Radiation dose-volume effects in the esophagus

Evaluation of Radiation Therapy Treatment Plans in a Randomized Phase 2 Trial Comparing 2 Schedules of Twice-Daily Thoracic Radiation Therapy in Limited Stage Small Cell Lung Cancer

PURPOSE

There is limited clinical data for recommendations on how to deliver thoracic radiation therapy (TRT) concurrently with chemotherapy in limited-stage small cell lung cancer. We reviewed radiation therapy treatment plans in a randomized phase 2 trial comparing high-dose with standard-dose twice-daily TRT to assess treatment planning techniques, dose-volume data for target volumes and organs at risk (OARs), evaluate compliance with the protocol, associations with radiation-induced toxicity, and whether an imbalance in treatment planning parameters might be a reason for the large survival benefit of the higher dose (median overall survival 43.6 vs 22.6 months).

METHODS AND MATERIALS

In the study, 170 patients were to receive 4 courses of platinum/etoposide and were randomized to receive twice-daily TRT of 60 Gy/40 fractions (fx) or 45 Gy/30 fx. TRT treatment plans for those who received 1 or more fx of TRT (n = 166) were analyzed.

RESULTS

The most common treatment planning technique was 3-dimensional conformal radiation therapy (67%). The 75th percentile of the reported dose-volume parameters for the OARs were within the protocol-recommended limits for both groups. Mean doses to the esophagus of 25.5 Gy (IQR, 20.2-31.3; 60 Gy/40 fx) and 24.3 Gy (IQR, 20.3-27.5; 45 Gy/30 fx) were associated with 21% and 18% ≥ grade 3 acute esophagitis, respectively. In the 60 Gy/40 fx group, a mean dose to the lungs of 16.5 Gy (IQR, 15.8-16.9), V20 Gy of 29.5% (IQR, 28.8-30.4), and V5 Gy of 65.6% (IQR, 61.5-68.7) led to ≥ grade 3 pneumonitis in 4% of the patients. There was no ≥ grade 3 pneumonitis in the 45 Gy/30 fx group. The treatment planning techniques, the percentage change in volumes between original and redelineated OARs, planning target volumes, relative doses, and laterality were well balanced between the randomly assigned groups.

CONCLUSIONS

Considering the incidences of severe radiation-induced toxicities were within the range of other recent trials, the reported doses to the OARs appear to be safe. Treatment planning parameters were well balanced between the randomly assigned groups, supporting that the survival benefit of the twice-daily 60 Gy/40 fx TRT schedule was due to the higher dose.

Heartbreaker: Detection and prevention of cardiotoxicity in hematological malignancies

Cancer survivors are at significant risk of cardiovascular (CV) morbidity and mortality; patients with hematologic malignancies have a higher rate of death due to heart failure compared to all other cancer subtypes. The majority of conventional hematologic cancer treatments is associated with increased risk of acute and long-term CV toxicity. The incidence of cancer therapy induced CV toxicity depends on the combination of patient characteristics and on the type, dose, and duration of the therapy. Early diagnosis of CV toxicity, appropriate referral, more specific cardiac monitoring follow-up and timely interventions in target patients can decrease the risk of CV adverse events, the interruption of oncological therapy, and improve the patient's prognosis. Herein, we summarize the CV effects of conventional treatments used in hematologic malignancies with a focus on definitions and incidence of the most common CV toxicities, guideline recommended early detection approaches, and preventive strategies before and during cancer treatments.

Robustness analysis of surface-guided DIBH left breast radiotherapy: personalized dosimetric effect of real intrafractional motion within the beam gating thresholds

PURPOSE

The robustness of surface-guided (SG) deep-inspiration breath-hold (DIBH) radiotherapy (RT) for left breast cancer was evaluated by investigating any potential dosimetric effects due to the residual intrafractional motion allowed by the selected beam gating thresholds. The potential reduction of DIBH benefits in terms of organs at risk (OARs) sparing and target coverage was evaluated for conformational (3DCRT) and intensity-modulated radiation therapy (IMRT) techniques.

METHODS

A total of 192 fractions of SGRT DIBH left breast 3DCRT treatment for 12 patients were analyzed. For each fraction, the average of the real-time displacement between the isocenter on the daily reference surface and on the live surface ("SGRT shift") during beam-on was evaluated and applied to the original plan isocenter. The dose distribution for the treatment beams with the new isocenter point was then calculated and the total plan dose distribution was obtained by summing the estimated perturbed dose for each fraction. Then, for each patient, the original plan and the perturbed one were compared by means of Wilcoxon test for target coverage and OAR dose-volume histogram (DVH) metrics. A global plan quality score was calculated to assess the overall plan robustness against intrafractional motion of both 3DCRT and IMRT techniques.

RESULTS

Target coverage and OAR DVH metrics did not show significant variations between the original and the perturbed plan for the IMRT techniques. 3DCRT plans showed significant variations for the left descending coronary artery (LAD) and the humerus only. However, none of the dose metrics exceeded the mandatory dose constraints for any of the analyzed plans. The global plan quality analysis indicated that both 3DCRT and IMRT techniques were affected by the isocenter shifts in the same way and, generally, the residual isocenter shifts more likely tend to worsen the plan in all cases.

CONCLUSION

The DIBH technique proved to be robust against residual intrafractional isocenter shifts allowed by the selected SGRT beam-hold thresholds. Small-volume OARs located near high dose gradients showed significant marginal deteriorations in the perturbed plans with the 3DCRT technique only. Global plan quality was mainly influenced by patient anatomy and treatment beam geometry rather than the technique adopted.

Obtaining organ-specific radiobiological parameters from clinical data for radiation therapy planning of head and neck cancers

Objective.Different radiation therapy (RT) strategies, e.g. conventional fractionation RT (CFRT), hypofractionation RT (HFRT), stereotactic body RT (SBRT), adaptive RT, and re-irradiation are often used to treat head and neck (HN) cancers. Combining and/or comparing these strategies requires calculating biological effective dose (BED). The purpose of this study is to develop a practical process to estimate organ-specific radiobiologic model parameters that may be used for BED calculations in individualized RT planning for HN cancers.Approach.Clinical dose constraint data for CFRT, HFRT and SBRT for 5 organs at risk (OARs) namely spinal cord, brainstem, brachial plexus, optic pathway, and esophagus obtained from literature were analyzed. These clinical data correspond to a particular endpoint. The linear-quadratic (LQ) and linear-quadratic-linear (LQ-L) models were used to fit these clinical data and extract relevant model parameters (alpha/beta ratio, gamma/alpha,dTand BED) from the iso-effective curve. The dose constraints in terms of equivalent physical dose in 2 Gy-fraction (EQD2) were calculated using the obtained parameters.Main results.The LQ-L and LQ models fitted clinical data well from the CFRT to SBRT with the LQ-L representing a better fit for most of the OARs. The alpha/beta values for LQ-L (LQ) were found to be 2.72 (2.11) Gy, 0.55 (0.30) Gy, 2.82 (2.90) Gy, 6.57 (3.86) Gy, 5.38 (4.71) Gy, and the dose constraint EQD2 were 55.91 (54.90) Gy, 57.35 (56.79) Gy, 57.54 (56.35) Gy, 60.13 (59.72) Gy and 65.66 (64.50) Gy for spinal cord, optic pathway, brainstem, brachial plexus, and esophagus, respectively. Additional two LQ-L parametersdTwere 5.24 Gy, 5.09 Gy, 7.00 Gy, 5.23 Gy, and 6.16 Gy, and gamma/alpha were 7.91, 34.02, 8.67, 5.62 and 4.95.Significance.A practical process was developed to extract organ-specific radiobiological model parameters from clinical data. The obtained parameters can be used for biologically based radiation planning such as calculating dose constraints of different fractionation regimens.

Explainable Artificial Intelligence to Identify Dosimetric Predictors of Toxicity in Patients with Locally Advanced Non-Small Cell Lung Cancer: A Secondary Analysis of RTOG 0617

PURPOSE

Dosimetric predictors of toxicity in patients treated with definitive chemoradiation for locally advanced non-small cell lung cancer are often identified through trial and error. This study used machine learning (ML) and explainable artificial intelligence to empirically characterize dosimetric predictors of toxicity in patients treated as part of a prospective clinical trial.

METHODS AND MATERIALS

A secondary analysis of the Radiation Therapy Oncology Group (RTOG) 0617 trial was performed. Multiple ML models were trained to predict grade ≥3 pulmonary, cardiac, and esophageal toxicities using clinical and dosimetric features. Model performance was evaluated using the area under the curve (AUC). The best performing model for each toxicity was explained using the Shapley Additive Explanation (SHAP) framework; SHAP values were used to identify relevant dosimetric thresholds and were converted to odds ratios (ORs) with confidence intervals (CIs) generated using bootstrapping to obtain quantitative measures of risk. Thresholds were validated using logistic regression.

RESULTS

The best-performing models for pulmonary, cardiac, and esophageal toxicities, outperforming logistic regression, were extreme gradient boosting (AUC, 0.739), random forest (AUC, 0.706), and naive Bayes (AUC, 0.721), respectively. For pulmonary toxicity, thresholds of a mean dose >18 Gy (OR, 2.467; 95% CI, 1.049-5.800; P = .038) and lung volume receiving ≥20 Gy (V20) > 37% (OR, 2.722; 95% CI, 1.034-7.163; P = .043) were identified. For esophageal toxicity, thresholds of a mean dose >34 Gy (OR, 4.006; 95% CI, 2.183-7.354; P < .001) and V20 > 37% (OR, 3.725; 95% CI, 1.308-10.603; P = .014) were identified. No significant thresholds were identified for cardiac toxicity.

CONCLUSIONS

In this data set, ML approaches validated known dosimetric thresholds and outperformed logistic regression at predicting toxicity. Furthermore, using explainable artificial intelligence, clinically useful dosimetric thresholds might be identified and subsequently externally validated.

