Optimizing radiation dose and fractionation for the definitive treatment of locally advanced non-small cell lung cancer

Cartilage Oligomeric Matrix Protein Promotes Radiation Resistance in Non-Small Cell Lung Cancer In Vitro

Cartilage oligomeric matrix protein (COMP) is an extracellular matrix protein that has recently been associated with worse patient outcomes in breast, prostate, colorectal and hepatocellular cancers. This study aimed to determine whether COMP was also associated with increased progression and resistance to radiation in non-small cell lung cancer (NSCLC). The proliferation, migration, invasion and cell viability of wild-type and COMP overexpressing NSCLC cell lines were assessed when treated with exogenous COMP, with or without radiation. In addition, these cells were treated with inhibitors of downstream signaling intermediates of COMP. Proteomics were performed on the A549 cell line treated with COMP, radiation and inhibitors. NSCLC cells treated with COMP or overexpressing COMP had greater proliferation, migration, invasion and viability when irradiated compared to non-overexpressed cells treated with radiation alone, but this effect was reversed when treated with Src or PI3k inhibitors. The NCI-H1437 cell line exhibited a decrease in proliferation when treated with exogenous COMP, however COMP overexpression mitigated the radiation-induced reduction. Proteomics analyses indicate that COMP promotes oxidative phosphorylation and drug resistance pathways. Therefore, COMP overexpression and treatment with exogenous COMP appears to protect NSCLC cells against radiation in vitro, however treatment with inhibitors reverses COMP-mediated protection and progression.

The Combination of Temporal and Spatial Dose Fractionation in Microbeam Radiation Therapy

Background: Microbeam radiation therapy (MRT) is an advanced preclinical approach in radiotherapy that utilizes spatially fractionated dose distributions by collimating x-rays into micrometer-wide, planar beams. While the benefits of temporal fractionation are well established and widely incorporated into conventional radiotherapy protocols, the interplay between MRT and temporal dose fractionation remains largely unexplored. In this study, we investigate the effects of combining temporal and spatial dose fractionation by assessing clonogenic cell survival following temporally fractionated MRT with varying irradiation angles, compared to conventional broad-beam (BB) irradiation. Methods: A lung tumor cell line (A549) and a normal lung cell line (MRC-5) were irradiated with a total number of four fractions with a 24 h interval between each fraction. We compared a temporally fractionated BB regime to two temporally fractionated MRT schemes with either overlapping MRT fields or MRT fields with a 45° rotation per fraction. Subsequently, the clonogenic cell survival assay was used by analyzing the corresponding survival fractions (SFs). Results: The clonogenic survival of A549 tumor cells differed significantly between microbeam radiation therapy with rotation (MRT + R) and overlapping MRT. However, neither MRT + R nor overlapping MRT showed statistically significant differences compared to the broad-beam (BB) irradiation for A549. In contrast, the normal tissue cell line MRC-5 exhibited significantly higher clonogenic survival following both MRT + R and overlapping MRT compared to BB. Conclusions: This study demonstrates that combining temporal and spatial fractionation enhances normal tissue cell survival while maintaining equivalent tumor cell kill, potentially increasing the therapeutic index. Our findings support the feasibility of delivering temporally fractionated doses using different MRT modalities and provide clear evidence of the therapeutic benefits of temporally fractionated MRT.

Nicaraven attenuates the acquired radioresistance of established tumors in mouse models via PARP inhibition

Nicaraven has been reported to inhibit the activity of poly (ADP-ribose) polymerase (PARP). In this study, we investigated the probable ability of nicaraven to attenuate cancer radioresistance during fractionated radiotherapy. Tumor models were established in C57BL/6 mice and BALB/c nude mice by subcutaneous injection of Lewis mouse lung carcinoma cancer cells and A549 human lung cancer cells, respectively. When the tumors had grown to approximately 100 mm3, we initiated fractionated radiotherapy. Nicaraven or saline was administered immediately after each irradiation exposure. Compared to saline treatment, nicaraven administration significantly induced gamma-H2AX foci formation and cell apoptosis in tumors at 1 or 3 days after an additional challenge exposure to 10 Gy and inhibited tumor growth during the short-term follow-up period, suggesting increased radiosensitivity of cancer cells. Moreover, the expression of PARP in tumor tissue was decreased by nicaraven administration. Our data suggest that nicaraven likely attenuates the acquired radioresistance of cancers through PARP inhibition.

"Mid-P strategy" versus "internal target volume strategy in locally advanced non small cell lung cancer: Clinical results from the randomized non-comparative phase II study Mid-P

BACKGROUND

Locally advanced non-small cell lung cancer (LA-NSCLC) reported poor 5-year survival rates with frequent local or regional recurrences. Personalized RT may contribute to improve control and clinical outcome. We investigated efficacy and tolerance of "Mid-position" (Mid-P) strategy versus the conventional Internal Target Volume (ITV) strategy in LA-NSCLC patients treated by definitive conformal radiotherapy.

METHODS

This prospective non-comparative randomized monocentric phase II trial included adult patients with non-resected, non-metastatic, non-previously irradiated proven LA-NSCLC treated with definitive normo-fractionated conformal radiotherapy (+/- chemotherapy). Allocated patients (randomisation 2:1) were treated using Mid-P or ITV strategy. A Fleming single-stage design (1-sided α = 0.1, 80 % power, P0 = 30 %, P1 = 50 %) planned enrolment of 36 patients in the Mid-P group. The ITV group ensured the absence of selection bias. The primary outcome was 1-year progression-free- survival (1y-PFS) rate.

RESULTS

Among 54 eligible patients included from September 2012 to May 2018, 51 patients were analyzed (Mid-P: N = 34; ITV: 17). The 1y-PFS was 38 % (1-sided 95 %CI 25 %-not reached) with Mid-P strategy, and 47 % (95 %CI [27 %-not reached[) with ITV. Loco-regional failure as first event mainly occurred within radiation-field regardless the strategy. Acute and middle-term radiation toxicities were observed with both strategies.

