According to Nussbaum et al., 24-45% of cancer patients develop cerebral metastases during their disease. Brain metastases are generally associated with a poor prognosis and high morbidity2. Published median survival rates after WBRT are between 2 and 7 months3. Standard of care in multiple BM is WBRT delivered as total dose of 30 Gy in 10 fractions, leading to modest palliation with a median survival of 3 to 5 months 4-6. Prognostic factors include the RPA-classification, performance status, response to steroids and evidence of systemic disease3,6.

Unfortunately, intracerebral recurrence happens 7-9. For example, in the cohort of Meyners et al. (2010) on WBRT in relatively radio-resistant tumours, median time to recurrence was 4.5 months and the local control rates at 6 and 12 months after radiotherapy were 37% and 15%, respectively10. Furthermore, the treatment of intracerebral recurrence after previous WBRT is challenging. In case of ≤ 3 recurrent BM, surgery or stereotactic radiosurgery (SRS) are options. One other option, especially in case of \>3 recurrent BM is repeated WBRT. In this setting, one of the first reports on repeated WBRT was published by Cooper et al. in 199011. The authors reported on repeated WBRT (n=52) consisting of a total dose of 25 Gy in 10 fractions. Response to re-irradiation was seen in about 40% of the patients. Furthermore, the patients improved by at least one level in their neurologic function status. Survival after second therapy averaged 5 months. In the report by Wong et al. (1996) median dose of retreatment (n=86) was 20 Gy12. Resolution of symptoms was achieved in 27% of patients, partial improvement in 43% and no improvement or worsening of symptoms was seen in 29% of patients. The majority of patients had no significant toxicity in consequence of re-irradiation. Five patients had radiographic abnormalities of their brain consistent with radiation-related changes. One patient had symptoms of dementia that was thought to be caused by radiotherapy. Sadikov et al. (2007) reported on 72 patients who underwent repeated WBRT for recurrent or progressive BM13. The median survival after re-irradiation was 4.1 months. One patient was reported having memory impairment and pituitary insufficiency after 5 months of progression-free survival.

In the report by Mayer et al. on re-irradiation tolerance of the human brain (this analysis was focused on recurrent glioma), the authors concluded that radiation-induced brain tissue necrosis is likely to occur at normalized tolerance doses of cumulative \> 100 Gy14.

The recent QUARTZ trial investigated the efficacy of WBRT vs. OSC in patients with non-small cell lung cancer and low performance status. The results suggest that WBRT, even in the primary situation, offers no substantial benefit to most patients with brain metastases from NSCLC in terms of improved survival, overall quality of life, or reduction of steroid use in this cohort15.

In the present trial, the primary endpoint (time to WHO PS deterioration to more than 3) as well as the secondary endpoints QoL, overall survival, radiation-induced toxicity and functional independence assessed by the Barthel Index of Activities of Daily Living (ADL) in patients previously treated with WBRT requiring repeated WBRT for intracerebral tumour progression will be evaluated.