Model development of dose and volume predictors for esophagitis induced during chemoradiotherapy for lung cancer as a step towards radiobiological treatment planning

BACKGROUND

Currently, radiation therapy treatment planning system intends biological optimization that relies heavily upon plan metrics from tumor control probability (TCP) and normal tissue complication probability (NTCP) modeling. Implementation and expansion of TCP and NTCP models with alternative data is an important step towards reliable radiobiological treatment planning. In this retrospective single institution study, the treatment charts of 139 lung cancer patients treated with chemo-radiotherapy were reviewed and correlated dosimetric predictors with the incidence of esophagitis and established NTCP model of esophagitis grade 1 and 2 for lung cancer patients.

METHODS

Esophagus is an organ at risk (OAR) in lung cancer radiotherapy (RT). Esophagitis is a common toxicity induced by RT. In this study, dose volume parameters Vx (Vx: percentage esophageal volume receiving ≥ x Gy) and mean esophagus dose (MED) as quantitative dose-volume metrics, the esophagitis grade 1 and 2 as endpoints, were reviewed and derived from the treatment planning system and the electronic medical record system. Statistical analysis of binary logistic regression and probit were performed to have correlated the probability of grade 1 and 2 esophagitis to MED and Vx. IBM SPSS software version 24 at 5% significant level (α = 0.05) was used in the statistical analysis.

RESULTS

The probabilities of incidence of grade 1 and 2 esophagitis proportionally increased with increasing the values of Vx and MED. V20, V30, V40, V50 and MED are statistically significant good dosimetric predictors of esophagitis grade 1. 50% incidence probability (TD50) of MED for grade 1 and 2 esophagitis were determined. Lyman Kutcher Burman model parameters, such as, n, m and TD50, were fitted and compared with other published findings. Furthermore, the sigmoid shaped dose responding curve between probability of esophagitis grade 1 and MED were generated respecting to races, gender, age and smoking status.

CONCLUSIONS

V20, V30, V40 and V50 were added onto Quantitative Analysis of Normal Tissue Effects in the clinic, or QUANTEC group's dose constrains of V35, V50, V70 and MED. Our findings may be useful as both validation of 3-Dimensional planning era models and also additional clinical guidelines in treatment planning and plan evaluation using radiobiology optimization.

Caution against simultaneous integrated boost radiotherapy for upper thoracic esophageal squamous cell carcinoma: results from a single-arm phase II trial

PURPOSE

To explore the feasibility and safety of simultaneous integrated boost technology (SIB) with elective nodal irradiation (ENI) to the cervical and upper mediastinal lymph node (LN) regions in upper thoracic esophageal squamous cell carcinoma (ESCC).

MATERIAL AND METHODS

Patients with pathologically proven unresectable upper thoracic ESCC were assigned 50.4 Gy/28 fractions (F) to the clinical target volume (encompassing the ENI area of cervical and upper mediastinal LN regions) and a boost of 63 Gy/28 F to the gross tumor volume. Chemotherapy consisted of courses of concurrent cisplatin (20 mg/m2) and docetaxel (20 mg/m2) weekly for 6 weeks. The primary endpoint was toxicity.

RESULTS

Between Jan 2017 and Dec 2019, 28 patients were included. The median follow-up time for all patients was 24.6 months (range 1.9-53.5). Radiation-related acute toxicity included esophagitis, pneumonia and radiodermatitis, all of which were well managed and reversed. Late morbidity included esophageal ulcer, stenosis, fistula and pulmonary fibrosis. Grade III esophageal stenosis and fistula was seen in 11% (3/28) and 14% (4/28) patients, respectively. The cumulative incidence rate of late esophageal toxicity was 7.7%, 19.2% and 24.6% at 6, 12 and 18 months, respectively. There was significant difference of the occurrence of severe late esophageal toxicity among the different volume levels of the esophagus, and cervical and upper mediastinal LNs which received ≥ 63 Gy stratified by the tertiles (p = 0.014).

CONCLUSIONS

Despite the acceptably tolerated acute toxicity of SIB in concurrent CRT with ENI to the cervical and upper mediastinal LN regions for upper thoracic ESCC, the incidence of severe late esophageal toxicity was relatively high. Cautions are provided against easy clinical application of SIB (50.4 Gy/28F to the CTV, 63 Gy/28F to the GTV) in upper thoracic ESCC. Further exploration on dose optimization is warranted.

Construction of an immune-related lncRNA-miRNA-mRNA regulatory network in radiation-induced esophageal injury in rats

Radiation-induced esophageal injury (RIEI) is an adverse reaction of radiation therapy in patients with esophageal cancer, lung cancer and other malignant tumors. Competitive endogenous RNA (ceRNA) network is known to play a significant role in the onset and progression of many diseases, but the exact mechanism of ceRNA in RIEI has not been fully elucidated. In this study, rat esophaguses were obtained after conducting irradiation under different doses (0 Gy, 25 Gy, 35 Gy). Total RNA was extracted and mRNA, lncRNA, circRNA, and miRNA sequencing was performed. Multiple dose-dependent differentially expressed RNAs (dd-DERs), including 870 lncRNAs, 82 miRNAs, 2478 mRNAs, were obtained through the integration of differential expression analysis and dose-dependent screening (35 Gy ≥ 25 Gy > 0 Gy, or 35 Gy ≤ 25 Gy < 0 Gy). Co-expression analysis and prediction of the binding site in dd-DER were conducted and 27 lncRNAs, 20 miRNAs, and 168 mRNAs were selected to construct a ceRNA network. As the immune microenvironment is crucial for RIEI progression, we constructed an immune-related ceRNA network consisting of 11 lncRNAs, 9 miRNAs, and 9 mRNAs. The expression levels of these immune-related RNAs were verified by RT-qPCR. Immune infiltration analysis showed that the RNAs in the immune-related ceRNA network were mainly associated with the proportion of monocytes, M2 macrophages, activated NK cells, and activated CD4+ memory T cells. Drug sensitivity analysis was conducted based on the expression levels of mRNAs in the immune-related ceRNA network, and small molecule drugs with preventive and therapeutic effects on RIEI were identified. In summary, an immune-related ceRNA network associated with RIEI progression was constructed in this study. The findings provide useful information on new potential targets for the prevention and treatment of RIEI.

Cardiac metabolic changes on 18 F-positron emission tomography after thoracic radiotherapy predict for overall survival in esophageal cancer patients

PURPOSE

Heart doses have been shown to be predictive of cardiac toxicity and overall survival (OS) for esophageal cancer patients. There is potential for functional imaging to provide valuable cardiac information. The purpose of this study was to evaluate the cardiac metabolic dose-response using 18 F-deoxyglucose (FDG)-PET and to assess whether standard uptake value (SUV) changes in the heart were predictive of OS.

METHODS

Fifty-one patients with esophageal cancer treated with radiation who underwent pre- and post-treatment FDG-PET scans were retrospectively evaluated. Pre- and post-treatment PET-scans were rigidly registered to the planning CT for each patient. Pre-treatment to post-treatment absolute mean SUV (SUVmean) changes in the heart were calculated to assess dose-response. A dose-response curve was generated by binning each voxel in the heart into 10 Gy dose-bins and analyzing the SUVmean changes in each dose-bin. Multivariate cox proportional hazard models were used to assess whether pre-to-post treatment cardiac SUVmean changes predicted for OS.

RESULTS

The cardiac dose-response curve demonstrated a trend of increasing cardiac SUV changes as a function of dose with an average increase of 0.044 SUV for every 10 Gy dose bin. In multivariate analysis, disease stage and SUVmean change in the heart were predictive (p < 0.05) for OS.

CONCLUSIONS

Changes in pre- to post-treatment cardiac SUV were predictive of OS with patients having a higher pre- to post-treatment cardiac SUV change surviving longer.

Radiation-induced inferior brachial plexopathy after stereotactic body radiotherapy: Pooled analyses of risks

INTRODUCTION

Radiation-induced brachial plexopathy (RIBP), resulting in symptomatic motor or sensory deficits of the upper extremity, is a risk after exposure of the brachial plexus to therapeutic doses of radiation. We sought to model dosimetric factors associated with risks of RIBP after stereotactic body radiotherapy (SBRT).

METHODS

From a prior systematic review, 4 studies were identified that included individual patient data amenable to normal tissue complication probability (NTCP) modelling after SBRT for apical lung tumors. Two probit NTCP models were derived: one from 4 studies (including 221 patients with 229 targets and 18 events); and another from 3 studies (including 185 patients with 192 targets and 11 events) that similarly contoured the brachial plexus.

RESULTS

NTCP models suggest ≈10% risks associated with brachial plexus maximum dose (Dmax) of ∼32-34 Gy in 3 fractions and ∼40-43 Gy in 5 fractions. RIBP risks increase with increasing brachial plexus Dmax. Compared to previously published data from conventionally-fractionated or moderately-hypofractionated radiotherapy for breast, lung and head and neck cancers (which tend to utilize radiation fields that circumferentially irradiate the brachial plexus), SBRT (characterized by steep dose gradients outside of the target volume) exhibits a much less steep dose-response with brachial plexus Dmax > 90-100 Gy in 2-Gy equivalents.

CONCLUSIONS

A dose-response for risk of RIBP after SBRT is observed relative to brachial plexus Dmax. Comparisons to data from less conformal radiotherapy suggests potential dose-volume dependences of RIBP risks, though published data were not amenable to NTCP modelling of dose-volume measures associated with RIBP after SBRT.

Surface-guided DIBH radiotherapy for left breast cancer: impact of different thresholds on intrafractional motion monitoring and DIBH stability

PURPOSE

To compare two left breast cancer patient cohorts (tangential vs. locoregional deep-inspiration breath-hold - DIBH treatment) with different predefined beam gating thresholds and to evaluate their impact on motion management and DIBH stability.

METHODS

An SGRT-based clinical workflow was adopted for the DIBH treatment. Intrafractional monitoring was performed by tracking both the respiratory signal and the real-time displacement between the isocenter on the daily reference surface and on the live surface ("SGRT shift"). Beam gating tolerances were 5 mm/4 mm for the SGRT shifts and 5 mm/3 mm for the gating window amplitude for breast tangential and breast + lymph nodes locoregional treatments, respectively. A total of 24 patients, 12 treated with a tangential technique and 12 with a locoregional technique, were evaluated for a total number of 684 fractions. Statistical distributions of SGRT shift and respiratory signal for each treatment fraction, for each patient treatment, and for the two population samples were generated.

