Propensity score-based comparison of survival and radiation pneumonitis after definitive chemoradiation for esophageal cancer: Intensity-modulated radiotherapy versus three-dimensional conformal radiotherapy

Clinical, Dosimetric and Radiomic Features Predictive of Lung Toxicity After (Chemo)Radiotherapy

BACKGROUND

Treatment of locally advanced non small cell lung cancer (LA-NSCLC) is based on (chemo)radiotherapy, which may cause acute lung toxicity: radiation pneumonitis (RP). Its frequency seems to increase by the use of adjuvant durvalumab therapy.

AIMS

To identify clinical, dosimetric, and radiomic factors associated with grade (G)≥2 RP and build a prediction model based on selected parameters.

PATIENTS AND METHODS

This is a retrospective multicenter cohort study including patients receiving radiation therapy between 2015 and 2019 for LA-NSCLC. Baseline computed tomography scanners were segmented to extract radiomic features from the "Lung - Tumor" volume. Variables associated with the risk of G≥2 RP in the descriptive analysis were then selected for explanatory analysis, followed by predictive analysis.

RESULTS

153 patients were included in 4 centers (51 with G≥2 RP). Factors associated with G≥2 RP included a high initial hemoglobin level, dosimetric factors (mean dose to healthy lungs, lung V20Gy and V13Gy), the addition of maintenance durvalumab, and 7 radiomic features (intensity distribution and texture). Other factors were associated with an increased risk of G≥2 RP in our explanatory model, such as older age, low Tiffeneau ratio, and a decreased initial platelet count. The best-performing predictive model was a random forest-based learning model using clinical, dosimetric, and radiomic variables, with an area under the ROC curve of 0.72 (95%CI [0.63; 0.80]) versus 0.64 for models using one type of data.

CONCLUSION

The addition of radiomic features to clinical and dosimetric ones improves prediction of the occurrence of G≥2 RP in patients receiving radiotherapy for lung cancer.

Dosimetric evaluation of simplified intensity-modulated radiation therapy for thoracic tumors

To evaluate the feasibility of multi-parameters combined simplified intensity-modulated radiation therapy (sIMRT) planning in thoracic tumors and provide guidance for clinical practice. A total of 34 patients with thoracic tumors who underwent radiotherapy during 2019 to 2020 in our hospital were retrospectively analyzed. The same experienced medical physicist designed the sIMRT planning. The sIMRT planning limited the maximum number of segments per beam-field, the minimum segment area, and the minimum number of segment monitor units (MU), remaining consistent with the conventional intensity-modulated radiation therapy (IMRT). Comparative analysis of the difference in the irradiation dose to the tumor target area, and organs at risk, and delivery validate between 2 groups. The sIMRT slightly increased the tumor target area irradiation dose, but the homogeneity index was similar when compared with IMRT (P > .05). The sIMRT planning significantly reduced the low dose-volume area of the lungs (left lung, V5: 2.5%; right lung, V5: 3.1%; V10: 1.8%; lungs, V5: 3.2%; V10: 1.5%, P < .05) and significantly increased the high dose-volume area of the lungs, heart, and esophagus, while meeting the clinical dose-restriction requirements. Moreover, the planning delivery validation showed that significantly reduced the treatment time (6.5 ± 1.9 minutes vs 8.8 ± 2.0 minutes, P < .0001) and total MU (386.3 ± 109.4 MU vs 406.3 ± 107.9 MU, P < .05). This simplified sIMRT method can meet the requirements of thoracic tumors radiotherapy planning, and has higher time effectiveness. In the future, it needs to be further explored in clinical practice.

Improper lung volume-dose parameters are risk factors for acute fatal radiation pneumonitis among esophageal cancer patients receiving chemoradiotherapy: a case-control study

Background

Definitive concurrent chemoradiotherapy (DCRT) is the standard treatment for locally advanced unresectable esophageal cancer (EC). However, acute fatal radiation pneumonitis (AFRP) is one of the most harmful complications and it is still controversial which factors pose a greater risk.

