Radiotherapy With Curative Intent in Patients With Early-stage, Medically Inoperable, Non–Small-cell Lung Cancer: A Systematic Review

A Comprehensive Primer on Radiation Oncology for Non-Radiation Oncologists

Background: Multidisciplinary management is crucial in cancer diagnosis and treatment. Multidisciplinary teams include specialists in surgery, medical therapies, and radiation therapy (RT), each playing unique roles in oncology care. One significant aspect is RT, guided by radiation oncologists (ROs). This paper serves as a detailed primer for non-oncologists, medical students, or non-clinical investigators, educating them on contemporary RT practices. Methods: This report follows the process of RT planning and execution. Starting from the decision-making in multidisciplinary teams to the completion of RT and subsequent patient follow-up, it aims to offer non-oncologists an understanding of the RO's work in a comprehensive manner. Results: The first step in RT is a planning session that includes obtaining a CT scan of the area to be treated, known as the CT simulation. The patients are imaged in the exact position in which they will receive treatment. The second step, which is the primary source of uncertainty, involves the delineation of treatment targets and organs at risk (OAR). The objective is to ensure precise irradiation of the target volume while sparing the OARs as much as possible. Various radiation modalities, such as external beam therapy with electrons, photons, or particles (including protons and carbon ions), as well as brachytherapy, are utilized. Within these modalities, several techniques, such as three-dimensional conformal RT, intensity-modulated RT, volumetric modulated arc therapy, scattering beam proton therapy, and intensity-modulated proton therapy, are employed to achieve optimal treatment outcomes. The RT plan development is an iterative process involving medical physicists, dosimetrists, and ROs. The complexity and time required vary, ranging from an hour to a week. Once approved, RT begins, with image-guided RT being standard practice for patient alignment. The RO manages acute toxicities during treatment and prepares a summary upon completion. There is a considerable variance in practices, with some ROs offering lifelong follow-up and managing potential late effects of treatment. Conclusions: Comprehension of RT clinical effects by non-oncologists providers significantly elevates long-term patient care quality. Hence, educating non-oncologists enhances care for RT patients, underlining this report's importance.

Twenty Years of Advancements in a Radiotherapy Facility: Clinical Protocols, Technology, and Management

BACKGROUND

Hypo-fractionation can be an effective strategy to lower costs and save time, increasing patient access to advanced radiation therapy. To demonstrate this potential in practice within the context of temporal evolution, a twenty-year analysis of a representative radiation therapy facility from 2003 to 2022 was conducted. This analysis utilized comprehensive data to quantitatively evaluate the connections between advanced clinical protocols and technological improvements. The findings provide valuable insights to the management team, helping them ensure the delivery of high-quality treatments in a sustainable manner.

METHODS

Several parameters related to treatment technique, patient positioning, dose prescription, fractionation, equipment technology content, machine workload and throughput, therapy times and patients access counts were extracted from departmental database and analyzed on a yearly basis by means of linear regression.

RESULTS

Patients increased by 121 ± 6 new per year (NPY). Since 2010, the incidence of hypo-fractionation protocols grew thanks to increasing Linac technology. In seven years, both the average number of fractions and daily machine workload decreased by -0.84 ± 0.12 fractions/year and -1.61 ± 0.35 patients/year, respectively. The implementation of advanced dose delivery techniques, image guidance and high dose rate beams for high fraction doses, currently systematically used, has increased the complexity and reduced daily treatment throughput since 2010 from 40 to 32 patients per 8 h work shift (WS8). Thanks to hypo-fractionation, such an efficiency drop did not affect NPY, estimating 693 ± 28 NPY/WS8, regardless of the evaluation time. Each newly installed machine was shown to add 540 NPY, while absorbing 0.78 ± 0.04 WS8. The COVID-19 pandemic brought an overall reduction of 3.7% of patients and a reduction of 0.8 fractions/patient, to mitigate patient crowding in the department.

CONCLUSIONS

The evolution of therapy protocols towards hypo-fractionation was supported by the use of proper technology. The characteristics of this process were quantified considering time progression and organizational aspects. This strategy optimized resources while enabling broader access to advanced radiation therapy. To truly value the benefit of hypo-fractionation, a reimbursement policy should focus on the patient rather than individual treatment fractionation.

Stereotactic Body Radiation Therapy (SBRT) for Oligorecurrent/Oligoprogressive Mediastinal and Hilar Lymph Node Metastasis: A Systematic Review

Simple Summary

This paper is a review of the literature on oligorecurrent/oligoprogressive mediastinal and hilar lymph node metastasis treated with SBRT. The use of mediastinal SBRT had historically been not feasible in view of the expected toxicity due to the proximity of critical structures such as the airways and esophagus. Despite the heterogeneity and lack of some data in the studies analyzed, this literature review is the first published and can be a valid guide for the radiotherapist in the management of oligometastatic/oligoprogressive patients, with particular regard to the radiotherapy doses, dose constraints for organs at risk, and clinical outcomes.

