Single-arm phase II study of conformal radiation therapy and temozolomide plus fractionated stereotactic conformal boost in high-grade gliomas: final report.

PURPOSE

To assess survival, local control and toxicity using fractionated stereotactic conformal radiotherapy (FSCRT) boost and temozolomide in high-grade gliomas (HGGs).

PATIENTS AND METHODS

Patients affected by HGG, with a CTV(1)(clinical target volume, representing tumor bed ± residual tumor + a margin of 5 mm) ≤ 8 cm were enrolled into this phase II study. Radiotherapy (RT, total dose 6,940 cGy) was administered using a combination of two different techniques: three-dimensional conformal radiotherapy (3D-CRT, to achieve a dose of 5,040 or 5,940 cGy) and FSCRT boost (19 or 10 Gy) tailored by CTV(1)diameter (≤ 6 cm and > 6 cm, respectively). Temozolomide (75 mg/m(2)) was administered during the first 2 or 4 weeks of RT. After the end of RT, temozolomide (150-200 mg/m(2)) was administered for at least six cycles. The sample size of 41 patients was assessed by the single proportion-powered analysis.

RESULTS

41 patients (36 with glioblastoma multiforme [GBM] and five with anaplastic astrocytoma [AA]) were enrolled; RTOG neurological toxicities G1-2 and G3 were 12% and 3%, respectively. Two cases of radionecrosis were observed. At a median follow-up of 44 months (range 6-56 months), global and GBM median overall survival (OS) were 30 and 28 months. The 2-year survival rate was significantly better compared to the standard treatment (63% vs. 26.5%; p < 0.00001). Median progression-free survival (PFS) was 11 months, in GBM patients 10 months.

CONCLUSION

FSCRT boost plus temozolomide is well tolerated and seems to increase survival compared to the standard treatment in patients with HGG.