Aim

This case-control study aims to investigate the relationship between AFRP and lung volume-dose parameters in patients with esophageal cancer undergoing DCRT.

Methods

Cases are patients who died of AFRP after DCRT, whereas controls are patients who did not develop RP. Participants were enrolled using the International Classification of Diseases Codes Searching and then verified by medical record review. One-to-three propensity score matching was performed between EC patients undergoing DCRT who died from AFRP and those who did not develop radiation pneumonitis(RP). Prognostic factors were determined using univariate and multivariate analyses. The exposure factors were lung volume-dose parameters, including V5, V20, V30, and mean lung dose (MLD). Overall survival was compared between the two groups of patients before and after propensity score matching.

Results

17 cases were confirmed with AFRP among 568 EC patients were treated with DCRT between June 2008 and June 2013, and 51 cases with no RP matched by PSM method in the control group. The median V5 and MLD values in the case group were significantly higher than the control group: 88.39% versus 65.045% and 17.325 gray (Gy) versus 14.38 Gy, respectively. V5 > 60%, V20 > 25%, and MLD > 15 Gy were identified as independent risk factors for AFRP. V5 > 80% significantly increased the susceptibility to AFRP and predicted worse overall survival.

Conclusion

V5 > 60%, V20 > 25% and MLD > 15 Gy are key risk factors for AFRP in EC patients undergoing DCRT. Furthermore, V5 > 80% is a strong indicator of mortality risk.

Effect of replanning boost radiotherapy plan in locally advanced unresectable middle to lower thoracic esophageal cancer

Thoracic bulky esophageal cancer shrinks during radiotherapy, changing the location and shape of the surrounding heart and lungs. The current study aimed to explore how replanning by volumetric-modulated arc radiotherapy (VMAT) and three-dimensional conformal radiotherapy (3DCRT) influences the target coverage and dose to organs at risk in locally advanced unresectable middle to lower thoracic esophageal cancer. We retrospectively collected CT simulation images of initial and boost radiotherapy plans for locally advanced unresectable thoracic esophageal cancer in 17 consecutive patients. First, we created boost plans of 20 Gy using 3DCRT and VMAT on the initially acquired CT images. Second, we replicated the process on CT images acquired after 20-40 Gy of radiotherapy. We then compared non-replanned boost radiotherapy plans with replanned boost plans. Replanned radiotherapy delivered more conformal doses to the target and reduced heart and lung doses. VMAT reduced more irradiated mean doses to the heart than 3DCRT in the case of replanning (1.7 and 1.1 Gy, p < 0.001). Replanning to accommodate tumor shrinkage during radiotherapy effectively lowers the irradiated doses to the heart and lungs in patients with locally advanced unresectable middle to lower thoracic esophageal cancer, especially those treated with VMAT.

Radiation pneumonitis prediction with dual-radiomics for esophageal cancer underwent radiotherapy

BACKGROUND

To integrate radiomics and dosiomics features from multiple regions in the radiation pneumonia (RP grade ≥ 2) prediction for esophageal cancer (EC) patients underwent radiotherapy (RT).

METHODS

Total of 143 EC patients in the authors' hospital (training and internal validation: 70%:30%) and 32 EC patients from another hospital (external validation) underwent RT from 2015 to 2022 were retrospectively reviewed and analyzed. Patients were dichotomized as positive (RP+) or negative (RP-) according to CTCAE V5.0. Models with radiomics and dosiomics features extracted from single region of interest (ROI), multiple ROIs and combined models were constructed and evaluated. A nomogram integrating radiomics score (Rad_score), dosiomics score (Dos_score), clinical factors, dose-volume histogram (DVH) factors, and mean lung dose (MLD) was also constructed and validated.

