The Association of Incidental Radiation Dose to the Heart Base with Overall Survival and Cardiac Events after Curative-intent Radiotherapy for Non-small Cell Lung Cancer: Results from the NI-HEART Study

AIMS

Cardiac disease is a dose-limiting toxicity in non-small cell lung cancer radiotherapy. The dose to the heart base has been associated with poor survival in multiple institutional and clinical trial datasets using unsupervised, voxel-based analysis. Validation has not been undertaken in a cohort with individual patient delineations of the cardiac base or for the endpoint of cardiac events. The purpose of this study was to assess the association of heart base radiation dose with overall survival and the risk of cardiac events with individual heart base contours.

MATERIALS AND METHODS

Patients treated between 2015 and 2020 were reviewed for baseline patient, tumour and cardiac details and both cancer and cardiac outcomes as part of the NI-HEART study. Three cardiologists verified cardiac events including atrial fibrillation, heart failure and acute coronary syndrome. Cardiac substructure delineations were completed using a validated deep learning-based autosegmentation tool and a composite cardiac base structure was generated. Cox and Fine-Gray regressions were undertaken for the risk of death and cardiac events.

RESULTS

Of 478 eligible patients, most received 55 Gy/20 fractions (96%) without chemotherapy (58%), planned with intensity-modulated radiotherapy (71%). Pre-existing cardiovascular morbidity was common (78% two or more risk factors, 46% one or more established disease). The median follow-up was 21.1 months. Dichotomised at the median, a higher heart base Dmax was associated with poorer survival on Kaplan-Meier analysis (20.2 months versus 28.3 months; hazard ratio 1.40, 95% confidence interval 1.14-1.75, P = 0.0017) and statistical significance was retained in multivariate analyses. Furthermore, heart base Dmax was associated with pooled cardiac events in a multivariate analysis (hazard ratio 1.75, 95% confidence interval 1.03-2.97, P = 0.04).

CONCLUSIONS

Heart base Dmax was associated with the rate of death and cardiac events after adjusting for patient, tumour and cardiovascular factors in the NI-HEART study. This validates the findings from previous unsupervised analytical approaches. The heart base could be considered as a potential sub-organ at risk towards reducing radiation cardiotoxicity.

Simulation CT Features and Radiation Cardiotoxicity in Non-Small Cell Lung Cancer

PURPOSE/OBJECTIVE(S)

Radiation cardiotoxicity is a significant clinical dilemma in non-small cell lung cancer (NSCLC) radiation therapy (RT). Baseline cardiovascular (CV) status may influence the risk of cardiotoxicity, and may be ascertainable from the appearance of the heart on simulation computed tomography (CT). We examined the association of CT features with incidental heart dose and risk of cardiac events in NSCLC.

MATERIALS/METHODS

Patients treated with curative-intent RT between 2015 and 2020 at a regional center were identified. Clinical notes were interrogated for baseline patient and CV health details, and follow-up CV events. Cardiac events were verified by a cardiologist. A deep learning-based auto-segmentation tool was applied, allowing extraction of a pre-specified list of volume parameters in a programming environment. CAC was graded as none, mild, moderate and severe in patients with a non-contrast scan. The craniocaudal relationship of the PTV and heart (Feng atlas) were annotated.

