The risk of death from heart disease in patients with nonsmall cell lung cancer who receive postoperative radiotherapy: analysis of the Surveillance, Epidemiology, and End Results database

Cardiovascular Substructure Dose and Cardiac Events following Proton- and Photon-Based Chemoradiotherapy for Non-Small Cell Lung Cancer

Purpose

Radiation therapy (RT) plays a critical role in treating locally advanced non-small cell lung cancer but has been associated with deleterious cardiac effects. We hypothesized that RT dose to certain cardiovascular substructures may be higher among those who experience post-chemoradiation (CRT) cardiac events, and that dose to specific substructures-the great vessels, atria, ventricles, and left anterior descending coronary artery-may be lower with proton- versus photon-based RT.

Methods and Materials

In this retrospective review, we selected 26 patients who experienced cardiac events after CRT for locally advanced non-small cell lung cancer and matched them to 26 patients who did not experience cardiac events after CRT. Matching was done based on RT technique (protons vs photons), age, sex, and cardiovascular comorbidity. For each patient, the whole heart and 10 cardiovascular substructures on the RT planning computerized tomography scan were manually contoured. Dosimetric comparisons were made between those who did and did not experience cardiac events and between the proton and photon groups.

Results

There was no significant difference in heart or any cardiovascular substructure dose between those patients who experienced post-treatment cardiac events and those who did not (P > .05 for all). The mean heart dose in the patients receiving proton therapy was significantly lower than the mean heart dose in the patients receiving photon therapy (P = .032). The left ventricle, right ventricle, and the left anterior descending artery also had significantly lower doses (by multiple measures) when treated with protons (P = .0004, P < .0001, and P = .0002, respectively).

Conclusions

Proton therapy may have a significant effect on decreasing dose to individual cardiovascular substructures compared with photon therapy. There was no significant difference in heart dose or dose to any cardiovascular substructure between patients who did and did not experience post-treatment cardiac events. Further research should be done to assess the association between cardiovascular substructure dose and post-treatment cardiac events.

Endothelial activation and fibrotic changes are impeded by laminar flow-induced CHK1-SENP2 activity through mechanisms distinct from endothelial-to-mesenchymal cell transition

Background

The deSUMOylase sentrin-specific isopeptidase 2 (SENP2) plays a crucial role in atheroprotection. However, the phosphorylation of SENP2 at T368 under disturbed flow (D-flow) conditions hinders its nuclear function and promotes endothelial cell (EC) activation. SUMOylation has been implicated in D-flow-induced endothelial-to-mesenchymal transition (endoMT), but the precise role of SENP2 in counteracting this process remains unclear.

Method

We developed a phospho-specific SENP2 S344 antibody and generated knock-in (KI) mice with a phospho-site mutation of SENP2 S344A using CRISPR/Cas9 technology. We then investigated the effects of SENP2 S344 phosphorylation under two distinct flow patterns and during hypercholesteremia (HC)-mediated EC activation.

Result

Our findings demonstrate that laminar flow (L-flow) induces phosphorylation of SENP2 at S344 through the activation of checkpoint kinase 1 (CHK1), leading to the inhibition of ERK5 and p53 SUMOylation and subsequent suppression of EC activation. We observed a significant increase in lipid-laden lesions in both the aortic arch (under D-flow) and descending aorta (under L-flow) of female hypercholesterolemic SENP2 S344A KI mice. In male hypercholesterolemic SENP2 S344A KI mice, larger lipid-laden lesions were only observed in the aortic arch area, suggesting a weaker HC-mediated atherogenesis in male mice compared to females. Ionizing radiation (IR) reduced CHK1 expression and SENP2 S344 phosphorylation, attenuating the pro-atherosclerotic effects observed in female SENP2 S344A KI mice after bone marrow transplantation (BMT), particularly in L-flow areas. The phospho-site mutation SENP2 S344A upregulates processes associated with EC activation, including inflammation, migration, and proliferation. Additionally, fibrotic changes and up-regulated expression of EC marker genes were observed. Apoptosis was augmented in ECs derived from the lungs of SENP2 S344A KI mice, primarily through the inhibition of ERK5-mediated expression of DNA damage-induced apoptosis suppressor (DDIAS).

Summary

In this study, we have revealed a novel mechanism underlying the suppressive effects of L-flow on EC inflammation, migration, proliferation, apoptosis, and fibrotic changes through promoting CHK1-induced SENP2 S344 phosphorylation. The phospho-site mutation SENP2 S344A responds to L-flow through a distinct mechanism, which involves the upregulation of both mesenchymal and EC marker genes.

Treatment Decisions for Resectable Non-Small-Cell Lung Cancer: Balancing Less With More?

For patients with non-small-cell lung cancer (NSCLC), the outcomes for patients with resectable disease are historically poor compared with other solid organ malignancies. In recent years, there have been significant advances in multidisciplinary care, which have resulted in improved outcomes. Innovations in surgical oncology include the use of limited resection and minimally invasive techniques. Recent data in radiation oncology have suggested refinements in pre- and postoperative radiation therapy, resulting in optimization of techniques in the curative setting. Finally, the success of immune checkpoint inhibitors and targeted therapies in the advanced setting has paved the way for inclusion in the adjuvant and neoadjuvant settings, resulting in recent regulatory approvals for four regimens (CheckMate-816, IMpower010, PEARLS, ADAURA). In this review, we will provide an overview of the seminal studies informing advancements in optimal surgical resection, radiation treatment, and systemic therapy for resectable NSCLC. We will summarize the key data on survival outcomes, biomarker analyses, and future directions for perioperative studies.

Association of cardiac calcium burden with overall survival after radiotherapy for non-small cell lung cancer

Background and purpose

Coronary calcifications are associated with coronary artery disease in patients undergoing radiotherapy (RT) for non-small cell lung cancer (NSCLC). We quantified calcifications in the coronary arteries and aorta and investigated their relationship with overall survival (OS) in patients treated with definitive RT (Def-RT) or post-operative RT (PORT).

Materials and methods

We analyzed 263 NSCLC patients treated from 2004 to 2017. Calcium burden was ascertained with a Hounsfield unit (HU) cutoff of > 130 in addition to a deep learning (DL) plaque estimator. The HU cutoff volumes were defined for coronary arteries (Plaque_Coro) and coronary arteries and aorta combined (Plaque_Coro+Ao), while the DL estimator ranged from 0 (no plaque) to 3 (high plaque). Patient and treatment characteristics were explored for association with OS.

Results

The median Plaque_Coro and Plaque_Coro+Ao was 0.75 cm³ and 0.87 cm³ in the Def-RT group and 0.03 cm³ and 0.52 cm³ in the PORT group. The median DL estimator was 2 in both cohorts. In Def-RT, large Plaque_Coro (HR:1.11 (95%CI:1.04-1.19); p = 0.008), and Plaque_Coro+Ao (HR:1.06 (95%CI:1.02-1.11); p = 0.03), and poor Karnofsky Performance Status (HR: 0.97 (95%CI: 0.94-0.99); p = 0.03) were associated with worse OS. No relationship was identified between the plaque volumes and OS in PORT, or between the DL plaque estimator and OS in either Def-RT or PORT.

Conclusions

Coronary artery calcification assessed from RT planning CT scans was significantly associated with OS in patients who underwent Def-RT for NSCLC. This HU thresholding method can be straightforwardly implemented such that the role of calcifications can be further explored.

The prognostic value of postoperative radiotherapy in right tumor for lung related death: based on SEER database and real-world data

Background

Postoperative radiotherapy (PORT) is a therapeutic strategy for patients with non-small cell lung cancer (NSCLC). Nevertheless, some studies suggesting PORT does not improve overall survival (OS) including Lung ART phase III trial. The role of PORT and high-risk groups need to be confirmed.

Methods

Patients from the Surveillance, Epidemiology, and End Results program (SEER) from 2004 to 2015 were eligible. Aged ≥18 years with stage IIIA-N2 NSCLC, accepted PORT or not were considered for the study. Cox regression analyses and multivariate competing risk model were performed. Propensity score matching (PSM) was conducted. Data from a single-center study in China were used for validation.

Results

In all patients with IIIA-N2 NSCLC, death from respiratory illness increased year by year, with right lung-related deaths accounting for the main proportion. In SEER database, PORT was detrimental for OS after PSM (hazard ratio [HR], 1.088; 95% CI, 1.088-1.174; P = 0.031), with a same trend for death from the lungs (HR, 1.13; 95% CI, 1.04-1.22; P = 0.005). Right tumor receiving PORT were prone to death from lung disease(HR, 1.14; 95% CI, 1.02-1.27; P = 0.018). In China single-center cohort, PORT was significantly correlated with deteriorated OS (HR 1.356; 95% CI 1.127-1.632; P <0.01), especially in the right laterality (HR 1.365; 95% CI 1.062-1.755; P = 0.015).

Conclusions

PORT was a risk factor for stage IIIA-N2 NSCLC patients, particularly with characters of right laterality, male sex, age ≥65 years, and advanced tumor stage. These patients are more likely to death from lung disease after PORT.

Update on Adjuvant Treatment in Resectable Non-Small Cell Lung Cancer and Potential Biomarkers Predicting Postoperative Relapse

A significant proportion of patients with non-small cell lung cancer (NSCLC) is diagnosed in the early and resectable stage. Despite the use of platinum-based adjuvant chemotherapy, there was only a marginal increase in overall survival and a 15% decrease in relapse. With the advents of immunotherapy and epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI), the landscape of adjuvant treatment in completely resectable NSCLC is changing. Postoperative radiotherapy can be beneficial to patients who underwent surgical resection in certain clinical settings. In addition, new biomarkers that predict efficacy of EGFR TKI and immunotherapy as adjuvant treatment are also necessary. In this review, recent updates in adjuvant treatment in resectable NSCLC were briefly explained.

