Radiosurgery Research Articles

Outcomes of Different Surgical Interventions for Treating Trigeminal Neuralgia: A Review.

Trigeminal neuralgia (TN) is a debilitating condition characterized by severe facial pain. Various surgical interventions are employed to manage this condition, including microvascular decompression (MVD), percutaneous radiofrequency rhizotomy (PRR), glycerol rhizotomy, percutaneous balloon compression (PBC), and stereotactic radiosurgery such as Gamma Knife radiosurgery (GKRS). This review synthesizes the outcomes of these interventions to provide an understanding of their efficacy and associated risks. MVD, known for its high initial relief rates, shows substantial long-term effectiveness, with recurrence rates varying based on patient demographics and comorbidities. GKRS offers significant pain relief with a favorable adverse event profile; however, recurrence rates increase over time, necessitating repeat procedures for sustained efficacy. PBC demonstrates high initial success, but pain recurrence is common, especially in patients with atypical TN. PRR provides immediate relief with a manageable recurrence rate and is particularly suitable for elderly patients and those with comorbidities. Glycerol rhizotomy, a cost-effective procedure, yields comparable outcomes to other interventions but requires careful patient selection. This review highlights the importance of tailored treatment approaches based on individual patient profiles, emphasizing the need for precise diagnostic criteria and careful patient selection to optimize outcomes. Long-term follow-up and the potential for repeat interventions are critical considerations in managing TN surgically.

Predictors of Hydrocephalus Risk After Stereotactic Radiosurgery for Vestibular Schwannomas: Utility of the Evans Index.

Hydrocephalus after Gamma Knife® stereotactic radiosurgery (SRS) for vestibular schwannomas is a rare but manageable occurrence. Most series report post-SRS communicating hydrocephalus in about 1% of patients, thought to be related to a release of proteinaceous substances into the cerebrospinal fluid. While larger tumor size and older patient age have been associated with post-SRS hydrocephalus, the influence of baseline ventricular anatomy on hydrocephalus risk remains poorly defined. A single-institution retrospective cohort study examining patients who developed symptomatic communicating hydrocephalus after undergoing Gamma Knife® SRS for unilateral vestibular schwannomas from 2011 to 2021 was performed. Patients with prior hydrocephalus and cerebrospinal fluid diversion or prior surgical resection were excluded. Baseline tumor volume, third ventricle width, and Evans Index (EI)-maximum width of the frontal horns of the lateral ventricles/maximum internal diameter of the skull-were measured on axial postcontrast T1-weighted magnetic resonance imaging. A total of 378 patients met the inclusion criteria; 14 patients (3.7%) developed symptomatic communicating hydrocephalus and 10 patients (2.6%) underwent shunt placement and 4 patients (1.1%) were observed with milder symptoms. The median age of patients who developed hydrocephalus was 69 years (IQR, 67-72) and for patients younger than age 65 years, the risk was 1%. For tumor volumes <1 cm3, the risk of requiring shunting was 1.2%. The odds of developing symptomatic hydrocephalus were 5.0 and 7.7 times higher in association with a baseline EI > 0.28 (P = .024) and tumor volume >3 cm3 (P = .007), respectively, in multivariate analysis. Fourth ventricle distortion on pre-SRS imaging was significantly associated with hydrocephalus incidence (P < .001). Patients with vestibular schwannoma with higher baseline EI, larger tumor volumes, and fourth ventricle deformation are at increased odds of developing post-SRS hydrocephalus. These patients should be counseled regarding risk of hydrocephalus and carefully monitored after SRS.

Cyclin-dependent kinase 4/6 inhibitors combined with stereotactic ablative radiotherapy in oligometastatic HR-positive/HER2-negative breast cancer patients.