Abstract

Introduction: Mediastinal or hilar lymph node metastases are a challenging condition in patients affected by solid tumors. Stereotactic body radiation therapy (SBRT) could play a crucial role in the therapeutic management and in the so-called “no-fly zone”, delivering high doses of radiation in relatively few treatment fractions with excellent sparing of healthy surrounding tissues and low toxicity. The aim of this systematic review is to evaluate the feasibility and tolerability of SBRT in the treatment of mediastinal and hilar lesions with particular regard to the radiotherapy doses, dose constraints for organs at risk, and clinical outcomes. Materials and methods: Two blinded investigators performed a critical review of the Medline, Web of Knowledge, Google Scholar, Scopus, and Cochrane databases according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement (PRISMA), starting from a specific question: What is the clinical impact of SBRT for the treatment of oligorecurrent/oligoprogressive mediastinal and hilar metastasis? All retrospective and prospective clinical trials published in English up to February 2022 were analyzed. Results: A total of 552 articles were identified and 12 of them were selected with a total number of 478 patients treated with SBRT for mediastinal or hilar node recurrence. All the studies are retrospective, published between 2015 and 2021 with a median follow-up ranging from 12 to 42.2 months. Studies following SBRT for lung lesions or retreatments after thorax radiotherapy for stage III lung cancer were also included. The studies showed extensive heterogeneity in terms of patient and treatment characteristics. Non-small cell lung cancer was the most frequently reported histology. Different dose schemes were used, with a higher prevalence of 4–8 Gy in 5 or 6 fractions, but dose escalation was also used up to 52 Gy in 4 fractions with dose constraints mainly derived from RTOG 0813 trial. The radiotherapy technique most frequently used was volumetric modulated arc therapy (VMAT) with a median PTV volume ranging from 7 to 25.7 cc. The clinical outcome seems to be very encouraging with 1-year local control (LC), overall survival (OS) and progression-free survival (PFS) rates ranging from 84 to 94%, 53 to 88% and 23 to 53.9%, respectively. Half of the studies did not report toxicity greater than G3 and only five cases of fatal toxicity were reported. CONCLUSIONS: From the present review, it is not possible to draw definitive conclusions because of the heterogeneity of the studies analyzed. However, SBRT appears to be a safe and effective option in the treatment of mediastinal and hilar lymph node recurrence, with a good toxicity profile. Its use in clinical practice is still limited, and there is extensive heterogeneity in patient selection and fractionation schedules. Good performance status, small PTV volume, absence of previous thoracic irradiation, and administration of a high biologically effective dose (BED) seem to be factors that correlate with greater local control and better survival rates. In the presence of symptoms related to the thoracic lymph nodes, SBRT determines a rapid control that lasts over time. We look forward to the prospective studies that are underway for definitive conclusions.

Impact of tumor size and location on lung dose difference between stereotactic body radiation therapy techniques for non-small cell lung cancer

Background

To evaluate the lung dose differences between three‐dimensional conformal radiotherapy (3D‐CRT) and intensity‐modulated radiation therapy (IMRT) techniques for lung stereotactic body radiation therapy (SBRT) and the correlations with tumor characteristics, such as size and location.

Methods

Dosimetric comparisons between the two SBRT techniques in high‐ and low‐ to intermediate‐dose regions were retrospectively performed using four planning indices and lung‐dose parameters in 31 lung tumors. The magnitude of differences in these parameters was analyzed with relation to the planning target volume (PTV) and location‐related parameters.

Results

The absolute differences between the two techniques in lung‐dose parameters were small in both ipsilateral and bilateral lungs. The dosimetric differences were mainly correlated with the PTV rather than location‐related parameters, with positive and negative correlations with the high‐dose and intermediate‐dose parameters, respectively. The distances from the ipsilateral lung centroid to the PTV center were not correlated with the differences in any of the lung‐dose parameters. Additionally, the negative correlations with the MLD and V20 differences disappeared after applying a more rapid dose fall‐off in the IMRT plans for tumors with small PTVs of ≤15 cc.

Conclusions

Lung dose differences between the 3D‐CRT and IMRT techniques for lung SBRT were mainly correlated with the PTV rather than location‐related parameters. Together with the dosimetric benefit in high‐dose lung regions of IMRT for larger tumors, the relative increases in the MLD and V20 for small‐sized tumors could be reduced by applying a more rapid dose fall‐off outside the PTV.

Guiding Principles in the Management of Synchronous and Metachronous Primary Non-Small Cell Lung Cancer

Multiple lung cancers can be found simultaneously, with incidence ranging from 1% to 8%. Documentation of more than 1 pulmonary lesion can be challenging, because these solid, ground-glass, or mixed-density tumors may represent multicentric malignant disease or intrapulmonary metastases. If mediastinal nodal and distant deposits are excluded, surgery should be contemplated. After surgical treatment of lung cancer, patients should be followed closely for an undetermined period of time. Good clinical judgment is of outmost importance in deciding which individuals will benefit from those surgical interventions and which are candidates for alternate therapies. Every case should be discussed in a multidisciplinary meeting.