Myocardial Contractility Pattern Characterization in Radiation-Induced Cardiotoxicity Using Magnetic Resonance Imaging: A Pilot Study with ContractiX

Radiation therapy (RT) plays an integral role in treating thoracic cancers, despite the risk of radiation-induced cardiotoxicity. We hypothesize that our newly developed magnetic resonance imaging (MRI)-based contractility index (ContractiX) is a sensitive marker for early detection of RT-induced cardiotoxicity in a preclinical rat model of thoracic cancer RT. Adult salt-sensitive rats received image-guided heart RT and were imaged with MRI at 8 weeks and 10 weeks post-RT or sham. The MRI exam included cine and tagging sequences to measure left-ventricular ejection fraction (LVEF), mass, myocardial strain, and ContractiX. Furthermore, ventricular torsion, diastolic strain rate, and mechanical dyssynchrony were measured. Statistical analyses were performed between the sham, 8 weeks post-RT, and 10 weeks post-RT MRI parameters. The results showed that both LVEF and myocardial mass increased post-RT. Peak systolic strain and ContractiX significantly decreased post-RT, with a more relative reduction in ContractiX compared to strain. ContractiX showed an inverse nonlinear relationship with LVEF and continuously decreased with time post-RT. While early diastolic strain rate and mechanical dyssynchrony significantly changed post-RT, ventricular torsion changes were not significant post-RT. In conclusion, ContractiX measured via non-contrast MRI is a sensitive early marker for the detection of subclinical cardiac dysfunction post-RT, and it is superior to other MRI cardiac measures.

The efficacy of postoperative radiotherapy for patients with non-small cell lung cancer: An updated systematic review and meta-analysis

The controversy over the efficacy of postoperative radiotherapy (PORT) has existed for a long time. The present study reassessed the overall survival (OS) and disease-free survival (DFS) data to investigate whether PORT can improve survival in resectable non-small cell lung cancer (NSCLC) patients. The following databases were used to perform literature search: PubMed, Web of Science, China National Knowledge Infrastructure (CNKI), and Embase (from January 1, 1986 to July 5, 2021). The results of overall survival (OS) and disease-free survival (DFS) were calculated as hazard ratio (HR). Confidence intervals are chosen with 95% confidence intervals. A total of 12 RCTs and 19 retrospective cohort studies were found to meet the inclusion criteria. A significant DFS improvement was detected in the PORT group (4111 patients from 15 studies), although statistical difference was not detected for OS between the non-PORT and PORT groups (31 studies, 49,342 total patients). PORT prolonged OS in patients undergoing PORT plus postoperative chemotherapy (POCT) and in pN2 patients. Patients with a median radiation dose of 50.4 Gy and a median radiation dose of 54 Gy had a better OS after PORT. However, if the total radiotherapy dose went up to 60 Gy, PORT increased the risk of death in NSCLC patients. Significant difference in OS was not found in the results of studies with regard to treatment methods, pathologic stages, study type, radiation beam quality, and radiation dose. Patients undergoing postoperative chemoradiotherapy and pN2 patients can benefit from PORT. Patients exposed to median radiation doses of 50.4 and 54 Gy demonstrated relatively good efficacy. For patients with non-small-cell lung cancer, PORT has not been proven to extend OS, but its effect on DFS remains strong.

Radiation therapy induces immunosenescence mediated by p90RSK

Radiation therapy (RT) to the chest increases the patients' risk of cardiovascular disease (CVD). A complete understanding of the mechanisms by which RT induces CVD could lead to specific preventive, therapeutic approaches. It is becoming evident that both genotoxic chemotherapy agents and radiation induce mitochondrial dysfunction and cellular senescence. Notably, one of the common phenotypes observed in cancer survivors is accelerated senescence, and immunosenescence is closely related to both cancer risk and CVD development. Therefore, suppression of immunosenescence can be an ideal target to prevent cancer treatment-induced CVD. However, the mechanism(s) by which cancer treatments induce immunosenescence are incompletely characterized. We isolated peripheral blood mononuclear cells (PBMCs) before and 3 months after RT from 16 thoracic cancer patients. We characterized human immune cell lineages and markers of senescence, DNA damage response (DDR), efferocytosis, and determinants of clonal hematopoiesis of indeterminant potential (CHIP), using mass cytometry (CyTOF). We found that the frequency of the B cell subtype was decreased after RT. Unsupervised clustering of the CyTOF data identified 138 functional subsets of PBMCs. Compared with baseline, RT increased TBX21 (T-bet) expression in the largest B cell subset of Ki67-/DNMT3a+naïve B cells, and T-bet expression was correlated with phosphorylation of p90RSK expression. CD38 expression was also increased in naïve B cells (CD27-) and CD8+ effector memory CD45RA T cells (TEMRA). In vitro, we found the critical role of p90RSK activation in upregulating (1) CD38+/T-bet+ memory and naïve B, and myeloid cells, (2) senescence-associated β-gal staining, and (3) mitochondrial reactive oxygen species (ROS) after ionizing radiation (IR). These data suggest the crucial role of p90RSK activation in immunosenescence. The critical role of p90RSK activation in immune cells and T-bet induction in upregulating atherosclerosis formation has been reported. Furthermore, T-bet directly binds to the CD38 promoter region and upregulates CD38 expression. Since both T-bet and CD38 play a significant role in the process of immunosenescence, our data provide a cellular and molecular mechanism that links RT-induced p90RSK activation and the immunosenescence with T-bet and CD38 induction observed in thoracic cancer patients treated by RT and suggests that targeting the p90RSK/T-bet/CD38 pathway could play a role in preventing the radiation-associated CVD and improving cancer prognosis by inhibiting immunosenescence.

Postoperative radiotherapy with modern techniques does not improve survival for operable stage IIIA-N2 non-small cell lung cancer

OBJECTIVES

This study aims to evaluate whether postoperative radiotherapy using newer techniques (intensity-modulated radiotherapy [IMRT]) is associated with improved survival for patients with stage IIIA-N2 non-small cell lung cancer (NSCLC) who underwent complete resection.

METHODS

The overall survival of patients with stage IIIA-N2 NSCLC who received postoperative IMRT versus no postoperative IMRT following induction chemotherapy and lobectomy in the National Cancer Database from 2010-2018 was assessed via Kaplan-Meier analysis, Cox proportional hazards analysis and propensity score-matched analysis. Additional survival analyses were also conducted in patients with completely resected stage IIIA-pN2 NSCLC who had upfront lobectomy (without induction therapy) followed by adjuvant chemotherapy alone or adjuvant chemotherapy with postoperative IMRT. Only patients receiving IMRT, which is a newer, more conformal radiotherapy technique, were included. Patients with positive surgical margins were excluded.

RESULTS

A total of 3203 patients with stage IIA-N2 NSCLC who underwent lobectomy were included. Five hundred eighty-eight (18.4%) patients underwent induction chemotherapy followed by lobectomy, and 2615 (82%) underwent lobectomy followed by chemotherapy. In unadjusted, multivariable-adjusted, and propensity score--matched analyses, there were no significant differences in overall survival between the patients who also received postoperative IMRT versus those who did not.

CONCLUSIONS

In this national analysis, the use of postoperative IMRT was not associated with improved survival in patients with completely resected stage IIIA-N2 NSCLC with or without induction chemotherapy.

Primary site as a novel prognostic factor for cardiovascular mortality post-radiotherapy in limited-stage small cell lung cancer: A large population-based study

Background

The effect of primary site on cardiovascular mortality (CVM) post-radiotherapy (RT) in patients with limited-stage small cell lung cancer (LS-SCLC) remains unclear.

Methods

We screened the Surveillance, Epidemiology, and End Results (SEER) database between 1988 and 2013. We used cumulative incidence function (CIF) curves to compare CVM incidences, and performed Cox proportional hazards and Fine-Gray competing risk analyses to identify independent risk factors of CVM. Propensity score matching (PSM) analysis was conducted.

Results

Among enrolled 4,824 patients (median age 57 years old, 49.2% were male), CVM accounts for 10.0% of all deaths after 5 years since cancer diagnosis. Hazard ratios (HRs) for CVM were 1.97 (95% CI: 1.23–3.16, P = 0.005) for main bronchus (MB) patients, 1.65 (95% CI: 1.04–2.63, P = 0.034) for lower lobe (LL) patients and 1.01 (95% CI: 0.40–2.59, P = 0.977) for middle lobe (ML) patients compared to upper lobe (UL) patients. CIF curves showed that the cumulative CVM incidence was greater in the re-categorized MB/LL group compared to UL/ML group both before PSM (P = 0.005) and after PSM (P = 0.012). Multivariate regression models indicated that MB/LL was independently associated with an increased CVM risk, before PSM (HR_Cox: 1.79, 95% CI: 1.23–2.61, P = 0.002; HR_Fine−Gray: 1.71, 95% CI: 1.18–2.48, P = 0.005) and after PSM (HR_Cox: 1.88, 95% CI: 1.20–2.95, P = 0.006; HR_Fine−Gray: 1.79, 95% CI: 1.15–2.79, P = 0.010).

Conclusions

MB/LL as the primary site is independently associated with an increased CVM risk post-RT in patients with LS-SCLC.

Role of Adjuvant Radiotherapy in Non-Small Cell Lung Cancer-A Review

Simple Summary

The role of postoperative radiotherapy (PORT) in completely resected non-small cell lung cancer (NSCLC) with ipsilateral mediastinal lymph node involvement (pN2) is controversial. The aim of our review was to study the literature relating to PORT for completely resected NSCLC patients with pN2 involvement. The Lung ART and PORT-C trials indicate better locoregional control with PORT, but this has not yet translated into survival benefits. Given the conflicting results, guidelines do not recommend the use of PORT routinely. Future research should focus on identifying subgroups of patients who might benefit from PORT.