Cyclin-dependent kinase 4/6 inhibitors (CDK4/6i) have significantly improved the survival of patients with hormone receptor-positive HER2-negative advanced breast cancer (ABC). Although stereotactic ablative radiotherapy (SABR) is used more often in routine clinical practice, data on the safety and efficacy of combining SABR with CDK4/6i are lacking. Herein, we present the results of SABR combined with CDK4/6i in ABC. Patients with ABC who received CDK4/6i and SABR between 2018 and 2023 were analysed. Among 384 patients treated with CDK4/6i, 34 patients received 44 courses of SABR. Two-year progression-free survival (PFS) was 63.6% (95% CI, 45.8-88.3), and the median PFS was 32 months. Three-year overall survival (OS) was 88.9% (95% CI, 77.7-100). Two-year local control (LC) was 92.7% (95% CI, 83.4-100). Median OS and LC were not reached. The subgroup analysis showed the difference in survival between oligometastatic patients (OMD) and non-OMD subgroup. Two-year PFS was 69.2% (95% CI, 44.5-100) in OMD compared with 57.4% (95% CI, 36-91.7) in the non-OMD (P = .042). Three-year OS was 90% (95% CI, 73.2-100) in OMD compared with 86.2% (95% CI, 70-100) in the non-OMD (P = .67). Median PFS and OS in the non-OMD were 26 and 56 months, respectively, and were not reached in OMD. Fifteen patients required CDK4/6i dose reduction, and 2 discontinued treatment due to toxicity. No difference in high-grade toxicity was observed between the sequential and concurrent SABR. The addition of SABR to CDK4/6i seems to be safe and effective, especially in patients with oligometastatic disease. In advanced breast cancer patients treated with CDK4/6i, SABR provides a high local control and may provide additional benefit in an oligometastatic setting.

Right hepatectomy in absence of the left portal vein using the porto-rex shunt procedure

Abstract Objectives Exact knowledge of the portal vein (PV) anatomy is essential for any hepatobiliary procedure. Absence of the portal bifurcation with the complete blood flow to the left lobe coming from the right portal vein (RPV) is an extremely rare anatomical variation. Case presentation In this situation, a solitary metachronous colorectal liver metastasis with suspected infiltration of the RPV and the right bile duct was detected in a 51-year-old male patient. Neither percutaneous ablation nor stereotactic radiotherapy were considered indicated due to the close proximity to the central structures. Hence, a surgical two-step procedure was scheduled. First, a porto-rex shunt with an 8 mm PTFE graft to maintain the portal blood flow to the left lobe was performed. In addition, the RPV was ligated during the same procedure. After recovery, the procedure was completed with a right hepatectomy. The final pathological report confirmed invasion of the right bile duct and the RPV and resection margins were tumor-free. Conclusion This case shows that careful preoperative assessment of vascular anatomy is critical. The use of the porto-rex shunt allowed a potentially curative resection in an otherwise irresectable situation.

Complete response in a lung adenocarcinoma with pleural metastases initially treated with gefitinib and switched to osimertinib after cerebral oligo-progression with unknown T790M mutation: a case report and review of literature

BackgroundFirst- and second-generation anti-epithelial growth factor receptor tyrosine kinase inhibitors have shown great efficacy in the treatment of advanced adenocarcinoma with epithelial growth factor receptor mutations, but this efficacy is limited by certain resistance mechanisms, in particular the T790M mutation, which must be screened before second-line treatment with osimertinib is indicated. The search for this mutation is sometimes difficult, especially in cases of intracranial relapse, through this case report we attempt to discuss the possibility of initiating treatment with osimertinib despite an unknown T790M mutation in such situation.Case reportWe present the case of a 70-year-old Moroccan male patient diagnosed with non-small cell lung carcinoma initially metastatic to the pleura with an epithelial growth factor receptor mutation who received gefitinib in first line with a complete response, he subsequently presented with cerebral oligo-progression with extra cranial stability. The patient was started on osimertinib with unknown T790M status, as it was impossible to perform a cerebral biopsy, the evolution was characterized by a partial response followed by stereotactic radiotherapy then a complete response for 2 years.ConclusionWe can discuss osimertinib as an option for patients with stage IV non-small cell lung cancer with brain oligo-progression on prior tyrosine kinase inhibitors and unknown T790M status, further studies are needed in this area.