Stereotactic Radiation for Lung Cancer: A Practical Approach to Challenging Scenarios

Stereotactic body radiation therapy (SBRT) is an effective and well-tolerated treatment for medically inoperable patients with early stage NSCLC. SBRT is a noninvasive treatment involving the delivery of ablative radiation doses with high precision in the course of a few treatments. Relative to conventionally fractionated radiation, SBRT achieves superior local control and survival. SBRT use has increased dramatically in the past 15 years and is currently considered the standard of care in cases of inoperable early stage NSCLC. It is being increasingly applied to more complex patient populations at higher risk of treatment-related toxicity. In these more complex patients, there is an increasing need to balance patient and treatment factors in selecting the optimal patients for SBRT. Here, we review several challenging clinical scenarios often encountered in thoracic multidisciplinary tumor boards.

Salvage Surgery for Non-Small Cell Lung Cancer After Definitive Radiotherapy

BACKGROUND

The aim of this study was to describe the characteristics and outcomes of patients with non-small cell lung cancer undergoing salvage surgery after chemoradiotherapy, conventional external beam, stereotactic body radiotherapy, and ion beam radiotherapy.

METHODS

We retrospectively evaluated patients who underwent salvage surgery between 2010 and 2016. Data on perioperative morbidity and mortality and patient outcomes were analyzed.

RESULTS

In total, 156 patients were included; of those, 110 were categorized into category 1, chemoradiotherapy or conventional external beam; and 46 into category 2, stereotactic body radiotherapy or ion beam radiotherapy. Three-year overall survival (OS) and recurrence-free survival (RFS) in category 1 were 67.3% and 49.8%, respectively. In category 1, pathological nodal stage was an independent prognosticator of both OS (hazard ratio [HR] = 3.53, 95% confidence interval [CI], 1.05-11.83) and RFS (HR = 4.32, 95% CI, 1.32-14.14). In category 2, 3-year OS and RFS were 57.7% and 46.4%, respectively. Age 70 years and greater at initial treatment was the only independent prognosticator of OS (HR = 5.61; 95% CI, 1.44-21.87), whereas age at initial treatment (HR = 6.13; 95% CI, 1.38-27.12) and pathological nodal metastasis (HR = 3.84; 95% CI, 1.40-10.57) were independent prognosticators for RFS. Overall 30- and 90-day mortality were 0% and 0.9% in category 1 and 0% and 4.3% in category 2, respectively.

CONCLUSIONS

Patients who undergo salvage surgery can have reasonable outcomes, and salvage surgery can be considered in selected patients.

A comparison of two modalities of stereotactic body radiation therapy for peripheral early-stage non-small cell lung cancer: results of a prospective French study

OBJECTIVES

This prospective, observational, non-randomized multicentric study was conducted to compare efficiency and toxicity using different modalities of stereotactic body radiation therapy (SBRT) in early-stage peripheral non-small cell lung cancer (NSCLC).

METHODS

From 9 April to 11 December, 106 patients were treated according to the local equipment availability for peripheral NSCLC with SBRT: 68 by linear accelerator equipped for SBRT and 38 by Cyberknife^®. Multivariate analysis and propensity score analysis using Inverse Probability Treatment Weighting (IPTW) were undertaken in an effort to adjust for potential bias due to non-randomization.

RESULTS

2-year local control rates were 97.0% (95% CI: [90.6%; 99.4%]) with SBRT by Linac vs 100% (95% CI: ([100%; 100%]) with Cyberknife^® (p = 0.2839). 2-year PFS and 2-year OS rates were 52.7% (95% CI [39.9%;64.0%]) versus 54.1% (95% CI [36.8; 68.6%]) (p = 0.8582) and 65.1% (95% CI: [51.9%; 75.5%] versus 83.9% (95% CI: [67.5%; 92.4%] (p = 0.0831) using Linac and Cyberknife^® respectively. Multivariate regression analysis indicates no significant effect of SBRT treatment type on PFS or OS. Local relapse could not be modeled due to the small number of events (n = 2). Acute and late toxicity rates were not significantly different. After IPTW adjustment, results were unchanged.

CONCLUSIONS

No difference in efficiency or toxicity was shown after SBRT of peripheral NSCLC treatment using Linac or Cyberknife^®.

ADVANCES IN KNOWLEDGE

This is the first large prospective non-randomized study focusing on peripheral localized NSCLC comparing SBRT using an appropriately equipped linac with Cyberknife^®. No significant difference in efficiency or toxicity was shown in this situation.

