NCOG-21. EFFECT OF PNEUMOCYSTIS JIROVECII PNEUMONIA PROPHYLAXIS ON HEMATOLOGIC TOXICITY IN PATIENTS RECEIVING CHEMORADIATION FOR PRIMARY BRAIN TUMORS

Abstract INTRODUCTION Management of diffuse gliomas often includes radiation plus concomitant and adjuvant temozolomide. Hematologic toxicities are common from this therapy. Patients frequently receive prophylaxis against pneumocystis jirovecii pneumonia (PJP) during chemoradiation; however, some PJP drugs have the potential to independently cause myelosuppression which could exacerbate hematologic chemoradiation requiring chemotherapy dose reduction or cessation. We seek understand differences in frequency when either trimethoprim/sulfamethoxazole (TMP/SMX) pentamidine used for prophylaxis. METHODS This was a retrospective chart review patients with primary brain tumors who were treated first-time concurrent temozolomide between April 2014-August 2021 at Huntsman Cancer Institute. Chi squared analysis evaluate effect choice on risk neutropenia, lymphopenia, thrombocytopenia within one month finishing chemoradiation. Logistic regression performed Common Terminology Criteria Adverse Events (CTCAE) score lowest neutrophil, lymphocyte, platelet count. RESULTS 217 included analysis. 144 received TMP/SMX, 69 pentamidine, 1 dapsone, 3 no initiation Of 15.4% developed an absolute neutrophil count < 1,500 cells/µL while occurred 7.2% receiving (p=0.10). Platelet 100,000 18.1% TMP/SMX 20.3% (p=0.70). Worst CTCAE scores similar groups. CONCLUSION Our study provides preliminary evidence that type does not appear significantly impact toxicity temozolomide; there trend toward higher rates neutropenia larger analyses needed further these findings.