Hypopituitarism after gamma knife radiosurgery for pituitary adenomas: long-term results from a single-center experience

ObjectiveThe aim of this study was to investigate the incidence and risk factors of new-onset hypopituitarism after gamma knife radiosurgery (GKRS) for pituitary adenomas in a single center.MethodsIn this retrospective study, 241 pituitary adenoma patients who underwent GKRS from 1993 to 2016 were enrolled. These patients had complete endocrine, imaging, and clinical data before and after GKRS. The median follow-up time was 56.0 (range, 12.7–297.6) months.ResultsFifty patients (20.7%) developed new-onset hypopituitarism after GKRS, including hypogonadism (n = 22), hypothyroidism (n = 29), hypocortisolism (n = 20), and growth hormone deficiency (n = 4). The median time to new-onset hypopituitarism was 44.1 (range, 13.5–141.4) months. The rates of new-onset hypopituitarism were 7%, 16%, 20%, 39%, and 45% at 1, 3, 5, 10, and 15 years, respectively. For those patients treated with a single GKRS, sex (p = 0.012), suprasellar extension (p = 0.048), tumor volume (≥ 5 cm3) (p < 0.001), tumor progression (p = 0.001), pre-existing hypopituitarism (p = 0.011), and previous surgery (p = 0.009) were significantly associated with new-onset hypopituitarism in univariate analysis. In the multivariate analysis, tumor volume (≥ 5 cm3) and tumor progression were associated with new-onset hypopituitarism (hazard ratio [HR] = 3.401, 95% confidence interval [CI] = 1.708–6.773, p < 0.001 and HR = 3.594, 95% CI = 1.032–12.516, p = 0.045, respectively). For patients who received 2 or more times GKRS, no risk factors associated with new-onset hypopituitarism were found.ConclusionNew-onset hypopituitarism was not uncommon after GKRS for pituitary adenomas. In this study, large tumor volume (≥ 5 cm3) and tumor progression were associated with new-onset hypopituitarism after a single GKRS.

Treatment Reproducibility in Brain Stereotactic Radiotherapy Using a Shim Mask Versus a Standard Mask.

Introduction This study aimed to evaluate the setup accuracy of the new shim mask with mouth bite compared to the standard full brain mask in stereotactic radiosurgery (SRS) and radiotherapy (SRT) treatments for brain metastases or tumors. Method A combined retrospective and prospective design was employed, involving 40 patients treated at our center. Patients previously treated using standard head masks formed the retrospective cohort, while those treated with the Shim mask and mouth bite formed the prospective cohort. Daily cone-beam computed tomography (CBCT) scans were obtained before each treatment session to ensure patient setup accuracy. Key metrics included absolute shifts in translational and rotational directions, the number of repeat CBCTs, and the time interval between CBCTs. Results The Shim mask significantly reduced the mean setup errors in the lateral translation (p=0.022) from 0.17 cm (SD=0.10) to 0.10 cm (SD=0.10), and in X-axis rotation (p=0.030) from 0.79° (SD=0.43) to 0.47° (SD=0.47). By considering cutoff points of 1 mm in translational and 1° in rotational directions, the Shim mask was significantly more accurate in the lateral direction (p=0.004). Moreover, while 70% of patients in the standard group required repeat CBCT scans, none in the Shim group did, resulting in an average time saving of 10.4 minutes per patient. Conclusion The Shim mask with mouth bite offers enhanced immobilization accuracy in SRT/SRS treatments, leading to time and potential cost savings by reducing the need for repeat CBCT scans. This underscores the importance of adopting innovative immobilization techniques to optimize patient outcomes.