CONCLUSION

Local control and survival remain poor using the Mid-P strategy in this prospective randomized non-comparative monocentric study investigating Mid-P strategy versus ITV strategy in LA-NSCLC. Since the Mid-P strategy is not integrated into routine software, and perceived as a time-consuming method, Mid-P strategy cannot be recommended in LA-NSCLCC treated by definitive normo-fractionated conformal radiotherapy outside clinical trials.

Efficiency of moderately hypofractionated radiotherapy in NSCLC cell model

Background

The current standard of radiotherapy for inoperable locally advanced NSCLCs with single fraction doses of 2.0 Gy, results in poor outcomes. Several fractionation schedules have been explored that developed over the past decades to increasingly more hypofractionated treatments. Moderate hypofractionated radiotherapy, as an alternative treatment, has gained clinical importance due to shorter duration and higher patient convenience. However, clinical trials show controversial results, adding to the need for pre-clinical radiobiological studies of this schedule.

Methods

We examined in comparative analysis the efficiency of moderate hypofractionation and normofractionation in four different NSCLC cell lines and fibroblasts using several molecular-biological approaches. Cells were daily irradiated with 24x2.75 Gy (moderate hypofractionation) or with 30x2 Gy (normofractionation), imitating the clinical situation. Proliferation and growth rate via direct counting of cell numbers, MTT assay and measurements of DNA-synthesizing cells (EdU assay), DNA repair efficiency via immunocytochemical staining of residual γH2AX/53BP1 foci and cell surviving via clonogenic assay (CSA) were experimentally evaluated.

Results

Overall, the four tumor cell lines and fibroblasts showed different sensitivity to both radiation regimes, indicating cell specificity of the effect. The absolute cell numbers and the CSA revealed significant differences between schedules (P < 0.0001 for all employed cell lines and both assays) with a stronger effect of moderate hypofractionation.

Conclusion

Our results provide evidence for the similar effectiveness and toxicity of both regimes, with some favorable evidence towards a moderate hypofractionation. This indicates that increasing the dose per fraction may improve patient survival and therapy outcomes.

Will Nigella sativa oil protect parotid glands of rats against cranium gamma irradiation? Histological and immunohistochemical evaluation

BACKGROUND

Radiation plays an essential role in treating malignancies. Radiation exposure of salivary glands often results in permanent loss of their functions; therefore, their protection against radiation is crucial. Nigella sativa oil (NSO) is a useful antioxidant against free radicals. The purpose of this study was to investigate the radio-protective effect of NSO on oxidative injury of parotid glands of gamma-irradiated rats.

METHODS

Twenty-eight male albino rats were divided into four groups (n = 7): Group 1: Neither NSO nor radiation, Group 2: Rats received NSO 400 mg/kg, Group 3: Rats received 15 Gy cranium gamma irradiation & Group 4: Rats received gamma irradiation and NSO. Rats were sacrificed two weeks after the last NSO dose. Histological sections of parotid glands were stained with H&E, Masson's trichrome and anti-TGF-β antibodies. Area percentage of Masson's trichrome and TGF-β expression was morphometrically examined.

RESULTS

Parotid glands of control and NSO groups revealed normal morphology. Gamma-irradiated glands showed loss of normal acinar architecture and slight acinar shrinkage. NSO treatment of gamma-irradiated glands preserved acinar outline and architecture. Masson's trichrome stained samples revealed trace amounts of collagen fibers in control and NSO groups, and excessive amounts of collagen fibers in gamma-irradiated group, in addition to few collagen fibers for gamma-irradiated glands treated with NSO. Additionally, control and NSO groups showed negative TGF-β expression. Gamma-irradiated group showed high TGF-β expression, while NSO treated gamma-irradiated group showed moderate TGF-β expression.

CONCLUSIONS

Gamma-irradiation adversely affected parotid glands, and in contrast, NSO seemed to positively counteract this adverse effect.

Hypofractionated Radiotherapy followed by Hypofractionated Boost with weekly concurrent chemotherapy for Unresectable Stage III Non-Small Cell Lung Cancer: Results of A Prospective Phase II Study (GASTO-1049)

PURPOSE

We launched a prospective phase 2 clinical trial to explore the safety and efficacy of hypofractionated radiation therapy (hypo-RT) followed by hypofractionated boost (hypo-boost) combined with concurrent weekly chemotherapy in patients with unresectable locally advanced non-small cell lung cancer (LA-NSCLC).

METHODS AND MATERIALS

Patients with newly diagnosed LA-NSCLC with unresectable stage III disease were recruited between June 2018 and June 2020. Patients were treated with hypo-RT (40 Gy in 10 fractions) followed by hypo-boost (24-28 Gy in 6-7 fractions) combined with concurrent weekly chemotherapy (docetaxel 25 mg/m2 and nedaplatin 25 mg/m2). The primary endpoint of the study was progression-free survival (PFS), and the secondary endpoints included overall survival (OS), locoregional failure-free survival (LRFS), distant metastasis-free survival (DMFS), objective response rate (ORR), and toxicities.

RESULTS

From June 2018 to June 2020, 75 patients were enrolled with a median follow-up duration of 28.0 months. The ORR of the whole cohort was 94.7%. Disease progression or death was recorded in 44 (58.7%) patients, with a median PFS of 21.6 months (95% confidence interval [CI], 15.6-27.6 months). The 1- and 2-year PFS rates were 81.3% (95% CI, 72.5%-90.1%) and 43.3% (95% CI, 31.5%-55.1%), respectively. The median OS, DMFS, and LRFS had not been reached at the time of the last follow-up. The 1- and 2-year OS rates were 94.7% (95% CI, 89.6%-99.8%) and 72.4% (95% CI, 62.0%-82.8%), respectively. The most frequent acute nonhematologic toxicity was radiation esophagitis. Grade (G) 2 and G3 acute radiation esophagitis were observed in 20 (26.7%) and 4 (5.3%) patients, respectively. Thirteen patients (13/75, 17.3%) had G2 pneumonitis and no G3-G5 acute pneumonitis occurred during follow-up.

