5-Year survival in Danish patients with advanced non-small cell lung cancer treated with immune checkpoint inhibitor monotherapy.

BACKGROUND: Convincing results from randomized controlled trials (RCTs) have led to increasing use of immune checkpoint inhibitors (ICI) as part of standard therapies in real-world (RW) scenarios. However, RW patients differ clinically from RCT populations and might have reduced long-term survival. Currently, only sparse data on 3-5-year survival rate for RW patients with advanced non-small cell lung cancer (NSCLC) treated with ICI exist. MATERIALS AND METHODS: A multicenter study was performed including 729 patients with advanced NSCLC receiving monotherapy with ICI (retrospective data (n = 566) and prospective data (n = 163)). Detailed baseline clinical characteristics, programmed death-ligand 1 (PD-L1) tumor proportion score (TPS), and baseline haematological count were registered. Kaplan-Meier estimates and log-rank test were used for survival analyses, Cox regression for determination of prognostic factors. RESULTS: Median time of follow-up (FU) was 48.7 months (IQR 37.2-54.3). Median overall survival (OS) in first line treatment was 20.4 months (IQR 8.5-45.0) compared to 11.4 months (IQR 4.6-27.1) in ≥2nd line (HR 1.48, 95% CI 1.25-1.75). Estimated probability of OS was 30% at 3 years, 23% at 4 years, and 13% at 5 years in first line compared to 17, 13, and 11% in ≥2nd line, respectively. For those with performance status (PS) 2, the 2-year OS rate was 32% (95% CI 0.22-0.43) compared to 5% (95% CI 0.01-0.15) in patients with PD-L1 ≥ 50% versus <50%, respectively. CONCLUSIONS: Compared to RCTs, long-term OS and PFS rates are lower in real-world patients treated with ICI in first line but much improved compared to historic rates on chemotherapy. A promising flattening of both the OS and progression free survival curves illustrates that also a subset of real-world patients obtain long-term remission. Patients with PS 2 and PD-L1 ≥ 50% may obtain clinically meaningful 2-year PFS and OS rates.

Outcomes of prophylactic cranial irradiation in patients with small cell lung cancer in the modern era of baseline magnetic resonance imaging of the brain.

BACKGROUND: For decades many patients with small cell lung cancer (SCLC) have been offered prophylactic cranial irradiation (PCI) to prevent brain metastases (BM). However, the role of PCI is debated in the modern era of increased brain magnetic resonance imaging (MRI) availability. BM in SCLC patients may respond to chemotherapy, and if a negative MRI is used in the decision to use of PCI in the treatment strategy, the timing of brain MRI may be crucial when evaluating the effect of PCI. This retrospective study investigates the impact of PCI outcomes in patients with SCLC staged with brain MRI prior to chemotherapy. MATERIALS AND METHODS: This study included 245 patients diagnosed SCLC/mixed NSCLC-SCLC treated between 2012 and 2019. The population was analyzed separately for limited disease (LS-SCLC) and extensive disease (ES-SCLC). Patients were divided into groups based on baseline brain MRI prior to chemotherapy and PCI. The primary endpoint was time to symptomatic BM. Secondary endpoints were overall survival (OS), and progression-free survival (PFS). RESULTS: In patients with LS-SCLC staged with brain MRI the probability of developing symptomatic BM at one year was 4% vs. 22% (p < 0.05), median OS was 55 vs. 24 months (p < 0.05), and median PFS was 30 vs. 10 months (p < 0.05) with and without PCI, respectively. No differences in probability of symptomatic BM and survival outcomes were observed in ES-SCLC. In a multivariate regression analysis, no variables were statistically significant associated with the risk of developing symptomatic BM in patients with LS-SCLC and ES-SCLC. For patients with ES-SCLC staged with brain MRI, PS (HR = 3.33, CI; 1.41-7.89, p < 0.05) was associated with poor survival. CONCLUSION: This study found that PCI in LS-SCLC patients staged with brain MRI had lower incidence of symptomatic BM and improved survival outcomes suggesting PCI as standard of care. Similar benefit of PCI in patients with ES-SCLC was not found.

Clinical features affecting efficacy of immune checkpoint inhibitors in pretreated patients with advanced NSCLC: a Danish nationwide real-world study.