Surgically targeted radiation therapy versus stereotactic radiation therapy: A dosimetric comparison for brain metastasis resection cavities

BackgroundSurgically targeted radiation therapy (STaRT) with Cesium-131 seeds embedded in a collagen tile is a promising treatment for recurrent brain metastasis. In this study, the biological effective doses (BED) for normal and target tissues from STaRT plans were compared with those of external beam radiotherapy (EBRT) modalities. MethodsNine patients (n=9) with 12 resection cavities (RCs) who underwent STaRT (cumulative physical dose of 60 Gy to a depth of 5 mm from the RC edge) were replanned with CyberKnife® (CK), Gamma Knife® (GK), and intensity modulated proton therapy (IMPT) using an SRT approach (30 Gy in 5 fractions). Statistical significance comparing D95% and D90% in BED10Gy (BED10Gy95% and BED10Gy90%) and to RC + 0 to + 5 mm expansion margins, and parameters associated with radiation necrosis risk (V83Gy, V103Gy, V123Gy and V243Gy) to the normal brain were evaluated by a Wilcoxon-signed rank test. ResultsFor RC+0 mm, median BED10Gy90% for STaRT (90.1 Gy10, range: 64.1-140.9 Gy10) was significantly higher than CK (74.3 Gy10, range:59.3-80.4 Gy10, p=0.04), GK (69.4 Gy10, range: 59.8-77.1 Gy10, p=0.005), and IMPT (49.3 Gy10, range: 49.0-49.7 Gy10, p=0.003), respectively. However, for the RC+5 mm, the median BED10Gy90% for STaRT (34.1 Gy10, range: 22.2-59.7 Gy10) was significantly lower than CK (44.3 Gy10, range: 37.8-52.4 Gy10), and IMPT (46.6 Gy10, range: 45.1-48.5 Gy10), respectively but not significantly different from GK (34.1 Gy10, range: 22.8-47.0 Gy10). The median V243Gy was significantly higher in CK (11.7 cc, range: 4.7-20.1 cc), GK(6.2 cc, range: 2.3-11.9 cc) and IMPT (19.9 cc, range: 11.1-36.6 cc) compared to STaRT (1.1 cc, range: 0.0-7.8 cc) (p<0.01). ConclusionThis comparative analysis suggests the STaRT approach may treat recurrent brain tumors effectively via delivery of higher radiation doses with equivalent or greater BED up to at least 3 mm from the RC edge as compared to EBRT approaches.

Stereotactic Ablative Radiation for Oligoprogressive Cancers: Results of the Randomized Phase 2 STOP Trial

This trial examined if patients with ≤5 sites of oligoprogression benefit from the addition of stereotactic ablative radiotherapy (SABR) to standard of care (SOC) systemic therapy. We enrolled patients with 1-5 metastases progressing on systemic therapy, and after stratifying by type of systemic therapy (cytotoxic vs. non-cytotoxic), randomized 1:2 between continued SOC treatment vs. SABR to all progressing lesions plus SOC. The trial was initially limited to non-small cell lung cancer but was expanded to include all non-hematologic malignancies to meet accrual goals. The primary endpoint was progression-free survival (PFS). Secondary endpoints included overall survival (OS), lesional control, quality of life, adverse events (AEs), and duration of systemic therapy post-randomization. Ninety patients with 127 oligoprogressive metastases were enrolled across 8 Canadian institutions, with 59 randomized to SABR and 31 to SOC. Median age was 67 years and 39 (43%) were female. The most common primary sites were lung (44%), genitourinary (23%) and breast (13%). Protocol adherence in the SOC arm was suboptimal, with 11 patients (35%) either receiving high-dose/ablative therapies (conflicting with trial protocol) or withdrawing from the study. Median follow-up was 31 months. There was no difference in PFS between arms (median PFS 8.4 months in the SABR arm vs. 4.3 months in the SOC arm but curves cross and 2-year PFS was 9% vs. 24% respectively, p=0.91). Median OS was 31.2 months vs. 27.4 months, respectively (p=0.22). Lesional control was superior with SABR (70% vs. 38% respectively, p=0.0015). There were 2 (3.4%) grade 3 and no grade 4/5 AEs attributable to SABR. SABR was well-tolerated with superior lesional control but did not improve PFS or OS. Accrual to this study was difficult, and the results may have been impacted by an unwillingness to forgo ablative treatments on the SOC arm. (NCT02756793).

