[The effect of extent of tumor resection on the outcome of combined therapy in patients with glioblastoma multiforme].

INTRODUCTION

The importance of the extent of surgery as a prognostic factor in multiform glioblastoma has been investigated for years. Some studies could not establish its influence on survival of patients treated with surgery, postoperative radiotherapy, with or without chemotherapy. On the other hand, there are data suggesting benefit for patients treated with more aggressive surgical approach. The aim of this study was to investigate the influence of the extent of surgery on survival/progression-free survival of patients with multiform glioblastoma treated with two consecutive protocols of a combined approach.

MATERIAL AND METHODS

Of 86 patients that entered this study, thirty-seven were treated with surgery, postoperative hyperfractionated radiotherapy using 1.2 Gy b.i.d. to a total tumour dose of 72 Gy in 60 fractions in 30 treatment days and adjuvant chemotherapy consisting of BCNU, vincristine, procarbazine and cisplatin for up to 6 cycles or until tumour progression. Forty-nine patients were treated with surgery and postoperative accelerated hyperfractionated radiotherapy using 1.5 Gy b.i.d. fractions to a total tumour dose of 66 Gy in 44 fractions during 22 treatment days. BCNU and hydroxyurea were given once weekly during the irradiation period. Surgery consisted of biopsy in 25 patients and subtotal or gross total tumour resection in 61 patients. Patients treated with a more radical surgery had longer median survival time and higher 1- and 2-year survival rates than those treated with biopsy (56 v.s. 29 weeks, respectively; 62% and 23% v.s. 16% and 0%, respectively; long rank, p = 0.0000) (Figure 1). They also had longer median time to tumour progression and higher 1-year progression-free survival rate than those treated with biopsy only (33 v.s. 21 weeks, respectively; 20% v.s. 0%, respectively; log rank, p = 0.00000) (Figure 2). Multivariate analyses using both survival and progression-free survival as endpoints confirmed that the extent of surgery was an independent prognostic factor, together with the age, tumour location, and interfraction interval (Tables 3 and 4).

DISCUSSION

The benefit of a more radical surgery remains controversial in patients with multiform glioblastoma, although maximal tumour reduction should be supported from the cytokinetic point of view. Findings of various authors support this view. Results of this study add further evidence that the aggressive surgical approach carries significant benefit for patients with multiform glioblastoma regarding the survival and progression-free survival. These observations are confirmed with multivariate analyses that showed independent influence of this prognostic factor.