BACKGROUND: Immune checkpoint inhibitors (ICIs) are implemented as standard treatment for patients with advanced non-small cell lung cancer (NSCLC) in first-line and subsequent-line treatment. However, certain subgroups such as patients with older age, poor performance status (PS), and severe comorbidity are underrepresented in the randomized controlled trials (RCTs). This study aimed to assess overall survival (OS), treatment data, and clinical features affecting second- or subsequent-line ICI efficacy in an unselected, Danish, nationwide NSCLC population. METHODS: Patients with advanced NSCLC who started nivolumab or pembrolizumab as second-line or subsequent-line treatment between 1 September 2015, and 1 October 2018, were identified from institutional records of all Danish oncology departments. Clinical and treatment data were retrospectively collected. Descriptive statistics and survival analyses were performed. RESULTS: Data were available for 840 patients; 49% females. The median age was 68 years (19% were ≥75 years), 19% had PS ≥2, and 36% had moderate to severe comorbidity. The median OS (mOS) was 12.2 months; 15.1 months and 10.0 months in females and males, respectively. The median time-to-treatment discontinuation (mTTD) and median progression-free survival (mPFS) was 3.2 and 5.2 months, respectively. Patients with PS ≥2 had a mOS of 4.5 months, mTTD of 1.1 month, and mPFS of 2.0 months. In multivariable Cox regression analysis, male sex (HR = 1.35, 95% CI 1.11-1.62), PS >0 (PS 1, HR = 1.88, 95% CI 1.52-2.33; PS ≥2, HR = 4.15, 95% CI 3.13-5.5), liver metastases (HR = 1.72, 95% CI 1.34-2.22), and bone metastases (HR = 1.27, 95% CI 1.03-1.58) were significant poor prognostic OS factors. CONCLUSIONS: Danish real-world patients with advanced NSCLC treated with second- or subsequent-line ICI had an OS comparable to results from RCTs. Women, frail and older patients constituted a higher proportion than in previous RCTs. Clinical features associated with poor OS were male sex, PS ≥1 (in particular PS ≥2), bone-, and liver metastases.

High-dose versus standard-dose twice-daily thoracic radiotherapy for patients with limited stage small-cell lung cancer: an open-label, randomised, phase 2 trial.

BACKGROUND: Concurrent chemoradiotherapy is standard treatment for limited stage small-cell lung cancer (SCLC). Twice-daily thoracic radiotherapy of 45 Gy in 30 fractions is considered to be the most effective schedule. The aim of this study was to investigate whether high-dose, twice-daily thoracic radiotherapy of 60 Gy in 40 fractions improves survival. METHODS: This open-label, randomised, phase 2 trial was done at 22 public hospitals in Norway, Denmark, and Sweden. Patients aged 18 years and older with treatment-naive confirmed limited stage SCLC, Eastern Cooperative Oncology Group (ECOG) performance status 0-2, and measurable disease according to the Response Evaluation Criteria in Solid Tumors version 1.1 were eligible. All participants received four courses of intravenous cisplatin 75 mg/m2 or carboplatin (area under the curve 5-6 mg/mL × min, Calvert's formula) on day 1 and intravenous etoposide 100 mg/m2 on days 1-3 every 3 weeks. Participants were randomly assigned (1:1) in permuted blocks (sized between 4 and 10) stratifying for ECOG performance status, disease stage, and presence of pleural effusion to receive thoracic radiotherapy of 45 Gy in 30 fractions or 60 Gy in 40 fractions to the primary lung tumour and PET-CT positive lymph node metastases starting 20-28 days after the first chemotherapy course. Patients in both groups received two fractions per day, ten fractions per week. Responders were offered prophylactic cranial irradiation of 25-30 Gy. The primary endpoint, 2-year overall survival, was assessed after all patients had been followed up for a minimum of 2 years. All randomly assigned patients were included in the efficacy analyses, patients commencing thoracic radiotherapy were included in the safety analyses. Follow-up is ongoing. This trial is registered at ClinicalTrials.gov, NCT02041845. FINDINGS: Between July 8, 2014, and June 6, 2018, 176 patients were enrolled, 170 of whom were randomly assigned to 60 Gy (n=89) or 45 Gy (n=81). Median follow-up for the primary analysis was 49 months (IQR 38-56). At 2 years, 66 (74·2% [95% CI 63·8-82·9]) patients in the 60 Gy group were alive, compared with 39 (48·1% [36·9-59·5]) patients in the 45 Gy group (odds ratio 3·09 [95% CI 1·62-5·89]; p=0·0005). The most common grade 3-4 adverse events were neutropenia (72 [81%] of 89 patients in the 60 Gy group vs 62 [81%] of 77 patients in the 45 Gy group), neutropenic infections (24 [27%] vs 30 [39%]), thrombocytopenia (21 [24%] vs 19 [25%]), anaemia (14 [16%] vs 15 [20%]), and oesophagitis (19 [21%] vs 14 [18%]). There were 55 serious adverse events in 38 patients in the 60 Gy group and 56 serious adverse events in 44 patients in the 45 Gy group. There were three treatment-related deaths in each group (one neutropenic fever, one aortic dissection, and one pneumonitis in the 60 Gy group; one thrombocytic bleeding, one cerebral infarction, and one myocardial infarction in the 45 Gy group). INTERPRETATION: The higher radiotherapy dose of 60 Gy resulted in a substantial survival improvement compared with 45 Gy, without increased toxicity, suggesting that twice-daily thoracic radiotherapy of 60 Gy is an alternative to existing schedules. FUNDING: The Norwegian Cancer Society, The Liaison Committee for Education, Research and Innovation in Central Norway, the Nordic Cancer Union, and the Norwegian University of Science and Technology.