RESULTS

Lateral cumulative distributions of SGRT shifts for both locoregional and tangential samples were consistent with a null shift, whereas longitudinal and vertical ones were slightly negative (mean values < 1 mm). The distribution of the percentage of beam on time with SGRT shift > 3 mm, > 4 mm, or > 5 mm was extended toward higher values for the tangential sample than for the locoregional sample. The variability in the DIBH respiration signal was significantly greater for the tangential sample.

CONCLUSION

Different beam gating thresholds for surface-guided DIBH treatment of left breast cancer can impact motion management and DIBH stability by reducing the frequency of the maximum SGRT shift and increasing respiration signal stability when tighter thresholds are adopted.

Head and Neck Radiation Therapy Patterns of Practice Variability Identified as a Challenge to Real-World Big Data: Results From the Learning from Analysis of Multicentre Big Data Aggregation (LAMBDA) Consortium

Purpose

Outside of randomized clinical trials, it is difficult to develop clinically relevant evidence-based recommendations for radiation therapy (RT) practice guidelines owing to lack of comprehensive real-world data. To address this knowledge gap, we formed the Learning from Analysis of Multicenter Big Data Aggregation consortium to cooperatively implement RT data standardization, develop software solutions for data analysis, and recommend clinical practice change based on real-world data analyzed. The first phase of this "Big Data" study aimed at characterizing variability in clinical practice patterns of dosimetric data for organs at risk (OARs) that would undermine subsequent use of large-scale, electronically aggregated data to characterize associations with outcomes. Evidence from this study was used as the basis for practical recommendations to improve data quality.

Methods and Materials

Dosimetric details of patients with head and neck cancer treated with radiation therapy between 2014 and 2019 were analyzed. Institutional patterns of practice were characterized, including structure nomenclature, volumes, and frequency of contouring. Dose volume histogram (DVH) distributions were characterized and compared with institutional constraints and literature values.

Results

Plans for 4664 patients treated to a mean plan dose of 64.4 ± 13.2 Gy in 32 ± 4 fractions were aggregated. Before implementation of TG-263 guidelines in each institution, there was variability in OAR nomenclature across institutions and structures. With evidence from this study, we identified a targeted and practical set of recommendations aimed at improving the quality of real-world data.

Conclusions

Quantifying similarities and differences among institutions for OAR structures and DVH metrics is the launching point for next steps to investigate potential relationships between DVH parameters and patient outcomes.

Effects of Microbeam Irradiation on Rodent Esophageal Smooth Muscle Contraction

BACKGROUND

High-dose-rate radiotherapy has shown promising results with respect to normal tissue preservation. We developed an ex vivo model to study the physiological effects of experimental radiotherapy in the rodent esophageal smooth muscle.

METHODS

We assessed the physiological parameters of the esophageal function in ex vivo preparations of the proximal, middle, and distal segments in the organ bath. High-dose-rate synchrotron irradiation was conducted using both the microbeam irradiation (MBI) technique with peak doses greater than 200 Gy and broadbeam irradiation (BBI) with doses ranging between 3.5-4 Gy.

RESULTS

Neither MBI nor BBI affected the function of the contractile apparatus. While peak latency and maximal force change were not affected in the BBI group, and no changes were seen in the proximal esophagus segments after MBI, a significant increase in peak latency and a decrease in maximal force change was observed in the middle and distal esophageal segments.

CONCLUSION

No severe changes in physiological parameters of esophageal contraction were determined after high-dose-rate radiotherapy in our model, but our results indicate a delayed esophageal function. From the clinical perspective, the observed increase in peak latency and decreased maximal force change may indicate delayed esophageal transit.

Using inflammatory indexes and clinical parameters to predict radiation esophagitis in patients with small-cell lung cancer undergoing chemoradiotherapy

OBJECTIVE

Radiation esophagitis (RE) is a common adverse effect in small cell lung cancer (SCLC) patients undergoing thoracic radiotherapy. We aim to develop a novel nomogram to predict the acute severe RE (grade≥2) receiving chemoradiation in SCLC patients.

MATERIALS AND METHODS

the risk factors were analyzed by logistic regression, and a nomogram was constructed based on multivariate analysis results. The clinical value of the model was evaluated using the area under the receiver operating curve (ROC) curve (AUC), calibration curves, and decision curve analysis (DCA). The correlations of inflammation indexes were assessed using Spearman correlation analysis.

RESULTS

Eighty-four of 187 patients (44.9%) developed grade ≥2 RE. Univariate analysis indicated that concurrent chemoradiotherapy (CCRT, p < 0.001), chemotherapy cycle (p = 0.097), system inflammation response index (SIRI, p = 0.048), prognostic-nutrition index (PNI, p = 0.073), platelets-lymphocyte radio (PLR, p = 0.026), platelets-albumin ratio (PAR, p = 0.029) were potential predictors of RE. In multivariate analysis, CCRT [p < 0.001; OR, 3.380; 95% CI, 1.767-6.465], SIRI (p = 0.047; OR, 0.436; 95% CI, 0.192-0.989), and PAR (p = 0.036; OR, 2.907; 95% CI, 1.071-7.891) were independent predictors of grade ≥2 RE. The AUC of nomogram was 0.702 (95% CI, 0.626-0.778), which was greater than each independent predictor (CCRT: 0.645; SIRI: 0.558; PAR: 0.559). Calibration curves showed high coherence between the predicted and actual observation RE, and DCA displayed satisfactory clinical utility.

CONCLUSION

In this study, CCRT, SIRI, and PAR were independent predictors for RE (grade ≥2) in patients with SCLC receiving chemoradiotherapy. We developed and validated a predictive model through these factors. The developed nomogram with superior prediction ability can be used as a quantitative model to predict RE.

Exposure of the heart in lung cancer radiation therapy: A systematic review of heart doses published during 2013 to 2020

BACKGROUND AND PURPOSE

Lung cancer radiotherapy increases the risk of cardiotoxicity and heart radiation dose is an independent predictor of poor survival. This study describes heart doses and strategies aiming to reduce exposure.

MATERIALS AND METHODS

A systematic review of lung cancer dosimetry studies reporting heart doses published 2013-2020 was undertaken. Doses were compared according to laterality, region irradiated, treatment modality (stereotactic ablative body radiotherapy (SABR) and non-SABR), planning technique, and respiratory motion management.

RESULTS

For 392 non-SABR regimens in 105 studies, the average MHD was 10.3 Gy (0.0-48.4) and was not significantly different between left and right-sided tumours. It was similar between IMRT and 3DCRT (10.9 Gy versus 10.6 Gy) and lower with particle beam therapy (proton 7.0 Gy; carbon-ion 1.9 Gy). Active respiratory motion management reduced exposure (7.4 Gy versus 9.3 Gy). For 168 SABR regimens in 35 studies, MHD was 4.0 Gy (0.0-32.4). Exposure was higher in central and lower lobe lesions (6.3 and 5.8 Gy respectively). MHD was lowest for carbon ions (0.5 Gy) compared to other techniques. Active respiratory motion management reduced exposure (2.4 Gy versus 5.0 Gy). Delineation guidelines and Dose Volume Constraints for the heart varied substantially.

CONCLUSIONS

There is scope to reduce heart radiation dose in lung cancer radiotherapy. Consensus on planning objectives, contouring and DVCs for the heart may lead to reduced heart doses in the future. For IMRT, more stringent optimisation objectives may reduce heart dose. Active respiratory motion management or particle therapy may be considered in situations where cardiac dose is high.

Radiation-Induced Esophagitis in Non-Small-Cell Lung Cancer Patients: Voxel-Based Analysis and NTCP Modeling

Simple Summary

Radiation-induced esophagitis (RE) is a common dose-limiting complication associated with concurrent chemoradiation therapy for Non-Small-Cell Lung Cancer (NSCLC), and a wide range of esophageal dosimetric parameters have been described as predictive of RE. In this study, we characterize the risk of RE for NSCLC patients enrolled in a prospective trial comparing intensity-modulated RT versus passive scattering proton therapy for locally advanced NSCLC. Dose patterns associated with RE were analyzed by applying voxel-based analysis approaches, and predictive models for RE were finally investigated. Two predictive models for acute RE with good cross-validated predictive performances and discrimination capability were developed (thoracic esophageal model: ROC-AUC = 0.73; whole esophagus model: ROC-AUC = 0.70).

Abstract

The aim of our study is to characterize the risk of radiation-induced esophagitis (RE) in a cohort of Non-Small-Cell Lung Cancer (NSCLC) patients treated with concurrent chemotherapy and photon/proton therapy. For each patient, the RE was graded according to the CTCAE v.3. The esophageal dose-volume histograms (DVHs) were extracted. Voxel-based analyses (VBAs) were performed to assess the spatial patterns of the dose differences between patients with and without RE of grade ≥ 2. Two hierarchical NTCP models were developed by multivariable stepwise logistic regression based on non-dosimetric factors and on the DVH metrics for the whole esophagus and its anatomical subsites identified by the VBA. In the 173 analyzed patients, 76 (44%) developed RE of grade ≥ 2 at a median follow-up time of 31 days. The VBA identified regions of significant association between dose and RE in a region encompassing the thoracic esophagus. We developed two NTCP models, including the RT modality and a dosimetric factor: V_55Gy for the model related to the whole esophagus, and the mean dose for the model designed on the thoracic esophagus. The cross-validated performance showed good predictions for both models (ROC-AUC of 0.70 and 0.73, respectively). The only slight improvement provided by the analysis of the thoracic esophageal subsites might be due to the relevant sparing of cervical and lower thoracic esophagus in the analyzed cohort. Further studies on larger cohorts and a more heterogeneous set of dose distributions are needed to validate these preliminary findings and shed further light on the spatial patterns of RE development.

Gut Microbiota Characteristics Are Associated With Severity of Acute Radiation-Induced Esophagitis

BACKGROUND

Acute radiation-induced esophagitis (ARIE) is one of the most debilitating complications in patients who receive thoracic radiotherapy, especially those with esophageal cancer (EC). There is little known about the impact of the characteristics of gut microbiota on the initiation and severity of ARIE.

