ESTRO 37 Abstract book

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ESTRO 37

terms of overall survival and most secondary endpoints (Lancet Oncol 2014;15:387-95). A trend for patients with 5-10 tumors to undergo SRS alone has since became apparent. The next step is to reappraise whether SRS alone treatment results for tumor numbers ≥10 differ from those for 2-9. During the past two decades, several retrospective studies have demonstrated the SRS alone treatment strategy to have certain benefits for carefully- selected patients with ≥10 BMs, i.e., sufficiently long survival period, with lower incidences of neurological death, neurological deterioration, local recurrence and SRS-related complications. Herein, we introduce our Mito experiences with SRS for ≥10 BMs, employing a case- matched study on 934 patients, 467 each in the groups with 2-9 BMs and ≥10 BMs. Post-SRS treatment results, i.e., median survival time and cumulative incidences of neurological death, neurological deterioration, local recurrence, repeat SRS for new lesions and SRS-related complications, were not inferior for patients with ≥10 BMs as compared to those with 2-9 BMs. We conclude that patients with ≥10 tumors are not unfavorable candidates for SRS alone. SP-0684 Against the motion J.F. Daisne 1 1 CHU-UCL-Namur- site Sainte-Elisabeth, Radiation Oncology, NAMUR, Belgium Abstract text Brain metastases from solid tumours are constantly increasing in incidence because people live longer thanks to improved systemic treatments [1]. As a consequence, there is an increase in radiotherapy needs. In the meantime, most centres tend to abandon whole brain radiotherapy (WBRT) in favour of stereotactic radiosurgery (SRS) for patients presenting up to ten lesions, even in the postoperative setting. This heavy trend is “justified” by randomized studies showing that, in up to 3 intact lesions, SRS is equivalent to SRS + WBRT for overall survival while maintaining a better cognitive outcome on the mid-term [2,3]. The same conclusions were drawn from a randomized study comparing SRS to WBRT in the postoperative setting [4]. A meta-analysis on three of the four published randomized trials [2,3,5,6] found an advantage in overall survival to omitting WBRT in patients younger than 50 years [7]. In the same time, the QUARTZ study did not find any advantage of WBRT in terms of QALY, overall survival or corticoids dependence compared to best supportive care (BSC) for patients presenting with brain metastases from non small cell lung cancer [8]. The JLKG (non randomized) prospective study showed that patients treated with SRS for five to ten metastases had the same outcome in terms of overall survival and needs of salvage treatments compared to patients with four or less intact lesions [9]. Anyway, does it mean that no indication persists in 2018 and that WBRT should be abandoned? The criticical analysis of these articles puts this deduction in doubt. In the QUARTZ study, most patients presented a bad prognosis (RPA 3 in 38% and DS-GPA < 2 in 80%) and eleven percent randomized to WBRT did not receive the planned dose. Altogether, these are potential biases favouring the BSC arm. Moreover, the forest plot analysis shows that some patients still benefit from WBRT, i.e. those younger than 60, presenting a good Karnofsky performance status (≥ 70) or a DS-GPA ≥ 2.5 and a controlled primary [8]. In the four studies of SRS versus SRS + WBRT in up to 3 or 4 lesions, all showed a significant decrease in local and distant brain control, necessitating more follow-up with regular magnetic resonance imaging (MRI) and salvage treatments [2,3,5,6]. Beyond the necessity to buy dedicated (and more expensive) machines for SRS deliverance, it induces also an increase in MRI prescriptions, a more expensive imaging technique with long waiting lists in most countries. Though statistically

significant, the gain in neurocognitive functions is small enough that its clinical significance is questionable. The identification of the hippocampus as a key structure for neurocognition and the development of techniques to minimize its irradiation open the way to a rebirth of the WBRT. A prospective phase II trial demonstrated that the risk of peri-hippocampic relapse was 8% and that the neurocognitive functions were maintained in long survivors (> 6 months) [10]. The ongoing NRGCC-001 and 003 randomized trials should define more clearly the place of hippocampal avoidance (HA) WBRT. If these trials confirm the benefit of HA strategies, new randomized studies should be set up to challenge SRS to HA-WBRT with dose escalation on metastases by SRS or simultaneous integrated boost [11]. REFERENCES [1] Tabouret E. Anticancer Res 2012;32:4655–62. [2] Chang EL. Lancet Oncol 2009. [3] Brown PD. Jama 2016;316:401–9. [4] Brown PD,. Lancet Oncol 2017;0:1049–60. [5] Aoyama H. Jama 2006;295:2483–91. [6] Kocher M. J Clini Oncol 2011;29:134–41. [7] Sahgal A. Int J Radiat Oncol Biol Phys 2015;91:710– 7. [8] Mulvenna P. Lancet 2016;388:2004–14. [9] Yamamoto M. Lancet Oncol 2014;15:387–95. [10] Gondi V. Journal of Clinical Oncology 2014;32:3810–6. [11] Oehlke O. Strahlenther Onkol 2015;191:461–9. SP-0685 For the motion: A paradigm shift B. Baumert 1 1 Paracelsus-Klinik, Radiotherapy, Osnabrueck, Germany Abstract text The landscape in the treatment of brain metastases is changing. Numbers of patients with newly diagnosed brain metastases are increasing due to improved imaging and detection of brain metastases as well as prolonged survival due to advances in systemic treatment. More aggressive treatment concepts for patients with oligo- metastatic disease have been developed and curative indications increase. New systemic treatment possibilities like targeted therapies are available for brain metastases, partially with high response rates and thus making whole brain radiotherapy partially superfluous. Diagnosis and therapy concepts change and are increasingly based on molecular markers of the primary tumor. Some of the new targeted therapies are additive to radiation and could potentially further increase local control but also toxicity. Focal and precise modern radiation techniques have been established and have improved local control of brain metastases. A paradigm shift has taken place from whole brain radiation therapy (WBRT) towards local treatments like radiosurgery (SRS), stereotactic radiotherapy (SRT) or postoperative adjuvant radiation of the operation cavity. Randomized trials have shown efficacy of SRS/SRT alone to treat >= 5 metastases, large cohorts studies even for up to 10 brain metastases. With prolonged survival and increased tumor control questions of long term toxicity get increasingly important. Outcome towards quality-of-life and neurotoxicity need to be addressed. Recent studies investigate the possibilities of reduction of toxicities by radiation of the resection cavity only and have shown increased local control compared to operation alone. The use of SRS/SRT is another method to spare the hippocampus and therefore, avoid neurotoxicity. Focal radiotherapy avoids hair loss of the whole skull and thus increases quality-of-life. These facts and results can be weighed against the use of whole-brain radiotherapy (WBRT) in many settings especially in the light of randomized studies which have shown no increase in overall survival. Treatment strategies for patients with brain metastases