RESULTS

A total of 478 patients were included, with a median age of 70 and Charlson Index of 5. The median mean heart dose was 6.3 Gy (IQR 2.7-11.4). The median lung V20 was 20.0% (IQR 14.8-27.1). Cardiovascular risk factors were common, with most patients having 2 (39%) or 3 (31%). A history of previous cardiac events was common, including myocardial infarction (14%), arrhythmia (11%) or heart failure (9%). A total of 6.9% and 7.1% patients developed a new atrial arrhythmia (AA) or heart failure (HF) after completing RT. The volume metrics with the highest AUC for AA and HF events were the left atrium (LA) (AUC 0.67, p = 0.0002) and left ventricle:right ventricle (LV:RV) ratio (AUC 0.66, p = 0.0021). Kaplan-Meier analysis for cardiac events dichotomizing at the optimal cut-point for maximum sensitivity and specificity demonstrated significantly different rates for both AA (LA 109cc, HR 3.35, 95% CI 1.64-6.83, p = 0.0009) and HF (LV:RV ratio 1.61, HR 2.37, 95% CI 1.19-4.74, p = 0.0143). Only 2 patients with non-contrast scans developed a myocardial infarction, both had mild CAC. The incidence of pooled cardiac events was not significantly different between patients with no (n = 2/21, 9.5%), mild (n = 10/38, 26.3%), moderate (n = 8/53, 15.1%) and severe (n = 7/24, 29.2%) CAC (p = 0.3916). Where the inferior border of the PTV was above the superior border of the heart, mean heart dose was significantly lower than compared with overlap of levels (1.9 Gy v 9.7 Gy, p<0.0001), and this was true for 3DCRT (n = 139, p<0.001), IMRT (n = 94, p<0.001) and VMAT (n = 145, p<0.001) patients.

CONCLUSION

LA volume and LV:RV volume ratio are predictive for the development of AA and HF respectively. CAC grade did not differentiate patients by risk of cardiac events. Where the craniocaudal level of the PTV doesn't overlap with the level of the heart, the cardiac dose is likely to be very low. Several simulation CT features are associated with cardiac events following treatment for NSCLC and prospective evidence of cardiac risk could enable medical optimization prior to RT.

Patient-Level and Endpoint-Specific Clinico-Dosimetric Analysis of the Cardiac Base as a Mediator of Radiation Cardiotoxicity in Non-Small Cell Lung Cancer

PURPOSE/OBJECTIVE(S)

Cardiac disease is a dose-limiting toxicity in non-small cell lung cancer (NSCLC) radiation therapy. Radiation dose to the cardiac base is associated with poor overall survival in several clinical studies, but has not been validated in a non-dose escalated cohort, or with individual patient delineations. In this study we examined the impact of cardiac base dose on overall survival (OS) and cardiac events (CEs), and interrogated the relationships of the substructures comprising the heart base with OS and CEs.

MATERIALS/METHODS

Patients with stage I-III NSCLC treated with curative-intent radiation therapy between 2015 and 2020 at a regional cancer center were identified. Clinical notes were examined for baseline patient, tumor and cardiac details, and both cancer and cardiac outcomes. Three cardiologists verified CEs. Cardiac delineations were completed using a validated deep learning-based autosegmentation tool. Cox and Fine and Gray regressions were undertaken for the risk of death and CEs respectively, accounting for pre-specified evidence-based dose metrics and clinically relevant cardiac covariates.

RESULTS

Most patients received 55 Gy/20# (n = 461/478, 96%) without chemotherapy (58%), planned with VMAT (51%) or IMRT (20%). Pre-existing cardiovascular morbidity was common, with 78% having ≥2 risk factors, and 46% having >1 established cardiac disease. The median follow-up was 21.1 months. Dichotomized at the median, higher heart base Dmax was associated with poorer survival on Kaplan-Meier analysis (21.6 months (95% CI 19.3-24.9) versus 29.4 months (95% CI 21.6-36.6), p = 0.021), and remained significant when statistically compared in published multivariate models. In a multivariate analysis for pooled acute CEs, heart base Dmax was associated with CEs (HR 1.75, 95% CI 1.01-1.06, p = 0.04), but this was not the case for individual CEs. Using Fine and Gray models to account for the competing risk of death, left main coronary maximum dose was associated with atrial fibrillation (p = 0.024), proximal right coronary artery V15 (p = 0.023) and mean dose (p = 0.032), and the right atrium mean dose (p = 0.029) were associated with heart failure. No dose-volume metrics were significantly associated with acute coronary syndrome. None of the constituent base substructures dose were significantly associated with death.