RESULTS

Models with Rad_score_Lung&Overlap and Dos_score_Lung&Overlap achieved a better area under curve (AUC) of 0.818 and 0.844 in the external validation in comparison with radiomics and dosiomics models with features extracted from single ROI. Combining four radiomics and dosiomics models using support vector machine (SVM) improved the AUC to 0.854 in the external validation. Nomogram integrating Rad_score, and Dos_score with clinical factors, DVH factors, and MLD further improved the RP prediction AUC to 0.937 and 0.912 in the internal and external validation, respectively.

CONCLUSION

CT-based RP prediction model integrating radiomics and dosiomics features from multiple ROIs outperformed those with features from a single ROI with increased reliability for EC patients who underwent RT.

Quality of life and survival outcomes of patients with inoperable esophageal squamous cell carcinoma after definitive radiation therapy: A multicenter retrospective observational study in China from 2015 to 2016

Objectives

To investigate the health-related quality of life (HRQL) of long-term survivors of inoperable esophageal squamous cell carcinoma (ESCC) treated with definitive radiation therapy, the real-world trends in the use of advanced radiation techniques, and their impact on the survival outcomes of ESCC patients.

Methods

In this multicenter retrospective observational study, the medical records related to demographics and treatment of ESCC patients who were treated with definitive radiation therapy at 14 provincial hospitals in China from 1 January 2015 to 31 December 2016 were analyzed. A HRQL questionnaire was completed by survivors and collected by doctors at the final follow-up. The difference in quality of life between patients with or without recurrence was compared using the Wilcoxon-Mann-Whitney test. Overall survival (OS) was estimated using the Kaplan-Meier method and the group differences were assessed by unstratified log-rank test. The Cox proportional hazards model with Efron's method of tie handling was used to calculate the risk factors for OS.

Results

The data of a total of 3,308 patients were collected for this study, 248 were excluded because of missing data, and a final of 3,060 patients were included in the analysis. Most patients (2,901; 94.8%) received intensity-modulated radiotherapy (IMRT)/volumetric-modulated arc therapy (VMAT)/tomotherapy (TOMO). The 5-year OS rate was 30%. Patients who received either two-dimensional radiotherapy (2DRT; HR, 2.43 [95% CI, 1.70-3.47]; P < 0.001) or three-dimensional radiotherapy (3DRT; HR, 1.45 [95% CI, 1.14-1.84]; P = 0.003) had a significantly increased risk of death compared to those who received IMRT/VMAT/TOMO. Of the 716 (23.4%) long-term survivors who completed the HRQL questionnaire, nearly 70% patients were still able to swallow normally or almost normally, and >80% patients did not experience weight loss. Nearly 80% patients found life very enjoyable or were fairly enjoying life.

Conclusions

This large, multicenter retrospective study on ESCC patients who received definitive radiation therapy found that most ESCC survivors are satisfied with their quality of life. Most patients received advanced radiation technology. Patients who received either 2DRT or 3DRT had a significantly increased risk of death compared to those who received advanced radiation technology.

Nomogram based on circulating lymphocyte subsets for predicting radiation pneumonia in esophageal squamous cell carcinoma

Purpose

Currently, the relationship between radiation pneumonia (RP) and circulating immune cell in patients with esophageal squamous cell carcinoma (ESCC) remains unclear. This study aimed to explore the relationship between RP and circulating lymphocyte subsets in patients with ESCC receiving chemoradiotherapy (CRT), and develop a nomogram model to predict RP. Since we should implement clinical intervention to ≥ grade 2 RP, a nomogram model for ≥ grade 2 RP was also established to provide an early warning.

