Long-term adjuvant administration of temozolomide in patients with glioblastoma multiforme: experience of a single institution.

Purpose: Long-term administration of adjuvant temozolomide is common practice in many institutions, especially when treatment is well tolerated and stable disease is achieved. In this study, we evaluate the feasibility and efficacy of long-term temozolomide in patients with glioblastoma multiforme treated at a single institution.

Methods: One hundred and fourteen patients with newly diagnosed glioblastoma were followed for the course of their disease. Treatment consisted of surgery [gross total resection (GTR) subtotal resection (STR) or biopsy] followed by radiotherapy and concomitant temozolomide. Adjuvant temozolomide was administered until evidence for progressive disease or serious side effects occurred. Follow-up was routinely performed every 3 months.

Results: One hundred and fourteen patients with glioblastoma multiforme received a median of 6 cycles of adjuvant first-line temozolomide (range 1-57). For patients with less than 6 cycles, chemotherapy was stopped in 60% for reasons other than progression, while only in 17% of patients receiving 6 or more (P < 0.0001). Median TTP was 7 months (95% CI: 6-10 months). PFS after 6 months was 53%. Median OS in all patients was 15 months (95% CI: 13-18 months). TTP and OS directly correlate with the amount of chemotherapy cycles (each P < 0.0001). No significant influence of the extent of surgical treatment on PFS (P = 0.2141) and OS (P = 0.4308) could be detected.

Conclusion: This data set suggests that long-term administration of temozolomide is safe and efficacious. Side effects occur more frequently in the early phase of drug administration (<6 cycles). There is a strong correlation of long-term temozolomide on PFS and OS regardless of the extent of surgery and other factors.