Abstract

Background: For patients with completely resected non-small cell lung cancer (NSCLC) with ipsilateral mediastinal lymph node involvement (pN2), the administration of adjuvant chemotherapy is the standard of care. The role of postoperative radiation therapy (PORT) is controversial. Methods: We describe the current literature focusing on the role of PORT in completely resected NSCLC patients with pN2 involvement and reflect on its role in current guidelines. Results: Based on the results of the recent Lung ART and PORT-C trials, the authors conclude that PORT cannot be generally recommended for all resected pN2 NSCLC patients. A substantial decrease in the locoregional relapse rate without translating into a survival benefit suggests that some patients with risk factors might benefit from PORT. This must be balanced against the risk of cardiopulmonary toxicity with potentially associated mortality. Lung ART has already changed the decision making for the use of PORT in daily practice for many European lung cancer experts, with lower rates of recommendations for PORT overall. Conclusions: PORT is still used, albeit decreasingly, for completely resected NSCLC with pN2 involvement. High-level evidence for its routine use is lacking. Further analyses are required to identify patients who would potentially benefit from PORT.

Indications and Parameters Around Postoperative Radiation Therapy for Lung Cancer

Patients with locally advanced resected non-small-cell lung cancer present a high risk of relapse. Although adjuvant platinum-based chemotherapy has become the standard of care, the role of postoperative radiation therapy (PORT) has been controversial for years. In patients with incomplete resection, PORT should be proposed, on the basis of a strong consensus, despite the absence of randomized evidence. In patients with completely resected (R0) non-small-cell lung cancer, a meta-analysis showed poorer outcomes after PORT in the absence of mediastinal involvement (pN0 and pN1). In patients with pN2, the role of PORT was less clear and required further research. The meta-analysis included trials using older radiation techniques and poorer quality of surgery according to today's standards, and selection of patients was not positron emission tomography-based. Newer retrospective and nonrandomized studies and subgroup analyses of randomized trials evaluating adjuvant chemotherapy suggested a survival benefit of PORT in patients with pN2 R0. Two recent randomized trials (Lung ART and PORT-C) evaluating conformal PORT versus no PORT retrieved no disease-free survival advantage for stage IIIA-N2 patients, even if mediastinal relapse was significantly decreased with PORT. PORT had no effect on survival, possibly given the high rate of distant relapse and risk of additional cardiopulmonary toxicity. Ongoing and future analyses are planned in Lung ART to identify patients for whom PORT could be recommended. Incorporation of newer systemic treatments (immune checkpoint inhibitors or targeted therapy in oncogene-addicted patients) is underway in the neoadjuvant and/or adjuvant setting. Better identification of patients at a high risk of disease recurrence, with analysis of circulating tumor DNA, on the basis of the detection of postsurgical minimal (or molecular) residual disease is warranted in future studies.

Postoperative radiotherapy versus no postoperative radiotherapy in patients with completely resected non-small-cell lung cancer and proven mediastinal N2 involvement (Lung ART): an open-label, randomised, phase 3 trial

BACKGROUND

In patients with non-small-cell lung cancer (NSCLC), the use of postoperative radiotherapy (PORT) has been controversial since 1998, because of one meta-analysis showing a deleterious effect on survival in patients with pN0 and pN1, but with an unclear effect in patients with pN2 NSCLC. Because many changes have occurred in the management of patients with NSCLC, the role of three-dimensional (3D) conformal PORT warrants further investigation in patients with stage IIIAN2 NSCLC. The aim of this study was to establish whether PORT should be part of their standard treatment.

METHODS

Lung ART is an open-label, randomised, phase 3, superiority trial comparing mediastinal PORT to no PORT in patients with NSCLC with complete resection, nodal exploration, and cytologically or histologically proven N2 involvement. Previous neoadjuvant or adjuvant chemotherapy was allowed. Patients aged 18 years or older, with an WHO performance status of 0-2, were recruited from 64 hospitals and cancer centres in five countries (France, UK, Germany, Switzerland, and Belgium). Patients were randomly assigned (1:1) to either the PORT or no PORT (control) groups via a web randomisation system, and minimisation factors were the institution, administration of chemotherapy, number of mediastinal lymph node stations involved, histology, and use of pre-treatment PET scan. Patients received PORT at a dose of 54 Gy in 27 or 30 daily fractions, on five consecutive days a week. Three dimensional conformal radiotherapy was mandatory, and intensity-modulated radiotherapy was permitted in centres with expertise. The primary endpoint was disease-free survival, analysed by intention to treat at 3 years; patients from the PORT group who did not receive radiotherapy and patients from the control group with no follow-up were excluded from the safety analyses. This trial is now closed. This trial is registered with ClinicalTrials.gov number, NCT00410683.

FINDINGS

Between Aug 7, 2007, and July 17, 2018, 501 patients, predominantly staged with 18F-fluorodeoxyglucose (18F-FDG) PET (456 [91%]; 232 (92%) in the PORT group and 224 (90%) in the control group), were enrolled and randomly assigned to receive PORT (252 patients) or no PORT (249 patients). At the cutoff date of May 31, 2019, median follow-up was 4·8 years (IQR 2·9-7·0). 3-year disease-free survival was 47% (95% CI 40-54) with PORT versus 44% (37-51) without PORT, and the median disease-free survival was 30·5 months (95% CI 24-49) in the PORT group and 22·8 months (17-37) in the control group (hazard ratio 0·86; 95% CI 0·68-1·08; p=0·18). The most common grade 3-4 adverse events were pneumonitis (13 [5%] of 241 patients in the PORT group vs one [<1%] of 246 in the control group), lymphopenia (nine [4%] vs 0), and fatigue (six [3%] vs one [<1%]). Late-grade 3-4 cardiopulmonary toxicity was reported in 26 patients (11%) in the PORT group versus 12 (5%) in the control group. Two patients died from pneumonitis, partly related to radiotherapy and infection, and one patient died due to chemotherapy toxicity (sepsis) that was deemed to be treatment-related, all of whom were in the PORT group.

INTERPRETATION

Lung ART evaluated 3D conformal PORT after complete resection in patients who predominantly had been staged using (18F-FDG PET-CT and received neoadjuvant or adjuvant chemotherapy. 3-year disease-free survival was higher than expected in both groups, but PORT was not associated with an increased disease-free survival compared with no PORT. Conformal PORT cannot be recommended as the standard of care in patients with stage IIIAN2 NSCLC.

FUNDING

French National Cancer Institute, Programme Hospitalier de Recherche Clinique from the French Health Ministry, Gustave Roussy, Cancer Research UK, Swiss State Secretary for Education, Research, and Innovation, Swiss Cancer Research Foundation, Swiss Cancer League.

Lymph Node Parameters Predict Adjuvant Chemoradiotherapy Efficacy and Disease-Free Survival in Pathologic N2 Non-Small Cell Lung Cancer

Pathologic N2 non-small cell lung cancer (NSCLC) is prominently intrinsically heterogeneous. We aimed to identify homogeneous prognostic subgroups and evaluate the role of different adjuvant treatments. We retrospectively collected patients with resected pathologic T1-3N2M0 NSCLC from the Shanghai Chest Hospital as the primary cohort and randomly allocated them (3:1) to the training set and the validation set 1. We had patients from the Fudan University Shanghai Cancer Center as an external validation cohort (validation set 2) with the same inclusion and exclusion criteria. Variables significantly related to disease-free survival (DFS) were used to build an adaptive Elastic-Net Cox regression model. Nomogram was used to visualize the model. The discriminative and calibration abilities of the model were assessed by time-dependent area under the receiver operating characteristic curves (AUCs) and calibration curves. The primary cohort consisted of 1,312 patients. Tumor size, histology, grade, skip N2, involved N2 stations, lymph node ratio (LNR), and adjuvant treatment pattern were identified as significant variables associated with DFS and integrated into the adaptive Elastic-Net Cox regression model. A nomogram was developed to predict DFS. The model showed good discrimination (the median AUC in the validation set 1: 0.66, range 0.62 to 0.71; validation set 2: 0.66, range 0.61 to 0.73). We developed and validated a nomogram that contains multiple variables describing lymph node status (skip N2, involved N2 stations, and LNR) to predict the DFS of patients with resected pathologic N2 NSCLC. Through this model, we could identify a subtype of NSCLC with a more malignant clinical biological behavior and found that this subtype remained at high risk of disease recurrence after adjuvant chemoradiotherapy.

Preoperative and postoperative radiotherapy (RT) for non-small cell lung cancer: still an open question

Preoperative and postoperative radiotherapy (PORT) with or without chemotherapy has been used in non-small cell lung cancer (NSCLC) for decades. Numerous trials have investigated the potential survival benefit of this strategy, but despite greater knowledge of the disease, considerable technological developments in imaging and radiotherapy, and significant progress in surgery, many questions remain unsolved. In this review, we summarize the current knowledge on this problem and discuss issues which still require elucidation.

Risk of cardiac-related mortality in stage IIIA-N2 non-small cell lung cancer: Analysis of the Surveillance, Epidemiology, and End Results (SEER) database

Background

In this study, we aimed to investigate the association between postoperative radiotherapy (PORT) and cardiac‐related mortality in patients with stage IIIA‐N2 non‐small cell lung cancer (NSCLC) using the Surveillance, Epidemiology, and End Results (SEER) database.

Methods

The United States (US) population based on the SEER database was searched for cardiac‐related mortality among patients with stage IIIA‐N2 NSCLC. Cardiac‐related mortality was compared between the PORT and Non‐PORT groups. Accounting for mortality from other causes, Fine and Gray's test compared cumulative incidences of cardiac‐related mortality between both groups. Univariate and multivariate analysis were performed using the competing risk model.