Patients and methods

This study retrospectively included 121 patients with ESCC receiving CRT from Guangxi Medical University Cancer Hospital from 2013 to 2021. Independent factors associated with occurrence of RP and ≥ grade 2 RP were identified by univariate and multivariate logistic regression analysis in the training cohort, and incorporated into nomograms. The predictive accuracy and discrimination of the model was assessed using Concordance Index (C-index), calibration curve and decision curve analysis (DCA). And each model was internally validated. Additionally, to verify the optimized predictive performance of the nomograms, the area under the ROC curve (AUC) of each nomogram was compared to that of single independent risk factors, lung V10 and lung V20, respectively. Moreover, each model was further evaluated for risk stratification to identify populations at high risk of RP and ≥ grade 2 RP.

Results

Multivariate analysis suggested that TNM stage, post-RT percentage of CD8+ T cell, and lung V15 were independent predictive factors of RP. Besides, pre- and post-RT percentage of CD8+ T cell, and V15 were independent factors of ≥ grade 2 RP. The C-indexes of RP and ≥ grade 2 RP nomograms were 0.809 (95% CI: 0.715-0.903) and 0.787 (95% CI: 0.685-0.889) in the training cohort, respectively. And the C-indexes of RP and ≥ grade 2 RP nomograms were 0.718 (95% CI: 0.544-0.892) and 0.621 (95% CI: 0.404-0.837) in the validation cohort, respectively. The calibration curves showed that the predicted values of model agreed well with actual observations. Moreover, DCA results indicated the applicability and accuracy of the models to predict RP and ≥ grade 2 RP. After stratification, the incidence of the high-risk group was significantly higher than that of the low-risk group with respect to either RP or ≥ grade 2 RP.

Conclusion

TNM stage, post-RT percentage of CD8+ T cell, and lung V15 were the independent predictors of RP toxicity. Pre- and post-RT percentage of CD8+ T cell, and lung V15 were the independent factors of ≥ grade 2 RP toxicity. The nomograms based on circulating lymphocyte subsets can robustly predict RP and ≥ grade 2 RP, guiding clinicians in risk stratification and early intervention.

Association of volumetric-modulated arc therapy with radiation pneumonitis in thoracic esophageal cancer

The lung volume receiving low-dose irradiation has been reported to increase in volumetric-modulated arc radiotherapy (VMAT) compared with three-dimensional conformal radiotherapy (3DCRT) for thoracic esophageal cancer, which raises concerns regarding radiation pneumonitis (RP) risk. This single institutional retrospective cohort study aimed to explore whether VMAT for thoracic esophageal cancer was associated with RP. Our study included 161 patients with thoracic esophageal cancer, of whom 142 were definitively treated with 3DCRT and 39 were treated with VMAT between 2008 and 2018. Radiotherapy details, dose-volume metrics, reported RP risk factors and RP incidence were collected. The RP risk factors were assessed via multivariate analysis. Dose-volume analysis showed that VMAT delivered more conformal dose distributions to the target volume (P < 0.001) and reduced V30 Gy of heart (57% vs 41%, P < 0.001) but increased V5 Gy (54% vs 41%, P < 0.001) and V20 Gy (20% vs 17%, P = 0.01) of lungs compared with 3DCRT. However, the 1-year incidence rates of RP did not differ between the two techniques (11.3% in 3DCRT vs 7.7% in VMAT, P = 0.53). The multivariate analysis suggested that the presence of interstitial lung disease (ILD) (P = 0.01) and V20 Gy of lungs ≥20% (P = 0.008) were associated with RP. Conclusively, VMAT increased the lung volume receiving low to middle doses irradiation, although this might not be associated with RP. Further studies are needed to investigate the effect of using VMAT for delivering conformal dose distributions on RP.

Progression-free survival at 3 years is a reliable surrogate for 5-year overall survival for patients suffering from locally advanced esophageal squamous cell carcinoma

Background

Despite 3‐year survival being used as a primary endpoint in some randomized controlled trials (RCTs), limited evidence supports the use of intermediate endpoints to evaluate the effect of new therapies in esophageal squamous cell cancer (ESCC). This study aimed to systematically evaluate progression‐free survival at 3 years (3‐year PFS) and overall survival (OS) among patients with ESCC.