MATERIALS AND METHODS

Gut microbiota samples of EC patients undergoing radiotherapy (n = 7) or concurrent chemoradiotherapy (n = 42) were collected at the start, middle, and end of the radiotherapy regimen. Assessment of patient-reported ARIE was also performed. Based on 16S rRNA gene sequencing, changes of the gut microbial community during the treatment regimen and correlations of the gut microbiota characteristics with the severity of ARIE were investigated.

RESULTS

There were significant associations of several properties of the gut microbiota with the severity of ARIE. The relative abundance of several genera in the phylum Proteobacteria increased significantly as mucositis severity increased. The predominant genera had characteristic changes during the treatment regimen, such as an increase of opportunistic pathogenic bacteria including Streptococcus. Patients with severe ARIE had significantly lower alpha diversity and a higher abundance of Fusobacterium before radiotherapy, but patients with mild ARIE were enriched in Klebsiella, Roseburia, Veillonella, Prevotella_9, Megasphaera, and Ruminococcus_2. A model combining these genera had the best performance in prediction of severe ARIE (area under the curve: 0.907).

CONCLUSION

The characteristics of gut microbiota before radiotherapy were associated with subsequent ARIE severity. Microbiota-based strategies have potential use for the early prediction of subsequent ARIE and for the selection of interventions that may prevent severe ARIE.

Acute and Late Esophageal Toxicity Following Stereotactic Ablative Radiotherapy to Thoracic Tumors near or Abutting the Esophagus

PURPOSE

To evaluate the incidence of acute and late esophageal toxicity in patients with thoracic tumors near or abutting the esophagus treated with stereotactic ablative radiotherapy (SABR).

METHODS AND MATERIALS

Among patients with thoracic tumors treated with SABR, we identified those with tumors near or abutting the esophagus. Using the linear-quadratic model with an α/ß ratio of 10, we determined the correlation between dosimetric parameters and esophageal toxicity graded using the Common Terminology Criteria for Adverse Events (CTCAE), version 5.0.

RESULTS

Out of 2200 patients treated with thoracic SABR, 767 patients were analyzable for esophageal dosimetry. We identified 55 patients with tumors near the esophagus (52 evaluable for esophagitis grade), 28 with PTV overlapping the esophagus. Median follow-up and overall survival were 16 and 23 months respectively. Thirteen patients (25%) developed temporary grade 2 acute esophageal toxicity, 11 (85%) of whom had PTV overlapping the esophagus. Symptoms resolved within 1-3 months in 12 patients, and 6 months in all patients. No grade 3-5 toxicity was observed. Only 3 patients (6%) developed late or persistent grade 2 dysphagia or dyspepsia of uncertain relationship to SABR. Cumulative incidence of acute esophagitis was 15% and 25% at 14 days and 60 days respectively. Acute toxicity correlated on univariate analysis with esophageal D_max, D_1cc, D_2cc, D_max/D_prescription and whether the PTV was overlapping the esophagus. Esophageal D_max (BED₁₀) < 62 Gy, D_1cc (BED₁₀) < 48 Gy, D_2cc (BED₁₀) < 43 Gy, and D_max/D_prescription < 85% was associated with <20% risk of grade 2 acute esophagitis. Only 2 local recurrences occurred.

CONCLUSIONS

Although 25% of patients with tumors near the esophagus developed acute esophagitis (39% of those with PTV overlapping the esophagus), these toxicities were all grade 2 and all temporary. This suggests the safety and efficacy of thoracic SABR for tumors near or abutting the esophagus when treating with high conformity and sharp dose gradients.

Post-operative radiation therapy for non-small cell lung cancer: A comparison of radiation therapy techniques

OBJECTIVES

Post-operative radiation therapy (PORT) in locally advanced non-small cell lung cancer (LA-NSCLC) has historically been associated with toxicity. Conformal techniques like intensity modulated radiation therapy (IMRT) have the potential to reduce acute and long-term toxicity from radiation therapy. Among patients receiving PORT for LA-NSCLC, we identified factors associated with receipt of IMRT and evaluated the association between IMRT and toxicity.

METHODS

We queried the Surveillance, Epidemiology, and End Results (SEER)-Medicare database between January 1, 2006 to December 31, 2014 to identify patients diagnosed with Stage II or III NSCLC and who received upfront surgery and subsequent PORT. Baseline differences between patients receiving 3-dimentional conformal radiation therapy (3D-CRT) and IMRT were assessed using the chi-squared test for proportions and the t-test for means. Multivariable logistic regression was used to identify predictors of receipt of IMRT and pulmonary, esophageal, and cardiac toxicity. Propensity-score matching was employed to reduce the effect of known confounders.

RESULTS

A total of 620 patients met the inclusion criteria, among whom 441 (71.2%) received 3D-CRT and 179 (28.8%) received IMRT. The mean age of the cohort was 73.9 years and 54.7% were male. The proportion of patients receiving IMRT increased from 6.2% in 2006 to 41.4% in 2014 (P < 0.001). IMRT was not associated with decreased pulmonary (OR 0.89; 95% CI, 0.62-1.29), esophageal (OR 1.09; 95% CI, 0.0.75-1.58), or cardiac toxicity (OR 1.02; 95% CI, 0.69-1.51). These findings held on propensity-score matching. Clinical risk factors including comorbidity and prior treatment history were associated with treatment toxicity.

CONCLUSION

In a cohort of elderly patients, the use of IMRT in the setting of PORT for LA-NSCLC was not associated with a difference in toxicity compared to 3D-CRT. This finding suggests that outcomes from PORT may be independent of radiotherapy treatment technique.

Comparison of dose volumetric parameters of oesophagus in the radiation treatment of carcinoma breast with and without oesophagus delineation

Aim:

There are only limited studies available in literature that discuss methods to reduce the oesophageal dose and acute oesophagitis during breast cancer radiotherapy. The aim of this study is to compare dose volumetric parameters of oesophagus in radiation treatment of breast with and without oesophagus delineation.

Methods:

Treatment plans of 44 patients, who underwent chest wall and supraclavicular fossa irradiation, were selected for the study. Oesophagus was later delineated and treatment replanned using three-dimensional conformal radiotherapy (3DCRT) considering oesophagus as an organ at risk (OAR). The dose prescribed was 40 Gy/15 fractions to the planning target volume (PTV). Dose volumetric parameters of oesophagus such as maximum dose (Dmax), mean dose (Dmean), the percentage of oesophagus volume receiving ≥15Gy (V15), ≥25Gy(V25), ≥33Gy(V33) and ipsilateral lung volume parameters V4, V8 and V16 were compared with already executed plans in which oesophagus was not delineated.

Results:

Contouring the oesophagus as an OAR as a part of the radiotherapy treatment for Carcinoma Breast resulted in statistically significant reduction in dose to the oesophagus. No statistically significant change was found in the ipsilateral lung volume parameters. No compromise in plan quality was required as evident from the statistically non-significant differences in Homogeneity index and Conformity index.

Findings:

3DCRT planning with oesophagus delineation can be considered as a method to reduce oesophageal dose and the acute oesophageal toxicity during radiotherapy for carcinoma breast.

Duration of acute esophageal toxicity in concomitant radio-chemotherapy for non-small cell lung cancer with different fractionation schedules

OBJECTIVES

In our previous prospective trial on accelerated hypofractionated concomitant radiochemotherapy (AHRT-CHT) for non-small-cell lung cancer (NSCLC), the incidence of grade ≥3 acute esophageal toxicity (AET) was similar to that reported for conventionally fractionated concomitant radiochemotherapy (CFRT-CHT), but its duration was prolonged. Thus, we aimed to compare the duration of grade ≥3 AET between AHRT-CHT and CFRT-CHT.

METHODS

Clinical data of 76 NSCLC patients treated with CFRT-CHT (60-66 Gy/2 Gy) during 2015-2020 were retrospectively compared with the data of 92 patients treated with AHRT-CHT (58.8 Gy/2.8 Gy) in the prospective trial. The maximum grade of AET, incidence, and duration of grade ≥3 AET were the end points. Univariate and multivariate analyses were applied to correlate clinical and treatment variables with these end points.

RESULTS

Neither the maximum grade of AET (p = 0.71), nor the incidence of grade ≥3 AET (p = 0.87) differed between the two groups. The number of CHT cycles delivered (2 vs 1, p = 0.005) and higher esophagus mean BED (p = 0.009) were significant predictors for a higher maximum grade of AET; older age was a significant predictor for higher incidence of grade ≥3 AET (p = 0.03). The median duration of grade ≥3 AET in AHRT-CHT and CFRT-CHT group was 30 days (range 5-150) vs 7 days (range 3-20), respectively, p = 0.0005. In multivariate analysis, only the AHRT-CHT schedule (p=0.003) was a significant predictor for a longer duration of grade ≥3 AET.

CONCLUSION

Despite similar incidence of grade ≥3 AET, its duration is significantly prolonged in NSCLC patients treated with AHRT-CHT compared to CFRT-CHT.

ADVANCES IN KNOWLEDGE

Reporting only the rate of grade ≥3 AET in clinical trials may underestimate the real extent of the esophageal toxicity; its duration should also be routinely reported.

Development and prospective validation of a spatial dose pattern based model predicting acute pulmonary toxicity in patients treated with volumetric arc-therapy for locally advanced lung cancer

INTRODUCTION

(Chemo)-radiotherapy is the standard treatment for patients with locally advanced lung cancer (LALC) not accessible to surgery. Despite strict application of dose constraints, acute toxicities such as acute pulmonary toxicity (APT) remain frequent, and may impact treatment's compliance and patients' quality of life. Previously, on a population treated with intensity-modulated photon therapy or passive scattering proton therapy, spatial dose patterns associated with APT were identified in the lower lungs, especially in the posterior right lung. In the present study, we aim to define these spatial dose patterns on a retrospective cohort treated by volumetric-arctherapy (VMAT) and to validate our findings prospectively.