Tumour motion analysis from planning to end of treatment course for a large cohort of peripheral lung SBRT targets.

BACKGROUND: The aim is to quantify and analyse tumour motion during a course of treatment for lung SBRT patients. MATERIAL AND METHODS: Peak-to-peak motion of 483 tumours in 441 patients treated with peripheral lung SBRT at a single institution over a two year period was measured on planning CT and at all treatment fractions. Planning 4D-CT scans were analysed using our clinical workflow involving deformable propagation of the delineated target to all phases. Similarly, acquisition of the 4D-CBCT data followed the clinical workflow based on XVI 5.0 available on Elekta linacs. Differences and correlations of the peak-to-peak motion on the planning CT and at treatment were analysed. RESULTS: On the planning CT, a total of 81.4% of the tumours had a peak-to-peak motion <10 mm, and 96.1% had <20 mm. The largest motion was observed in the CC direction, with largest amplitude for tumours located in the caudal posterior part of the lung. The difference in amplitude in CC between planning CT and first fraction had a mean and standard deviation of 0.3 mm and 3.5 mm, respectively, and the largest differences were observed in the caudal posterior part of the lung. Patients with a difference in tumour motion amplitude exceeding two standard deviations (>7 mm) at the first fraction were evaluated individually, and they all had poor 4DCT image quality. The difference between the first and second/third fractions had a mean and standard deviation of 0.4 mm/0.5 mm and 2.0 mm/1.9 mm. CONCLUSION: Tumour motion at first treatment was similar to motion at planning, and motion at subsequent treatments was very similar to motion at first treatment. Large tumour motions are located towards the caudal posterior tumour locations. Patients with poor 4D-CT image quality should be closely followed at the first treatment to verify the motion.

Survival after stereotactic radiotherapy in patients with early-stage non-small cell lung cancer.

Introduction: Stereotactic radiotherapy (SBRT) is the treatment of choice for inoperable early stage non-small cell lung cancer (NSCLC). We report analyses of the influence of age on survival after SBRT. Methods and material: From 2005 to 2017, 544 previously un-irradiated patients with early stage NSCLC had SBRT. The data were analyzed in four age groups: A: -69 (176 pts), B: 70-74 (115 pts), C: 75-79 (131 pts) and D: 80 years or older (122 pts). Two SBRT dose regimes were used: 45 Gy/3F (N = 103) and 66 Gy/3F (N = 441). Results: All patients had a follow up (time to censoring, FU) of at least 16 months, the median FU being 48.0 months. The median age was 74.4 years. The overall survival (OS) was associated with age. The median OS was 50.7, 45.9, 45.4 and 33.0 months, and the 5-year OS was 45%, 32%, 33% and 18% in groups A, B, C and D, respectively. No difference was found between groups B and C, while OS in group A was significantly better than remaining groups, and the OS in group D significantly poorer. In multivariable analyses, OS was heavily influenced by age, Charlson's comorbidity index (CCI) and performance status (PS). For lung cancer-specific survival (LCSS), only increasing tumor diameter and PS were associated with poor survival. Conclusions: The OS was influenced by age, but the study suggests that a cut point of 75 year is inappropriate in evaluating the effect of old age on survival. Poor PS was associated with poor OS. CCI influenced OS, but not LCSS, which was only affected by PS and tumor size.

