. We then compared the results of RMPV (rituximab, methotrexate, procarbazine, vincristine)/reduce dose WBRT (rd-WBRT) therapy to the historical regimens to examine if RMPV therapy could overcome the drawbacks of the past regimens. We report here our experience with RMPV therapy from Nagoya University where our Department of Neurosurgery carries out all neuro-oncologic duties including systemic chemotherapy.
DeVIC group had a higher response rate compared to HD-MTX group (DeVIC 95%, HD-MTX 50%). One year overall and progression free survival was also longer in DeVIC group. These results highlighted the need to improve the initial response as a major issue to be resolved in HD-MTX therapy. On the other hand, RMPV therapy achieved a much better response (complete remission 86%) with induction chemotherapy alone. One year and two year overall survival after RMPV therapy was 100% and 75% respectively. Moreover, incidence of leukoencephalopathy was lower in RMPV patients, where rd-WBRT of 23.4 Gy was administered, compared to HD-MTX group with WBRT of 40 Gy. There was one case of treatment limiting toxicity in the RMPV group where treatment was discontinued after severe gastro-intestinal hemorrhage. Although RMPV therapy caused more adverse events than HD-MTX in general, there was no significant difference between grade 4 neutropenia requiring G-CSF administration (RMPV 28%, HD-MTX 7.1%, p=0.186).
Our results show that RMPV could overcome the drawbacks of HD-MTX monotherapy. These results are one of the first reports of newly diagnosed PCNSL treated with RMPV/rd-WBRT in a Japanese population. These promising results require further investigation preferably with a prospective trial carried out in an institution with the capacity to properly manage the possible adverse events.