METHODS

For the training cohort, we retrospectively included all patients treated in our institution by VMAT for a LALC between 2015 and 2018. APT was scored according to the CTCAE v4.0 scale. All dose maps were registered to a thorax phantom using a segmentation-based elastic registration. Voxel-based analysis of local dose differences was performed with a non-parametric permutation test accounting for n = 10.000 permutations, producing a 3-dimensional significance maps on which clusters of voxels that exhibited significant dose differences (p < 0.05) between the two toxicity groups (APT ≥ grade 2 vs APT < grade 2) were identified. A prediction model (Pmap-Model) was then built using a neural network approach and then applied to an observational prospective cohort for validation. The model was evaluated using the Area under the curve (AUC) and the balanced accuracy (Bacc: mean of the sensitivity and specificity).

RESULTS

165 and 42 patients were included in the training and validation cohorts, with respective APT rates of 22.4% and 19.1%. In the training cohort, a cluster of voxels (Pmap-region) was identified in the posterior right lung. In the training cohort, the Pmap-Model combining 11 features among which the mean dose to the Pmap-region resulted in an AUC of 0.99 and a Bacc of 99.2 using an 8% probability threshold. Using the same voxel cluster on the validation cohort, the Pmap-model resulted in an AUC of 0.81 and a Bacc of 82.0.

CONCLUSION

Our APT-prediction model was successfully validated in a prospective cohort treated by VMAT. Regional radiosensitivity should be considered in usual lung dose constraints, opening the possibility of easily implementable adaptive dosimetry planning.

Evolution of systemic therapy for stages I-III non-metastatic non-small-cell lung cancer

The treatment goal for patients with early-stage lung cancer is cure. Multidisciplinary discussions of surgical resectability and medical operability determine the modality of definitive local treatment (surgery or radiotherapy) and the associated systemic therapies to further improve the likelihood of cure. Trial evidence supports cisplatin-based adjuvant therapy either after surgical resection or concurrently with radiotherapy. Consensus guidelines support neoadjuvant chemotherapy in lieu of adjuvant chemotherapy and carboplatin-based regimens for patients who are ineligible for cisplatin. The incorporation of newer agents, now standard for patients with stage IV lung cancer, into the curative therapy paradigm has lagged owing to inefficient trial designs, the lengthy follow-up needed to assess survival end points and a developmental focus on the advanced-stage disease setting. Surrogate end points, such as pathological response, are being studied and might shorten trial durations. In 2018, the anti-PD-L1 antibody durvalumab was approved for patients with stage III lung cancer after concurrent chemoradiotherapy. Since then, the study of targeted therapies and immunotherapies in patients with early-stage lung cancer has rapidly expanded. In this Review, we present the current considerations in the treatment of patients with early-stage lung cancer and explore the current and future state of clinical research to develop systemic therapies for non-metastatic lung cancer.

Evolution of systemic therapy for stages I-III non-metastatic non-small-cell lung cancer

The treatment goal for patients with early-stage lung cancer is cure. Multidisciplinary discussions of surgical resectability and medical operability determine the modality of definitive local treatment (surgery or radiotherapy) and the associated systemic therapies to further improve the likelihood of cure. Trial evidence supports cisplatin-based adjuvant therapy either after surgical resection or concurrently with radiotherapy. Consensus guidelines support neoadjuvant chemotherapy in lieu of adjuvant chemotherapy and carboplatin-based regimens for patients who are ineligible for cisplatin. The incorporation of newer agents, now standard for patients with stage IV lung cancer, into the curative therapy paradigm has lagged owing to inefficient trial designs, the lengthy follow-up needed to assess survival end points and a developmental focus on the advanced-stage disease setting. Surrogate end points, such as pathological response, are being studied and might shorten trial durations. In 2018, the anti-PD-L1 antibody durvalumab was approved for patients with stage III lung cancer after concurrent chemoradiotherapy. Since then, the study of targeted therapies and immunotherapies in patients with early-stage lung cancer has rapidly expanded. In this Review, we present the current considerations in the treatment of patients with early-stage lung cancer and explore the current and future state of clinical research to develop systemic therapies for non-metastatic lung cancer.

A proof of concept treatment planning study of gated proton radiotherapy for cardiac soft tissue sarcoma

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Challenges of a cardiac target due to the respiration, the heart motion and the interplay effect.

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Cardiac respiratory double gating with additional ECG signals for proton radiotherapy.

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Proton planning study with a cardiac-gated CT scan obtained at the end-expiration.

Background and Purpose

Few studies on radiotherapy of cardiac targets exist, and none using a gating method according to cardiac movement. This study aimed to evaluate the dose-volume advantage of using cardiac-respiratory double gating (CRDG) in terms of target location with additional ECG signals in comparison to respiratory single gating (RSG) for proton radiotherapy of targets in the heart.

Materials and Methods

Cardiac motion was modeled using a cardiac-gated four-dimensional computed tomography scan obtained at the end-expiration. Plans with the prescription dose of 50 Gy (RSG and CRDG plans at diastole and systole phases) were compared in terms of clinically relevant dose-volume criteria for various target sizes and seven cardiac subsites. Potential dose sparing by utilizing CRDG over RSG was quantified in terms of surrounding organ at risk (OAR) doses while the dose coverage to the targets was fully ensured.

Results

The average mean dose reductions were 28 ± 10% when gated at diastole and 21 ± 12% at systole in heart and 30 ± 17% at diastole and 8 ± 9% at systole in left ventricle compared to respiratory single gating. The diastole phase was optimal for gated treatments for all target locations except right ventricle and interventricular septum. The right ventricle target was best treated at the systole phase. However, an optimal gating phase for the interventricular septum target could not be determined.

Conclusions

We have studied the dose-volume benefits of CRDG for each cardiac subsite, and demonstrated that CRDG may spare organs at risk better than RSG.

Prevention and management of acute esophageal toxicity during concomitant chemoradiotherapy for locally advanced lung cancer

BACKGROUND

Standard treatment for locally advanced non-small cell lung cancer (LA-NSCLC) is concomitant chemoradiotherapy. The survival benefit of combined treatment is partially counterbalanced by an increased rate of acute esophageal toxicity. Several pharmaceutical products are available for prevention and management of esophagitis, including Faringel Plus.

AIM

To assess the incidence and the grade, identify the correlations with clinical, dosimetric, and therapeutic variables, and analyse the role of Faringel Plus as a pharmaceutical preventive measure against acute esophageal toxicity.

METHODS

Patients with LA-NSCLC treated with concomitant radiochemotherapy were retrospectively reviewed. Acute esophagitis and dysphagia were graded according to Common Terminology Criteria for Adverse Events version 5.0. Clinical, dosimetric, and therapeutic correlations were investigated using χ² test.

RESULTS

Among the 23 analysed patients, 18 (78.3%) and 1 (4.3%) developed G2 and G3 esophagitis, respectively; G1-2 dysphagia were reported in 11 cases (47.8%). No statistically significant correlation between the variables considered and acute esophageal toxicity was identified. In the group of patients who received Faringel Plus as preventive treatment (10 subjects, 43.5%), dysphagia presentation time was significantly longer (p = 0.038); esophagitis onset time was longer and symptoms duration was shorter. Faringel Plus allowed a reduction in the use of analgesic drugs.

CONCLUSIONS

Acute mild esophageal toxicity was confirmed to be a common side effect in this setting. No clinical-dosimetric parameter has been demonstrated to be effective in predicting acute esophageal toxicity. The use of Faringel Plus appears effective as a therapeutic and prophylactic tool to manage acute esophageal toxicity.

Unexpected toxicity of CDK4/6 inhibitor palbociclib and radiotherapy

Background

Cyclin‐dependent kinase (CDK) 4/6 inhibitors have recently been approved for the treatment of hormone receptor–positive and HER2‐negative metastatic breast cancer in association with endocrine therapy in postmenopausal women. Data on the interaction of CDK4/6 inhibition and radiotherapy are scarce, but some studies show unexpected toxicity.

Cases

We report three cases of unexpected severe or prolonged soft tissue, skin, and gastrointestinal toxicity in patients treated with a combination of radiotherapy and the CDK4/6 inhibitor palbociclib.

Conclusion

These cases indicate a possible interaction between radiotherapy and palbociclib. Therefore, we recommend using radiotherapy cautiously when combined with CDK4/6 inhibitors.

Imaging of the post-radiation chest in lung cancer

Radiation therapy using conventional fractionated external-beam or high-precision dose techniques including three-dimensional conformal radiotherapy, stereotactic body radiation therapy, intensity-modulated radiation therapy, and proton therapy, is a key component in the treatment of patients with lung cancer. Knowledge of the radiation technique used, radiation treatment plan, expected temporal evolution of radiation-induced lung injury and patient-specific parameters, such as previous radiotherapy, concurrent chemoradiotherapy, and/or immunotherapy, is important in imaging interpretation. This review discusses factors that affect the development and severity of radiation-induced lung injury and its radiological manifestations with emphasis on the differences between conventional radiation and high-precision dose radiotherapy techniques.

Preoperative Radiochemotherapy in Esophageal Squamous Cell Cancer with 5-Fluorouracil/Cisplatin or Carboplatin/Paclitaxel: Treatment Practice over a 20-Year Period and Implications for the Individual Treatment Modalities

Simple Summary

We retrospectively studied outcomes in patients treated with preoperative radiochemotherapy and surgery for esophageal squamous cell cancer. We put a special focus on the comparison of patients treated with 5-fluorouracil/cisplatin (‘Walsh’) or carboplatin/paclitaxel (‘CROSS’). First, the higher age and more comorbidities of ‘CROSS’ patients, along with a shorter intensive care/intermediate care unit stay, might reflect an improvement in supportive and surgical/perioperative procedures in the periods. Second, the ‘CROSS’ patients experienced more hematologic toxicity and were less likely to complete chemotherapy as per protocol. This indicates that efforts should be taken to guide patients through a toxic treatment regimen. Third, the negative prognostic impact of radiochemotherapy-related toxicities and the duration of the intensive care/intermediate care unit stay underlines that further optimization of treatment procedures remains an important goal. Toxicity profiles could be improved by tailoring the regimen to individual patients (e. g., careful use of the taxane-based regimen in elderly patients).