Is Local Ablative Stereotactic Radiation Therapy a Valuable Rescue Strategy for Time on Drug in Patients Enrolled in Phase I Trials?

Patients with advanced tumours enrolled in phase I trials display strong treatment expectations and few therapeutic alternatives. When oligo-acquired resistance (≤3 lesions of disease progression; OAR) occurs, local ablative stereotactic radiotherapy (SRT) could allow disease control and continuing the experimental systemic treatment. Data from patients enrolled in phase I trials evaluating systemic treatments, who experienced OAR while on the phase I systemic therapy and subsequently received SRT between 01/2014-04/2023 were retrospectively analysed. PFS1 (trial entry to OAR), PFS2 (SRT to first subsequent relapse), time to next systemic treatment (TTNT), and OS were assessed. First subsequent patterns of relapse after SRT were distinguished as OAR2, which could be locally rechallenged, or systemic acquired resistance (>3 lesions of disease progression; SAR). When available, correlations between molecular profile and pathway enrichments of OAR and SAR were explored. Forty-two patients with 52 oligoprogressive lesions were analysed. The median follow-up was 24 months. SRT allowed a median PFS2 of 7.1 months and a median TTNT of 12.8 months. PFS2 included 49% OAR2 and 51% SAR. Median time to first subsequent relapse (9.6 months vs 3.5 months, P=0.014) and TTNT (22.4 months vs 7.6 months, P<0.001) were longer for OAR2 as compared to SAR. No severe toxicities were reported. A PFS1 <6 months and de novo oligoprogressive lesions associated with the presence of SAR. More diverse enriched gene pathways were observed for SAR as compared to OAR2. In patients enrolled in phase I trials, OAR managed with SRT may increase time on investigational systemic treatments. Predictive factors reflecting tumour aggressiveness and clonal heterogeneity could help deciphering OAR2 from SAR and maximize SRT output in the oligoprogressive setting.

Dosimetric comparison of ZAP-X, Gamma Knife, and CyberKnife stereotactic radiosurgery for single brain metastasis

PurposeTo evaluate the dosimetric characteristics of ZAP-X stereotactic radiosurgery (SRS) for single brain metastasis by comparing with two mature SRS platforms.MethodsThirteen patients with single brain metastasis treated with CyberKnife (CK) G4 were selected retrospectively. The prescription dose for the planning target volume (PTV) was 18–24 Gy for 1–3 fractions. The PTV volume ranged from 0.44 to 11.52 cc.Treatment plans of thirteen patients were replanned using the ZAP-X plan system and the Gamma Knife (GK) ICON plan system with the same prescription dose and organs at risk (OARs) constraints. The prescription dose of PTV was normalized to 70% for both ZAP-X and CK, while it was 50% for GK. The dosimetric parameters of three groups included the plan characteristics (CI, GI, GSI, beams, MUs, treatment time), PTV (D2, D95, D98, Dmin, Dmean, Coverage), brain tissue (volume of 100%-10% prescription dose irradiation V100%-V10%, Dmean) and other OARs (Dmax, Dmean),all of these were compared and evaluated. All data were read and analyzed with MIM Maestro. One-way ANOVA or a multisample Friedman rank sum test was performed, where p < 0.05 indicated significant differences.ResultsThe CI of GK was significantly lower than that of ZAP-X and CK. Regarding the mean value, ZAP-X had a lower GI and higher GSI, but there was no significant difference among the three groups. The MUs of ZAP-X were significantly lower than those of CK, and the mean value of the treatment time of ZAP-X was significantly shorter than that of CK. For PTV, the D95, D98, and target coverage of CK were higher, while the mean of Dmin of GK was significantly lower than that of CK and ZAP-X. For brain tissue, ZAP-X showed a smaller volume from V100% to V20%; the statistical results of V60% and V50% showed a difference between ZAP-X and GK, while the V40% and V30% showed a significant difference between ZAP-X and the other two groups; V10% and Dmean indicated that GK was better. Excluding the Dmax of the brainstem, right optic nerve and optic chiasm, the mean value of all other OARs was less than 1 Gy. For the brainstem, GK and ZAP-X had better protection, especially at the maximum dose.ConclusionFor the SRS treating single brain metastasis, all three treatment devices, ZAP-X system, CyberKnife G4 system, and GammaKnife system, could meet clinical treatment requirements. The newly platform ZAP-X could provide a high-quality plan equivalent to or even better than CyberKnife and Gamma Knife, with ZAP-X presenting a certain dose advantage, especially with a more conformal dose distribution and better protection for brain tissue. As the ZAP-X systems get continuous improvements and upgrades, they may become a new SRS platform for the treatment of brain metastasis.