CONCLUSION

Dose to the heart base was associated with increased mortality and an increased pooled cardiac event rate. Accounting for endpoint-specific clinical covariates, only select constituent substructures of the heart base were associated with CEs and no substructures were independently associated with survival. Together, these findings are suggestive of possible interplay between the constituent base substructures in their mediation of radiation cardiotoxicity.

UK 2022 Consensus on Normal Tissue Dose-Volume Constraints for Oligometastatic, Primary Lung and Hepatocellular Carcinoma Stereotactic Ablative Radiotherapy

The use of stereotactic ablative radiotherapy (SABR) in the UK has expanded over the past decade, in part as the result of several UK clinical trials and a recent NHS England Commissioning through Evaluation programme. A UK SABR Consortium consensus for normal tissue constraints for SABR was published in 2017, based on the existing literature at the time. The published literature regarding SABR has increased in volume over the past 5 years and multiple UK centres are currently working to develop new SABR services. A review and update of the previous consensus is therefore appropriate and timely. It is hoped that this document will provide a useful resource to facilitate safe and consistent SABR practice.

Long-term Survival with 18-Fluorodeoxyglucose Positron Emission Tomography-directed Therapy in Non-small Cell Lung Cancer with Synchronous Solitary Brain Metastasis

AIMS

At diagnosis, <1% of patients with non-small cell lung cancer (NSCLC) have synchronous solitary brain metastasis (SSBM). In prior cohorts without 18-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) staging, definitive treatment to intracranial and intrathoracic disease showed a 5-year overall survival (OS) of 11-21%. We investigated the long-term survival outcomes for patients with SSBM NSCLC, diagnosed in the FDG-PET/CT era and treated definitively with local therapies to both intracranial and intrathoracic sites of disease.

MATERIALS AND METHODS

This retrospective study assessed patients staged with FDG-PET/CT who received definitive lung and SSBM treatment from February 1999 to December 2017. A lung-molecular graded prognostic assessment (lung-molGPA) score was assigned for each patient using age, performance status score, and, where carried out, molecular status. Overall survival and progression-free survival (PFS) were calculated using Kaplan-Meier methods. Cox proportional hazard models determined OS and PFS prognostic factors.

RESULTS

Forty-nine patients newly diagnosed with NSCLC and SSBM had a median age of 63 years (range 34-76). The median follow-up of all patients was 3.9 years. Thirty-three patients (67%) had ≥T2 disease, 23 (47%) had ≥N2. At 2 years, 45% of first failures were intracranial only (95% confidence interval 30-59). At 3 and 5 years, OS was 45% (95% confidence interval 32-63) and 30% (95% confidence interval 18-51), respectively. In ≥N1 disease, 5-year OS was 34% (95% confidence interval 18-63). The 3- and 5-year PFS was 8% (95% confidence interval 3-22) and 0%, respectively. Higher lung-molGPA was associated with longer OS (hazard ratio 0.26, 95% confidence interval 0.11-0.61, P = 0.002). Higher lung-molGPA (hazard ratio 0.33, 95% confidence interval 0.15-0.71, P = 0.005) and lower N-stage (hazard ratio 1.56, 95% confidence interval 1.13-2.15, P = 0.007) were associated with longer PFS.

CONCLUSIONS

Definitive treatment of patients with NSCLC and SSBM staged with FDG-PET/CT can result in 5-year survivors, including those with ≥N1 disease.

Radiotherapy Trial Set-up in the UK: Identifying Inefficiencies and Potential Solutions

AIMS

Radiotherapy clinical trials are integral to the development of new treatments to improve the outcomes of patients with cancer. A collaborative study by the National Cancer Research Institute Clinical and Translational Radiotherapy Research Working Group and the National Institute for Health Research was carried out to understand better if and why inefficiencies occur in the set-up of radiotherapy trials in the UK.