Methods

We identified 528 patients newly diagnosed with locally advanced ESCC who received definitive radiotherapy. OS was compared with an age‐ and sex‐matched general Chinese population using the standardized mortality ratio (SMR). Regression analysis was used to validate the correlation between PFS and OS using published data.

Results

The annual risk of progression decreased to 11.5% after 3 years. Patients who did not achieve 3‐year PFS had a median postprogression survival (PPS) of 7.3 months, with a 5‐year OS rate of 9.6% and a SMR of 15.0 (95% confidence interval [CI], 12.9–17.5). Conversely, the SMR for patients who achieved 3‐year PFS was 0.9 (95% CI, 0.6–1.3). We observed a significant correlation between log hazard ratio (HR) (PFS) and log HR (OS) at the trial level (r = 0.89; 95% CI, 0.88–0.90). The strongest correlation was observed between 3‐year PFS and 5‐year OS in RCTs and retrospective studies.

Conclusions

Patients exhibiting progression within 3 years experienced poor survival, whereas patients achieving 3‐year PFS had excellent outcomes. Our study supports 3‐year PFS as a reliable primary endpoint for study design and risk stratification in locally advanced ESCC.

The impact of lymphopenia during chemoradiotherapy using photons or protons on the clinical outcomes of esophageal cancer patients

We assessed the development of lymphopenia during concurrent chemoradiotherapy (CRT) using X-ray versus proton beams and the impact on survival in patients with esophageal cancer. Among patients with esophageal cancer who were administered concurrent CRT with a curative intent at our institute from 2014 to 2018, 69 (15 receiving X-ray radiotherapy (XRT) and 54 receiving proton beam therapy [PBT]) who underwent weekly blood testing during treatment were enrolled. The absolute lymphocyte counts (ALC) at 1, 5 and 6 weeks were significantly higher in the patients who received PBT than in those who received XRT (p = 0.002, p = 0.006 and p = 0.009, respectively), and a similar trend in the neutrophil-to-lymphocyte ratio (NLR) was observed (p = 0.003 at 5 weeks). The 2-year overall survival (OS) and progression-free survival (PFS) rates tended to be higher in the patients who maintained an ALC ≥200 compared with those who did not (p = 0.083 and p = 0.053, respectively), and similar trends were observed in the NLR (p = 0.061 and p = 0.038, respectively). Dose-volume analysis revealed significant correlations between volumes of the thoracic bones irradiated by 5-50 Gy and minimum ALCs and maximum NLR. These findings suggested that PBT prevented the development of lymphopenia during CRT by reducing the irradiated volume of the thoracic bone, and the maintained lymphocyte count is possibly one of the early predictors for survival in patients with esophageal cancer.

Computed Tomography-Based Delta-Radiomics Analysis for Discriminating Radiation Pneumonitis in Patients With Esophageal Cancer After Radiation Therapy

PURPOSE

Our purpose was to construct a computed tomography (CT)-based delta-radiomics nomogram and corresponding risk classification system for individualized and accurate estimation of severe acute radiation pneumonitis (SARP) in patients with esophageal cancer (EC) after radiation therapy.

METHODS AND MATERIALS

Four hundred patients with EC were enrolled from 2 independent institutions and were divided into the training (n = 200) and validation (n = 200) cohorts. Eight hundred fifty radiomics features of lung were extracted from treatment planning images, including the positioning CT before radiation therapy (CT₁) and the resetting CT after receiving 40 to 45 Gy (CT₂). The longitudinal net changes in radiomics features from CT₁ to CT₂ were calculated and defined as delta-radiomics features. Least absolute shrinkage and selection operator algorithm was performed to features selection and delta-radiomics signature building. Integrating the signature with multidimensional clinicopathologic, dosimetric, and hematological predictors of SARP, a novel CT-based delta-radiomics nomogram was established according to multivariate analysis. The clinical application values of nomogram were both evaluated in the training and validation cohorts by concordance index, calibration curves, and decision curve analysis. Recursive partitioning analysis was used to generate a risk classification system.