The effect of tumor laterality on survival for non-small cell lung cancer patients treated with radiotherapy.

Background: The treatment of choice for patients with locally advanced non-small cell lung cancer (LA-NSCLC) in good performance status is definitive radiotherapy (RT), the five-year survival being approximately 25-30%. Advances in the diagnostic procedures and treatment modalities in NSCLC have increased the overall survival, making identifying factors with impact on survival increasingly relevant. Recent research indicates that tumor laterality has impact on the survival of patients with LA-NSCLC treated with definitive RT. The aim of this study was to investigate whether tumor laterality impacted overall survival. Material and methods: All patients with stage IIa-IIIb NSCLC planned for curative intended RT from 2008 to 2013 at Odense University Hospital were analyzed to compare overall survival of patients with right-sided vs. left-sided tumors. Log-rank test was performed to test for differences in survival rates and Cox regression analyses to test for possible confounders. No patients were lost to follow-up. Results: In total, 164 patients had a tumor in the right lung and 118 had tumor in the left lung. All patients had at least 4.5 years' follow-up. Median overall survival was 19 months (right) and 22.5 months (left) p = .729. Three-year overall survival was 31% (right) and 35% (left). In Cox regression analyses age, performances status and total mean lung dose were statistically significant with a hazard ratio (HR) = 1.03 (95% Cl: 1.01-1.05), HR = 1.60 (95% Cl: 1.12-2.28), and HR = 1.11 (95% Cl: 1.06-1.16), respectively. Conclusion: This study did not verify that laterality has a significant impact on survival in LA-NSCLC patients treated with curative intended RT.

Efficacy and safety of immune checkpoint inhibitors in a Danish real life non-small cell lung cancer population: a retrospective cohort study.

Background: To investigate effect and toxicity of immune checkpoint inhibition (ICI) in a Danish real-life non-small cell lung cancer (NSCLC) population. By including patients underrepresented in clinical trials, such as those with brain metastasis (BM), higher age, more comorbidity and poorer performance status (ECOG), comparison of unselected patients to clinical trial populations is possible. Material and methods: Real life data were gathered from 118 consecutive NSCLC patients with incurable NSCLC treated with ICI at the Department of Oncology at the University Hospital of Odense, Denmark from September 2015 to April 2018. Immune-related adverse events (irAEs) grades 3-5 were registered prospectively during the same period. Additional patient related data were obtained retrospectively from patients' files. Overall survival (OS) and progression-free survival (PFS) were calculated using the Kaplan-Meier estimates, the log-rank test and cox regression analysis performed for factors affecting survival. Results: Median age for patients was 66 years (IQR 59-71) and 62 years (range: 55-64) for those with BM. Females 63%; adenocarcinoma (AC)/squamous/others 69%/23%/8%; ECOG ≥ 2 10%; bone/brain/liver metastases 36%/18%/15%; PD-L1 (TPS) <1%/ ≥ 1%/ ≤ 49%/ ≥ 50%/NR: 3%/14%/68%/15%; baseline autoimmunity 10%, Charlson's Comorbidity Index Score (CCIS) ≥ 2 39%, treatment line: 1st/2nd/ ≥ 3rd 39%/30%/31%. Median OS for patients receiving ICI in ≥2 line was 11.5 months versus not reached in first line (HR 2.6, [95% CI: 1.3-5.0], p = .005). For patients with BM, the median OS was 8.2 months (HR 1.38, [95% CI: 0.7-2.5], p = .37). Twenty-four percent of patients terminated ICI due to irAE grades 3-5 alone (grade 5, n = 1), which were not associated with higher age or BM. Conclusions: OS and PFS were comparable to clinical trial reports. Long-lasting remission is also possible in patients with BM. Real-life populations have higher rates of irAE grades 3 and 4 than reported in clinical trials, but it does not seem to impact median OS.

First clinical experiences with a high field 1.5 T MR linac.

