Low platelet counts in patients with glioblastoma.

Abstract

e13565 Background: Radiotherapy and concurrent chemotherapy with Temozolomide (TMZ) have myelosuppressive effect, and thrombocytopenia is commonly seen in this patient population seen in 5-10% of glioblastoma (GBM) patients. There is a lack of data analyzing the thrombocytopenia and it’s on the progression free survival (PFS) or overall survival (OS) of these patients. The primary objective of this study was to identify the degree of thrombocytopenia in newly diagnosed GBM patients receiving concurrent TMZ based chemoradiation (CRT). Secondary objectives included associations between thrombocytopenia PFS, and OS. Methods: We retrospectively reviewed 484 newly diagnosed GBM patients who underwent surgery followed by standard of care CRT. We also analyzed the association between platelet counts and age, sex, MGMT methylation status, and extent of surgical resection. Platelet count was collected at the time of surgery, CRT start date, and two, four, six, and ten weeks post-CRT start date. Patients were grouped into quartiles according to their platelets count. Results: Of the 484 patients collected, 308 were males, 139 had gross total resection of the tumor, 229 patients were older than 65 years, and 171 (42.1%) were MGMT methylated. In a univariate analysis, a platelet count less than 180,000 (lowest quartile) was associated with higher mortality (HR 1.63, P < 0.001) but had no significant association with PFS (HR 1.16, P = 0.48). Among the 118 patients who had platelet count lower than 180,000, 4 had platelets count less than 100,000 necessitating their TMZ to be stopped during CRT. In a multivariate analysis model adjusting for age, gender, MGMT status, and type of surgery, platelet counts less than 180,000 was also associated with significantly higher mortality (HR 1.60, P < 0.001). Conclusions: Our study concluded that patients who had platelet counts less than 180,000 at the time of surgery or CRT with TMZ had significantly higher mortality (HR 1.60, P < 0.001) but had no association with PFS (HR 1.16, P = 0.48).[Table: see text]

Evaluating hematologic parameters in newly diagnosed and recurrent glioblastoma: Prognostic utility and clinical trial implications of myelosuppression

“…For lymphopenia, neutropenia, and thrombocytopenia, we used criteria for grade 3 toxicity from CTCAE v4.0. 15 At pre-op time point, 11.9% (56/469) of patients had grade 3 or higher lymphopenia, none reached grade 3 or higher neutropenia and 0.5% (2/418) had thrombocytopenia. At post-op, pre-CRT time point, 15.4% (97/628) of patients had grade 3 or higher lymphopenia, 0.4% (2/515) had grade 3 or higher neutropenia and 1.3% (7/538) had thrombocytopenia.…”