Reirradiation of primary brain tumours: survival, clinical response and prognostic factors

First, the aim was to determine the survival and quality of life after reirradiation of relapsing primary malignant brain tumours. The second aim was to assess the influence of a set of potentially prognostic factors on survival.

Forty-two patients received reirradiation for recurring primary brain tumours. The interval between the two consecutive treatments was at least 1 year. External beam irradiation for the initial and recurrent tumour was usually delivered with two opposing lateral fields or two wedged fields in orthogonal directions. The median physical doses of the first and second radiation course were 50 and 46 Gy, respectively. The median cumulative biological equivalent doses (BED) were 200.4 (alpha/beta = 2 Gy) and 115.2 Gy (alpha/beta = 10 Gy). During follow-up, corticosteroid medication and the WHO-performance were registered at regular intervals. The radiological response was assessed by reviewing all available CT- and MRI-films. Potentially prognostic factors with respect to survival were evaluated by both univariate and multivariate analyses.

A clinical response (i.e. clinical improvement) was seen in 24% of the patients. Of the evaluable patients, nearly one-third showed a complete (8%) or partial (22%) radiological response. The median overall survival (OS) and progression-free survival (PFS) after retreatment were 10.9 and 8.6 months, respectively. By multivariate analysis, four independent prognostic factors for survival were identified: (1), the WHO-score before retreatment (P = 0.002); (2), the length of the interval between treatments (P = 0.008); (3), the tumour histology; and (4), the response to initial treatment (P values, 0.04). The median survival times for patients with WHO-scores of 0-1 and > or = 2 were 14.0 and 7.4 months, respectively. Patients with oligodendrogliomas had a median OS of 27.5 months, whereas patients with astrocytomas had a median OS of 6.9 months after retreatment. Long-term complications of retreatment were seen in three patients, all of whom had a cumulative BED(2) of > 204 Gy (with alpha/beta = 2 Gy). The quality of life after retreatment, however, was well preserved in the majority of patients. They remained ambulant and capable of self-care until the time of progression which occurred after 8.6 months (median PFS).

After an initial treatment with radiation up to tolerance levels of normal brain tissue, reirradiation of recurring primary brain tumours seems feasible. During the time until clinical progression, patients remained independent with a reasonable quality of life.