Results

From 1988 to 2016, 7290 patients met the inclusion criteria: 3386 patients were treated with PORT and 3904 patients with Non‐PORT. The five‐year overall incidence of cardiac‐related mortality was 3.01% in the PORT group and 3.26% in the Non‐PORT group. Older age, male sex, squamous cell lung cancer, earlier year of diagnosis and earlier T stage were independent adverse factors for cardiac‐related mortality. However, PORT use was not associated with an increase in the hazard for cardiac‐related mortality (subdistribution hazard ratio [SHR] = 0.99, 95% confidence interval [CI]: 0.78–1.24, p = 0.91). When evaluating cardiac‐related mortality in each time period, the overall incidence of cardiac‐related mortality was decreased over time. There were no statistically significant differences based on PORT use in all time periods.

Conclusions

With a median follow‐up of 25 months, no significant differences were found in cardiac‐related mortality between the PORT and Non‐PORT groups in stage IIIA‐N2 NSCLC patients.

Patient prognostic scores and association with survival improvement offered by postoperative radiotherapy for resected IIIA/N2 non-small cell lung cancer: A population-based study

BACKGROUND

Currently, there is no consensus on the role of postoperative adjuvant radiotherapy (PORT) for resected stage IIIA/N2 non-small cell lung cancer (NSCLC). Our study sought to determine which patients may be able to benefit from PORT, based on a patient prognostic score.

METHODS

A retrospective cohort study was conducted to identify patients diagnosed with IIIA/N2 NSCLC between 1988 and 2016 in the SEER database. Eligible patients were divided into the following two groups: PORT group and non-PORT group. We classified patient prognostic scores as an ordinal factor and stratified patients based on prognostic scores. A Cox proportional hazards model with propensity score weighting was performed to evaluate cancer-specific mortality (CSM) between the two groups.

RESULTS

We identified 7060 eligible patients with IIIA/N2 NSCLC, 2833 (40.1%) in the PORT group and 4227 (59.9%) in the non-PORT group. Overall, the 10-year CSM rate in the weighted cohorts was 70.4% in the PORT group, 72.0% in the non-PORT group, and patients who received PORT had a lower CSM rate (p = 0.001). Compared with the non-PORT group, significant survival improvements in the PORT group were observed in patients with higher age, grade, T stage and lymph node ratio (LNR), and without chemotherapy. The improved survival of patients receiving PORT was significantly correlated with patient prognostic scores (p < 0.001).

CONCLUSIONS

In our population-based study, the prognostic score was associated with the survival improvement offered by PORT in IIIA/N2 NSCLC, suggesting that prognostic scores and clinicopathological characteristics may be helpful in proper candidate selection for PORT.

Single Institution Experience of Proton and Photon-based Postoperative Radiation Therapy for Non-small-cell Lung Cancer

INTRODUCTION

Postoperative radiation therapy (PORT) for non-small-cell lung cancer remains controversial with studies showing no overall survival (OS) benefit in the setting of excessive cardiopulmonary toxicity. Proton beam therapy (PBT) can potentially reduce toxicity with improved organ-at-risk sparing. We evaluated outcomes of PORT patients treated with PBT and intensity-modulated radiation therapy (IMRT).

MATERIALS AND METHODS

This is a retrospective review of 136 PORT patients (61 PBT, 75 IMRT) treated from 2003 to 2016. A Kaplan-Meier analysis was performed to assess oncologic outcomes. A Cox regression was conducted to identify associated factors. Total toxicity burden (TTB) was defined as grade ≥ 2 pneumonitis, cardiac, or esophageal toxicity.

RESULTS

Median OS was 76 and 46 months for PBT and IMRT with corresponding 1- and 5-year OS of 85.3%, 50.9% and 89.3%, 37.2% (P = .38), respectively. V30 Gy heart (odds ratio [OR], 144.9; 95% confidence interval [CI], 2.91-7214; P = .013) and V5 Gy lung (OR, 15.8; 95% CI, 1.22-202.7; P = .03) were predictive of OS. Organ-at-risk sparing was improved with PBT versus IMRT; mean heart 2.0 versus 7.4 Gy (P < .01), V30 Gy heart 2.6% versus 10.7% (P < .01), mean lung 7.9 versus 10.4 Gy (P = .042), V5 Gy lung 23.4% versus 42.1% (P < .01), and V10 Gy lung 20.4% versus 29.6% (P < .01). TTB was reduced with PBT (OR, 0.35; 95% CI, 0.15-0.83; P = .017). Rates of cardiac toxicity were 14.7% IMRT and 4.9% PBT (P = .09). Rates of ≥ grade 2 pneumonitis were 17.0% IMRT and 4.9% PBT (P = .104).

CONCLUSION

PBT improved cardiac and lung sparing and reduced toxicity compared with IMRT. Considering the impact of cardiopulmonary toxicity on PORT outcomes, PBT warrants prospective evaluation.

Dose-Dependent Radiation-Induced Myocardial Damage in Esophageal Cancer Treated With Chemoradiotherapy: A Prospective Cardiac Magnetic Resonance Imaging Study

Purpose

The purpose of this prospective study was to evaluate radiation-induced myocardial damage after mediastinal radiation therapy (RT) using late gadolinium-enhancement (LGE) magnetic resonance imaging (MRI).

Methods and Materials

We enrolled 19 patients with esophageal cancer who were expected to have long-term survival by definitive treatment. They underwent delayed contrast-enhanced MRI (19 patients before treatment, 19 patients 6 months after treatment, and 12 patients 1.5 years after treatment). Dose distribution of the left ventricle was made using computed tomography, and the dose volume histogram of the left ventricle was calculated. Myocardial signal intensities in individual MRIs were normalized by the mean values in regions receiving low doses (<5 Gy). Changes in the normalized signal intensities after mediastinal radiation therapy were compared among regions where irradiation doses were 0 to 10 Gy, 10 to 20 Gy, 20 to 30 Gy, 30 to 40 Gy, 40 to 50 Gy, and 50 to 60 Gy, and we investigated whether intensity change was detected in a dose-dependent manner.

Results

The registered patients were treated with concurrent chemoradiotherapy with a median total dose of 60 Gy (50.4-66 Gy). Chemotherapy consisting of cisplatin and 5-fluorouracil was administered. In the population-based dose-response curve, dose-dependent intensity changes progressively increased in regions receiving more than 30 Gy. The averages of relative intensity change at 6 months and 1.5 years after treatment were 1.1% and −1.9% at 20 to 30 Gy and 37.5% and 17.5% at 40 to 50 Gy, respectively. LGE in regions receiving more than 30 Gy was detected in 68% (13/19) of the patients.

Conclusions

A dose-dependent relationship for myocardial signal intensity change was found by using LGE MRI. It may be necessary to reduce the volume of the myocardium receiving more than 30 Gy.

Heart dose linked with cardiac events and overall survival in lung cancer radiotherapy: A meta-analysis

BACKGROUND

The aim of this study was to investigate the link between heart dose and overall survival, the link between heart dose and cardiac events and whether radiation-induced heart diseases were associated with overall survival in lung cancer radiotherapy.

METHODS

We performed a literature search by using Pubmed, Embase, China National Knowledge Infrastructure (CNKI) databases. Pairs of reviewers independently screened literature according to the inclusion criteria, extracted data, assessed methodological quality, and publication bias. The primary end points included overall survival and cardiac events. I was calculated in a heterogeneity assessment. Publication bias was evaluated by using Begg funnel plot and Egger test.

RESULTS

Ten studies including 1 randomized controlled trial, 3 post hoc analysis of prospective trials, and 6 cohort studies were identified. The meta-analysis showed that heart volume receiving ≥5 Gy (HV5) (hazard ratio [HR] = 1.01; 95% confidence interval [CI]: 1.00-1.01), heart volume receiving ≥30 Gy (HV30) (HR = 1.01; 95% CI: 1.00-1.02), heart volume receiving ≥50 Gy (HV50) (HR = 1.05; 95%CI: 1.00-1.10), and mean heart dose (MHD) (HR = 1.01; 95%CI:1.00-1.02) all were associated with worse overall survival. In addition, the MHD (HR = 1.03; 95% CI: 1.02-1.05), HV5 (HR = 1.02; 95% CI: 1.01-1.03), and HV30 (HR = 1.02; 95% CI: 1.01-1.03) were significantly associated with all grade cardiac events. Meanwhile, compared with those who did not receive radiotherapy, the radiotherapy group experienced a significantly increased risk for cardiac-specific mortality (HR = 1.297; 95% CI: 1.213-1.387). However, the results did not show that cardiac events were associated with overall survival in lung cancer radiotherapy (HR = 1.472; 95% CI: 0.988-2.193).

CONCLUSION

Exposure of the heart to radiation increased the risk of cardiac events during radiotherapy for lung cancer. Meanwhile, heart dose including HV5 and HV30 were predictors of overall survival in lung cancer radiotherapy. It is necessary to constrain the heart dose when perform thoracic radiation therapy to decrease the incidence of cardiac events and improve the overall survival.

Optimized cardiac functional MRI of small-animal models of cancer radiation therapy

Cardiac MRI of small animal models of cancer radiation therapy (RT) is a valuable tool for studying the effect of RT on the heart. However, standard cardiac MRI exams require long scanning times, which is challenging for sick animals that may not survive extended periods of imaging under anesthesia. The purpose of this study is to develop an optimized, fast MRI exam for comprehensive cardiac functional imaging of small-animal models of cancer RT. Ten adult female rats (2 non-irradiated and 8 irradiated) were scanned using the developed exam. Optimal imaging parameters were determined, which minimized scanning time while ensuring measurement accuracy and avoiding imaging artifacts. This optimized, fast MRI exam lasted for 30 min, which was tolerated by all animals. EF was normal in all imaged rats, although it was significantly increased in the irradiated rats, which also showed ventricular hypertrophy. However, myocardial strain was significantly reduced in the irradiated rats. In conclusion, a fast MRI exam has been developed for comprehensive cardiac functional imaging of rats in 30 min, with optimized imaging parameters to ensure accurate measurements and tolerance by irradiated rats. The generated strain measurements provide an early marker of regional cardiac dysfunction before global function is affected.

