Tolerability of PCV in low grade glioma: A real world experience

Background In the phase III RTOG 9802 trial, median overall survival (OS) increased from 7.8 years with radiotherapy alone to 13.3 years (P = .002) with adjuvant procarbazine, lomustine, and vincristine (PCV) following surgery for low grade glioma. Although the PCV regimen improved survival, there were significant toxicities. We hypothesised more frequent toxicities would be observed in clinical practice. We aimed to identify and quantify toxicities in the real world setting in a National Neuro-Oncology centre. Methods Patients with low grade glioma who received PCV following radiotherapy from Nov 2014 to Nov 2018 were identified from Institutional databases. Data on toxicities, dose reductions, dose delays and treatment discontinuation were collected from paper and electronic patient records. Results A total of 41 patients with low grade glioma were identified. Patients were predominantly male (n = 28) and the median age at diagnosis was 41. Of these, 28/41 patients had a diagnosis of oligodendroglioma and 13/41 had astrocytoma. The majority of patients had tumours with favourable molecular features such as IDH mutations (n = 38) and 1p19q co deletions (n = 23). Only 4 patients completed 6 cycles of chemotherapy without any dose modification or delay. 16 patients completed PCV with dose reductions and dose delays at various levels. The dose intensity was as follows: procarbazine: 69%, lomustine: 71% and vincristine: 68%. Neutropaenia and thrombocytopaenia (table) were the major causes of treatment discontinuation (14/21 patients). Three patients had disease progression during chemotherapy and two patient’s treatment was discontinued due to abnormal LFTs. Three patients opted not to continue chemo due to intolerability in context of grade 3 to 4 fatigue and GI symptoms. At median follow up of 17 months, 9/41 patients have had disease progression. Table: 430P . Our Study % RTOG 9802% Patient Completed PCV 48 56 Median Number of Cycles Completed 3 3.5 Thrombocytopenia G2 (50-75) 71 9 G3 (25-50) 17 18 G4 ( 2 0 Neutropenia G2(1-1.5) 87 9 G3(0.5-0.1) 31 35 G4( 7 8 Conclusions Frequent toxicities are observed with PCV in clinical practice. Our data suggest it might be preferable to adjust doses from the start of chemotherapy to improve tolerability. Legal entity responsible for the study The authors. Funding Has not received any funding. Disclosure All authors have declared no conflicts of interest.