Purpose: A 1.5 T MR Linac (MRL) has recently become available. MRL treatment workflows (WF) include online plan adaptation based on daily MR images (MRI). This study reports initial clinical experiences after five months of use in terms of patient compliance, cases, WF timings, and dosimetric accuracy. Method and materials: Two different WF were used dependent on the clinical situation of the day; Adapt To Position WF (ATP) where the reference plan position is adjusted rigidly to match the position of the targets and the OARs, and Adapt To Shape WF (ATS), where a new plan is created to match the anatomy of the day, using deformable image registration. Both WFs included three 3D MRI scans for plan adaptation, verification before beam on, and validation during IMRT delivery. Patient compliance and WF timings were recorded. Accuracy in dose delivery was assessed using a cylindrical diode phantom. Results: Nineteen patients have completed their treatment receiving a total of 176 fractions. Cases vary from prostate treatments (60Gy/20F) to SBRT treatments of lymph nodes (45 Gy/3F) and castration by ovarian irradiation (15 Gy/3F). The median session time (patient in to patient out) for 127 ATPs was 26 (21-78) min, four fractions lasted more than 45 min due to additional plan adaptation. For the 49 ATSs a median time of 12 (1-24) min was used for contouring resulting in a total median session time of 42 (29-91) min. Three SBRT fractions lasted more than an hour. The time on the MRL couch was well tolerated by the patients. The median gamma pass rate (2 mm,2% global max) for the adapted plans was 99.2 (93.4-100)%, showing good agreement between planned and delivered dose. Conclusion: MRL treatments, including daily MRIs, plan adaptation, and accurate dose delivery, are possible within a clinically acceptable timeframe and well tolerated by the patients.

Trends in lung cancer in elderly in Denmark, 1980-2012.

BACKGROUND: Lung cancer is an increasing problem in the older patient population due to the improvement in life expectation of the Western population. In this study we examine trends in lung cancer incidence and mortality in Denmark from 1980 to 2012 with special focus on the elderly. MATERIAL AND METHODS: Lung cancer was defined as ICD-10 codes C33-34. Data derived from the NORDCAN database with comparable data on cancer incidence, mortality, prevalence, and relative survival in the Nordic countries, where the Danish data were delivered from the Danish Cancer Registry and the Danish Cause of Death Registry with follow-up for death or emigration until the end of 2013. RESULTS: In 2012, about 50% of lung cancers were diagnosed among persons aged 70 years or more. For men and women older than 75 years the incidence rates have been increasing and for those aged 80-84 years, the rates have doubled since 1980. Due to the poor survival, similar trends were seen in mortality rates. Over the period, the one-year relative survival rates almost doubled in patients aged 70 years or more, but still only 25% of the patients aged 80-89 years survived their lung cancer for one year. CONCLUSION: The incidence of lung cancer is closely linked to the pattern of tobacco smoking with the differences between gender and age groups reflecting smoking behavior in birth cohorts. Elderly patients with lung cancer are a heterogeneous group in whom treatment should be offered according to comorbidity and a geriatric assessment.

Age dependent prognosis in concurrent chemo-radiation of locally advanced NSCLC.

BACKGROUND: Clinical trials indicate that the benefit of adding concurrent chemotherapy to radiotherapy of locally advanced non-small cell lung cancer (NSCLC) for fit elderly is similar to the benefit for younger patients. However, since elderly patients are under-represented in most trials, the results might be due to selection bias, thus reports from a cohort of consecutively treated patients are warranted. The current single institution study reports on the influence of age on survival of locally advanced NSCLC patients treated with radiotherapy combined with or without concurrent chemotherapy. MATERIAL AND METHODS: Altogether, 478 patients completed radical radiotherapy in doses of 60-66 Gy/30-33 fractions from 1995 to June 2012; 137 of the patients had concurrent chemotherapy. The data was analyzed in age groups<60, 60-69, and ≥70 years. RESULTS: In the analyses of overall and lung cancer specific survival the hazard ratio was related to the use of concurrent chemotherapy was 0.49 (95% CI 0.29; 0.82), 0.68 (95% CI 0.48; 0.98) and 1.01 (95% CI 0.67; 1.51) for the age groups<60, 60-69, and ≥70, respectively. CONCLUSION: Use of concurrent chemotherapy to radiotherapy of locally advanced NSCLC was associated with a survival benefit in patient younger than 70 years which was not the case for patients older than 70 years, indicating the need to be careful when selecting elderly patients for concurrent chemo-radiation.

Pattern of loco-regional failure after definitive radiotherapy for non-small cell lung cancer.