Quantification of Myocardial Dosimetry and Glucose Metabolism Using a 17-Segment Model of the Left Ventricle in Esophageal Cancer Patients Receiving Radiotherapy

Objective

Previous studies have shown that increased cardiac uptake of ¹⁸F-fluorodeoxyglucose (FDG) on positron emission tomography (PET) may be an indicator of myocardial injury after radiotherapy (RT). The primary objective of this study was to quantify cardiac subvolume dosimetry and ¹⁸F-FDG uptake on oncologic PET using a 17-segment model of the left ventricle (LV) and to identify dose limits related to changes in cardiac ¹⁸F-FDG uptake after RT.

Methods

Twenty-four esophageal cancer (EC) patients who underwent consecutive oncologic ¹⁸F-FDG PET/CT scans at baseline and post-RT were enrolled in this study. The radiation dose and the ¹⁸F-FDG uptake were quantitatively analyzed based on a 17-segment model. The ¹⁸F-FDG uptake and doses to the basal, middle and apical regions, and the changes in the ¹⁸F-FDG uptake for different dose ranges were analyzed.

Results

A heterogeneous dose distribution was observed, and the basal region received a higher median mean dose (18.36 Gy) than the middle and apical regions (5.30 and 2.21 Gy, respectively). Segments 1, 2, 3, and 4 received the highest doses, all of which were greater than 10 Gy. Three patterns were observed for the myocardial ¹⁸F-FDG uptake in relation to the radiation dose before and after RT: an increase (5 patients), a decrease (13 patients), and no change (6 patients). In a pairing analysis, the ¹⁸F-FDG uptake after RT decreased by 28.93 and 12.12% in the low-dose segments (0–10 Gy and 10–20 Gy, respectively) and increased by 7.24% in the high-dose segments (20–30 Gy).

Conclusion

The RT dose varies substantially within LV segments in patients receiving thoracic EC RT. Increased ¹⁸F-FDG uptake in the myocardium after RT was observed for doses above 20 Gy.

The Role of Postoperative Radiation Therapy for pN2 Non-small-cell Lung Cancer

BACKGROUND

The role for postoperative radiation therapy (PORT) for patients with non-small-cell lung cancer (NSCLC) with mediastinal lymph node (LN) involvement (pN2 disease) is controversial. We compared surgery alone with PORT among patients with pN2 NSCLC. We then performed subset analyses to better delineate patients that might benefit from PORT.

PATIENTS AND METHODS

We conducted a propensity score (PS)-matched, inverse probability of treatment weighting (IPTW) Surveillance, Epidemiology, and End Results (SEER) analysis of patients with pN2 disease from 1989 to 2016 with surgery alone or PORT. Multiple imputation with chained equations was used for missing LN data.

RESULTS

A total of 8631 patients were included in this analysis; 4579 underwent surgery alone, and 4052 underwent PORT. Following PS matching and IPTW, there was no difference in overall survival (OS) (hazard ratio [HR], 0.99; P = .76). However, PORT improved OS among a subset of patients with a LN positive to sampled ratio ≥ 50% (HR, 0.90; P = .01). Moreover, there was a trend towards improved OS among this subset, even with chemotherapy (HR, 0.91; P = .09).

CONCLUSION

PORT is not associated with an improvement or detriment in OS for all patients with pN2 NSCLC. However, patients with a positive to sampled LN ratio ≥ 50% may benefit, regardless of chemotherapy status. Nevertheless, PORT will remain the standard of care as we await the results of the ongoing LUNG ART trial.

Radiation Therapy for Thoracic Malignancies

Radiotherapy is the most commonly used nonsurgical modality in treatment of lung cancers, non-small cell lung cancer (NSCLC) in particular. Radiation therapy has been increasingly used as definitive radical treatment, either alone or in combination with concurrent chemoradiation for locally advanced disease. More recently with the advent of novel radiation techniques and modalities such as stereotactic radiotherapy and proton therapy, radiotherapy can now be used as sole radical treatment of small solitary tumors. This article reviews the current indications and future directions of radiotherapy in lung cancer management.

Cardiac toxicity of lung cancer radiotherapy

Radical radiotherapy of lung cancer with dose escalation has been associated with increased tumor control. However, these attempts to continually improve local control through dose escalation, have met mixed results culminating in the findings of the RTOG trial 0617, where the heart dose was associated with a worse overall survival, indicating a significant contribution to radiation-induced cardiac morbidity. It is, therefore, very likely that poorly understood cardiac toxicity may have offset any potential improvement in overall survival derived from dose escalation and may be an obstacle that limits disease control and survival of patients. The manifestations of cardiac toxicity are relatively common after high dose radiotherapy of advanced lung cancers and are independently associated with both heart dose and baseline cardiac risk. Toxicity following the treatment may occur earlier than previously thought and, therefore, heart doses should be minimized. In patients with lung cancer, who not only receive substantial heart dose, but are also older with more comorbidities, all cardiac events have the potential to be clinically significant and life-threatening. Sophisticated radiation treatment planning techniques, charged particle therapy, and modern imaging methods in radiotherapy planning, may lead to reduction of the heart dose, which could potentially improve the clinical outcomes in patients with lung cancer. Efforts should be made to minimize heart radiation exposure whenever possible even at doses lower than those generally recommended. Heart doses should be limited as much as possible. A heart dosimetry as a whole is important for patient outcomes, rather than emphasizing just one parameter.

Dose to the cardio-pulmonary system and treatment-induced electrocardiogram abnormalities in locally advanced non-small cell lung cancer

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ECG abnormalities after chemo-RT in LA-NSCLC are common (35%–67%).

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Non-specific ECG abnormalities are associated with a high superior vena cava dose.

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Reducing cardiopulmonary dose is likely to lead to less radiation-induced cardiac toxicity.

Introduction

High dose radiotherapy (RT) has been associated with unexpectedly short survival times for locally advanced Non-Small Cell Lung Cancer (LA-NSCLC) patients. Here we tested the hypothesis that cardiac substructure dose is associated with electrocardiography (ECG) assessed abnormalities after RT for LA-NSCLC.

Materials and methods

Pre- and post-RT ECGs were analyzed for 155 LA-NSCLC patients treated to a median of 64 Gy in 1.8–2.0 Gy fractions using intensity-modulated RT plus chemotherapy (concurrent/sequential: 64%/36%) between 2004 and 2014. ECG abnormalities were classified as new Arrhythmic, Ischemic/Pericardial, or Non-specific (A_ΔECG, I/P_ΔECG, or NS_ΔECG) events. Abnormalities were modeled as time to ECG events considering death a competing risk, and the variables considered for analysis were fractionation-corrected dose-volume metrics (α/β = 3 Gy) of ten cardio-pulmonary structures (aorta, heart, heart chambers, inferior and superior vena cava, lung, pulmonary artery) and 15 disease, patient and treatment characteristics. Each abnormality was modelled using bootstrapping and a candidate predictor was suggested by a median multiple testing-adjusted p-value ≤0.05 across the 1000 generated samples. Forward-stepwise multivariate analysis was conducted in case of more than one candidate.

Results

At a median of eight months post-RT, the rate of A_ΔECG, I/P_ΔECG, and NS_ΔECG was 66%, 35%, and 67%. Both A_ΔECG and I/P_ΔECG were associated with worse performance status (p = 0.007, 0.03), while a higher superior vena cava minimum dose was associated with NS_ΔECG (p = 0.002).

Conclusion

This study suggests that higher radiation doses to the cardio-pulmonary system lead to non-specific ECG abnormalities. Reducing dose to this system, along with effective tumor control, is likely to decrease radiation-induced cardiac toxicity.

Are heart doses associated with survival in patients with non-small cell lung cancer who received post-operative thoracic radiotherapy?: A national population-based study

The aim of this retrospective national cohort study is to assess the association between various radiation heart dosimetric parameters (RHDPs), acute myocardial infarct (AMI) and overall survival (OS) outcomes in non-small cell lung cancer (NSCLC) patients treated with post-operative thoracic radiotherapy (PORT) using contemporary radiation techniques.We identified patients with stage I to III NSCLC treated with PORT at the 2 national cancer institutions from 2007 to 2014. We linked their electronic medical records to the national AMI and death registries. Univariable Cox regression was performed to assess the association between various RHDPs, AMI, and OS.We included 43 eligible patients with median follow-up of 36.6 months. Median age was 64 years. Majority of the patients had pathological stage III disease (72%). Median prescription dose was 60Gy. Median mean heart dose (MHD) was 9.4Gy. There were no AMI events. The 5-year OS was 34%. Univariable Cox regression showed that age was significantly associated with OS (hazard ratio, 1.06; 95% confidence interval, 1.01 to 1.10; P = .008). Radiation heart doses, including MHD, volume of heart receiving at least 5, 25, 30, 40, 50Gy and dose to 30% of heart volume, were not significantly associated with OS.There is insufficient evidence to conclude that RHDPs are associated with OS for patients with NSCLC treated with PORT in this study. Studies with larger sample size and longer term follow-up are needed to assess AMI outcome.

Is the Importance of Heart Dose Overstated in the Treatment of Non-Small Cell Lung Cancer? A Systematic Review of the Literature

PURPOSE

Some recent studies have suggested a relationship between cardiac dose and mortality in non-small cell lung cancer (NSCLC), but others have reported conflicting data. The goal of this study was to conduct a systematic review and meta-analysis to provide an evidence-based estimate of the relationship between cardiac dose and mortality in these patients.

