Distribution and prognostic significance of myelotoxicity in newly diagnosed glioblastoma in a real-life cohort: Time to treat more aggressively?

Background: Glioblastoma represents one of the most aggressive and fatal primary brain tumors in adults. Chemotherapeutic agents, while integral to management, frequently induce varying levels of myelotoxicity. The aim is to investigate the clinical impact of myelotoxicity in patients treated with the CeTeG versus the Stupp regimen which has not yet been systematically investigated under real-world conditions. Methods: This retrospective study included patients with newly diagnosed glioblastoma who underwent radiochemotherapy. Peripheral blood counts were systematically assessed throughout first-line therapy, starting at the initiation of radiation and continuing until either first disease progression or death, whichever occurred earlier. Results: Among 161 identified patients, 133 (83%) were assigned to the myelotoxicity cohort and 28 (17%) to the non-myelotoxicity cohort. Female sex was independently associated with a higher incidence of myelotoxicity (p = 0.007). In multivariate analysis leukopenia ≥ grade 2 was significantly associated with improved progression-free and overall survival in both the overall and CeTeG cohorts. Neutropenia ≥ grade 2 similarly correlated with improved survival outcomes in the overall cohort. Prophylaxis against pneumocystis jiroveci pneumonia was associated with a significant survival advantage in both the overall and Stupp cohorts, as was lymphopenia grade 3-4. Conclusion: Myelotoxicity at the time of glioblastoma diagnosis does not seem to be detrimental to patient outcomes. Our findings highlight the importance of pneumocystis jiroveci prophylaxis in the Stupp regimen. This raises the intriguing question of whether future chemotherapy dosages could be tailored based on individual blood values, potentially exceeding current standard doses. Prospective studies are needed to explore these possibilities, including the feasibility of high-dose therapies similar to those used in leukemia treatment.