gms | German Medical Science

Objective: In glioblastoma patients the standard of care consists in radiotherapy with concomitant temozolomide followed by six cycles adjuvant temozolomide on day 1 to 5 in a 28 day cycle. However, except for the initial study design, there is no rationale restricting the adjuvant therapy to 6 cycles and, therefore, many reports propagate continuing treatment until tumor progression, if the patients is stable after six cycles.

Methods: We retrospectively evaluated the progression free survival in patients, who reached the sixth cycle without tumor progression. In Rostock (centre A) the policy was to limit the adjuvant temozolomide to six cycles, in Berlin (centre B) glioblastoma patients were treated with temozolomide until tumor progression. We started the analysis after finishing the sixth cycle. The endpoint was the radiographic tumor progression, death or clinical decline.

Results: 202 patients with glioblastoma and primary temozolomide treatment were recorded in the two centres between 2005 and 2010. 42 patients were progression free after 6 cycles temozolomide and had evaluable follow-ups and MRI data to enter the analysis. 11 patients in centre A received 6 (range 6–6) adjuvant cycles and 31 patients in centre B received 12 (range 7–28) cycles temozolomide. The patients in centre A were older (65 vs. 54 years, p = 0.02). However, there was no significant advantage in progression free survival due to the prolonged chemotherapy (p = 0.69; log rank).

Conclusions: Adjuvant temozolomide in first line glioblastoma patients should be limited to six cycles until prospective data prove the benefit of any additional therapy.