Abstract

We retrospectively studied outcomes in patients treated with preoperative radiochemotherapy and surgery for esophageal squamous cell cancer. We put special focus on the comparison of patients treated with 5-fluorouracil/cisplatin (‘Walsh’) or carboplatin/paclitaxel (‘CROSS’). We compared characteristics between patients treated according to ‘Walsh’ vs. ‘CROSS’. Cox regression was performed to test for an association of parameters with outcomes. Study eligibility was met by 90 patients. First, the higher age and more comorbidities of the ‘CROSS’ patients, along with a shorter intensive care/intermediate care stay, might reflect an improvement in supportive and surgical/perioperative procedures over the periods. Second, the ‘CROSS’ patients experienced more hematologic toxicity and were less likely to complete chemotherapy as per protocol. This indicates that efforts should be taken to guide patients through a toxic treatment regimen by supportive measures. Third, the negative prognostic impact of radiochemotherapy-related toxicities (i.e., dysphagia and hematologic toxicities) and the duration of the intensive care/intermediate care unit stay underlines that further optimization of treatment procedures remains an important goal. We found no differences in tumor downstaging and survival between treatment regimen. Toxicity profiles could be improved by tailoring the regimen to individual patients (e.g., careful use of the taxane-based regimen in elderly patients).

GOECP/SEOR radiotherapy guidelines for small-cell lung cancer

Small cell lung cancer (SCLC) accounts for approximately 20% of all lung cancers. The main treatment is chemotherapy (Ch). However, the addition of radiotherapy significantly improves overall survival (OS) in patients with non-metastatic SCLC and in those with metastatic SCLC who respond to Ch. Prophylactic cranial irradiation reduces the risk of brain metastases and improves OS in both metastatic and non-metastatic patients. The 5-year OS rate in patients with limited-stage disease (non-metastatic) is slightly higher than 30%, but less than 5% in patients with extensive-stage disease (metastatic). The present clinical guidelines were developed by Spanish radiation oncologists on behalf of the Oncologic Group for the Study of Lung Cancer/Spanish Society of Radiation Oncology to provide a current review of the diagnosis, planning, and treatment of SCLC. These guidelines emphasise treatment fields, radiation techniques, fractionation, concomitant treatment, and the optimal timing of Ch and radiotherapy. Finally, we discuss the main indications for reirradiation in local recurrence.

Personalizing Radiotherapy Prescription Dose Using Genomic Markers of Radiosensitivity and Normal Tissue Toxicity in NSCLC

INTRODUCTION

Cancer sequencing efforts have revealed that cancer is the most complex and heterogeneous disease that affects humans. However, radiation therapy (RT), one of the most common cancer treatments, is prescribed on the basis of an empirical one-size-fits-all approach. We propose that the field of radiation oncology is operating under an outdated null hypothesis: that all patients are biologically similar and should uniformly respond to the same dose of radiation.

METHODS

We have previously developed the genomic-adjusted radiation dose, a method that accounts for biological heterogeneity and can be used to predict optimal RT dose for an individual patient. In this article, we use genomic-adjusted radiation dose to characterize the biological imprecision of one-size-fits-all RT dosing schemes that result in both over- and under-dosing for most patients treated with RT. To elucidate this inefficiency, and therefore the opportunity for improvement using a personalized dosing scheme, we develop a patient-specific competing hazards style mathematical model combining the canonical equations for tumor control probability and normal tissue complication probability. This model simultaneously optimizes tumor control and toxicity by personalizing RT dose using patient-specific genomics.

RESULTS

Using data from two prospectively collected cohorts of patients with NSCLC, we validate the competing hazards model by revealing that it predicts the results of RTOG 0617. We report how the failure of RTOG 0617 can be explained by the biological imprecision of empirical uniform dose escalation which results in 80% of patients being overexposed to normal tissue toxicity without potential tumor control benefit.

CONCLUSIONS

Our data reveal a tapestry of radiosensitivity heterogeneity, provide a biological framework that explains the failure of empirical RT dose escalation, and quantify the opportunity to improve clinical outcomes in lung cancer by incorporating genomics into RT.

Early Prediction of Acute Esophagitis for Adaptive Radiation Therapy

PURPOSE

Acute esophagitis (AE) is a common dose-limiting toxicity in radiation therapy of locally advanced non-small cell lung cancer (LA-NSCLC). We developed an early AE prediction model from weekly accumulated esophagus dose and its associated local volumetric change.

METHODS AND MATERIALS

Fifty-one patients with LA-NSCLC underwent treatment with intensity modulated radiation therapy to 60 Gy in 2-Gy fractions with concurrent chemotherapy and weekly cone beam computed tomography (CBCT). Twenty-eight patients (55%) developed grade ≥2 AE (≥AE2) at a median of 4 weeks after the start of radiation therapy. For early ≥AE2 prediction, the esophagus on CBCT of the first 2 weeks was deformably registered to the planning computed tomography images, and weekly esophagus dose was accumulated. Week 1-to-week 2 (w1→w2) esophagus volume changes including maximum esophagus expansion (MEex%) and volumes with ≥x% local expansions (VEx%; x = 5, 10, 15) were calculated from the Jacobian map of deformation vector field gradients. Logistic regression model with 5-fold cross-validation was built using combinations of the accumulated mean esophagus doses (MED) and the esophagus change parameters with the lowest P value in univariate analysis. The model was validated on an additional 18 and 11 patients with weekly CBCT and magnetic resonance imaging (MRI), respectively, and compared with models using only planned mean dose (MED_Plan). Performance was assessed using area under the curve (AUC) and Hosmer-Lemeshow test (P_HL).

RESULTS

Univariately, w1→w2 VE10% (P = .004), VE5% (P = .01) and MEex% (P = .02) significantly predicted ≥AE2. A model combining MED_W2 and w1→w2 VE10% had the best performance (AUC = 0.80; P_HL = 0.43), whereas the MED_Plan model had a lower accuracy (AUC = 0.67; P_HL = 0.26). The combined model also showed high accuracy in the CBCT (AUC = 0.78) and MRI validations (AUC = 0.75).

CONCLUSIONS

A CBCT-based, cross-validated, and internally validated model on MRI with a combination of accumulated esophagus dose and local volume change from the first 2 weeks of chemotherapy significantly improved AE prediction compared with conventional models using only the planned dose. This model could inform plan adaptation early to lower the risk of esophagitis.

Toxicity after volumetric modulated arc therapy for lung cancer: a monocentric retrospective study

Background

Intensity-modulated radiotherapy (RT) is now widely implemented and has replaced classical three-dimensional (3D)-RT in many tumor sites, as it allows a better target dose conformity and a better sparing of organs a risk (OAR), at the expense, however, of increasing the volume of low dose to normal tissues. Clinical data on toxicities using volumetric modulated arc therapy (VMAT) in lung cancer remain scarce. We aimed to report both acute (APT) and late (LPT) pulmonary and acute (AET) and late (LET) oesophageal toxicities in such setting.

Methods

All patients treated for a primary lung cancer with VMAT +/- chemotherapy (ChT) in our center from 2014 to 2018 were retrospectively included. Usual clinical, treatment and dosimetric features were collected. Univariate analysis was performed using the receiver operative characteristics approach while multivariate analysis (MVA) relied on logistic regression, calculated with Medcalc 14.8.1.

Results

In total, 167 patients were included, with a median age of 66 years (39-88 years). Median radiation dose was 66 Gy (30-66 Gy); 82% patients received concomitant (32.3%), induction (25.7%) or induction followed by concomitant ChT (24%). After a median follow-up of 14.0 months, the G ≥2 APT, AET, LPT and LET rates were 22.2%, 30.0%, 16.8% and 5.4%, respectively with low grade ≥3 toxicity rates (respectively, 3%, 6.6%, 3% and 0%). On MVA, APT was significantly associated with V30 to the homolateral lung, AET with age, LPT with MEVS while no feature remained significantly correlated with LET.

Conclusions

Low rates of pulmonary and esophageal toxicity were observed in our cohort. Larger prospective studies are needed to confirm these results.

Radiation-induced damage in the upper gastrointestinal tract: clinical presentation, diagnostic tests and treatment options

Radiation-induced damage of the upper gastrointestinal (GI) tract results from radiation of GI tumors or structures adjacent to the GI tract. Radiation-induced damages of the upper GI tract may be acute or delayed, and ranges from lack of appetite, mucosal inflammation (i.e. esophagitis, gastritis, duodenitis) to ulcers, which may be complicated by perforation, penetration, bleeding and stenosis. Radiation-related factors as well as individual patient predisposing factors may increase susceptibility to post-radiation damage. High quality evidence for the treatment of radiation-induced GI damage is scarce and the management is often extrapolated from studies on GI lesions of different etiology. Treatment depends on severity and localization of the radiation-induced damage, and ranges from supportive and dietary measures to endoscopic interventions or surgery. Modern radiation techniques may decrease the incidence and severity of the radiation-induced upper gastrointestinal disease.

Radiomics analysis of 3D dose distributions to predict toxicity of radiotherapy for lung cancer

PURPOSE

(Chemo)-radiotherapy (RT) is the gold standard treatment for patients with locally advanced lung cancer non accessible for surgery. However, current toxicity prediction models rely on clinical and dose volume histograms (DVHs) and remain unsufficient. The goal of this work is to investigate the added predictive value of the radiomics approach applied to dose maps regarding acute and late toxicities in both the lungs and esophagus.

METHODS

Acute and late toxicities scored using the CTCAE v4.0 were retrospectively collected on patients treated with RT in our institution. Radiomic features were extracted from 3D dose maps considering Gy values as grey-levels in images. DVH and usual clinical factors were also considered. Three toxicity prediction models (clinical only, clinical + DVH and combined, i.e., including clinical + DVH + radiomics) were incrementally trained using a neural network on 70% of the patients for prediction of grade ≥2 acute and late pulmonary toxicities (APT/LPT) and grade ≥2 acute esophageal toxicities (AET). After bootstrapping (n = 1000), optimal cut-off values were determined based on the Youden Index. The trained models were then evaluated in the remaining 30% of patients using balanced accuracy (BAcc).