METHODS AND MATERIALS

A systematic review of MEDLINE (PubMed) and Embase databases (inception to January 2018) was performed according to PRISMA guidelines. Studies that evaluated cardiac dosimetric factors in patients with NSCLC and included outcomes of cardiac events, cardiac mortality, and/or overall survival were identified.

RESULTS

From 5614 patients across 22 studies, a total of 214 cardiac dosimetric parameters (94 unique) were assessed as possible predictors of cardiac toxicity or death. Assessed predictors included general (eg, mean heart dose [MHD]), threshold-based (eg, heart V5), and anatomic-based (eg, atria, ventricles) dosimetric factors. The most commonly analyzed parameters were MHD, heart V5, and V30. Most studies did not make corrections for multiplicity of testing. For overall survival, V5 was found to be significant on multivariable analysis (MVA) in 1 of 11 studies and V30 in 2 of 12 studies; MHD was not significant in any of 8 studies. For cardiac events, V5 was found to be significant on multivariable analysis in 1 of 2 studies, V30 in 1 of 3 studies, and MHD in 2 of 4 studies. A meta-analysis of the data could not be performed because most negative studies did not report effect estimates.

CONCLUSIONS

Consistent heart dose-volume parameters associated with overall survival of patients with NSCLC were not identified. Multiplicity of testing is a major issue and likely inflates the overall risk of type I errors in the literature. Future studies should specify predictors a priori, correct for multiplicity of testing, and report effect estimates for nonsignificant variables.

Prognostic and Added Value of Echocardiographic Strain for Prediction of Adverse Outcomes in Patients with Locally Advanced Non-Small Cell Lung Cancer after Radiotherapy

Radiotherapy (RT) is potentially related to cardiotoxicity, which may partially offset the benefits of cancer treatment. We sought to evaluate subclinical myocardial dysfunction using speckle tracking echocardiography after RT and to explore the associations between early cardiac effects and adverse outcomes in patients with non-small cell lung cancer (NSCLC). In total, 112 patients with stage III NSCLC who were scheduled to receive RT were prospectively recruited. A reduction in global longitudinal strain (GLS) was observed immediately after RT and at 6 mo after RT (6 m-RT). In multivariable analysis, the percentage change in GLS from baseline to 6 mo (ΔGLS%_{6 m-RT}) (hazard ratio = 1.202, 95% confidence interval: 1.095-1.320, p < 0.001) was an independent predictor of all-cause mortality. Based on receiver operating characteristic curve analysis, ΔGLS%_{6 m-RT} ≥13.65% had 65.9% sensitivity and 85.2% specificity for predicting mortality in NSCLC patients (area under the curve = 0.784, 95% confidence interval: 0.692-0.876, p < 0.001). These findings should encourage physicians to perform echocardiography early after RT.

Dosimetric Predictors of Symptomatic Cardiac Events After Conventional-Dose Chemoradiation Therapy for Inoperable NSCLC

INTRODUCTION

We hypothesized that higher cardiac doses correlates with clinically significant cardiotoxicity after standard-dose chemoradiation therapy (CRT) (∼60 Gy) for inoperable NSCLC.

METHODS

We retrospectively reviewed the records of 140 patients with inoperable NSCLC treated with concurrent CRT from 2007 to 2015. Extracted data included baseline cardiac status, dosimetric parameters to the whole heart (WH) and cardiac substructures, and the development of post-CRT symptomatic cardiac events (acute coronary syndrome [ACS], arrhythmia, pericardial effusion, pericarditis, and congestive heart failure [CHF]). Competing risks analysis was used to estimate time to cardiac events.

RESULTS

Median follow-up was 47.4 months. Median radiation therapy dose was 61.2 Gy (interquartile range, 60 to 66 Gy). Forty patients (28.6%) developed 47 symptomatic cardiac events at a median of 15.3 months to first event. On multivariate analysis, higher WH doses and baseline cardiac status were associated with an increased risk of symptomatic cardiac events. The 4-year cumulative incidence of symptomatic cardiac events was 48.6% versus 18.5% for mean WH dose ≥ 20 Gy versus < 20 Gy, respectively (p = 0.0002). Doses to the WH, ventricles, and left anterior descending artery were associated with ACS/CHF, whereas doses to the WH and atria were not associated with supraventricular arrhythmias. Symptomatic cardiac events (p = 0.0001) were independently associated with death.

CONCLUSIONS

Incidental cardiac irradiation was associated with subsequent symptomatic cardiac events, particularly ACS/CHF, and symptomatic cardiac events were associated with inferior survival. These results support the minimization of cardiac doses among patients with inoperable NSCLC receiving standard-dose CRT.

Cardiac mortality in limited-stage small cell lung cancer

INTRODUCTION

Life expectancy of patients with limited-stage small cell lung cancer (LS-SCLC) continues to rise; thus, characterization of long-term toxicities is essential. Although there are emerging data linking cardiac irradiation doses with survival for non-small cell lung cancer, there are currently minimal data on cardiac-specific mortality (CSM) in LS-SCLC. The goal of this investigation was to evaluate CSM between left- and right-sided cases.

METHODS

The Surveillance, Epidemiology, and End Results database was queried for stage I-III primary SCLC patients receiving radiotherapy; CSM was compared between left- and right-sided diseases. Accounting for mortality from other causes, Gray's test compared cumulative incidences of CSM between both groups. Multiple multivariate models examined the independent effect of laterality on CSM, including the Fine and Gray competing risk model and the Cox proportional hazards model.

RESULTS

Of 19,692 patients, 7991 (41%) were left-sided and 11,701 (59%) were right-sided. Left-sided patients experienced significantly higher CSM overall (3.3% vs. 2.6%, p = 0.004). Laterality was an independent predictor of CSM in the overall population in the Fine and Gray competing risk model (p = 0.006) as well as the Cox proportional hazards model (p = 0.007). The overall hazard ratio for CSM by disease laterality was 1.27 (95% confidence interval, 1.08-1.50). Laterality had no statistical association with non-cardiac mortality in the Fine and Gray competing risk model (p = 0.130).

CONCLUSIONS

Although causation between radiotherapy and CSM in LS-SCLC cannot be stated based on these data, we encourage clinical attentiveness to cardiac-sparing radiotherapy for LS-SCLC, along with further investigation evaluating dosimetric correlates for cardiotoxicity.

Lung dose and the potential risk of death in postoperative radiation therapy for non-small cell lung cancer: A study using the method of stratified grouping

PURPOSE

Postoperative radiation therapy may have a detrimental effect on survival in patients with non-small cell lung cancer. We investigated the association of the lung radiation dose with the risk of death in patients treated with postoperative radiation therapy.

METHODS

We analyzed 178 patients with non-small cell lung cancer who received postoperative radiation therapy. The mean lung dose was calculated from dose-volume data, and we categorized patients into the high and low lung dose groups using 2 different methods; (1) simple grouping using the median lung dose of all patients, and (2) stratified grouping using the median lung dose of each subgroup sharing the same confounders. We compared clinical variables, and survival between the high and low lung dose groups.

RESULTS

In the simple grouping, there were no significant differences in survivals between the high and low lung dose groups. After stratification, the overall survival of low lung dose group was significantly longer than that of high lung dose group (5-year survival, 60.1% vs. 35.3%, p = 0.039). On multivariable analyses, the lung dose remained a significant prognostic factor for overall survival (hazard ratio, HR = 2.08, p = 0.019).

CONCLUSIONS

The lung dose was associated with the risk of death in patients with non-small cell lung cancer having the same confounders. Further studies evaluating the risk of death according to the lung dose will be helpful to administer more precise and individualized postoperative radiation therapy.

Proton therapy for post-operative radiation therapy of non-small cell lung cancer

Post-operative radiation therapy (PORT) is typically recommended for patients with locally advanced non-small cell lung cancer (NSCLC) with N2 mediastinal nodal involvement after surgical resection. The routine use of PORT, however, is controversial as older data demonstrated a detriment in overall survival in patients who received PORT. This detriment was thought to be due to older, more toxic radiation techniques. More recent data with modern radiation techniques demonstrates a local-regional and overall survival benefit with PORT in patients with N2 nodal involvement. Due to the competing risks of local-regional recurrence and cardiopulmonary toxicity in patients who are candidates for PORT, methods to widen the therapeutic window are needed. The physical characteristics of proton beam therapy allow for less radiation dose to the heart and lungs. Therefore, proton beam therapy has great potential in patients undergoing PORT. Initial dosimetric and clinical data have been published and are encouraging, but prospective data is needed to further understand the true benefit of proton therapy in patients undergoing PORT.

Trends in Cardiac Mortality in Patients With Locally Advanced Non-Small Cell Lung Cancer

PURPOSE

To use the Surveillance, Epidemiology, and End Results (SEER) database to compare cardiac-specific mortality (CSM) between left- and right-sided locally advanced non-small cell lung cancer (LA-NSCLC) patients treated with definitive radiation therapy; and to stratify these patients over fixed time intervals to assess for differences in events by treatment era.

METHODS AND MATERIALS

The SEER database was queried for patients with stage III NSCLC who received radiation therapy to compare CSM between left- and right-sided primary cases at 5 time intervals: 1988-1992, 1993-1997, 1998-2002, 2003-2007, and 2008-2012. Cumulative incidence of CSM was compared between left- and right-sided patients using Gray's test. The multivariate Fine and Gray competing risk model was used to compare CSM while accounting for other-cause mortality.

