Pattern of blood count change during craniospinal irradiation and the effect on progression free survival in medulloblastoma adult patients.

Abstract

e13500 Background: The primary treatment of medulloblastoma in adults is surgery followed by radiotherapy. Craniospinal irradiation in such patients holds a clinical significant effect on blood count drop, as more than 50% of bone marrow is irradiated during CSI. Precise guidelines on how often a patient's peripheral blood count should be monitored are yet to be established. Methods: A retrospective analysis of blood count data on 42 adult medulloblastoma patients who underwent surgical resection followed by CSI as 36-39.6Gy over 20-22 fractions followed by boost to posterior cranial fossa up to 54Gy and spinal boost up to 45Gy. The manner of blood count cells during radiotherapy and the correlation between WBC drop and outcome were examined. Results: Our study showed a drop in WBCs to 4 and below in 64% of patients during CSI. Eight patients (19%) had Hb drop below 12. There was no grade 3 or 4 anemia. Significant drop in neutrophils below 1500 was observed in 8 patients (20%), with 2.4% had grade 3 neutropenia. In 26 patients (62%) who developed platelets drop, three patients (7%) had platelets of less than 50000 (grade 3 and 4 thrombocytopenia). The Hb, lymphocyte, neutrophils, and platelets nadirs were 8.7 g/dL, 42 cells /microL, 720 cells /microL, and 1000 platelets/microL, respectively. The minimum interval between the nadir and starting radiotherapy for Hb, WBCs, and platelets were 13, 6, and 11 days, respectively. The median interval between the nadir and starting radiotherapy for all cells was 3 weeks. The median WBCs percentage drop was 71%. In 23 patients who had non-metastatic disease, the estimated three year progression free survival was 70%. In those who had WBC drop below 2.7 the PFS was 100% vs. 46%. (P value = 0.042). Conclusions: Some institutions reduced monitoring of CBC during conventional radiotherapy may result in financial saving; however, our study suggests the need for weekly CBC for patients receiving CSI irradiation. Fortunately, no one developed serious infection during radiotherapy, but a precaution should be there. A WBCs change during radiotherapy could reflect the outcome and may suggest more aggressive treatment in patients who had a nadir of 2.7 and above.