CONCLUSIONS

Hypo-RT followed by hypo-boost combined with concurrent weekly chemotherapy could yield satisfactory local control and survival outcomes with moderate radiation-induced toxicity in patients with LA-NSCLC. The new potent hypo-CCRT regimen significantly shortened treatment time and provided the potential opportunity for the combination of consolidative immunotherapy.

Comparison of the Medical Uses and Cellular Effects of High and Low Linear Energy Transfer Radiation

Exposure to ionizing radiation can occur during medical treatments, from naturally occurring sources in the environment, or as the result of a nuclear accident or thermonuclear war. The severity of cellular damage from ionizing radiation exposure is dependent upon a number of factors including the absorbed radiation dose of the exposure (energy absorbed per unit mass of the exposure), dose rate, area and volume of tissue exposed, type of radiation (e.g., X-rays, high-energy gamma rays, protons, or neutrons) and linear energy transfer. While the dose, the dose rate, and dose distribution in tissue are aspects of a radiation exposure that can be varied experimentally or in medical treatments, the LET and eV are inherent characteristics of the type of radiation. High-LET radiation deposits a higher concentration of energy in a shorter distance when traversing tissue compared with low-LET radiation. The different biological effects of high and low LET with similar energies have been documented in vivo in animal models and in cultured cells. High-LET results in intense macromolecular damage and more cell death. Findings indicate that while both low- and high-LET radiation activate non-homologous end-joining DNA repair activity, efficient repair of high-LET radiation requires the homologous recombination repair pathway. Low- and high-LET radiation activate p53 transcription factor activity in most cells, but high LET activates NF-kB transcription factor at lower radiation doses than low-LET radiation. Here we review the development, uses, and current understanding of the cellular effects of low- and high-LET radiation exposure.

Same-day consultation, simulation and lung Stereotactic Ablative Radiotherapy delivery on a Magnetic Resonance-linac

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A same-day consultation and lung SABR workflow was introduced, and experience in 10 patients reported.

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A detailed simulation procedure and the use of real-time cine magnetic resonance imaging enabled accurate treatment delivery.

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All patients reported satisfaction with the procedure, which improved patient convenience.

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On average, at least 94.4% (5th percentile) of the GTV was always located inside the PTV during beam-on.

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System-latency for triggering a beam-off event comprised 5.3% of the delivery time.

Background and Purpose

Magnetic resonance-guided radiotherapy (MRgRT) with real-time intra-fraction tumor motion monitoring allows for high precision Stereotactic Ablative Radiotherapy (SABR). This study aimed to investigate the clinical feasibility, patient satisfaction and delivery accuracy of single-fraction MR-guided SABR in a single day (one-stop-shop, OSS).

Methods and Materials

Ten patients with small lung tumors eligible for single fraction treatments were included. The OSS procedure consisted of consultation, treatment simulation, treatment planning and delivery. Following SABR delivery, patients completed a reported experience measure (PREM) questionnaire. Prescribed doses ranged 28–34 Gy. Median GTV was 2.2 cm³ (range 1.3–22.9 cm³). A gating boundary of 3 mm, and PTV margin of 5 mm around the GTV, were used with auto-beam delivery control. Accuracy of SABR delivery was studied by analyzing delivered MR-cines reconstructed from machine log files.

Results

All 10 patients completed the OSS procedure in a single day, and all reported satisfaction with the process. Median time for the treatment planning step and the whole procedure were 2.8 h and 6.6 h, respectively. With optimization of the procedure, treatment could be completed in half a day. During beam-on, the 3 mm tracking boundary encompassed between 78.0 and 100 % of the GTV across all patients, with corresponding PTV values being 94.4–100 % (5th-95th percentiles). On average, system-latency for triggering a beam-off event comprised 5.3 % of the delivery time. Latency reduced GTV coverage by an average of −0.3 %. Duty-cycles during treatment delivery ranged from 26.1 to 64.7 %.

Conclusions

An OSS procedure with MR-guided SABR for lung cancer led to good patient satisfaction. Gated treatment delivery was highly accurate with little impact of system-latency.

Radiotherapy as a tool to elicit clinically actionable signalling pathways in cancer

A variety of targeted anticancer agents have been successfully introduced into clinical practice, largely reflecting their ability to inhibit specific molecular alterations that are required for disease progression. However, not all malignant cells rely on such alterations to survive, proliferate, disseminate and/or evade anticancer immunity, implying that many tumours are intrinsically resistant to targeted therapies. Radiotherapy is well known for its ability to activate cytotoxic signalling pathways that ultimately promote the death of cancer cells, as well as numerous cytoprotective mechanisms that are elicited by cellular damage. Importantly, many cytoprotective mechanisms elicited by radiotherapy can be abrogated by targeted anticancer agents, suggesting that radiotherapy could be harnessed to enhance the clinical efficacy of these drugs. In this Review, we discuss preclinical and clinical data that introduce radiotherapy as a tool to elicit or amplify clinically actionable signalling pathways in patients with cancer.

A reinforcement learning approach for finding optimal policy of adaptive radiation therapy considering uncertain tumor biological response

Recent studies have shown that a tumor's biological response to radiation varies over time and has a dynamic nature. Dynamic biological features of tumor cells underscore the importance of using fractionation and adapting the treatment plan to tumor volume changes in radiation therapy treatment. Adaptive radiation therapy (ART) is an iterative process to adjust the dose of radiation in response to potential changes during the treatment. One of the key challenges in ART is how to determine the optimal timing of adaptations corresponding to tumor response to radiation. This paper aims to develop an automated treatment planning framework incorporating the biological uncertainties to find the optimal adaptation points to achieve a more effective treatment plan. First, a dynamic tumor-response model is proposed to predict weekly tumor volume regression during the period of radiation therapy treatment based on biological factors. Second, a Reinforcement Learning (RL) framework is developed to find the optimal adaptation points for ART considering the uncertainty in biological factors with the goal of achieving maximum final tumor control while minimizing or maintaining the toxicity level of the organs at risk (OARs) per the decision-maker's preference. Third, a beamlet intensity optimization model is solved using the predicted tumor volume at each adaptation point. The performance of the proposed RT treatment planning framework is tested using a clinical non-small cell lung cancer (NSCLC) case. The results are compared with the conventional fractionation schedule (i.e., equal dose fractionation) as a reference plan. The results show that the proposed approach performed well in achieving a robust optimal ART treatment plan under high uncertainty in the biological parameters. The ART plan outperformed the reference plan by increasing the mean biological effective dose (BED) value of the tumor by 2.01%, while maintaining the OAR BED within +0.5% and reducing the variability, in terms of the interquartile range (IQR) of tumor BED, by 25%.