RESULTS

Of 884,610 lung cancer patients, 52,624 met inclusion criteria; of these, 31,549 (60%) were right-sided and 21,075 (40%) were left-sided. When evaluating CSM in each of the 5 time periods, the overall incidence of CSM decreased over time. There was a statistically significant (P<.05) difference based on laterality in all time periods except 1988-1992 (P=.14). The subdistribution hazard ratio for CSM based on disease laterality in all time periods was 1.30 (95% confidence interval 1.18-1.42) and did not discernibly differ by time interval. On multivariate analysis using the Fine and Gray competing risk model, left-sided laterality independently predicted for CSS from 1993 to 2007 (P<.05).

CONCLUSIONS

Cardiac-specific mortality has decreased over time, and left-sided disease independently predicted for CSS during 1993-2007 but not 2008-2012. The time course of cardiac mortality seems to be early, consistent with other studies. These findings underscore the importance of minimizing cardiac irradiation during radiation treatment planning.

Heart dosimetric analysis of three types of cardiac toxicity in patients treated on dose-escalation trials for Stage III non-small-cell lung cancer

BACKGROUND AND PURPOSE

To assess associations between radiation dose/volume parameters for cardiac subvolumes and different types of cardiac events in patients treated on radiation dose-escalation trials.

MATERIAL AND METHODS

Patients with Stage III non-small-cell lung cancer received dose-escalated radiation (median 74 Gy) using 3D-conformal radiotherapy on six prospective trials from 1996 to 2009. Volumes analyzed included whole heart, left ventricle (LV), right atrium (RA), and left atrium (LA). Cardiac events were divided into three categories: pericardial (symptomatic effusion and pericarditis), ischemia (myocardial infarction and unstable angina), and arrhythmia. Univariable competing risks analysis was used.

RESULTS

112 patients were analyzed, with median follow-up 8.8 years for surviving patients. Nine patients had pericardial, seven patients had ischemic, and 12 patients had arrhythmic events. Pericardial events were correlated with whole heart, RA, and LA dose (eg, heart-V30 [p=0.024], RA-V30 [p=0.013], and LA-V30 [p=0.001]), but not LV dose. Ischemic events were correlated with LV and whole heart dose (eg, LV-V30 [p=0.012], heart-V30 [p=0.048]). Arrhythmic events showed borderline significant associations with RA, LA, and whole heart dose (eg, RA-V30 [p=0.082], LA-V30 [p=0.076], heart-V30 [p=0.051]). Cardiac events were associated with decreased survival on univariable analysis (p=0.008, HR 2.09), but only disease progression predicted for decreased survival on multivariable analysis.

CONCLUSIONS

Cardiac events were heterogeneous and associated with distinct heart subvolume doses. These data support the hypothesis of distinct etiologies for different types of radiation-associated cardiotoxicity.

Acute and Late Toxicities of Concurrent Chemoradiotherapy for Locally-Advanced Non-Small Cell Lung Cancer

For patients with unresectable locally-advanced non-small cell lung cancer (LA-NSCLC), concurrent chemoradiotherapy improves overall survival as compared to sequential chemotherapy and radiation therapy, but is associated with higher rates of toxicities. Acute, clinically significant esophagitis or pneumonitis can occur in one in five patients. The risks of esophagitis and pneumonitis can impact the decision to deliver concurrent therapy and limit the total dose of radiation therapy that is delivered. Hematologic toxicities and emesis are common toxicities from systemic therapies for LA-NSCLC and can result in delaying chemotherapy dosing or chemotherapy dose reductions. Late treatment morbidities, including pulmonary fibrosis and cardiac toxicities, can also significantly impact quality of life and potentially even survival. Recent advances in radiation therapy treatment delivery, better knowledge of normal tissue radiotherapy tolerances and more widespread and improved uses of supportive care and medical management of systemic therapy toxicities have improved the therapeutic ratio and reduced the rates of chemoradiotherapy-induced toxicities. This review details the acute and late toxicities associated with definitive chemoradiotherapy for LA-NSCLC and discusses toxicity management and strategies to mitigate the risks of treatment-related toxicities.

The Impact of Cardiac Radiation Dosimetry on Survival After Radiation Therapy for Non-Small Cell Lung Cancer

PURPOSE

The heart receives high radiation doses during radiation therapy of advanced-stage lung cancer. We have explored associations between overall survival, cardiac radiation doses, and electrocardiographic (ECG) changes in patients treated in IDEAL-CRT, a trial of isotoxically escalated concurrent chemoradiation delivering tumor doses of 63 to 73 Gy.

METHODS AND MATERIALS

Dosimetric and survival data were analyzed for 78 patients. The whole heart, pericardium, AV node, and walls of left and right atria (LA/RA-Wall) and ventricles (LV/RV-Wall) were outlined on radiation therapy planning scans, and differential dose-volume histograms (dDVHs) were calculated. For each structure, dDVHs were approximated using the average dDVH and the 10 highest-ranked structure-specific principal components (PCs). ECGs at baseline and 6 months after radiation therapy were analyzed for 53 patients, dichotomizing patients according to presence or absence of "any ECG change" (conduction or ischemic/pericarditis-like change). All-cause death rate (DR) was analyzed from the start of treatment using Cox regression.

RESULTS

38% of patients had ECG changes at 6 months. On univariable analysis, higher scores for LA-Wall-PC6, Heart-PC6, "any ECG change," and larger planning target volume (PTV) were significantly associated with higher DR (P=.003, .009, .029, and .037, respectively). Heart-PC6 and LA-Wall-PC6 represent larger volumes of whole heart and left atrial wall receiving 63 to 69 Gy. Cardiac doses ≥63 Gy were concentrated in the LA-Wall, and consequently Heart-PC6 was highly correlated with LA-Wall-PC6. "Any ECG change," LA-Wall-PC6 scores, and PTV size were retained in the multivariable model.

CONCLUSIONS

We found associations between higher DR and conduction or ischemic/pericarditis-like changes on ECG at 6 months, and between higher DR and higher Heart-PC6 or LA-Wall-PC6 scores, which are closely related to heart or left atrial wall volumes receiving 63 to 69 Gy in this small cohort of patients.

[Current knowledge on perioperative treatments of non-small cell lung carcinomas]

Surgery is still the main treatment in early-stage of non-small cell lung cancer with 5-year survival of stage IA patients exceeding 80%, but 5-year survival of stage II patients rapidly decreasing with tumor size, N status, and visceral pleura invasion. The major metastatic risk in such patients has supported clinical research assessing systemic or loco-regional perioperative treatments. Modern phase 3 trials clearly validated adjuvant or neo-adjuvant platinum-based chemotherapy in resected stage I-III patients as a standard treatment of which value has been reassessed several independent meta-analyses, showing a 5% benefit in 5y-survival, and a decrease of the relative risk for death around from 12 to 25%. Conversely perioperative treatments were not validated for stage IA and IB patients. In more advanced stage patients, neo-adjuvant radio-chemotherapy has not been validated either. Adjuvant radiotherapy for N2 patients is currently tested in the large international phase 3 trial Lung-ART/IFCT-0503. The development of video-assisted thoracic surgery (VATS) has helped adjuvant chemotherapies for elderly patients. Perioperative targeted treatments in NSCLC with EGFR or ALK molecular alterations is currently assessed in the U.S. ALCHEMIST prospective trial. Finally, the role of immune check-points inhibitors is currently evaluated in a large international phase 3 trial testing adjuvant anti-PD-L1 monoclonal antibody, the BR31/IFCT-1401 trial, while a proof-of principle neo-adjuvant trial IONESCO/IFCT-1601, has just begun by the end of the 2016 year, with survival results of both trials expected in 5 to 7 years.

Quantitatively Excessive Normal Tissue Toxicity and Poor Target Coverage in Postoperative Lung Cancer Radiotherapy Meta-analysis

BACKGROUND

A previous meta-analysis (MA) found postoperative radiotherapy (PORT) in lung cancer patients to be detrimental in N0/N1 patients and equivocal in the N2 setting. We hypothesized that treatment plans generated using MA protocols had worse dosimetric outcomes compared to modern plans.

PATIENTS AND METHODS

We retrieved plans for 13 patients who received PORT with modern planning. A plan was recreated for each patient using the 8 protocols included in MA. Dosimetric values were then compared between the modern and simulated MA plans.

RESULTS

A total of 104 MA plans were generated. Median prescribed dose was 50.4 (range, 50-60) Gy in the modern plans and 53.2 (30-60) Gy in the MA protocols. Median planning volume coverage was 96% (93%-100%) in the modern plans, versus 58% (0%-100%) in the MA plans (P < .001). Internal target volume coverage was 100% (99%-100%) versus 65% (0%-100%), respectively (P < .001). Organs at risk received the following doses: spinal cord maximum dose, 36.8 (4.6-50.4) Gy versus 46.8 (2.9-74.0) Gy (P < .001); esophageal mean dose, 22.9 (5.5-35) Gy versus 30.5 (11.1-52.5) Gy (P = .003); heart V30 (percentage of volume of an organ receiving at least a dose of 30 Gy), 16% (0%-45%) versus 35% (0%-79%) (P = .047); mean lung dose, 12.4 (3.4-24.3) Gy versus 14.8 (4.1-27.4) Gy (P = .008); and lung V20, 18% (4%-34%) versus 25% (8%-67%) (P = .023).

CONCLUSION

We quantitatively confirm the inferiority of the techniques used in the PORT MA. Our analysis showed a lower therapeutic ratio in the MA plans, which may explain the poor outcomes in the MA. The findings of the MA are not relevant in the era of modern treatment planning.

Causes of death in long-term lung cancer survivors: a SEER database analysis

BACKGROUND

Long-term (>5 years) lung cancer survivors represent a small but distinct subgroup of lung cancer patients and information about the causes of death of this subgroup is scarce.

METHODS

The Surveillance, Epidemiology and End Results (SEER) database (1988-2008) was utilized to determine the causes of death of long-term survivors of lung cancer. Survival analysis was conducted using Kaplan-Meier analysis and multivariate analysis was conducted using a Cox proportional hazard model. Clinicopathological characteristics and survival outcomes were assessed for the whole cohort.