RESULTS

167 patients were treated from 2015 to 2018: 78% non small-cell lung cancers, 14% small-cell lung cancers and 8% other histology with a median age at treatment of 66 years. Respectively, 22.2%, 16.8% and 30.0% experienced APT, LPT and AET. In the training set (n = 117), the corresponding BAcc for clinical only/clinical + DVH/combined were 0.68/0.79/0.92, 0.66/0.77/0.87 and 0.68/0.73/0.84. In the testing evaluation (n = 50), these trained models obtained a corresponding BAcc of 0.69/0.69/0.92, 0.76/0.80/0.89 and 0.58/0.73/0.72.

CONCLUSION

In patients with a lung cancer treated with RT, radiomic features extracted from 3D dose maps seem to surpass usual models based on clinical factors and DVHs for the prediction of APT and LPT.

Oesophageal-pericardial fistula: a rare complication of radiation-induced oesophagitis

Oesophageal-pericardial fistula after radiation therapy for lung cancer is a rare complication associated with a high mortality. In this case report, we present the case of 52-year-old women with late radiation-induced oesophagitis after chemoradiotherapy for a pulmonary adenocarcinoma, complicated by an oesophageal-pericardial fistula for which a transthoracic oesophagectomy with pericardial drainage was performed. The postoperative course was complicated by a fatal hypovolaemic shock due to a perforation of the descending aorta near the initial fistula track. In this case report, we illustrate the importance of thorough inspection of diagnostic images in this context and emphasize the role of endovascular repair in case an associated aortic perforation is suspected.

Sparing Organs at Risk with Simultaneous Integrated Boost Volumetric Modulated Arc Therapy for Locally Advanced Non-Small Cell Lung Cancer: An Automatic Treatment Planning Study

Background

The technique of simultaneous integrated boost volumetric modulated arc therapy (SIB-VMAT) has been widely used in locally advanced non-small cell lung cancer; however, its dosimetric advantages are seldom reported. This study aimed to quantify dosimetric advantages of SIB-VMAT.

Methods

Forty patients with stage III non-small cell lung cancer in our hospital were retrospectively included. SIB-VMAT and conventional VMAT (C-VMAT) plans were generated for every patient using the automatic treatment planning system. A reduced dose was delivered to PTV in SIB-VAMT plans compared to C-VMAT plans (50.4Gy vs 60Gy). The prescribed dose was 50.4 Gy in 28 fractions to PTV and 59.92 Gy in 28 fractions to PGTV in SIB-VMAT plans, while 60 Gy in 30 fractions to PTV in C-VMAT plans. Dose-volume metrics of PTV, total lung, heart, esophagus and spinal cord were recorded. The quality score was used to evaluate organs at risk (OAR) protection for two type prescription plans.

Results

Conformal coverage of the targets (PGTV/PTV) by 95% of the prescription dose was well achieved in radiation plans. SIB-VMAT plans achieved significantly higher quality score than C-VMAT plans (Mean: 68.15±13.32 vs 49.15±13.35, P<0.001). More plans scored above sixty in SIB-VMAT group compared to C-VMAT group (72.5% vs 20%, P<0.001). Notable reductions in mean dose, V₃₀, V₄₀ and V₅₀ of total lung were observed in SIB-VMAT plans compared to C-VMAT plans, with median decreased proportions of 6.5%, 8.7%, 19.6% and 32.1%, respectively. Statistically significant decrease in heart V₃₀ and V₄₀ was also achieved in SIB-VMAT plans, with median decreased proportions of 26.1% and 38.8%. SIB-VMAT plans achieved significant reductions in the maximum doses to both esophagus and spinal cord. Patients with CTV/(GTV+GTVnd) ≥8.6 showed more notable decrease in total lung V₅₀ (median, 33.6% vs 28.8%, P=0.001) in SIB-VMAT plans compared to those with the ratio being less than 8.6.

Conclusion

SIB-VMAT technique could lead to a substantial sparing of normal organs, including lung, heart, esophagus and cord, mainly through reducing high and inter-median dose exposure. Patients with CTV/(GTV+GTVnd) ≥8.6 might benefit more from SIB-VMAT.

Assessing the Need for Adjusted Organ-at-Risk Planning Goals for Patients Undergoing Adjuvant Radiation Therapy for Locally Advanced Breast Cancer with Proton Radiation

PURPOSE

Locally advanced breast cancer requires surgical management via lumpectomy or mastectomy with or without systemic therapy followed by chest wall or breast (CW) and comprehensive nodal irradiation (CNI). Radiation (RT) dose constraints for the heart and ipsilateral lung have been developed based on photon RT. Proton therapy (PBT) can deliver significantly lower doses of RT to these organs-at-risk (OARs) and may warrant adjustments to OAR planning goals.

METHODS AND MATERIALS

The RT plans of consecutive patients undergoing adjuvant CW-CNI RT with PBT within a single center were reviewed. A inital treatment volume, comprised of CW/intact breast + CNI (CTV_init) structure, including the CW and CNI but excluding any boost plans was analyzed. Frequency distributions were generated based on doses received by the heart, lungs, and esophagus for validated dosimetric parameters. Frequency distributions were generated and then stratified by laterality and compared using the Kruskal-Wallis H test. The 75th, 85th, and 95th percentiles for each dosimetric parameter were calculated, overall and by laterality. The 75th percentile (Q3), was used as a suggested primary goal, and the 95th percentile was used as a suggested secondary goal.

RESULTS

One hundred and seventy-two plans were analyzed. Forty-nine plans were right-sided, 107 were left-sided, and 16 were bilateral. The overall Q3 of the mean and V25 of the heart were 1.5 Gy and 1.7%, respectively. The mean and V25 to the heart differed significantly by laterality. Pulmonary values were similar to current recommendations. For all lateralites, the median volume of the esophagus receiving 70% prescription dose was ≤1 cm³.

CONCLUSIONS

We present the first dosimetric study providing complete OAR dose-volume histograms data for patients undergoing adjuvant pencil-beam scanning-PBT for locally advanced breast cancer, with detailed information on central tendencies, ranges and distributions of data. We have provided suggested planning goals and metrics for the lungs, heart, and esophagus; the latter 2 differing significantly from current Quantitative Analysis of Normal Tissue Effects in the Clinic (QUANTEC) constraints and classical photon goals.

Multi-view radiomics and dosiomics analysis with machine learning for predicting acute-phase weight loss in lung cancer patients treated with radiotherapy

We propose a multi-view data analysis approach using radiomics and dosiomics (R&D) texture features for predicting acute-phase weight loss (WL) in lung cancer radiotherapy. Baseline weight of 388 patients who underwent intensity modulated radiation therapy (IMRT) was measured between one month prior to and one week after the start of IMRT. Weight change between one week and two months after the commencement of IMRT was analyzed, and dichotomized at 5% WL. Each patient had a planning CT and contours of gross tumor volume (GTV) and esophagus (ESO). A total of 355 features including clinical parameter (CP), GTV and ESO (GTV&ESO) dose-volume histogram (DVH), GTV radiomics, and GTV&ESO dosiomics features were extracted. R&D features were categorized as first- (L1), second- (L2), higher-order (L3) statistics, and three combined groups, L1 + L2, L2 + L3 and L1 + L2 + L3. Multi-view texture analysis was performed to identify optimal R&D input features. In the training set (194 earlier patients), feature selection was performed using Boruta algorithm followed by collinearity removal based on variance inflation factor. Machine-learning models were developed using Laplacian kernel support vector machine (lpSVM), deep neural network (DNN) and their averaged ensemble classifiers. Prediction performance was tested on an independent test set (194 more recent patients), and compared among seven different input conditions: CP-only, DVH-only, R&D-only, DVH + CP, R&D + CP, R&D + DVH and R&D + DVH + CP. Combined GTV L1 + L2 + L3 radiomics and GTV&ESO L3 dosiomics were identified as optimal input features, which achieved the best performance with an ensemble classifier (AUC = 0.710), having statistically significantly higher predictability compared with DVH and/or CP features (p < 0.05). When this performance was compared to that with full R&D-only features which reflect traditional single-view data, there was a statistically significant difference (p < 0.05). Using optimized multi-view R&D input features is beneficial for predicting early WL in lung cancer radiotherapy, leading to improved performance compared to using conventional DVH and/or CP features.

Dose simulations of an early 20th century kilovoltage pneumonia radiotherapy technique performed with a modern fluoroscope

To simulate an early 20th century viral pneumonia radiotherapy treatment using modern fluoroscopy and evaluated it according to current dose guidelines. Monte Carlo was used to assess the dose distribution on an anthropomorphic phantom. Critical organs were: skin, breasts, esophagus, ribs, vertebrae, heart, thymus, and spinal cord. A 100 kV_p beam with 3 mm Al HVL, 25 × 25 cm² posterior-anterior (PA) field and 50 cm source-to-surface distance were simulated. Simulations had a resolution of 0.4 × 0.4 × 0.06 cm³ and a 6% uncertainty. Hundred percent dose was normalized to the skin surface and results were displayed in axial, coronal, and sagittal planes. Dose volume histograms were generated in MATLAB for further analysis. Prescription doses of 0.3, 0.5, and 1.0 Gy were applied to the 15% isodose for organ-dose comparison to current tolerances and potential risk of detriment. Ninety-five and ninety-seven percent of the right and left lung volumes, respectively, were well-covered by the 15% isodose line. For the 0.3, 0.5, and 1.0 Gy prescriptions, the maximum skin doses were 2.9, 4.8, and 9.6 Gy compared to a 2.0 Gy transient erythema dose threshold; left/right lung maximum doses were 1.44/1.46, 2.4/2.4, and 4.8/4.9 Gy compared to a 6.5 Gy pneumonitis and 30 Gy fibrosis thresholds; maximum heart doses were 0.5, 0.9, and 1.8 Gy compared to the 0.5 Gy ICRP-recommendation; maximum spinal cord doses were 1.4, 2.3, and 4.6 Gy compared to 7.0 Gy single fraction dose threshold. Maximum doses to other critical organs were below modern dose thresholds. A 100 kV_p PA field could deliver a 0.3 Gy or 0.5 Gy dose without risk of complications. However, a 1.0 Gy dose treatment could be problematic. Critical organ doses could be further reduced if more than one treatment field is used.