UNLABELLED: Non-small cell lung cancer (NSCLC) is associated with poor survival even though patients are treated with curatively intended radiotherapy. Survival is affected negatively by lack of loco-regional tumour control, but survival is also influenced by comorbidity caused by age and smoking, and occurrence of distant metastasis. It is challenging to evaluate loco-regional control after definitive radiotherapy for NSCLC since it is difficult to distinguish between radiation-induced damage to the lung tissue and tumour progression/recurrence. In addition it may be useful to distinguish between intrapulmonary failure and mediastinal failure to be able to optimize radiotherapy in order to improve loco-regional control even though it is not easy to discriminate between the two sites of failure. MATERIAL AND METHODS: This study is a retrospective analysis of 331 NSCLC patients treated with definitive radiotherapy from 2002 to 2011. The patients were treated consecutively at the Department of Oncology, Odense University Hospital, Denmark with at least 60 Gy. All patients were followed in a planned follow-up schedule and no patients were lost for follow-up. RESULTS: At the time of the analysis 93 patients had loco-regional failure only. Of these patients, 68 had intrapulmonary failure only, one patient had failure in mediastinum only, and 24 patients had intrapulmonary failure as well as mediastinal failure. Of the patients which had lung failure only, 78% had mediastinal involvement at treatment start. The only covariate with significant impact on developing intrapulmonary failure only was gross tumour volume. Median survival for the total group of 331 patients was 19 months. The median survival for patients with intrapulmonary failure only was 19 months, and it was 20 months for the patients with mediastinal relapse. CONCLUSION: We conclude that focus should be on increasing doses to intrapulmonary tumour volume, when dose escalation is applied to improve local tumour control in NSCLC patients treated with definitive radiotherapy, since most recurrences are located here.

Inhomogeneous dose escalation increases expected local control for NSCLC patients with lymph node involvement without increased mean lung dose.

BACKGROUND: Higher doses to NSCLC tumours are required to increase the low control rates obtained with conventional dose prescriptions. This study presents the concept of inhomogeneous dose distributions as a general way to increase local control probability, not only for isolated lung tumours but also for patients with involved lymph nodes. MATERIAL AND METHODS: Highly modulated IMRT plans with homogeneous dose distributions with a prescribed dose of 66Gy/33F were created for 20 NSCLC patients, staged T1b-T4 N0-N3, using standard PTV dose coverage of 95-107%. For each patient, an inhomogeneous dose distribution was created with dose constraints of: PTV-coverage ≥ 95%, same mean lung dose as obtained in the homogeneous dose plan, maximum doses of 45 and 66 Gy to spinal canal and oesophagus, respectively, and V74Gy < 1 cm(3) for each of: aorta, trachea + bronchi, the connective tissue in mediastinum, and the thorax wall. The dose was escalated using a TCP model implemented into the planning system. The difference in TCP values between the homogeneous and inhomogeneous plans were evaluated using two different TCP models. RESULTS: Dose escalation was possible for all patients. TCP values based on assumed homogeneous distribution of clonogenic cells either in the GTV, CTV or PTV showed absolute TCP increases of approximately 15, 10 and 5 percentage points, respectively. This increase in local control was obtained without increasing the mean lung dose. However, small increases in maximum doses to the mediastinum were observed: 2.5 Gy for aorta, 4.4 Gy for the connective tissue, 1.6 Gy for the heart, and 2.6 Gy for trachea + bronchi. CONCLUSION: Increased target doses and TCP values using inhomogeneous dose distributions could be achieved for all patients, regardless of lymph node involvement, tumour stage, location, and size. These new treatment plans have the potential to increase the local tumour control by 10-15 percentage points without compromising the clinically acceptable lung toxicity level.

Cumulative rib fracture risk after stereotactic body radiotherapy in patients with localized non-small cell lung cancer.