MATERIALS AND METHODS

Two online surveys collected information on the time taken for UK radiotherapy trials to reach key milestones during set-up and the research support currently being provided to radiotherapy centres to enable efficient clinical trial set-up. Semi-structured interviews with project managers and chief investigators identified better ways of working to improve trial set-up in the future.

RESULTS

The timelines for the set-up of 39 UK radiotherapy trials were captured in an online survey showing that the median time from grant approval to trial opening was 600 days (range 169-1172). There were 38 responses from radiotherapy centres to a survey asking about the current support provided for radiotherapy research. Most of these centres have more than one type of staff member dedicated to supporting radiotherapy research. The most frequent barrier to radiotherapy trial set-up identified was lack of physicists' time and lack of time for clinical oncologists to carry out research activities. Four main themes around trial set-up were identified from semi-structured interviews: the importance of communication and building relationships, the previous experience of the chief investigator and clinical trials units, a lack of resources and having the time and personnel required to produce trial documentation and to process trial approval requests.

CONCLUSIONS

This unique, collaborative project has provided up to date information about the current landscape of trial set-up and research support in the UK and identified several avenues on which to focus future efforts in order to support the excellent radiotherapy trial work carried out across the UK.

Delays in referral from primary care are associated with a worse survival in patients with esophagogastric cancer

NICE referral guidelines for suspected cancer were introduced to improve prognosis by reducing referral delays. However, over 20% of patients with esophagogastric cancer experience three or more consultations before referral. In this retrospective cohort study, we hypothesize that such a delay is associated with a worse survival compared with patients referred earlier. By utilizing Clinical Practice Research Datalink, a national primary care linked database, the first presentation, referral date, a number of consultations before referral and stage for esophagogastric cancer patients were determined. The risk of a referral after one or two consultations compared with three or more consultations was calculated for age and the presence of symptom fulfilling the NICE criteria. The risk of death according to the number of consultations before referral was determined, while accounting for stage and surgical management. 1307 patients were included. Patients referred after one (HR 0.80 95% CI 0.68-0.93 p = 0.005) or two consultations (HR 0.81 95% CI 0.67-0.98 p = 0.034) demonstrated significantly improved prognosis compared with those referred later. The risk of death was also lower for patients who underwent a resection, were younger or had an earlier stage at diagnosis. Those presenting with a symptom fulfilling the NICE criteria (OR 0.27 95% CI 0.21-0.35 p < 0.0001) were more likely to be referred earlier. This is the first study to demonstrate an association between a delay in referral and worse prognosis in esophagogastric patients. These findings should prompt further research to reduce primary care delays.

Introducing FDG PET/CT-guided chemoradiotherapy for stage III NSCLC in low- and middle-income countries: preliminary results from the IAEA PERTAIN trial

Purpose

Patients with stage III non-small-cell lung cancer (NSCLC) treated with chemoradiotherapy (CRT) in low- and middle-income countries (LMIC) continue to have a poor prognosis. It is known that FDG PET/CT improves staging, treatment selection and target volume delineation (TVD), and although its use has grown rapidly, it is still not widely available in LMIC. CRT is often used as sequential treatment, but is known to be more effective when given concurrently. The aim of the PERTAIN study was to assess the impact of introducing FDG PET/CT-guided concurrent CRT, supported by training and quality control (QC), on the overall survival (OS) and progression-free survival (PFS) of patients with stage III NSCLC.

Methods

The study included patients with stage III NSCLC from nine medical centres in seven countries. A retrospective cohort was managed according to local practices between January 2010 and July 2014, which involved only optional diagnostic FDG PET/CT for staging (not for TVD), followed by sequential or concurrent CRT. A prospective cohort between August 2015 and October 2018 was treated according to the study protocol including FDG PET/CT in treatment position for staging and multimodal TVD followed by concurrent CRT by specialists trained in protocol-specific TVD and with TVD QC. Kaplan–Meier analysis was used to assess OS and PFS in the retrospective and prospective cohorts.