Predicting the 3-Dimensional Dose Distribution of Multilesion Lung Stereotactic Ablative Radiation Therapy With Generative Adversarial Networks

PurposeAs stereotactic ablative radiotherapy (SABR) is being used to treat greater numbers of lung metastases, selecting the optimal dose and fractionation to balance local failure and treatment toxicity becomes increasingly challenging. Multi-lesion lung SABR plans include spatially diverse lesions with heterogenous prescriptions and interacting dose distributions. In this study, we developed and evaluated a generative adversarial network (GAN) to provide real-time dosimetry predictions for these complex cases. Methods and MaterialsA GAN was trained to predict dosimetry on a dataset of patients who received SABR for lung lesions at a tertiary center. Model input included the planning CT scan, the organs at risk and (OARs) target structures, and an initial estimate of exponential dose fall-off. Multi-lesion plans were split 80/20 for training and evaluation. Models were evaluated on voxel-voxel, clinical dose-volume-histogram, and conformality metrics. An out-of-sample validation and analysis of model variance were performed. ResultsThere were 125 multi-lesion plans from 102 patients with 357 lesions. Patients were treated to 2-7 lesions, with 19 unique dose-fractionation schemes over 1-3 courses of treatment. The out-of-sample validation set contained an additional 90 plans from 80 patients. The mean absolute difference (MAD) and gamma pass fraction (GPF) between the predicted and true dosimetry was <3 Gy and > 90% for all OARs. The absolute differences in lung V20 and CV14 were 1.40±0.99% and 75.8±42.0 cc respectively. The ratios of predicted to true R50%, R100% and D2cm were 1.00±0.16, 0.96±0.32, and 1.01±0.36 respectively. The out-of-sample validation set maintained MAD and GPF of <3 Gy and >90% for all OARs. The median standard deviation of variance in V20 and CV14 prediction was 0.49% and 22.2 cc respectively. ConclusionsA GAN for predicting the 3-D dosimetry of complex multi-lesion lung SABR is presented. Rapid dosimetry prediction can be used to assess treatment feasibility and explore dosimetric differences between varying prescriptions.

Stereotactic radiotherapy for managing ovarian cancer oligoprogression under poly (ADP-ribose) polymerase inhibitors (PARPi)

ObjectivePoly (ADP-ribose) polymerase inhibitors (PARPi) have become a new standard of care for the maintenance treatment of advanced epithelial ovarian cancer. This study aims to evaluate the efficacy and safety...

Botulinum toxin type a (BOTOX) in the management of glossopharyngeal neuralgia- A case series

Glossopharyngeal neuralgia [GPN] is a rare, debilitating neurologic condition characterized by intermittent pain radiating to the tongue, pharynx or ear that can be triggered by talking, swallowing or chewing. With an incidence of only 0.2-0.7 persons/100,000/year, the diagnosis is extremely challenging and often gets misdiagnosed and undiagnosed. Many treatment options have been tried by various clinicians in the past, such as medical therapy (antidepressants, opiods, antiepileptics, steroids, and membrane-stabilizing agents), nerve blocks with or without additives, gamma knife radiosurgery, radiofrequency ablation and microvascular decompression. Each of the aforementioned treatment modalities has its own merits and limitations. In the pursuit of delivering optimal treatment for pain relief in GPN and to improve patient's quality of life, we have explored the use of Botulinum toxin type A [BOTOX (Allegran®)]. BOTOX has been widely used in the treatment of chronic facial pain such as headaches, migraine, and trigeminal neuralgia. However, the use of BOTOX in the management of GPN has not been reported in the literature. Despite the small number of cases in our series, BOTOX therapy in GPN appears to be promising. However, further research with larger sample sizes and longer follow-up periods is needed to fully establish its efficacy and safety profile