Advances in Radiobiology of Stereotactic Ablative Radiotherapy

Radiotherapy (RT) has been developed with remarkable technological advances in recent years. The accuracy of RT is dramatically improved and accordingly high dose radiation of the tumors could be precisely projected. Stereotactic radiosurgery (SRS) and stereotactic body radiotherapy (SBRT), also known as stereotactic ablative radiotherapy (SABR), are rapidly becoming the accepted practice in treating solid small sized tumors. Compared with the conventional fractionation external beam radiotherapy (EBRT), SABR with very high dose per fraction and hypo-fractionated irradiation yields convincing and satisfied therapeutic effects with low toxicity, since tumor cells could be directly ablated like radiofrequency ablation (RFA). The impressive clinical efficacy of SABR is greater than expected by the linear quadratic model and the conventional radiobiological principles, i.e., 4 Rs of radiobiology (reoxygenation, repair, redistribution, and repopulation), which may no longer be suitable for the explanation of SABR's ablation effects. Based on 4 Rs of radiobiology, 5 Rs of radiobiology emphasizes the intrinsic radiosensitivity of tumor cells, which may correlate with the responsiveness of SABR. Meanwhile, SABR induced the radiobiological alteration including vascular endothelial injury and the immune activation, which has been indicated by literature reported to play a crucial role in tumor control. However, a comprehensive review involving these advances in SABR is lacking. In this review, advances in radiobiology of SABR including the role of the 4 Rs of radiobiology and potential radiobiological factors for SABR will be comprehensively reviewed and discussed.

Re-irradiation in the thorax - An analysis of efficacy and safety based on accumulated EQD2 doses

INTRODUCTION

Thoracic re-irradiation remains a challenge regarding the balance of local efficacy and acceptable toxicities. In this retrospective analysis we analyzed dosimetrical and clinical data of patients treated with thoracic re-irradiation based on accumulated EQD2Gy doses.

METHODS AND MATERIAL

We retrospectively analyzed the data of 42 consecutive single-institutional patients treated with repeated courses of thoracic radiotherapy from 12/2011 to 01/2017. Accumulated EQD2 dose distributions were calculated and dose parameters for organs at risk and target volumes were analysed.

RESULTS

The median prescription dose was 42.2 Gy (10-70.6 Gy) for all RT courses. The median Dmean of both lungs was 10.1 Gy₃ (range: 1.9 Gy₃-17.9 Gy₃) with a maximum D0.1 cc of 253.86 Gy₃. The median D0.1 cc of the esophagus was 62.2 Gy₃ with a maximum of 103.78 Gy₃. The maximum D0.1 cc for the bronchial tree was 187.33 Gy₃ (median 74.35 Gy₃) and for the Aorta 216.1 Gy₃ (median 70.9 Gy₃). Median OS after first re-irradiation was 19 months (range 1-45 months). 12-month local control after a course of re-irradiation was 52.6%. 80% of patients suffered from a G1-G2 toxicity, most frequently coughing. One patient suffered from a G5 complication probably unrelated to re-irradiation.

CONCLUSION

Even though several organs at risk received maximum accumulated doses of >100 Gy₃, thoracic reirradiation resulted in an acceptable toxicity profile. Local tumor control and overall survival remained encouraging even after multiple courses of thoracic radiotherapy.

Dose-volume effects of breast cancer radiation therapy on the risk of second oesophageal cancer

PURPOSE

To investigate the relationship between oesophagus dose-volume distribution and long-term risk of oesophageal cancer after radiation therapy for breast cancer.

MATERIALS AND METHODS

In a case-control study nested within a cohort of 289,748 ≥5-year survivors of female breast cancer treated in 1943-2003 in five countries, doses to the second primary cancer (D_SPC) and individual dose-volume histograms (DVH) to the entire oesophagus were reconstructed for 252 oesophageal cancer cases and 488 matched controls (median follow-up time: 13, range: 5-37 years). Using conditional logistic regression, we estimated excess odds ratios (EOR) of oesophageal cancer associated with DVH metrics. We also investigated whether DVH metrics confounded or modified D_SPC-related -risk estimates.

RESULTS

Among the DVH metrics evaluated, median dose (D_median) to the entire oesophagus had the best statistical performance for estimating risk of all histological types combined (EOR/Gy = 0.071, 95% confidence interval [CI]: 0.018 to 0.206). For squamous cell carcinoma, the most common subtype, the EOR/Gy for D_median increased by 31% (95% CI: 3% to 205%) for each increment of 10% of V30 (p = 0.02). Adjusting for DVH metrics did not materially change the EOR/Gy for D_SPC, but there was a borderline significant positive interaction between D_SPC and V30 (p = 0.07).

CONCLUSION

This first study investigating the relationship between oesophagus dose-volume distribution and oesophageal cancer risk showed an increased risk per Gy for D_median with larger volumes irradiated at high doses. While current techniques allows better oesophagus sparing, constraints applied to D_median and V30 could potentially further reduce the risk of oesophageal cancer.

Efficacy of Endoscopic Evaluation of Acute Radiation Esophagitis during Chemoradiotherapy with Proton Beam Therapy Boost for Esophageal Cancer

BACKGROUND/AIM

To evaluate the utility of endoscopy for assessing radiation esophagitis during chemoradiotherapy (CRT) with proton beam therapy (PBT) boost for esophageal cancer.

METHODS

Between December 2012 and December 2016, 38 patients with esophageal cancer were treated with CRT with PBT boost. To evaluate radiation esophagitis, endoscopy was performed after administration of CRT with standard PBT boost (total dose 50-60 Gy relative biological effectiveness [RBE]). Radiation esophagitis was evaluated and classified into 5 newly developed endoscopic grades (Fukui Acute Radiation Esophagitis [FARE] grade). The additional PBT boost was then adjusted and delivered (2-20 Gy [RBE]) to a maximum total dose of 74.4 Gy (RBE) based on the degree of radiation esophagitis, probability of residual tumor, and patient's general condition. To evaluate the utility of endoscopic examination, the incidences of adverse events graded according to National Cancer Institute Common Terminology Criteria for Adverse Events (CTCAE, version 4.0) were determined at the time of endoscopic examination after CRT with standard PBT boost (50-60 Gy [RBE]) and at the completion of treatment (60-74.4 Gy [RBE]), as well as during the 90 days from the beginning of treatment.

RESULTS

There was a significant correlation between FARE grade and CTCAE esophagitis grade (ρ = 0.48; p = 0.03). Moreover, endoscopy detected severe esophagitis in an asymptomatic patient. Radiation dose escalation was achieved without severe acute adverse events. There was no significant difference between the incidence of acute toxicity at the time of the CRT with standard PBT boost (50-60 Gy [RBE]) and the higher dose at the completion of treatment (60-74.4 Gy [RBE]), which suggests this dose escalation strategy is safe.

CONCLUSION

Endoscopic evaluation of radiation esophagitis using FARE grades was safely performed and useful for adjusting added radiation to ensure the safety of escalations in CRT with PBT boost for esophageal cancer.

Therapeutic effects of Co-Venenum Bufonis Oral Liquid on radiation-induced esophagitis in rats

To investigate the effects of Co-Venenum Bufonis Oral Liquid (cVBOL) on radiation-induced esophagitis in rats. Irradiation (30 Gy) with X-RAD 225 x-ray was applied to induce esophagitis in 64 Wistar rats and treated by different methods. The body weight of rats either in RT group, cVBOL+RT, or EM+RT group was significantly decreased when compared with that in normal group (P<0.0001). After irradiation, histopathological studies, immunohistochemistry, and MRI scanning on esophagus were performed. Serum TNF-α,IL-6 and IL-10 were also determined by ELISA at 7, 14, 21 and 28 days after radiation treatment. The results demonstrated that radiation caused esophageal injury and thickening of esophageal tissue layers. The esophageal tissues after radiation treatment showed typical pathological changes of esophagitis. Radiation also caused esophagus edema. Treatment of cVBOL reduced the severity of histological esophageal lesion, decreased the expression of bFGF and TGF-β1, and lowered serum levels of inflammatory cytokines including TNF-α, IL-6 and IL-10 over 28 days after radiation treatment. In conclusion, cVBOL treatment is effective to prevent radiation induced esophagitis and reduces radiation induced esophagitis may be mediated through its ant-inflammatory effects.

Exploring the Relationship of Radiation Dose Exposed to the Length of Esophagus and Weight Loss in Patients with Lung Cancer

PURPOSE

We investigate whether esophageal dose-length parameters (L_dose) can robustly predict significant weight loss-≥5% weight loss during radiation therapy (RT) compared with the weight before RT-in patients with lung cancer treated with definitive intent.

METHODS AND MATERIALS

Patients with lung cancer treated with conventionally fractionated RT between 2010 and 2018 were retrospectively identified. L_Fdose and L_Pdose, the length of full- and partial-circumferential esophagus receiving greater than a threshold dose in Gy, respectively, were created. Multivariate logistic regression examined the associations between individual L_dose and weight loss after adjusting for clinical parameters and correcting for multiple comparisons. Ridge logistic regression examined the relative importance of L_dose compared with dose-volume (V_dose), mean dose (D_mean), and clinical parameters in determining weight loss. Univariate logistic regression examined the unadjusted probability of weight loss for important L_dose parameters.

RESULTS

Among the 214 patients identified, median age was 66.9 years (range, 31.5-88.9 years), 50.5% (n = 108) were male, 68.2% (n = 146) had stage III lung cancer, median RT dose was 63 Gy (range, 60-66 Gy), and 88.3% (n = 189) received concurrent chemotherapy. Esophagus lengths receiving high full-circumferential (L_F50-L_F60) and high partial-circumferential doses (L_P60) were associated with significant weight loss (P ≤ .05). L_F65 and L_P65 reached near significance (P = .06 and .053, respectively). L_F65 > L_F60 > L_P65 were the most important dose parameters in determining weight loss compared with other L_dose, V_dose, and D_mean parameters.

CONCLUSIONS

Esophageal L_dose parameters are an efficient way of interpreting complex dose parameters in relation to weight loss toxicity among patients with lung cancer receiving definitive RT.