A modern review of the uncertainties in volumetric imaging of respiratory-induced target motion in lung radiotherapy

Radiotherapy has become a critical component for the treatment of all stages and types of lung cancer, often times being the primary gateway to a cure. However, given that radiation can cause harmful side effects depending on how much surrounding healthy tissue is exposed, treatment of the lung can be particularly challenging due to the presence of moving targets. Careful implementation of every step in the radiotherapy process is absolutely integral for attaining optimal clinical outcomes. With the advent and now widespread use of stereotactic body radiation therapy (SBRT), where extremely large doses are delivered, accurate, and precise dose targeting is especially vital to achieve an optimal risk to benefit ratio. This has largely become possible due to the rapid development of image-guided technology. Although imaging is critical to the success of radiotherapy, it can often be plagued with uncertainties due to respiratory-induced target motion. There has and continues to be an immense research effort aimed at acknowledging and addressing these uncertainties to further our abilities to more precisely target radiation treatment. Thus, the goal of this article is to provide a detailed review of the prevailing uncertainties that remain to be investigated across the different imaging modalities, as well as to highlight the more modern solutions to imaging motion and their role in addressing the current challenges.

The p53-53BP1-Related Survival of A549 and H1299 Human Lung Cancer Cells after Multifractionated Radiotherapy Demonstrated Different Response to Additional Acute X-ray Exposure

Radiation therapy is one of the main methods of treating patients with non-small cell lung cancer (NSCLC). However, the resistance of tumor cells to exposure remains the main factor that limits successful therapeutic outcome. To study the molecular/cellular mechanisms of increased resistance of NSCLC to ionizing radiation (IR) exposure, we compared A549 (p53 wild-type) and H1299 (p53-deficient) cells, the two NSCLC cell lines. Using fractionated X-ray irradiation of these cells at a total dose of 60 Gy, we obtained the survived populations and named them A549IR and H1299IR, respectively. Further characterization of these cells showed multiple alterations compared to parental NSCLC cells. The additional 2 Gy exposure led to significant changes in the kinetics of γH2AX and phosphorylated ataxia telangiectasia mutated (pATM) foci numbers in A549IR and H1299IR compared to parental NSCLC cells. Whereas A549, A549IR, and H1299 cells demonstrated clear two-component kinetics of DNA double-strand break (DSB) repair, H1299IR showed slower kinetics of γH2AX foci disappearance with the presence of around 50% of the foci 8 h post-IR. The character of H2AX phosphorylation in these cells was pATM-independent. A decrease of residual γH2AX/53BP1 foci number was observed in both A549IR and H1299IR compared to parental cells post-IR at extra doses of 2, 4, and 6 Gy. This process was accompanied with the changes in the proliferation, cell cycle, apoptosis, and the expression of ATP-binding cassette sub-family G member 2 (ABCG2, also designated as CDw338 and the breast cancer resistance protein (BCRP)) protein. Our study provides strong evidence that different DNA repair mechanisms are activated by multifraction radiotherapy (MFR), as well as single-dose IR, and that the enhanced cellular survival after MFR is reliant on both p53 and 53BP1 signaling along with non-homologous end-joining (NHEJ). Our results are of clinical significance as they can guide the choice of the most effective IR regimen by analyzing the expression status of the p53–53BP1 pathway in tumors and thereby maximize therapeutic benefits for the patients while minimizing collateral damage to normal tissue.

DNA damage response signaling pathways and targets for radiotherapy sensitization in cancer

Radiotherapy is one of the most common countermeasures for treating a wide range of tumors. However, the radioresistance of cancer cells is still a major limitation for radiotherapy applications. Efforts are continuously ongoing to explore sensitizing targets and develop radiosensitizers for improving the outcomes of radiotherapy. DNA double-strand breaks are the most lethal lesions induced by ionizing radiation and can trigger a series of cellular DNA damage responses (DDRs), including those helping cells recover from radiation injuries, such as the activation of DNA damage sensing and early transduction pathways, cell cycle arrest, and DNA repair. Obviously, these protective DDRs confer tumor radioresistance. Targeting DDR signaling pathways has become an attractive strategy for overcoming tumor radioresistance, and some important advances and breakthroughs have already been achieved in recent years. On the basis of comprehensively reviewing the DDR signal pathways, we provide an update on the novel and promising druggable targets emerging from DDR pathways that can be exploited for radiosensitization. We further discuss recent advances identified from preclinical studies, current clinical trials, and clinical application of chemical inhibitors targeting key DDR proteins, including DNA-PKcs (DNA-dependent protein kinase, catalytic subunit), ATM/ATR (ataxia-telangiectasia mutated and Rad3-related), the MRN (MRE11-RAD50-NBS1) complex, the PARP (poly[ADP-ribose] polymerase) family, MDC1, Wee1, LIG4 (ligase IV), CDK1, BRCA1 (BRCA1 C terminal), CHK1, and HIF-1 (hypoxia-inducible factor-1). Challenges for ionizing radiation-induced signal transduction and targeted therapy are also discussed based on recent achievements in the biological field of radiotherapy.