INTRODUCTION: Rib fracture is a known complication after stereotactic body radiotherapy (SBRT). Patient-related parameters are essential to provide patient-tailored risk estimation, however, their impact on rib fracture is less documented compared to dosimetric parameters. This study aimed to predict the risk of rib fractures in patients with localized non-small cell lung cancer (NSCLC) post-SBRT based on both patient-related and dosimetric parameters with death as a competing risk. MATERIALS AND METHODS: In total, 602 patients with localized NSCLC treated with SBRT between 2010-2020 at Odense University Hospital, Denmark were included. All patients received SBRT with 45-66 Gray (Gy)/3 fractions. Rib fractures were identified in CT-scans using a word embedding model. The cumulative incidence function was based on cause-specific Cox hazard models with variable selection based on cross-validation model likelihood performed using 50 bootstraps. RESULTS: In total, 19 % of patients experienced a rib fracture. The cumulative risk of rib fracture increased rapidly from 6-54 months post-SBRT. Female gender, bone density, near max dose to the rib, V30 and V40 to the rib, gross tumor volume, and mean lung dose were significantly associated with rib fracture risk in univariable analysis. The final multi-variable model consisted of V20 and V30 to the rib and mean lung dose. CONCLUSION: Female gender and low bone density in male patients are significant predictors of rib fracture risk. The final model predicting cumulative rib fracture risk of 19 % in patients with localized NSCLC treated with SBRT contained no patient-related parameters, suggesting that dosimetric parameters are the primary drivers.

Prediction of overall survival in patients with locally advanced pancreatic cancer using longitudinal diffusion-weighted MRI.

Background and purpose: Biomarkers for prediction of outcome in patients with pancreatic cancer are wanted in order to personalize the treatment. This study investigated the value of longitudinal diffusion-weighted magnetic resonance imaging (DWI) for prediction of overall survival (OS) in patients with locally advanced pancreatic cancer (LAPC) treated with stereotactic body radiotherapy (SBRT). Materials and methods: The study included 45 patients with LAPC who received 5 fractions of 10 Gy on a 1.5T MRI-Linac. DWI was acquired prior to irradiation at each fraction. The analysis included baseline values and time-trends of the apparent diffusion coefficient (ADC) and DWI parameters obtained using a decomposition method. A multivariable Cox proportional hazards model for OS was made using best-subset selection, using cross-validation based on Bootstrap. Results: The median OS from the first day of SBRT was 15.5 months (95% CI: 13.2-20.6), and the median potential follow-up time was 19.8 months. The best-performing multivariable model for OS included two decomposition-based DWI parameters: one baseline and one time-trend parameter. The C-Harrell index describing the model's discriminating power was 0.754. High baseline ADC values were associated with reduced OS, whereas no association between the ADC time-trend and OS was observed. Conclusion: Decomposition-based DWI parameters indicated value in the prediction of OS in LAPC. A DWI time-trend parameter was included in the best-performing model, indicating a potential benefit of acquiring longitudinal DWI during the SBRT course. These findings support both baseline and longitudinal DWI as candidate prognostic biomarkers, which may become tools for personalization of the treatment of patients with LAPC.

Adaptive MRI-guided stereotactic body radiation therapy for locally advanced pancreatic cancer - A phase II study.

PURPOSE: Stereotactic body radiotherapy (SBRT) has emerged as a promising new modality for locally advanced pancreatic cancer (LAPC). The current study evaluated the efficacy and toxicity of SBRT in patients with LAPC (NCT03648632). METHODS: This prospective single institution phase II study recruited patients with histologically or cytologically proven adenocarcinoma of the pancreas after more than two months of combination chemotherapy with no sign of progressive disease. Patients were prescribed 50-60 Gy in 5-8 fractions. Patients were initially treated on a standard linac (n = 4). Since 2019, patients were treated using online magnetic resonance (MR) image-guidance on a 1.5 T MRI-linac, where the treatment plan was adapted to the anatomy of the day. The primary endpoint was resection rate. RESULTS: Twenty-eight patients were enrolled between August 2018 and March 2022. All patients had non-resectable disease at time of diagnosis. Median follow-up from inclusion was 28.3 months (95 % CI 24.0-NR). Median progression-free and overall survival from inclusion were 7.8 months (95 % CI 5.0-14.8) and 16.5 months (95 % CI 10.7-22.6), respectively. Six patients experienced grade III treatment-related adverse events (jaundice, nausea, vomiting and/or constipation). One of the initial four patients receiving treatment on a standard linac experienced a grade IV perforation of the duodenum. Six patients (21 %) underwent resection. A further one patient was offered resection but declined. CONCLUSION: This study demonstrates that SBRT in patients with LAPC was associated with promising overall survival and resection rates. Furthermore, SBRT was safe and well tolerated, with limited severe toxicities.