Clinically validated model predicts the effect of intratumoral heterogeneity on overall survival for non-small cell lung cancer (NSCLC) patients

BACKGROUND AND OBJECTIVE

Radiation therapy is used in nearly 50% of cancer treatments in the developed world. Currently, radiation treatments are homogenous and fail to take into consideration intratumoral heterogeneity. We demonstrate the importance of considering intratumoral heterogeneity and the development of resistance during fractionated radiotherapy when the same dose of radiation is delivered for all fractions (Fractional Equivalent Dosing FED).

METHODS

A mathematical model was developed with the following parameters: a starting population of 10¹¹ non-small cell lung cancer (NSCLC) tumor cells, 48 h doubling time, and cell death per the linear-quadratic (LQ) model with α and β values derived from RSIα/β, in a previously described gene expression based model that estimates α and β. To incorporate both inter- and intratumor radiation sensitivity, RSIα/β output for each patient sample is assumed to represent an average value in a gamma distribution with the bounds set to -50% and +50% of RSIα/b. Therefore, we assume that within a given tumor there are subpopulations that have varying radiation sensitivity parameters that are distinct from other tumor samples with a different mean RSIα/β. A simulation cohort (SC) comprised of 100 lung cancer patients with available RSIα/β (patient specific α and β values) was used to investigate 60 Gy in 30 fractions with fractionally equivalent dosing (FED). A separate validation cohort (VC) of 57 lung cancer patients treated with radiation with available local control (LC), overall survival (OS), and tumor gene expression was used to clinically validate the model. Cox regression was used to test for significance to predict clinical outcomes as a continuous variable in multivariate analysis (MVA). Finally, the VC was used to compare FED schedules with various altered fractionation schema utilizing a Kruskal-Wallis test. This was examined using the end points of end of treatment log cell count (LCC) and by a parameter described as mean log kill efficiency (LKE) defined as: LCC  =  log10(tumorcellcount) [Formula: see text] RESULTS: Cox regression analysis on LCC for the VC demonstrates that, after incorporation of intratumoral heterogeneity, LCC has a linear correlation with local control (p = 0.002) and overall survival (p = < 0.001). Other suggested treatment schedules labeled as High Intensity Treatment (HIT) with a total 60 Gy delivered over 6 weeks have a lower mean LCC and an increased LKE compared to standard of care 60 Gy delivered in FED in the VC.

CONCLUSION

We find that LCC is a clinically relevant metric that is correlated with local control and overall survival in NSCLC. We conclude that 60 Gy delivered over 6 weeks with altered HIT fractionation leads to an enhancement in tumor control compared to FED when intratumoral heterogeneity is considered.

Targeting therapy-resistant lung cancer stem cells via disruption of the AKT/TSPYL5/PTEN positive-feedback loop

Cancer stem cells (CSCs) are regarded as essential targets to overcome tumor progression and therapeutic resistance; however, practical targeting approaches are limited. Here, we identify testis-specific Y-like protein 5 (TSPYL5) as an upstream regulator of CSC-associated genes in non-small cell lung cancer cells, and suggest as a therapeutic target for CSC elimination. TSPYL5 elevation is driven by AKT-dependent TSPYL5 phosphorylation at threonine-120 and stabilization via inhibiting its ubiquitination. TSPYL5-pT120 also induces nuclear translocation and functions as a transcriptional activator of CSC-associated genes, ALDH1 and CD44. Also, nuclear TSPYL5 suppresses the transcription of PTEN, a negative regulator of PI3K signaling. TSPYL5-pT120 maintains persistent CSC-like characteristics via transcriptional activation of CSC-associated genes and a positive feedback loop consisting of AKT/TSPYL5/PTEN signaling pathway. Accordingly, elimination of TSPYL5 by inhibiting TSPYL5-pT120 can block aberrant AKT/TSPYL5/PTEN cyclic signaling and TSPYL5-mediated cancer stemness regulation. Our study suggests TSPYL5 be an effective target for therapy-resistant cancer.

In order to assist the development of cancer stem cell (CSC) therapy, Kim et al identified testis-specific Y-like protein 5 (TSPYL5) as an upstream regulator of CSC-associated genes in non-small cell lung cancer cells. They demonstrated in cancer cell lines and in vivo that TSPYL5 activity is dependent on AKT signalling and that disruption of TSPYL5 signalling could serve as a potential strategy to tackle therapy-resistant cancers.

Hypofractionation and Stereotactic Body Radiation Therapy in Inoperable Locally Advanced Non-small Cell Lung Cancer

BACKGROUND AND AIM

Radiotherapy (RT) plays a key role in the control of locally advanced non-small cell lung cancer (LA-NSCLC). Throughout the years, different doses and fractionations of RT have been used in an attempt to optimize the results. Recently, special interest has been given to hypofractionation (hypoRT) and stereotactic body radiation therapy (SBRT). HypoRT is a relatively widespread treatment, although the accompanying level of evidence is limited. For its part, SBRT has been used specially to overdose specific areas of the disease as a boost after radiochemotherapy. In both cases, the study of how to integrate these RT tools with chemotherapy and immunotherapy is fundamental. In addition, the 2020 COVID-19 pandemic situation has sparked increased interest in hypofractionated treatments. In this review, we analyze the role of SBRT and hypoRT in the management of LA-NSCLC in accordance with current scientific evidence.