Hypofractionated vs. conventional radiation therapy for stage III non-small cell lung cancer treated without chemotherapy

Background: Patients with unresectable locally advanced NSCLC who refuse or are not candidates for chemotherapy often receive radiation therapy (RT) alone. Hypofractionated RT (HFRT) regimens are becoming increasingly common. An analysis of the National Cancer Database (NCDB) was performed to evaluate the practice patterns and outcomes of HFRT vs. conventionally fractionated RT (CFRT) in patients with stage III NSCLC undergoing definitive RT alone.Material and methods: The NCDB was queried for all patients with stage III NSCLC diagnosed between 2004 and 2014 who received RT alone. CFRT was defined as patients treated to a total dose of 60-80 Gy in 1.8-2 Gy daily fractions. HFRT was defined as patients treated to a total dose of 50-80 Gy in 2.25-4 Gy fractions. Logistic regression, univariable and multivariable analyses (MVAs) for overall survival (OS) and propensity score matched analyses (PSMAs) were performed.Results: A total of 6490 patients were evaluated: 5378 received CFRT and 1112 received HFRT. Median CFRT dose was 66 Gy in 2 Gy fractions vs. 58.5 Gy in 2.5 Gy fractions for HFRT. HFRT was associated with older age, lower biological effective dose (BED₁₀), academic facility type, higher T-stage and lower N-stage. On initial analysis, HFRT was associated with inferior OS (median 9.9 vs. 11.1 months, p<.001), but after adjusting for the imbalance in covariates such as age, BED₁₀, T-stage and N-stage using PSMA, the difference in survival was no longer significant (p=.1).Conclusions: In the appropriate clinical context, HFRT can be an option for patients with locally advanced NSCLC who are not candidates for chemotherapy or surgical resection. HFRT needs to be further studied in prospective trials to evaluate toxicity and tumor control.

Icariin induces apoptosis of human lung adenocarcinoma cells by activating the mitochondrial apoptotic pathway

Lung cancer is the largest cause of morbidity and mortality among tumor diseases. Traditional first-line chemotherapeutic drugs are frequently accompanied by serious side effects when used to treat tumors, thus, novel drugs with reduced toxic effects may improve a patients' quality of life. Icariin, an extract of herba epimedii, has been demonstrated to exhibit multiple antitumor effects with low toxicity. In the present study, cell cycle analysis, apoptosis assays, DAPI staining, CCK8 assays, xenograft tumor models, mitochondrial membrane potential analysis, western blotting and reverse transcription-quantitative PCR were performed to determine the molecular mechanism underlying icariin activity in the human lung adenocarcinoma cell lines, A549 and H1975. The results showed that icariin reduced proliferation of A549 and H1975 cells in a time- and dose-dependent manner in vitro to a greater degree than the control BEAS-2B cells, and this was associated with increased apoptosis, but not with cell cycle progression. In vivo experiments showed that icariin treatment significantly decreased proliferation of H1975 cells in a xenograft mouse model. Mechanistically, icariin activated the mitochondrial pathway by inhibiting the activation of the PI3K-Akt pathway-associated kinase, Akt, resulting in the activation of members of the caspase family of proteins, and thus inducing apoptosis of A549 cells. Taken together, the results revealed that icariin has anti-cancer properties in lung cancer in vitro and in vivo without any noticeable toxic effects on normal lung epithelial cells. Icariin in combination with conventional anti-cancer agents may be an effective therapeutic strategy for treatment of lung carcinoma.

Bronchoscopic Therapies for Peripheral Lung Malignancies

Current advances in guided bronchoscopy methods permit minimally invasive access to essentially any area of the lungs. This provides a potential means to treat patients with localized lung malignancies who might not otherwise tolerate conventional treatment, which commonly relies on surgical resection. Ablation methods have long been used for bronchoscopic treatment of central airway malignancies and percutaneous treatment of peripheral lung cancer. This article reviews ablation technologies being adapted for use with guided bronchoscopy and the current state of investigation for the treatment of peripheral lung malignancies.

A feasibility study of spatiotemporally integrated radiotherapy using the LQ model

This paper investigates the feasibility of spatiotemporally modulated radiotherapy (STMRT)-integrated model with explicit constraints on the tumor dose heterogeneity. In particular, we demonstrate the effect of the tumor dose heterogeneity on the tumor biologically effective dose (BED) achievable and optimal fractionation. We propose an STMRT model that simultaneously optimizes the dose distributions and fractionation schedule for each individual case with the maximum and minimum constraints on the tumor BED to explicitly control the level of tumor dose heterogeneity. Sixteen thoracic phantom cases were planned using (1) STMRT and (2) standard fractionation (60 Gy in 30 fractions fixed) IMRT. Constraints on the organs-at-risk (OAR) BED were identical for both plans. BEDs were calculated using the [Formula: see text] ratio of 10 Gy for the tumor and 3 Gy for all OARs. The maximum tumor BED for STMRT plans was constrained to be less than 100%-150% of the maximum tumor BED resulted from the standard fractionation plans. The mean tumor BED from STMRT plans was up to 110.7%, 128.3%, 135.0% and 148.0% of that from the standard fractionation plans when the maximum tumor BED was constrained to be less than 100%, 120%, 130% and 150% of the maximum BED achieved using the standard plans. The optimal number of fractions varied widely for different phantom geometries for the same radiobiological parameter values. The increase in the tumor BED and the range of optimal fractionation was larger with a larger tumor dose heterogeneity allowed. The results have shown the feasibility of personalizing fractionation schedule using an STMRT integrated model to deliver a maximum feasible BED to the tumor for a fixed OAR BED. The potential increase in the tumor BED was positively correlated to the tumor dose heterogeneity allowed.

