Re-evaluating the Efficacy and Toxicity of Procarbazine, Lomustine and Vincristine (PCV) in Relapsed Glioblastoma in the Concurrent/Adjuvant Temozolamide Era

Abstract

Background: Publication of the Stupp Trial in 2005 led to adoption of concurrent/adjuvant Temozolomide(TMZ) with radiotherapy as the standard of care for fit patients with newly diagnosed Glioblastoma. No accepted standard treatment exists for relapsed disease. However, nitrosurea based regimens are commonly used. Little published evidence exists for the use of such nitrosurea based regimens in the post-Stupp era. Patients and Method: We present a retrospective study of a cohort of patients between 2009 and 2014 treated with procarbazine, lomustine and vincristine (PCV) for disease progression after completing treatment with the Stupp regime. Result: 33 patients received PCV chemotherapy having previously been treated with the Stupp regime. Median age was 47 (range 23 to 74). The median number of cycles received was 2 (range 1 to 6). Patients underwent magnetic resonance imaging (MRI) to assess response: 19%, 23% & 58% showed Partial Response, Stable, and Progressive Disease respectively. The Median Overall Survival (OS) was 26 weeks. Median Progression Free Survival (PFS) was 17 weeks with Progression Free Survival at 6 months (PFS 6) of 20%. Grade 3/4 haematological toxicity was observed in 31% of patients, of these, 18% developed grade 3/4 thrombocytopenia. Non haematological toxicities included venous thromboembolism in 13% of cases. Treatment discontinuation due to toxicities occurred in 6% of patients. Conclusion: Our experience in this cohort of patients suggests that PCV in relapsed GBM following the Stupp regimen provides modest survival benefit but is relatively well tolerated with a low risk of serious toxicity.