Abstract 375P
Background
Most patients with glioblastoma will develop a recurrence despite initial aggressive therapy with maximum surgical resection and postoperative chemoradiation (CRT). A re-excision is often not feasible but palliative chemotherapy can be considered depending on fitness etc. In the absence of level 1 evidence, different chemotherapy regimens have been used in this setting. The aim of this study is to evaluate our approach which includes re-challenge temozolomide (TMZ) for patients with DFS >6 months after initial therapy and procarbazine/lomustine/vinctistine (PCV) for those exhibiting shorter responses to initial treatment.
Methods
We retrospectively collected and analysed the data of patients with glioblastoma treated with systemic therapy for recurrent disease during 2009-2019. After the initial diagnosis, they all had a surgical resection and received treatment on the Stupp protocol. The Response Assessment in Neuro-oncology (RANO) criteria was used to assess response to palliative chemotherapy after recurrence. Patient demographics and disease/treatment characteristics were described and survival outcomes were estimated using the Kaplan-Meier method. Haematological toxicities were recorded and chemotherapy-related admission rates were used as surrogate for other toxicities.
Results
56 patients were identified of which 20 received re-challenge TMZ and 36 received PCV. Measured from the start of palliative chemotherapy, the median PFS was 3 months for TMZ and 4 months for PCV while median OS was 5.5 months for TMZ and 6 months for PCV. Both regimens were reasonably well tolerated. Grade 3-4 haematological toxicity was 10% and Grade 1-2 was 25% with TMZ. Corresponding figures for PCV were 13.9% and 30%. Only 1 patient was admitted due to pneumonia (who had received PCV).
Conclusions
Re-challenging patients with recurrent glioblastoma with TMZ after a durable initial response to surgery + CRT and offering PCV to those with a less good response to primary therapy is a reasonable, pragmatic approach adopted by a lot of UK cancer centres. Our toxicity data suggests this treatment protocol is safe. Of interest, patients treated with re-challenge TMZ had the same PFS and OS as their PCV counterparts despite belonging in a theoretically better prognosis group.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.