RELEVANCE FOR PATIENTS

The objective of this article is to introduce professionals to the role that hypoRT and SBRT can play in the treatment of LA-NSCLC to offer the best treatment to their patients.

Dose and fractionation schedules in radiotherapy for non-small cell lung cancer

In the field of radiotherapy (RT), the issues of total dose, fractionation, and overall treatment time for non-small cell lung cancer (NSCLC) have been extensively investigated. There is some evidence to suggest that higher treatment intensity of RT, when given alone or sequentially with chemotherapy (CHT), is associated with improved survival. However, there is no evidence that the outcome is improved by RT at a higher dose and/or higher intensity when it is used concurrently with CHT. Moreover, some reports on the combination of full dose CHT with a higher biological dose of RT warn of the significant risk posed by such intensification. Stereotactic body radiotherapy (SBRT) provides a high rate of local control in the management of early-stage NSCLC through the use of high ablative doses. However, in centrally located tumors the use of SBRT may carry a risk of serious damage to the great vessels, bronchi, and esophagus, owing to the high ablative doses needed for optimal tumor control. There is a similar problem with moderate hypofractionation in radical RT for locally advanced NSCLC, and more evidence needs to be gathered regarding the safety of such schedules, especially when used in combination with CHT. In this article, we review the current evidence and questions related to RT dose/fractionation in NSCLC.

Variations in Demand across England for the Magnetic Resonance-Linac Technology, Simulated Utilising Local-level Demographic and Cancer Data in the Malthus Project

AIMS

Cancer incidence varies across England, which affects the local-level demand for treatments. The magnetic resonance-linac (MR-linac) is a new radiotherapy technology that combines imaging and treatment. Here we model the demand and demand variations for the MR-linac across England.

MATERIALS AND METHODS

Initial clinical indications were provided by the MR-linac consortium and introduced into the Malthus radiotherapy clinical decision trees. The Malthus model contains Clinical Commissioning Group (CCG) population, cancer incidence and stage presentation data (for lung and prostate) and simulated the demand for the MR-linac for all CCGs and Radiotherapy Operational Delivery Networks (RODN) across England.

RESULTS

Based on the initial target clinical indications, the MR-linac could service 16% of England's fraction burden. The simulated fractions/million population demand/annum varies between 3000 and 10 600 fractions/million at the CCG level. Focussing only on the cancer population, the simulated fractions/1000 cancer cases demand/annum ranges from 1028 to 1195 fractions/1000 cases. If a national average for fractions/million demand was then used, at the RODN level, the variation from actual annual demand ranges from an overestimation of 8400 fractions to an underestimation of 5800 fractions. When using the national average fractions/1000 cases, the RODN demand varies from an overestimation of 3200 fractions to an underestimation of 3000 fractions.

CONCLUSIONS

Planning cancer services is complex due to regional variations in cancer burden. The variations in simulated demand of the MR-linac highlight the requirement to use local-level data when planning to introduce a new technology.

A New Platinum-Based Prodrug Candidate for Chemotherapy and Its Synergistic Effect With Hadrontherapy: Novel Strategy to Treat Glioblastoma

Glioblastoma (GBM) is the most common tumor of the central nervous system. Current therapies, often associated with severe side effects, are inefficacious to contrast the GBM relapsing forms. In trying to overcome these drawbacks, (OC-6-44)-acetatodiamminedichlorido(2-(2-propynyl)octanoato)platinum(IV), also called Pt(IV)Ac-POA, has been recently synthesized. This new prodrug bearing as axial ligand (2-propynyl)octanoic acid (POA), a histone deacetylase inhibitor, has a higher activity due to (i) its high cellular accumulation by virtue of its high lipophilicity and (ii) the inhibition of histone deacetylase, which leads to the increased exposure of nuclear DNA, permitting higher platination and promoting cancer cell death. In the present study, we investigated the effects induced by Pt(IV)Ac-POA and its potential antitumor activity in human U251 glioblastoma cell line using a battery of complementary techniques, i.e., flow cytometry, immunocytochemistry, TEM, and Western blotting analyses. In addition, the synergistic effect of Pt(IV)Ac-POA associated with the innovative oncological hadrontherapy with carbon ions was investigated, with the aim to identify the most efficient anticancer treatment combination. Our in vitro data demonstrated that Pt(IV)Ac-POA is able to induce cell death, through different pathways, at concentrations lower than those tested for other platinum analogs. In particular, an enduring Pt(IV)Ac-POA antitumor effect, persisting in long-term treatment, was demonstrated. Interestingly, this effect was further amplified by the combined exposure to carbon ion radiation. In conclusion, Pt(IV)Ac-POA represents a promising prodrug to be incorporated into the treatment regimen for GBM. Moreover, the synergistic efficacy of the combined protocol using chemotherapeutic Pt(IV)Ac-POA followed by carbon ion radiation may represent a promising approach, which may overcome some typical limitations of conventional therapeutic protocols for GBM treatment.

Chemoradiotherapy by intensity-modulated radiation therapy with simultaneous integrated boost in locally advanced or oligometastatic non-small-cell lung cancer-a two center experience

Purpose

Integrating moderate hypofractionation to the macroscopic tumor with elective nodal irradiation while sparing the organs at risk (OAR) in chemoradiotherapy of locally advanced non-small-cell lung cancer.

Methods

From 2010–2018, treatment, patient and tumor characteristics of 138 patients from two radiation therapy centers were assessed. Chemoradiotherapy by intensity-modulated radiation therapy (IMRT) with a simultaneous integrated boost (SIB) to the primary tumor and macroscopic lymph node metastases was used.