RESULTS

A total of 78,701 lung cancer patients with >5 years survival were identified. This cohort included 54,488 patients surviving 5-10 years and 24,213 patients surviving >10 years. Among patients surviving 5-10 years, 21.8% were dead because of primary lung cancer, 10.2% were dead because of other cancers, 6.8% were dead because of cardiac disease and 5.3% were dead because of non-malignant pulmonary disease. Among patients surviving >10 years, 12% were dead because of primary lung cancer, 6% were dead because of other cancers, 6.9% were dead because of cardiac disease and 5.6% were dead because of non-malignant pulmonary disease. On multivariate analysis, factors associated with longer cardiac-disease-specific survival in multivariate analysis include younger age at diagnosis (p < .0001), white race (vs. African American race) (p = .005), female gender (p < .0001), right-sided disease (p = .003), adenocarcinoma (vs. large cell or small cell carcinoma), histology and receiving local treatment by surgery rather than radiotherapy (p < .0001).

CONCLUSION

The probability of death from primary lung cancer is still significant among other causes of death even 20 years after diagnosis of lung cancer. Moreover, cardiac as well as non-malignant pulmonary causes contribute a considerable proportion of deaths in long-term lung cancer survivors.

Efficacy of postoperative radiotherapy in patients with pathological stage N2 epidermal growth factor receptor wild type adenocarcinoma and squamous cell carcinoma lung cancer

PURPOSE

Few large, prospective, randomized studies have compared the effects of postoperative radiotherapy (PORT) in pathological N2 (pN2) with those of surgical resection alone. in terms of long-term survival in lung adenocarcinoma (adenoCA; wild-type [WT] epidermal growth factor receptor [EGFR]) and squamous cell carcinoma (squCA) settings. This nationwide cohort study clarifies the role of PORT in the survival of pN2 lung adenoCA (WT EGFR) and squCA patientsPatients and Methods: We analyzed data of patients with adenoCA (WT EGFR) and squCA collected from the Taiwan Cancer Registry database. The patients were categorized into five groups according to the treatment modality: Group 1 (surgery alone), Group 2 (adjuvant chemotherapy [CT] alone), Group 3 (adjuvant radiotherapy [RT] alone), Group 4 (adjuvant concurrent chemoradiotherapy [CCRT]), and Group 5 (adjuvant sequential CT and intensity-modulated RT [IMRT]).

RESULTS

We enrolled 588 lung adenoCA (WT EGFR) and squCA patients without distant metastasis. After adjustments for age at surgery, surgical years, and Charlson comorbidity index scores, the multivariate Cox regression analysis demonstrated that adjusted HRs (aHRs; 95% confidence intervals [CIs]) for the overall mortality of female lung adenoCA (WT EGFR) patients were 0.257 (0.111-0.594), 0.530 (0.226-1.243), 0.192 (0.069-0.534), and 0.399 (0.172-0.928) in Groups 2, 3, 4, and 5, respectively. For male lung squCA patients, the aHRs (95% CIs) for overall mortality were 0.269 (0.160-0.451), 0.802 (0.458-1.327), 0.597 (0.358-0.998), and 0.456 (0.265-0.783) in Groups 2, 3, 4, and 5, respectively.

CONCLUSIONS

Adjuvant CCRT or sequential CT and IMRT at ≥5000 cGy significantly reduced the mortality rate of female lung adenoCA (WT EGFR) and male squCA pN2 patients.

Survival impact of postoperative therapy modalities according to margin status in non-small cell lung cancer patients in the United States

OBJECTIVE

Unlike complete (R0) resection guidelines, current National Comprehensive Cancer Network (NCCN) adjuvant therapy guidelines after incomplete (R1/R2) resection of non-small cell lung cancer (NSCLC) are based on low-level evidence. We attempted to validate them.

METHODS

Patients with pathologic stage I-IIIA NSCLC from 2004 to 2011 in the National Cancer Database were stratified by margin status, NCCN-specified stage groupings, and adjuvant therapy exposure (none, radiotherapy, chemotherapy, or both). Five-year overall survival (OS) and hazard ratios, adjusted for patient and institutional characteristics, were compared. We used a parallel analysis of R0 resections to validate our methodology.

RESULTS

We analyzed 3461 R1/R2, and 78,979 R0 resections. After R0 resection, the NCCN-recommended option was associated with the best survival across all stage groups, supporting our analytic approach. Patients with R1/R2 stage IA treated with radiation had a 26% OS, compared with 58% with no treatment (P = .003). In patients with stage IB/IIA(N0) R1/R2, radiation was associated with a 25% OS compared with 47% with no treatment (P = .025) and 62% with chemotherapy (P < .007). Chemoradiation was not associated with a survival benefit in either group. Patients with IIA(N1)/IIB and IIIA had better survival with chemotherapy or chemoradiation. No group had a survival benefit with radiation alone.

CONCLUSIONS

NCCN adjuvant therapy guidelines after complete resection, based on high-level evidence, are validated, but not guidelines for patients with incompletely resected early-stage NSCLC, which are based on low-level evidence. Monomodality postoperative radiotherapy was not validated for any stage. Specific studies are needed to determine optimal management after incomplete resection.

Is pulmonary artery a dose-limiting organ at risk in non-small cell lung cancer patients treated with definitive radiotherapy?

PURPOSE

Our previous study suggested that some pulmonary artery (PA) dosimetric parameters were associated with mortality in unresectable non-small cell lung cancer (NSCLC) treated with definitive radiotherapy. The present study aims to analyze the impact of both PA and heart dosimetric parameters on survival of patients with NSCLC treated with definitive conventional fractionated radiotherapy (CFRT) in another independent research center and further determine whether the PA should be considered a dose-limiting organ at risk (OAR) for patients receiving thoracic CFRT.

METHODS

We performed a retrospective analysis of successive patients with medically inoperable or unresectable NSCLC treated with definitive radiotherapy or chemoradiotherapy from August 2010 to September 2014. Clinical and pathological information, PA and heart dosimetric factors, and follow-up data were collected from each patient's records and evaluated as potential prognostic factors for survival. Survival probabilities were estimated by the Kaplan-Meier method and compared by the log rank test. Cox proportional hazards regression models were performed to determine the independent predicators of survival. The optimal cutoff points of continuous dosimetric variables were determined by Youden index in receiver operating characteristic (ROC) analysis.

RESULTS

This study analyzed the records of 141 patients, 50.4% had adenocarcinoma, 71.6% had stage III disease, and 55% patients received concurrent chemoradiotherapy. Radiation dose ranged from 60 to 76 Gy in 30-38 fractions. Median follow up was 16.9 months. Median overall survival (OS) was 20.5 months (95% confidence interval [CI] 10.3-30.7 months), and 1-, 2-, 3-year OS rates were 75.2%, 58.2% and 56%, respectively. Univariate and multivariate analysis showed that Karnofsky Performance Status (KPS) score, Charlson's Comorbidity Index (CCI), T and N stage, PA invasion grade and the percentage of PA volume that received 40 to 55 Gy (PA V40-55) were significantly associated with OS. No significant associations were found between heart dosimetric factors and OS. Median OS of patients with PA invasion grade 0, 1, 2, and 3 were 41.8, 27.8, 12.7 and 7.5 months, respectively (P < 0.001). PA V40, V45, V50 and V55, using thresholds of 80%, 68%, 45%, and 32%, respectively, were independent predictors for OS.

CONCLUSIONS

PA invasion grade and PA V40-55 appear associated with OS in patients with NSCLC treated with definitive CFRT. We propose that PA be considered as a dose-limiting OAR for such patients.

Cardiac Toxicity After Radiotherapy for Stage III Non-Small-Cell Lung Cancer: Pooled Analysis of Dose-Escalation Trials Delivering 70 to 90 Gy

Purpose The significance of radiotherapy (RT) -associated cardiac injury for stage III non-small-cell lung cancer (NSCLC) is unclear, but higher heart doses were associated with worse overall survival in the Radiation Therapy Oncology Group (RTOG) 0617 study. We assessed the impact of heart dose in patients treated at our institution on several prospective dose-escalation trials. Patients and Methods From 1996 to 2009, 127 patients with stage III NSCLC (Eastern Cooperative Oncology Group performance status, 0 to 1) received dose-escalated RT to 70 to 90 Gy (median, 74 Gy) in six trials. RT plans and cardiac doses were reviewed. Records were reviewed for the primary end point: symptomatic cardiac events (symptomatic pericardial effusion, acute coronary syndrome, pericarditis, significant arrhythmia, and heart failure). Cardiac risk was assessed by noting baseline coronary artery disease and calculating the WHO/International Society of Hypertension score. Competing risks analysis was used. Results In all, 112 patients were analyzed. Median follow-up for surviving patients was 8.8 years. Twenty-six patients (23%) had one or more events at a median of 26 months to first event (effusion [n = 7], myocardial infarction [n = 5], unstable angina [n = 3], pericarditis [n = 2], arrhythmia [n = 12], and heart failure [n = 1]). Heart doses (eg, heart mean dose; hazard ratio, 1.03/Gy; P = .002,), coronary artery disease ( P < .001), and WHO/International Society of Hypertension score ( P = .04) were associated with events on univariable analysis. Heart doses remained significant on multivariable analysis that accounted for baseline risk. Two-year competing risk-adjusted event rates for patients with heart mean dose < 10 Gy, 10 to 20 Gy, or ≥ 20 Gy were 4%, 7%, and 21%, respectively. Heart doses were not associated with overall survival. Conclusion Cardiac events were relatively common after high-dose thoracic RT and were independently associated with both heart dose and baseline cardiac risk. RT-associated cardiac toxicity after treatment of stage III NSCLC may occur earlier than historically understood, and heart doses should be minimized.