ESTRO 38 Abstract book

S179 ESTRO 38

Purpose or Objective To investigate changes in neurocognitive function and quality of life (QoL) and their association with dosimetric parameters of various brain structures as well as clinical cofactors in adult brain tumour patients following proton Sixty-nine adult patients with primary brain tumours who received conventionally fractionated PBT were included in this study. Neurocognitive function according to the Montreal Cognitive Assessment (MoCA) test and QoL according to general EORTC-QLQ-C30 and brain tumour specific QLQ-BN20 questionnaires were scored prospectively at baseline and within 3-month-intervals up to one year after PBT. Dose-volume parameters of the retrospectively contoured structures hippocampus, thalamus, frontal and temporal lobes, amygdala, entire cerebellum, anterior cerebellum, and posterior cerebellum were extracted. Clinical parameters comprised age, sex, diagnosis and WHO grading, tumour volume, prescribed dose, concomitant chemotherapy, tumour resection and administration of corticosteroids. MoCA scores and differences to baseline values at different time points were correlated with self-reported QoL items (Spearman correlation r s ), clinical and dosimetric parameters (Mann-Whitney U test, logistic regression). A change of ≥3 points of the MoCA total score compared to baseline was considered clinically relevant. Unless otherwise stated, differences at 3 months after PBT compared to baseline are given. Results The MoCA total score remained stable over time for the majority of patients: Less than 10% of the patients had clinically relevant changes at respective time points. The QLQ-C30 items did not change over time. On the QLQ-BN20 symptom scale, significant increases were observed for the items hair loss (p=0.002) and seizure (p<0.042, up to 9 months after PBT). However, future uncertainty decreased significantly (p<0.042). MoCA scores were significantly correlated with self-reported QoL scores. At all time-points, MoCA total score correlated with QLQ-C30 cognitive function (r s : 0.31-0.57) and MoCA language scores with QLQ-BN20 communication deficit (r s : 0.36- 0.59). Clinically relevant differences in the MoCA total score were significantly associated with high dose parameters in the anterior, posterior and entire cerebellum (V55Gy, p<0.05), but not with clinical Neurocognitive function and QoL remained stable in the majority of brain tumour patients following PBT. Self- reported QoL was in accordance with the results of the objective MoCA test. Significant associations between dose-volume parameters and clinically relevant neurocognitive changes suggest that further sparing of organs at risk in treatment planning may lead to increased neurocognitive function and QoL for brain tumour patients. New planning constraints for further potential organs at risk, such as the cerebellum [1], should be discussed. [1] Eekers DBP et al. (2017) Clin Transl Radiat Oncol 8, 22–26. PV-0362 Long term outcomes of high-dose single- fraction radiosurgery for chordomas of the spine and sacrum C.J. Jin 1 , J. Berry-Candelario 2 , A. Reiner 3 , E. Lis 4 , M. Bilsky 2 , I. Laufer 2 , A. Schmitt 1 , D. HIgginson 1 , Y. Yamada 1 1 Memorial Sloan Kettering Cancer Center, Radiation Oncology, New York, USA; 2 Memorial Sloan Kettering Cancer Center, Neurosurgery, New York, USA ; 3 Memorial Sloan Kettering Cancer Center, Biostatistics, New York, USA; 4 Memorial Sloan Kettering Cancer Center, Neuroradiology, New York, USA beam therapy (PBT). Material and Methods parameters. Conclusion

Purpose or Objective To evaluate outcomes of patients with primary chordomas treated with spine stereotactic radiosurgery (SRS) alone or in combination with surgery, drawing from a single- institution database to elucidate treatment options associated with durable control of these conventionally Clinical records were reviewed for outcomes of patients with primary chordoma of the mobile spine and sacrum who underwent single-fraction SRS between 2006 and 2017. Patients were followed with spine MRI to determine local recurrence-free survival (LRFS). LRFS and overall survival (OS) were analyzed using the Kaplan-Meier method. Tumor location and extent of surgery were analyzed for significance in relation to LRFS and OS using univariate Cox regression. CTCAE v. 5.0 toxicity in relation to extent of surgery was analyzed using Fisher’s Exact Test. Results In total, 35 patients with de novo chordoma of the mobile spine (46%) and sacrum (54%) received SRS, with a median post-SRS follow-up of 40.3 months (range 2.0-122.9). The median PTV volume was 155.6 cm 3 (29.2-903.8 cm 3 ). The median PTV dose was 24 Gy (18-24 Gy), with a median V95 = 99.5% and D95 = 2395 cGy. Among 23 patients also undergoing surgery (66%), 39% underwent epidural decompression and instrumentation prior to SRS, while 61% underwent extensive resection including corpectomy or partial sacrectomy. One-third received SRS alone, including 4 patients who did not proceed to planned surgery based on lack of progression and patient preference. The 3- and 5-year LRFS rates were 86.2% and 80.5% respectively. Among 32 patients receiving 24 Gy (91%), the 3- and 5-year LRFS were 96.3% and 90.0%. Four developed metastatic disease (11%) at a median of 5.1 years (range 1.0-10.2). The 3- and 5-year OS rates were 90.0% and 84.3%. Spinal location (mobile spine, sacrum) and extent of surgery (none, epidural decompression, extensive resection) were not associated with LRFS or OS (p>.05). Patients undergoing partial sacrectomy or corpectomy developed higher surgical toxicity rates compared to patients undergoing decompression surgery (85% ≥Grade 2; 54% Grade 3 vs. 22% ≥Grade 2; 0% Grade 3) (p=0.001). The long-term ≥Grade 2 SRS toxicity rate was 31%, including 14% Grade 3 tissue necrosis, recurrent laryngeal nerve palsy, fracture, and secondary malignancy. Among 30 patients presenting with pain (100%), radiculopathy (23%), or neuropathy (34%), two- thirds reported symptom response to treatment, with rates of 40% complete response (CR), 23% partial response (PR), and 7% CR for pain with PR for neuropathy. FIGURE: Kaplan-Meier estimate of local recurrence-free survival and overall survival. radioresistant tumors. Material and Methods