Results

A total of 124 (90%) patients received concurrent chemotherapy. 106 (76%) patients had UICC (Union for International Cancer Control) stage ≥IIIB and 21 (15%) patients had an oligometastatic disease (UICC stage IV). Median SIB and elective total dose was 61.6 and 50.4 Gy in 28 fractions, respectively. Furthermore, 64 patients (46%) had an additional sequential boost to the primary tumor after the SIB-IMRT main series: median 6.6 Gy in median 3 fractions. The median cumulative mean lung dose was 15.6 Gy (range 6.2–29.5 Gy). Median follow-up and radiological follow-up for all patients was 18.0 months (range 0.6–86.9) and 16.0 months (range 0.2–86.9), respectively. Actuarial local control rates at 1, 2 and 3 years were 80.4, 68.4 and 57.8%. Median overall survival and progression-free survival was 30.0 months (95% confidence interval [CI] 23.5–36.4) and 12.1 months (95% CI 8.2–16.0), respectively. Treatment-related toxicity was moderate. Radiation-induced pneumonitis grade 2 and grade 3 occurred in 13 (9.8%) and 3 (2.3%) patients.

Conclusions

Chemoradiotherapy using SIB-IMRT showed promising local tumor control rates and acceptable toxicity in patients with locally advanced and in part oligometastatic lung cancer. The SIB concept, resulting in a relatively low mean lung dose, was associated with low numbers of clinically relevant pneumonitis. The overall survival appears promising in the presence of a majority of patients with UICC stage ≥IIIB disease.

Radiation Modalities Used in Lung Cancer: An Overview for Thoracic Surgeons

Radiation is a constantly evolving technology which plays a role in the management of lung cancer in a variety of settings: as an adjunct to surgery, definitively, and palliatively. Key aspects of radiation oncology-including acute and chronic toxicities of thoracic radiation and rationale for choosing one modality of radiation over another-may be obscure to those outside the field. We aim to provide a useful overview relevant for the thoracic surgeon of radiation technology and delivery. A review was performed of salient articles identifying radiation technologies used in lung cancer which were summarized and expounded upon with focus on integrating their history, evolution, and landmark trials establishing basis of their use. This article reviews the four fundamental means of external beam radiation employed in managing lung cancer and provides visual examples of comparison plans. We also touch on potential practice-changing developments in regards to proton therapy and radiation in the era of immunotherapy. Radiation oncology has evolved considerably over time to become a critical part of lung cancer management, particularly in early-stage inoperable disease and locally advanced disease. Maximizing tumor control while minimizing toxicity drives treatment strategies. Knowledge of these fundamentals will help the thoracic surgeon answer many questions patients pose regarding radiation.

Radioprotective Effect of Whey Hydrolysate Peptides against γ-Radiation-Induced Oxidative Stress in BALB/c Mice

Radiation therapy is widely used in the treatment of tumor diseases, but it can also cause serious damage to the body, so it is necessary to find effective nutritional supplements. The main purpose of this study is to evaluate the protective effect of whey hydrolysate peptides (WHPs) against ⁶⁰Coγ radiation damage in mice and explore the mechanism. BALB/c mice were given WHPs by oral gavage administration for 14 days. Then, some mice underwent a 30-day survival test after 8 Gy radiation, and other mice received 3.5 Gy radiation to analyze the changes in body weight, hematology and bone marrow DNA after three and 14 days. In addition, through further analysis of the level of oxidative stress and intestinal barrier function, the possible mechanism of the radioprotective effect of WHPs was explored. The study found WHPs can prolong survival time, restore body weight, and increase the number of peripheral blood white blood cells and bone marrow DNA content in irradiated mice. In addition, WHPs can significantly improve the antioxidant capacity, inhibit pro-inflammatory cytokines and protect the intestinal barrier. These results indicate that WHPs have a certain radioprotective effect in mice, and the main mechanism is related to reducing oxidative damage.

Is clinical target volume necessary?-a failure pattern analysis in patients with locally advanced non-small cell lung cancer treated with concurrent chemoradiotherapy using intensity-modulated radiotherapy technique

Background

Our previous dosimetric study showed that for locally advanced non-small cell lung cancer (LA-NSCLC), radiotherapy with intensity-modulated radiotherapy (IMRT) technique could deliver sufficient dose coverage to subclinical regions and reduce the dose to normal tissues with the omission of clinical target volume (CTV). To further clinically validate this strategy, we conducted the current study to analyze the failure pattern for patients with LA-NSCLC treated with concurrent chemotherapy and CTV-omitted IMRT. We also investigated the effects of target volumes on lymphopenia during radiotherapy to further test the potential benefits of CTV omission in anti-tumor immunotherapy.

Methods

A total of 63 patients with LA-NSCLC treated with CTV-omitted IMRT with concurrent chemotherapy were enrolled in this study. Their planning target volume (PTV) (also PTV-g) was expanded directly from gross tumor volume (GTV). A virtual CTV was expanded from GTV, and the PTV generated from virtual CTV was named planning target volume with CTV expansion (PTV-c). Treatment failures were divided into local, regional, and distant failures, and local–regional recurrences were classified into inside PTV-g (IN-PTV-g), between PTV-g and PTV-c (PTV-g-c), and outside PTV-c (OUT-PTV-c). The relationship between lymphopenia during radiotherapy and the target volumes was also evaluated using Spearman’s correlation analysis.

Results

Among the 60 patients with detailed follow-up data for recurrences, 46 (76.7%) experienced recurrences, with 18 (30.0%) being local recurrence, 5 (8.4%) being regional failure, and 33 (55.0%) being distant failure. For the 21 patients with local–regional recurrences, 16, 6, and 1 were IN-PTV-g, OUT-PTV-c, and PTV-g-c recurrences, respectively. Lymphopenia during radiotherapy was associated with both GTV and PTV, with larger volumes linked to severe lymphopenia.

Conclusions

CTV omission is feasible for LA-NSCLC treated with concurrent chemoradiotherapy and does not compromise failure inside the subclinical region. The radiation volumes were associated with lymphopenia during radiotherapy, with larger volumes related to severe lymphopenia. This finding supports the further exploration of CTV omission for immunotherapy.