Stereotactic body radiation therapy for mediastinal lymph node metastases: how do we fly in a 'no-fly zone'?

PURPOSE

To evaluate the treatment-induced toxicity (as primary endpoint) and the efficacy (as secondary endpoint) of stereotactic body radiation therapy (SBRT) in the treatment of mediastinal lymph nodes (LNs) in the so-called no-fly zone (NFZ) in cancers with various histology.

MATERIAL AND METHODS

Forty-two patients were retrospectively analyzed. Institutional dose/volume constraints for organs at risk (OARs) derived by published data were strictly respected. The correlation between treatment-related variables and toxicity was investigated by logistic regression, Chi-squared test or Fisher's exact test. Overall survival (OS), cause-specific survival (CSS), progression-free survival (PFS) and local control (LC) were collected from the follow-up reports. The impact of potential predictive factors on LC, PFS and OS were estimated by Cox proportional-hazard regression.

RESULTS

Median follow-up time was 16 months (range 1-41). Four patients had esophageal G1 toxicity. Ten and six patients had G1 and G2 pulmonary toxicity, respectively. Treatment site and irradiation technique were significantly correlated with G ≥ 2 and G ≥ 1 toxicity, respectively. OS probability at 19 months was 88.3% and corresponded to CSS. LC probability at 16 months was 66.3% (median LC duration: 22 months, range 1-41). Fifteen patients (35.7%) were disease-free at 25 months (median time, range 1-41). The biologically effective dose (BED) and the target dose coverage indexes were significantly correlated with LC.

CONCLUSIONS

SBRT can be considered as a safe treatment option for selected patients with oligo-metastases/recurrences in the NFZ, if strict dose/volume constraints are applied.

Tumor necrosis factor-related apoptosis-inducing ligand additive with Iodine-131 of inhibits non-small cell lung cancer cells through promoting apoptosis

Non-small-cell lung cancer (NSCLC) accounts for ~80% of human lung cancer cases and is the most common cause of cancer-associated mortality worldwide. Reports have indicated that tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and Iodine-131 (I-131) can induce tumor cell apoptosis. The purpose of the present study was to investigate the additive efficacy of TRAIL and I-131 on NSCLC cells. The present study demonstrated that additive treatment of TRAIL and I-131 (TRAIL-I-131) significantly inhibited the growth and aggressiveness of NSCLC cells compared with single TRAIL or I-131 treatment. Results demonstrated that TRAIL-I-131 treatment induced apoptosis of NSCLC cells, with western blot analysis confirming that TRAIL-I-131 treatment increased proapoptotic Bad and Bax expression levels, while antiapoptotic Bcl-2 and Bcl-w protein levels were decreased in NSCLC cells. The present study demonstrated that TRAIL-I-131 treatment inhibited vascular endothelial growth factor (VEGF) and activator protein-1 (AP-1) in NSCLC cells. Potential mechanism analyses identified that TRAIL-I-131 treatment induced apoptosis of NSCLC cells through caspase-9 activation. In vivo assays revealed that TRAIL-I-131 treatment significantly inhibited NSCLC tumor growth and increased apoptotic bodies in tumor tissues. Immunohistology demonstrated that caspase-9 was upregulated and VEGF was downregulated in tumor tissues in TRAIL-I-131-treated tumors. In conclusion, these results indicate that TRAIL combined with I-131 promoted apoptosis of NSCLC through caspase-9 activation, which may be a promising anticancer therapeutic schedule for the treatment of NSCLC.

Ultracentral Tumors Treated With Stereotactic Body Radiotherapy: Single-Institution Experience

INTRODUCTION

Patients with ultracentral lung tumors, whose planning target volume directly contacts or overlaps the proximal bronchial tree, trachea, esophagus, pulmonary vein, or pulmonary artery, may be at higher risk of toxicity when treated with stereotactic body radiotherapy (SBRT). We reviewed the outcomes and toxicities of ultracentral lung tumors and compared the results with central lung tumors.

PATIENTS AND METHODS

A review of our institutional prospective database of patients treated with lung SBRT from January 2006 to December 2015 was conducted. Patients with central tumors (RTOG 0813 definition) and ultracentral tumors were included.

RESULTS

In total, 180 central and 26 ultracentral tumors were analyzed. The majority of patients received 60 Gy in 8 fractions (53.9%) or 48 Gy in 4 fractions (29.1%). The rates of any grade 2 or higher toxicity were 8.4% (n = 16) in the central group and 7.9% (n = 2) in the ultracentral group (P = .88). There were no observed grade 4 or 5 toxicities. In the nonmetastatic primary lung cancer cohort (n = 182), the median overall survival was 39.4 months versus 23.8 months (P = .40) and cause-specific survival was 55.5 months versus 28.2 months (P = .34) for central and ultracentral tumors, respectively. The 2-year cumulative local, regional, and distant failure rates were 3.3% versus 0 (P = .36), 9.1% versus 5.0% (P = .5), and 17.7% versus 18.7% (P = .63) in the central and ultracentral groups, respectively.