Dosimetric predictors of acute and late gastrointestinal toxicities in stereotactic online adaptive magnetic resonance-guided radiotherapy (SMART) for locally advanced pancreatic adenocarcinoma

Background and purposeA retrospective evaluation of dosimetric predictors and leveraged dose-volume data for gastrointestinal (GI) toxicities for locally-advanced pancreatic cancer (LAPC) treated with daily stereotactic MRI-guided online-adaptive radiotherapy (SMART). Materials and methods147 patients with LAPC were treated with SMART at our institution between 2018 and 2021. Patients were evaluated using CTCAE V5.0 for RT-related acute (≤3 months) and late (>3 months) toxicities. Each organ at risk (OAR) was matched to a ≥ grade 2 (Gr2+) toxicity endpoint composite group. A least absolute shrinkage selector operator regression model was constructed by dose-volumes per OAR to account for OAR multicollinearity. A receiver operator curve (ROC) analysis was performed for the combined averages of significant toxicity groups to identify critical volumes per dose levels. Results18 of 147 patients experienced Gr2+ GI toxicity. 17 Gr2+ duodenal toxicities were seen; the most significant predictor was a V33Gy odds ratio (OR) of 1.69 per cc (95 % CI 1.14–2.88). 17 Gr2+ small bowel (SB) toxicities were seen; the most significant predictor was a V33Gy OR of 1.60 per cc (95 % CI 1.01–2.53). The AUC was 0.72 for duodenum and SB. The optimal duodenal cut-point was 1.00 cc (true positive (TP): 17.8 %; true negative (TN); 94.9 %). The SB cut-point was 1.75 cc (TP: 16.7 %; TN: 94.3 %). No stomach or large bowel dose toxicity predictors were identified. ConclusionsFor LAPC treated with SMART, the dose-volume threshold of V33Gy for duodenum and SB was associated with Gr2+ toxicities. These metrics can be utilized to guide future dose-volume constraints for patients undergoing upper abdominal SBRT.

Polish cross-cultural adaptation of a disease-specific quality-of-life instrument: The Penn Acoustic Neuroma Quality-of-Life Scale.

The medical community has shown a growing interest in developing methods for measuring and comparing objective patient outcomes coupled with subjective patient assessments. Questionnaires enable healthcare professionals to obtain the patient's perspective about their experienced vestibular schwannomas (VS) symptoms quickly. To date, in Poland, a cross-cultural adapted version of a disease-specific questionnaire for the measurement of quality of life (QoL) in patients with VS has not been produced. This study aimed to adapt the questionnaire evaluating disease-specific QoL in patients with VS (Penn Acoustic Neuroma Quality-of-Life Scale; PANQOL) to Polish and evaluate its psychometric properties. One-hundred twenty-four patients aged between 24 and 85 years (mean (M) = 60.17 ±standard deviation (SD) = 13.27) diagnosed with VS and treated with Gamma Knife were included in the study. We used a questionnaire translated from English into Polish by a bilingual professional, verified through a back-translation. The final version consisted of 26 items. The internal consistency of the Polish version of the PANQOL scale domains was measured using the Cronbach's alpha (α). To verify the validity of PANQOL subscales, a correlation analysis was conducted between the domains of PANQOL and other questionnaires, including the Assessment of Quality of Life (AQoL-8D), the Glasgow Benefit Inventory (GBI), the 5 Well-Being Index (WHO-5), the Skarzynski Tinnitus Scale (STS) for the presence of dizziness, and the Gardner-Robertson classes. The majority of PANQOL domains showed excellent or good internal consistency (for a PANQOL total of 0.934; for subscales in the range of 0.916-0.424). Our analysis showed strong correlations between the total PANQOL score and AQoL-8D utility score, as well as between the subscales. We observed weak to moderately significant relationships between GBI and PANQOL domains (r = 0.18-0.43), the WHO-5 (r = 0.18-0.56) and the STS scale (r = -0.40- -0.19). The results demonstrated that the POL-PANQOL is a reliable and valid questionnaire for measuring QoL.