A mini-review of X-ray photodynamic therapy (XPDT) nonoagent constituents' safety and relevant design considerations

Conventional photodynamic therapy (PDT) has proved effective in the management of primary tumors and individual metastases. However, most cancer mortality arises from wide-spread multiple metastases. The latter has thus become the principal target in oncology, and X-ray induced photodynamic therapy (XPDT or PDTX) offers a great solution for adapting the PDT principle to deep tumors and scattered metastases. Developing agents capable of being excited by X-rays and emitting visible light to excite photosensitizers is based on challenging physical and chemical technologies, but there are fundamental biological limitations that are to be accounted for as well. In the present review, we have established eight major groups of safety determinants of NPs encompassing 22 parameters of clinical applicability of XPDT nanoparticulate formulations. Most, if not all, of these parameters can be accounted for and optimized during the design and development of novel XPDT nanoparticles.

Downregulated Mucin 1 alleviates paclitaxel resistance in non‑small cell lung cancer cells

Multidrug resistance of non‑small cell lung cancer (NSCLC) is a common clinical problem, which is one of the main reasons leading to the failure of chemotherapy. Therefore, how to overcome or prevent drug resistance has become a hot and difficult issue in clinical research. The present study was designed to investigate the expression patterns, functions and underlying mechanisms of MUC1 in regulating paclitaxel‑resistant cell line A549/PR in NSCLC. RT‑qPCR and western blot was performed to determine the mRNA and protein level, respectively. CCK‑8 was conducted to determine the cell viability of A549/PR cells. Moreover, flow cytometry assay was applied to examine the apoptosis rate of A549/PR. Herein, the MUC1 was over‑expressed in clinic NSCLC tissues and A549/PR cells. Silence of MUC1 could obviously suppress the proliferation and promote apoptosis of A549/PR cells in treatment of paclitaxel through up‑regulating the expression of Bax and Caspase‑3, and down‑regulating the expression of Bcl‑2, suggesting that chemotherapy combined with the modulation of MUC1 might be characterized as a promising therapeutic approach to overcome paclitaxel‑resistance in NSCLC in the future.

Alternative Multidisciplinary Management Options for Locally Advanced NSCLC During the Coronavirus Disease 2019 Global Pandemic

The coronavirus disease 2019 (COVID-19) pandemic is currently accelerating. Patients with locally advanced NSCLC (LA-NSCLC) may require treatment in locations where resources are limited, and the prevalence of infection is high. Patients with LA-NSCLC frequently present with comorbidities that increase the risk of severe morbidity and mortality from COVID-19. These risks may be further increased by treatments for LA-NSCLC. Although guiding data is scarce, we present an expert thoracic oncology multidisciplinary (radiation oncology, medical oncology, surgical oncology) consensus of alternative strategies for the treatment of LA-NSCLC during a pandemic. The overarching goals of these approaches are the following: (1) reduce the number of visits to a health care facility, (2) reduce the risk of exposure to severe acute respiratory syndrome-coronavirus-2, (3) attenuate the immunocompromising effects of lung cancer therapies, and (4) provide effective oncologic therapy. Patients with resectable disease can be treated with definitive nonoperative management if surgical resources are limited or the risks of perioperative care are high. Nonoperative options include chemotherapy, chemoimmunotherapy, and radiation therapy with sequential schedules that may or may not affect long-term outcomes in an era in which immunotherapy is available. The order of treatments may be on the basis of patient factors and clinical resources. Whenever radiation therapy is delivered without concurrent chemotherapy, hypofractionated schedules are appropriate. For patients who are confirmed to have COVID-19, usually, cancer therapies may be withheld until symptoms have resolved with negative viral test results. The risk of severe treatment-related morbidity and mortality is increased for patients undergoing treatment for LA-NSCLC during the COVID-19 pandemic. Adapting alternative treatment strategies as quickly as possible may save lives and should be implemented through communication with the multidisciplinary cancer team.

Radiation dose escalation with modified fractionation schedules for locally advanced NSCLC: A systematic review

Concomitant chemo‐radiotherapy (cCRT) with 60 Gy in 30 fractions is the standard of care for stage 111 non‐small cell lung cancer (NSCLC). With a median overall survival of 28.7 months at best and maximum locoregional control rates of 70% at two years, the prognosis for these patients is still dismal. This systematic review summarizes data on dose escalation by alternative fractionation, which has been explored as a primary strategy to improve both local control and overall survival over the past three decades. A Pubmed literature search was performed according to the PRISMA guidelines. Because of the large variety of radiation regimens total doses were converted to EQD_2,T. Only studies using an EQD_2,T of at least 49.5 Gy, which corresponds to the conventional 60 Gy in six weeks, were included. In a total of 3256 patients, the median OS was 17 months (range 7.4–30 months). While OS was better for patients treated after the year 2000 (P = 0.003) or with a mandatory ¹⁸F‐FDG‐PET‐CT in the diagnostic work‐up (P = 0.001), treatment sequence did not make a difference (P = 0.106). The most commonly reported toxicity was acute esophagitis (AE) with a median rate of 24% (range 0%–84%). AE increased at a rate of 0.5% per Gy increment in EQD_2,T (P = 0.016). Dose escalation above the conventional 60 Gy using modified radiation fractionation schedules and shortened OTT yield similar mOS and LRC regardless of treatment sequence with a significant EQD_2,T dependent increase in AE.

Key points

Significant findings

Modified radiation dose escalation sequentially combined with chemotherapy yields similar outcome as concomitant treatment.

OS is better with the mandatory inclusion of FDG‐PET‐CT in the diagnostic work‐up.

The risk of acute esophagitis increases with higher EQD_2,T.

What this study adds

Chemo‐radiotherapy (CRT) with modified dose escalation regimens yields OS and LC rates in the range of standard therapy regardless of treatment sequence. This broadens the database of curative options in patients who are not eligible concomitant CRT.

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.