CONCLUSION

In our experience, with strict adherence to planning parameters, SBRT to ultracentral tumors resulted in effective local control and no excessive risk of toxicity compared to central tumors.

Flattening filter-free technique in volumetric modulated arc therapy for lung stereotactic body radiotherapy: A clinical comparison with the flattening filter technique

The present study sought to evaluate the impact of the flattening filter-free (FFF) technique in volumetric modulated arc therapy for lung stereotactic body radiotherapy. Its clinical safety and availability were compared with the flattening filter (FF) method. The cases of 65 patients who underwent lung volumetric modulated arc therapy-stereotactic body radiotherapy (VMAT-SBRT) using FF or FFF techniques were reviewed. A total of 55 Gy/4 fractions (fr) was prescribed for peripheral lesions or 56 Gy/7 fr for central lesions. The total monitor units (MU), treatment time, dose to tumors, dose to organs at risk, tumor control (local control rate, overall survival, progression-free survival) and adverse events between cases treated with FF and cases treated with the FFF technique were compared. A total of 35 patients were treated with conventional FF techniques prior to November 2014 and 30 patients were treated with FFF techniques after this date. It was revealed that the beam-on time was significantly shortened by the FFF technique (P<0.01). Other factors were similar for FFF and FF plans in respect to conformity (P=0.95), homogeneity (P=0.20) and other dosimetric values, including total MU and planning target volume/internal target volume coverage. The median follow-up period was 18 months (range, 2-35). One-year local control rates were 97.1 and 90.0% in the FF group and FFF groups, respectively (P=0.33). Grade 3 pneumonitis was observed in 5.8% of FF patients and 3.4% of FFF patients (P=1.00). No other adverse events ≥grade 3 were observed. The results of the study suggest that VMAT-SBRT using the FFF technique shortens the treatment time for lung SBRT while maintaining a high local control rate with low toxicity.

A SUVmax-based propensity matched analysis of stereotactic body radiotherapy versus surgery in stage I non-small cell lung cancer: unveiling the role of 18F-FDG PET/CT in clinical decision-making

BACKGROUND

The value of maximum standard uptake value (SUV_max) was overlooked in current studies comparing stereotactic body radiotherapy (SBRT) versus surgery for stage I non-small cell lung cancer (NSCLC). Herein, we aimed to compare the 3-year outcomes based on patients for whom SUV_max were available, and to explore the role of SUV_max in clinical decision-making.

METHODS

From January 2010 to June 2016, data of eligible patients were collected. Patient variables and clinical outcomes were compared in both unmatched and matched groups using propensity score matching (PSM). Multivariate analysis was performed for predictors of poor outcome. The relationship between treatment approach and survival outcome was also evaluated in subgroup patients stratified by SUV_max level.

RESULTS

A total of 425 patients treated with either surgery (325) or SBRT (100) were included. Patients receiving SBRT were significantly older, had a higher level of SUV_max and were more likely to have tumor of centrally located. Multivariate analysis showed that SUV_max and tumor size were significant predictors for 3-year OS, LRC, and PFS, while better PFS was also related to peripheral tumor and surgery. The result of PSM analysis also showed that compared to SBRT, surgery could only achieve better PFS. Subgroup analysis indicated that surgery had added advantage of 3-year LRC and PFS for patients in high SUV_max group (SUV_max > 8), but not in low SUV_max group.

CONCLUSIONS

The study found a superior PFS after surgery while OS and LRC did not differ between SBRT and surgery. Surgery should be recommended for tumor of high SUV_max.

Efficacy and safety of image-guidance radiotherapy by helical tomotherapy in patients with lung cancer

This study aimed to explore the efficacy and toxicity of image-guided stereotactic body radiotherapy (IGSBR) by helical tomotherapy in patients with lung cancer among Chinese Han population.A total of 21 patients with stage I lung cancer were included. They received a total of 60 Gy factions IGSBR. The outcomes included complete response (CR), partial response (PR), stable disease (SD), progress disease (PD), overall response rate (ORR), and overall survival (OS). In addition, toxicities were also recorded in this study.Three-year CR, PR, SD, PD, ORR, and OS were 47.6%, 38.1%, 9.5%, 4.8%, 85.7%, and 48.0 months, respectively. Additionally, mild toxicities were found in this study.This study demonstrated that IGSBR is efficacious for patients with stage I lung cancer with mild toxicities among Chinese Han population.