Radiation therapy in older patients with cancer.

The general population is aging, which expectedly will lead to a future increase in older patients with cancer. This review summarises the recent advances in radiotherapy. Technological advances have led radiotherapy to be an efficient and well-tolerated treatment option in older patient with cancer. Studies show no difference in toxicity and disease control rates compared with the ones in younger patients with cancer. MR-guided radiotherapy, proton therapy, and integration of artificial intelligence in treatment planning represent the latest advances in the field of radiotherapy and hold potential to further improve the treatment of older patients with cancer.

MR-guided stereotactic radiotherapy of infra-diaphragmatic oligometastases: Evaluation of toxicity and dosimetric parameters.

BACKGROUND AND PURPOSE: The SOFT trial is a prospective, multicenter, phase 2 trial investigating magnetic resonance (MR)-guided stereotactic ablative radiotherapy (SABR) for abdominal, soft tissue metastases in patients with oligometastatic disease (OMD) (clinicaltrials.gov ID NCT04407897). We present the primary endpoint analysis of 1-year treatment-related toxicity (TRAE). MATERIALS AND METHODS: Patients with up to five oligometastases from non-hematological cancers were eligible for inclusion. A risk-adapted strategy prioritized fixed organs at risk (OAR) constraints over target coverage. Fractionation schemes were 45-67.5 Gy in 3-8 fractions. The primary endpoint was grade ≥ 4 TRAE within 12 months post-SABR. The association between the risk of gastrointestinal (GI) toxicity and clinical and dosimetric parameters was tested using a normal tissue complication probability model. RESULTS: We included 121 patients with 147 oligometastatic targets, mainly located in the liver (41 %), lymph nodes (35 %), or adrenal glands (14 %). Nearly half of all targets (48 %, n = 71) were within 10 mm of a radiosensitive OAR. No grade 4 or 5 TRAEs, 3.5 % grade 3 TRAEs, and 43.7 % grade 2 TRAEs were reported within the first year of follow-up. We found a significant association between grade ≥ 2 GI toxicity and the parameters GI OAR D0.1cc, D1cc, and D20cc. CONCLUSION: In this phase II study of MR-guided SABR of oligometastases in the infra-diaphragmatic region, we found a low incidence of toxicity despite half of the lesions being within 10 mm of a radiosensitive OAR. GI OAR D0.1cc, D1cc, and D20cc were associated with grade ≥ 2 GI toxicity.

Impact of geometric correction on echo-planar imaging-based apparent diffusion coefficient maps for abdominal radiotherapy.

Objective. The apparent diffusion coefficient (ADC) extracted from diffusion-weighted magnetic resonance imaging (DWI) is a potential biomarker in radiotherapy (RT). DWI is often implemented with an echo-planar imaging (EPI) read-out due to speed, but unfortunately low geometric accuracy follows. This study aimed to investigate the influence of geometric distortions on the ADCs extracted from the gross tumor volume (GTV) and on the shape of the GTV in abdominal EPI-DWI.Approach. Twenty-one patients had EPI-DWI scans on a 1.5 T MRI sim before treatment and on a 1.5 T MRI-Linac at one of the first treatment fractions. Off-resonance correction with and without eddy current correction were applied to ADC maps. The clinical GTVs were deformed based on the same (but inverted) corrections to assess the local-regional geometric influence of distortions. Mean surface distance (MSD), Hausdorff distance (HD), and Dice similarity coefficient (DSC) were calculated to compare the original and distorted GTVs, and ADC values were calculated based on a mono-exponential model. Phantom measurements were performed to validate the applied correction method.Main results. The median (range) ADC change within the GTV after full distortion correction was 1.3% (0.02%-6.9%) for MRI-Sim and 1.5% (0.1%-6.4%) for MRI-Linac. The additional effect of the eddy current correction was small in both systems. The median (range) MSD, HD, and DSC comparing the original and off-resonance distorted GTVs for all patients were 0.43 mm (0.11-0.94 mm), 4.00 mm (1.00-7.81 mm) and 0.93 (0.82-0.99), respectively.Significance. Overall effect of distortion correction was small in terms of derived ADC values, indicating that distortion correction is unimportant for prediction of outcomes based on ADC. However, large local geometric changes occurred after off-resonance distortion correction for some patients, suggesting that if the spatial information from ADC maps is to be used for dose painting strategies, corrections should be applied.