Results

Guidelines for FDG PET/CT image acquisition and TVD were developed and published. All specialists involved in the PERTAIN study received training between June 2014 and May 2016. The PET/CT scanners used received EARL accreditation. In November 2018 a planned interim analysis was performed including 230 patients in the retrospective cohort with a median follow-up of 14 months and 128 patients in the prospective cohort, of whom 69 had a follow-up of at least 1 year. Using the Kaplan–Meier method, OS was significantly longer in the prospective cohort than in the retrospective cohort (23 vs. 14 months, p = 0.012). In addition, median PFS was significantly longer in the prospective cohort than in the retrospective cohort (17 vs. 11 months, p = 0.012).

Conclusion

In the PERTAIN study, the preliminary results indicate that introducing FDG PET/CT-guided concurrent CRT for patients with stage III NSCLC in LMIC resulted in a significant improvement in OS and PFS. The final study results based on complete data are expected in 2020.

Electronic supplementary material

The online version of this article (10.1007/s00259-019-04421-5) contains supplementary material, which is available to authorized users.

Differential Relapse Patterns for Non-small Cell Lung Cancer Subtypes Adenocarcinoma and Squamous Cell Carcinoma: Implications for Radiation Oncology

AIMS

Curative-intent (radical) radiotherapy aims to control local disease and cure non-small cell lung cancer (NSCLC). The predominant subtypes of NSCLC are adenocarcinoma and squamous cell carcinoma (SCC). The radiotherapy paradigm offered to patients does not differ according to these two subtypes. Relapse patterns and disease control rates for adenocarcinoma and SCC treated with radical radiotherapy were determined.

MATERIALS AND METHODS

A radical radiotherapy database covering the period from 2004 to June 2016 was examined to determine the first sites of relapse and the actuarial local and distant control rates.

RESULTS

In total, 537 patients with known pathological subtype were treated over the period. In 39 (7%), the site of first relapse was uncertain. Of the remainder, 203 (41%) had adenocarcinoma and 295 (59%) had SCC. At a median follow-up of 16.4 months, 58% had relapsed. There was a difference in relapse patterns (chi-squared test P < 0.0005), with a higher rate of first relapse locally in SCC (42% of all patients versus 24%) and a higher rate of first relapse in the brain for adenocarcinoma (14% versus 3%). The actuarial local control rate was worse for SCC (hazard ratio 0.6, 95% confidence interval 0.5-0.9, P = 0.002). The brain metastasis-free survival was worse for adenocarcinoma (hazard ratio 4.1, 95% confidence interval 2.2-7.5, P < 0.0001).

CONCLUSION

There is a difference in relapse patterns between NSCLC histological subtypes, indicating that these are distinct entities. This may have implications for follow-up policy and strategies to improve disease control.

The Abscopal Effect of Stereotactic Radiotherapy and Immunotherapy: Fool's Gold or El Dorado?

An 'abscopal' effect if often used to refer to distant tumour regression after localised irradiation. Since the first report of the abscopal effect in the 1950s, well-documented cases with radiotherapy alone are very rare. It is widely accepted that the immune response plays an important role in the abscopal effect, although the mechanism is still unclear. With the recent success of cancer immunotherapy, there is growing interest in combining immunotherapy with radiotherapy to boost abscopal response rates. Compared with conventional radiotherapy, stereotactic ablative radiotherapy (SABR) not only delivers ablative dose to the tumour, but may also induce robust immune responses. In this review we examine studies that combine SABR and immunotherapy. We review the preclinical rationale for SABR and immunotherapy combinations, the case for and against abscopal effects, and the current landscape of clinical trials.

An observational study of the timing of surgery, use of laparoscopy and outcomes for acute cholecystitis in the USA and UK

BACKGROUND

Evidence supports early laparoscopic cholecystectomy for acute cholecystitis. Differences in treatment patterns between the USA and UK, associated outcomes and resource utilization are not well understood.