Intraoperative radiotherapy after neurosurgical resection of brain metastases as institutional standard treatment- update of the oncological outcome form a single center cohort after 117 procedures.

Stereotactic radiotherapy (SRT) is the predominant method for the irradiation of resection cavities after resection of brain metastases (BM). Intraoperative radiotherapy (IORT) with 50kV x-rays is an alternative way to irradiate the resection cavity focally. We have already reported the outcome of our first 40 IORT patients treated until 2020. Since then, IORT has become the predominant cavity treatment in our center due to patients´ choice. We retrospectively analyzed the outcomes of all patients who underwent resection of BM and IORT between 2013 and August 2023 at Augsburg University Medical Center (UKA). We identified 105 patients with 117 resected BM treated with 50kV x-ray IORT. Median diameter of the resected metastases was 3.1cm (range 1.3 - 7.0cm). Median applied dose was 20Gy. All patients received standardized follow-up (FU) including three-monthly MRI of the brain. Mean FU was 14months, with a median MRI FU for patients alive of nine months. Median overall survival (OS) of all treated patients was 18.2months (estimated 1-year OS 57.7%). The observed local control (LC) rate of the resection cavity was 90.5% (estimated 1-year LC 84.2%). Distant brain control (DC) was 61.9% (estimated 1-year DC 47.9%). Only 16.2% of all patients needed WBI in the further course of disease. The observed radio necrosis rate was 2.6%. After 117 procedures IORT still appears to be a safe and appealing way to perform cavity RT after neurosurgical resection of BM with low toxicity and excellent LC.

Outcomes Analysis of Patients Receiving Local Ablative Therapy for Oligoprogressive Metastatic NSCLC Under First-Line Immunotherapy

ContextNonsmall Cell Lung Cancer (NSCLC) treatment relies on first-line immunotherapy as single agent or combined with chemotherapy. Oligoprogression may be observed in this setting. Material and MethodWe performed a European multicentric retrospective study on patients treated with first-line immunotherapy, who presented with oligoprogressive disease, treated with a local ablative treatment. ResultsA total of 61 patients were retrospectively included between 2018 and 2022. Twenty-four patients (39%) received immunotherapy as single agent, and 37 (61%) chemo-immunotherapy. First oligoprogression occurred more frequently in pre-existing metastatic sites (47% of patients). Median PFS1 (defined as time to first oligoprogression) was 11.5 months [IC95%: 10.0-12.3]. We observed that 37 patients (61%) progressed after first oligoprogression, and 20 (54%) from them presented second oligoprogression. Median OS for the whole cohort was 72.0 months [IC95%: 19.3-124.8], with positive correlation between OS and PFS1 (R=0.65, P < .0001). After loco-ablative treatment with radiotherapy, disease control rate was 89% with ablative radiotherapy: 88% with conventional radiotherapy, and 89% with stereotactic radiotherapy. ConclusionPatients with oligoprogression under/after immunotherapy have better prognosis with a high risk of subsequent oligoprogression.

407 Stereotactic magnetic resonance-guided online adaptive radiotherapy in kidney oligometastases

407 Stereotactic magnetic resonance-guided online adaptive radiotherapy in kidney oligometastases

103 The clinical outcomes of LINAC based stereotactic radiotherapy for multiple brain metastases

103 The clinical outcomes of LINAC based stereotactic radiotherapy for multiple brain metastases