Appropriate surgical modalities for stages T2a and T2b in the eighth TNM classification of lung cancer

Patients with tumors of 3 to 5 cm were divided into stages T2a (3 to 4 cm) and T2b (4 to 5 cm) based on the 8^th tumor-node-metastasis staging system for lung cancer. The objective of our study was to explore appropriate surgical modalities for the new stages, T2a and T2b. We selected 6,996 node-negative non-small-cell lung cancer patients with tumor sizes of 3 to 5 cm, diagnosed between 2009 and 2013, from the Surveillance, Epidemiology, and End Results (SEER) program. The Pearson \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\chi }^{2}$$\end{document}χ2. statistic test and Kaplan–Meier curve were used to analyze patient data. The prognosis of patients with stage T2a was significantly better than that of patients with stage T2b, both in overall survival (p = 0.018) and lung cancer specific survival (p = 0.001). For patients with stage T2a, lobectomy had a significantly better outcome. For patients with stage T2b, surgical modalities including pneumonectomy, segmental resection and lobectomy, had similar outcomes in terms of survival. Consequently, lobectomy was the most appropriate surgical treatment modality for new stage T2a patients, whereas, for new T2b patients, treatment outcome did not vary significantly with the choice of surgical modality.

Risk-adapted robotic stereotactic body radiation therapy for inoperable early-stage non-small-cell lung cancer

PURPOSE

To evaluate efficacy and toxicity of stereotactic body radiation therapy (SBRT) with CyberKnife® (Accuray, Sunnyvale, CA, USA) in a selected cohort of primary, medically inoperable early-stage non-small cell lung cancer (NSCLC) patients.

METHODS

From 2012 to 2016, 106 patients (median age 74 years, range 50-94 years) with primary NSCLC were treated with SBRT using CyberKnife®. Histologic confirmation was available in 87 patients (82%). For mediastinal staging, 92 patients (87%) underwent ¹⁸F-fluorodeoxyglucose positron-emission tomography (18-FDG-PET) and/or endobronchial ultrasound (EBUS)-guided lymph node biopsy or mediastinoscopy. Tumor stage (UICC8, 2017) was IA/B (T1a-c, 1-3 cm) in 86 patients (81%) and IIA (T2a/b, 3-5 cm) in 20 patients (19%). Depending on tumor localization, three different fractionation schedules were used: 3 fractions of 17Gy, 5 fractions of 11Gy, or 8 fractions of 7.5 Gy. Tracking was based on fiducial implants in 13 patients (12%) and on image guidance without markers in 88%.

RESULTS

Median follow-up was 15 months (range 0.5-46 months). Acute side effects were mild (fatigue grade 1-2 in 20% and dyspnea grade 1-2 in 17%). Late effects were observed in 4 patients (4%): 3 patients developed pneumonitis requiring therapy (grade 2) and 1 patient suffered a rib fracture (grade 3). In total, 9/106 patients (8%) experienced a local recurrence, actuarial local control rates were 88% (95% confidence interval, CI, 80-96%) at 2 years and 77% (95%CI 56-98%) at 3 years. The median disease-free survival time was 27 months (95%CI 23-31 months). Overall survival was 77% (95%CI 65-85%) at 2 years and 56% (95%CI 39-73%) at 3 years.

CONCLUSION

CyberKnife® lung SBRT which allows for real-time tumor tracking and risk-adapted fractionation achieves satisfactory local control and low toxicity rates in inoperable early-stage primary lung cancer patients.

Guideline for radiotherapy with curative intent in patients with early-stage medically inoperable non-small-cell lung cancer

OBJECTIVES

For this guideline, we investigated the effectiveness of radiotherapy with curative intent in medically inoperable patients with early-stage non-small-cell lung cancer (nsclc).

METHODS

The guideline was developed by Cancer Care Ontario's Program in Evidence-Based Care and by the Lung Cancer Disease Site Group through a systematic review of mainly retrospective studies, expert consensus, and formal internal and external reviews.

RECOMMENDATIONS

■ Stereotactic body radiation therapy (sbrt) with curative intent is an option that should be considered for patients with early-stage, node-negative, medically inoperable nsclc. Qualifying Statements■ Because of the high dose per fraction, the planning process and treatment delivery for sbrt require the use of advanced technology to maintain an appropriate level of safety. Consistent patient positioning and 4-dimensional analysis of tumour and critical structure motion during simulation and treatment delivery are essential.■ Preliminary results for proton-beam therapy have been promising, but the technique requires further clinical study.■ Recommended fractionation schemes for sbrt should result in a biologically effective dose of 100 or greater by the linear quadric model, choosing an α/β value of 10 [bed_10(LQ) ≥ 100]. Qualifying Statements■ Because of the increased risk of treatment-related adverse events associated with centrally located tumours, consideration of tumour size and proximity to critical central structures is required when determining the dose and fractionation.■ Examples of dose-fractionation schemes used in the included studies have been provided.■ Based on the current evidence and the opinion of the authors, radiation doses at bed_10(LQ) greater than 146 might significantly increase toxicity and should be avoided.■ Determination of the radiation bed by the linear quadratic model has limitations for the extreme hypofractionated schemes used in sbrt.