METHODS

In this retrospective, observational study using national administrative data, emergency patients admitted with acute cholecystitis were identified in England (Hospital Episode Statistics 1998-2012) and USA (National Inpatient Sample 1998-2011). Proportions of patients who underwent emergency cholecystectomy, utilization of laparoscopy and associated outcomes including length of stay (LOS) and complications were compared. The effect of delayed treatment on subsequent readmissions was evaluated for England.

RESULTS

Patients with a diagnosis of acute cholecystitis totaled 1,191,331 in the USA vs. 288 907 in England. Emergency cholecystectomy was performed in 628,395 (52.7% USA) and 45,299 (15.7% England) over the time period. Laparoscopy was more common in the USA (82.8 vs. 37.9%; p < 0.001). Pre-treatment (1 vs. 2 days; p < 0.001) and total ( 4 vs. 7 days; p < 0.001) LOS was lower in the USA. Overall incidence of bile duct injury was higher in England than the USA (0.83 vs. 0.43%; p < 0.001), but was no different following laparoscopic surgery (0.1%). In England, 40.5% of patients without an immediate cholecystectomy were subsequently readmitted with cholecystitis. An additional 14.5% were admitted for other biliary complications, amounting to 2.7 readmissions per patient in the year following primary admission.

CONCLUSION

This study highlights management practices for acute cholecystitis in the USA and England. Despite best evidence, index admission laparoscopic cholecystectomy is performed less in England, which significantly impacts subsequent healthcare utilization.

UK Consensus on Normal Tissue Dose Constraints for Stereotactic Radiotherapy

Six UK studies investigating stereotactic ablative radiotherapy (SABR) are currently open. Many of these involve the treatment of oligometastatic disease at different locations in the body. Members of all the trial management groups collaborated to generate a consensus document on appropriate organ at risk dose constraints. Values from existing but older reviews were updated using data from current studies. It is hoped that this unified approach will facilitate standardised implementation of SABR across the UK and will allow meaningful toxicity comparisons between SABR studies and internationally.

ICORG 10-14: NEOadjuvant trial in Adenocarcinoma of the oEsophagus and oesophagoGastric junction International Study (Neo-AEGIS)

BACKGROUND

Neoadjuvant therapy is increasingly the standard of care in the management of locally advanced adenocarcinoma of the oesophagus and junction (AEG). In randomised controlled trials (RCTs), the MAGIC regimen of pre- and postoperative chemotherapy, and the CROSS regimen of preoperative chemotherapy combined with radiation, were superior to surgery only in RCTs that included AEG but were not powered on this cohort. No completed RCT has directly compared neoadjuvant or perioperative chemotherapy and neoadjuvant chemoradiation. The Neo-AEGIS trial, uniquely powered on AEG, and including comprehensive modern staging, compares both these regimens.

METHODS

This open label, multicentre, phase III RCT randomises patients (cT2-3, N0-3, M0) in a 1:1 fashion to receive CROSS protocol (Carboplatin and Paclitaxel with concurrent radiotherapy, 41.4Gy/23Fr, over 5 weeks). The power calculation is a 10% difference in favour of CROSS, powered at 80%, two-sided alpha level of 0.05, requiring 540 patients to be evaluable, 594 to be recruited if a 10% dropout is included (297 in each group). The primary endpoint is overall survival, with a minimum 3-year follow up. Secondary endpoints include: disease free survival, recurrence rates, clinical and pathological response rates, toxicities of induction regimens, post-operative pathology and tumour regression grade, operative in-hospital complications, and health-related quality of life. The trial also affords opportunities for establishing a bio-resource of pre-treatment and resected tumour, and translational research.

DISCUSSION

This RCT directly compares two established treatment regimens, and addresses whether radiation therapy positively impacts on overall survival compared with a standard perioperative chemotherapy regimen Sponsor: Irish Clinical Research Group (ICORG).

TRIAL REGISTRATION

NCT01726452 . Protocol 10-14. Date of registration 06/11/2012.