RESULTS

The delta-radiomics signature consisting of 24 features was significantly associated with SARP status (P < .001). Incorporating it with other high-risk factors, Subjective Global Assessment score, pulmonary fibrosis score, mean lung dose, and systemic immune inflammation index, the developed delta-radiomics nomogram showed increased improvement in SARP discrimination accuracy with concordance index of 0.975 and 0.921 in the training and validation cohorts, respectively. Calibration curves and decision curve analysis confirmed the satisfactory clinical feasibility and utility of nomogram. The risk classification system displayed excellent performance on identifying SARP occurrence (P < .001).

CONCLUSIONS

The delta-radiomics nomogram and risk classification system as low-cost and noninvasive means exhibited superior predictive accuracy and provided individualized probability of SARP stratification for patients with EC.

Meta-analysis of efficacy and complications of intraluminal radioactive stent and common covered stent in treatment of advanced esophageal cancer

BACKGROUND

The main symptom of advanced esophageal cancer is dysphagia. Because there is no indication for surgery, in order to improve the patient's symptoms and quality of life, esophageal stent therapy has become the main palliative treatment. Based on the results of many studies, it can be speculated that intraluminal radioactive stent is better since it combines the function of ordinary stent and brachytherapy.

AIM

To evaluate the difference in the curative effect and complications between intraluminal radioactive stent (iodine 125 particle scaffold) and common covered stent in patients with mid-advanced esophageal cancer.

METHODS

A computer search of the electronic databases PubMed (1989/2020-03), Web of Science (2000/2020-03), Wiley Online Library (1992/2020-03), CNKI database (1978/2020-03), Wanfang database (1997/2020-03), and VIP database (2000/2020-03) and a manual search of Cochrance library were performed to retrieve articles using the method recommended by the Cochrance System Evaluator's Manual (version 4.2.2). The Oxford's 2011 evidence level assessment was used to evaluate the quality of the included articles, and Meta-analysis was performed using Revman 5.3 software.

RESULTS

Ten articles were finally included, with a total of 943 patients involved. Among the patients, 449 were implanted with an intraluminal radioactive stent and 494 were implanted with a common covered stent. A meta-analysis of 10 articles showed that the average survival time of the intraluminal radioactive stent group was 3.91 mo longer than that of the common covered stent group (95%CI: 1.68-6.13, Z = 3.44, P = 0.0006), and the median survival time was 3.12 mo longer 95%CI: 1.78-4.47, Z = 4.57, P = 0.0001). The dysphagia scores of the two groups of patients were significantly reduced within 1 and 3 mo after the stent was placed (P < 0.05), but there was no statistical difference between the two groups (P > 0.05). After stenting, there was no statistically significant difference in the incidence of pain (odds ratio [OR] = 0.89, 95%CI: 0.65-1.21, Z = 0.77, P = 0.44), bleeding (OR = 0.80, 95%CI: 0.52-1.22, Z = 1.03, P = 0.30), perforation (OR = 1.16, 95%CI: 0.55-2.43, Z = 0.39, P = 0.70), or stent displacement (R = 0.66, 95%CI: 0.31-1.38, Z = 1.10, P = 0.27) between the intraluminal radioactive stent group and the common covered stent group; but there was a statistical difference in the incidence of restenosis [OR = 0.61 , 95%CI (0.42-0.87), Z = 3.73 P = 0.006] between them.

CONCLUSION

The use of intraluminal radioactive stent in the treatment of advanced esophageal cancer can prolong the average survival time and median survival time of patients, and signficantly reduce the incidence of restenosis after surgery; however, the two types of stents have no significant difference in relieving the symptoms of dysphagia within 1-3 mo or in reducing postoperative complications such as pain, hemorrhage, perforation, and stent displacement.