Tumorvolumenminderung durch PCV-Therapie bei Patientinnen und Patienten mit Oligodendrogliomen

PCV (procarbazine, CCNU and vincristine) chemotherapy is an integral part of tumor-specific treatment in patients with oligodendroglioma and might be preceded by tumor resection and radiotherapy. PCV chemotherapy has been reported to decrease tumor volume, but to what extent has not been described yet.

The institutional database was screened for patients that had been diagnosed with CNS WHO grade 2 or 3 oligodendroglioma, IDH-mutant and 1p/19q co-deleted, between the years 2003 and 2019. Patients either diagnosed by biopsy or with postoperative residual tumor volume and having received PCV chemotherapy were included. Magnetic resonance imaging (MRI) pre- and post-chemotherapy had to be available for volumetric analyses. Tumors were segmented manually, and tumor volume decrease was correlated with patient data.

Forty-one patients were identified. Median overall tumor decrease after PC(V) was 26% (range 0-92%). In treatment naïve patients, median tumor volume decrease was 35% (range 0-92%). Ten patients (24%) showed a volume decrease of >50%. Comparing patients with a decrease over 50% versus less than 50% showed no differences in age (median, in years: 35 versus 41, p=0.27), sex (p=0.15), initial tumor volume (median, in ml: 65 versus 44, p=0.99), KPS (median: 90, p=0.44), WHO grade (p=0.99), contrast enhancement on MRI (p>0.99) or prior treatment regimens (p=0.26). The median number of completed cycles was higher in patients with a volume decrease >50% (6 versus 5, p=0.04). Progression-free survival was not associated with tumor volume decrease (HR 0.81, 95 CI 0.36-1.92, p=0.62).

PC(V) chemotherapy is associated with a substantial decrease in tumor volume in most patients with oligodendroglioma. Besides numbers of cycles completed, current demographic and risk factors do not sufficiently predict therapy response on MRI. As one fourth of all patients showed a volume decrease of >50%, evaluation of PCV as a neoadjuvant treatment strategy might be warranted.