Image guidance: past and future of radiotherapy

Image guidance has been playing a decisive role throughout the history of radiotherapy, but developments in 3D-and 4D imaging data acquisition using computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET) have significantly boosted the precision of conformal radiotherapy. An overarching aim of radiotherapy is conforming the treatment dose to the tumor in order to optimally limit a high radiation dose outside the target. Stereotactic, intensity modulated, and adaptive radiotherapy are all largely based on appropriately using imaging information both before and during treatment delivery using on-board imaging devices. While pretreatment imaging for planning has reached a very high level in the past two decades, the next step will be to further refine and accelerate imaging during treatment delivery, resulting in adaptation of the dose fluence during a patient’s treatment in various scenarios, some of which are discussed in this article.

The evolving role of radiotherapy in non-small cell lung cancer

Lung cancer is the most commonly diagnosed cancer and biggest cause of cancer mortality worldwide with non-small cell lung cancer (NSCLC) accounting for most cases. Radiotherapy (RT) plays a key role in its management and is used at least once in over half of patients in both curative and palliative treatments. This narrative review will demonstrate how the evolution of RT for NSCLC has been underpinned by improvements in RT technology. These improvements have facilitated geometric individualization, increasingly accurate treatment and now offer the ability to deliver truly individualized RT. In this review, we summarize and discuss recent developments in the field of advanced RT in early stage, locally advanced and metastatic NSCLC. We highlight limitations in current approaches and discuss future potential treatment strategies for patients with NSCLC.

Isoflavone-mediated radioprotection involves regulation of early endothelial cell death and inflammatory signaling in Radiation-Induced lung injury

Purpose: Vascular damage and inflammation are limiting toxic effects of lung cancer radiotherapy, which lead to pneumonitis and pulmonary fibrosis. We have demonstrated that soy isoflavones (SIF) mitigate these toxic effects at late time points after radiation. However, the process by which SIF impacts the onset of radiation-induced inflammation remains to be elucidated. We have now investigated early events of radiation-induced inflammation and identified cellular and molecular signaling patterns by endothelial cells that could be modified by SIF to control vascular damage and the initiation of lung inflammation.Materials and methods: Histopathological, cellular and molecular studies were performed on mouse lungs from C57Bl/6 mice treated with 10 Gy of thoracic radiation (XRT) in conjunction with daily oral SIF treatment given prior and after radiation. Parallel studies were performed in-vitro using EA.hy926 endothelial cell line with SIF and radiation. Immunohistochemistry, western blots analysis, and flow cytometry were performed on lung tissue or EA.hy926 cells to analyze endothelial cells, their patterns of cell death or survival, and signaling molecules involved in inflammatory events.Results: Histopathological differences in inflammatory infiltrates and vascular injury in lungs, including vascular endothelial cells, were observed with SIF treatment at early time points post-XRT. XRT-induced expression of proinflammatory adhesion molecule ICAM-1 cells was reduced by SIF in-vitro and in-vivo in endothelial cells. Molecular changes in endothelial cells with SIF treatment in conjunction with XRT included increased DNA damage, reduced cell viability and cyclin B1, and inhibition of nuclear translocation of NF-κB. Analysis of cell death showed that SIF treatment promoted apoptotic endothelial cell death and decreased XRT-induced type III cell death. In-vitro molecular studies indicated that SIF + XRT increased apoptotic caspase-9 activation and production of IFNβ while reducing the release of inflammatory HMGB-1 and IL-1α, the cleavage of pyroptotic gasdermin D, and the release of active IL-1β, which are all events associated with type III cell death.Conclusions: SIF + XRT caused changes in patterns of endothelial cell death and survival, proinflammatory molecule release, and adhesion molecule expression at early time points post-XRT associated with early reduction of immune cell recruitment. These findings suggest that SIF could mediate its radioprotective effects in irradiated lungs by limiting excessive immune cell homing via vascular endothelium into damaged lung tissue and curtailing the overall inflammatory response to radiation.

Synchronous Oligometastatic Non-small Cell Lung Cancer Managed With Curative-Intent Chemoradiation Therapy: Long-term Outcomes From a Single Institution

Purpose

We examined long-term clinical outcomes among patients with synchronous oligometastatic non-small cell lung cancer (NSCLC) treated at our institution with definitive thoracic chemoradiation therapy (CRT) and local therapy to all oligometastatic lesions.

Methods and Materials

A retrospective review identified 38 patients with synchronous oligometastatic NSCLC (≤3 metastatic lesions) who were treated with definitive CRT to the primary tumor and regional lymph nodes between 1999 and 2017 at our institution. Of the 38 patients, 27 patients (71%) received induction chemotherapy, all of whom responded or stabilized with initial systemic therapy before consideration of CRT. Most patients received chemotherapy concurrently with radiation therapy (n = 32; 84%) and local therapy to the metastatic disease site(s) (n = 34; 89%). We assessed patterns of progression or failure, overall survival (OS), progression-free survival (PFS), and toxicities.

Results

The median follow-up duration was 54.9 months. Most patients (84%) presented with N2 to N3 disease. The brain or central nervous system was the most common site of disease progression and occurred in 16 of 28 patients (57%) experiencing any progression and 10 of 16 patients (63%) who initially presented with brain oligometastases. Median OS was 21.1 months (95% confidence interval [CI], 15.6-49.0 months), and median PFS 9.7 months (95% CI, 8.2-14.4 months). The 1-, 2-, and 4-year OS rates were 75.7%, 45.0%, and 33.7%, respectively. On multivariate analysis, both locoregional progression (hazard ratio: 5.8; 95% CI, 2.2-15.0; P = .0003) and distant progression (hazard ratio: 6.0; 95% CI, 2.3-15.4; P = .0002), when treated as time-dependent covariates, were associated with inferior OS. Grade ≥3 esophagitis occurred in 9% and grade ≥3 pneumonitis in 5% of patients with evaluable data.

Conclusions

Patients with synchronous oligometastatic NSCLC and a high regional nodal burden treated with definitive thoracic CRT experienced favorable survival outcomes and low toxicity. At our institution, treating oligometastatic disease with CRT after systemic therapy is incorporated into the treatment plan from the onset of therapy, and we monitor the neuraxis closely for progression during and after treatment. Future research should focus on novel treatment combinations, such as immunotherapy or targeted systemic therapy as appropriate to further improve tumor control and survival.