Evaluating risk factors of radiation pneumonitis after stereotactic body radiation therapy in lung tumor: Meta-analysis of 9 observational studies

Endobronchially Implanted Real-Time Electromagnetic Transponder Beacon-Guided, Respiratory-Gated SABR for Moving Lung Tumors: A Prospective Phase 1/2 Cohort Study

Purpose

Endobronchial electromagnetic transponder beacons (EMT) provide real-time, precise positional data of moving lung tumors. We report results of a phase 1/2, prospective, single-arm cohort study evaluating the treatment planning effects of EMT-guided SABR for moving lung tumors.

Methods and Materials

Eligible patients were adults, Eastern Cooperative Oncology Group 0 to 2, with T1-T2N0 non-small cell lung cancer or pulmonary metastasis ≤4 cm with motion amplitude ≥5 mm. Three EMTs were endobronchially implanted using navigational bronchoscopy. Four-dimensional free-breathing computed tomography simulation scans were obtained, and end-exhalation phases were used to define the gating window internal target volume. A 3-mm expansion of gating window internal target volume defined the planning target volume (PTV). EMT-guided, respiratory-gated (RG) SABR was delivered (54 Gy/3 fractions or 48 Gy/4 fractions) using volumetric modulated arc therapy. For each RG-SABR plan, a 10-phase image-guided SABR plan was generated for dosimetric comparison. PTV/organ-at-risk (OAR) metrics were tabulated and analyzed using the Wilcoxon signed-rank pair test. Treatment outcomes were evaluated using RECIST (Response Evaluation Criteria in Solid Tumours; version 1.1).

Results

Of 41 patients screened, 17 were enrolled and 2 withdrew from the study. Median age was 73 years, with 7 women. Sixty percent had T1/T2 non-small cell lung cancer and 40% had M1 disease. Median tumor diameter was 1.9 cm with 73% of targets located peripherally. Mean respiratory tumor motion was 1.25 cm (range, 0.53-4.04 cm). Thirteen tumors were treated with EMT-guided SABR and 47% of patients received 48 Gy in 4 fractions while 53% received 54 Gy in 3 fractions. RG-SABR yielded an average PTV reduction of 46.9% (P < .005). Lung V5, V10, V20, and mean lung dose had mean relative reductions of 11.3%, 20.3%, 31.1%, and 20.3%, respectively (P < .005). Dose to OARs was significantly reduced (P < .05) except for spinal cord. At 6 months, mean radiographic tumor volume reduction was 53.5% (P < .005).

Conclusions

EMT-guided RG-SABR significantly reduced PTVs of moving lung tumors compared with image-guided SABR. EMT-guided RG-SABR should be considered for tumors with large respiratory motion amplitudes or those located in close proximity to OARs.

Ultra-high dose-rate proton FLASH improves tumor control

BACKGROUND AND PURPOSE

Proton radiotherapy (PRT) offers potential benefits over other radiation modalities, including photon and electron radiotherapy. Increasing the rate at which proton radiation is delivered may provide a therapeutic advantage. Here, we compared the efficacy of conventional proton therapy (CONVpr) to ultrahigh dose-rate proton therapy, FLASHpr, in a mouse model of non-small cell lung cancers (NSCLC).

MATERIALS AND METHODS

Mice bearing orthotopic lung tumors received thoracic radiation therapy using CONVpr (<0.05 Gy/s) and FLASHpr (>60 Gy/s) dose rates.

RESULTS

Compared to CONVpr, FLASHpr was more effective in reducing tumor burden and decreasing tumor cell proliferation. Furthermore, FLASHpr was more efficient in increasing the infiltration of cytotoxic CD8+ T-lymphocytes inside the tumor while simultaneously reducing the percentage of immunosuppressive regulatory T-cells (Tregs) among T-lymphocytes. Also, compared to CONVpr, FLASHpr was more effective in decreasing pro-tumorigenic M2-like macrophages in lung tumors, while increasing infiltration of anti-tumor M1-like macrophages. Finally, FLASHpr treatment reduced expression of checkpoint inhibitors in lung tumors, indicating reduced immune tolerance.

CONCLUSIONS

Our results suggest that FLASH dose-rate proton delivery modulates the immune system to improve tumor control and might thus be a promising new alternative to conventional dose rates for NSCLC treatment.

Benchmarking machine learning approaches to predict radiation-induced toxicities in lung cancer patients

Background and purpose

Radiation-induced toxicities are common adverse events in lung cancer (LC) patients undergoing radiotherapy (RT). An accurate prediction of these adverse events might facilitate an informed and shared decision-making process between patient and radiation oncologist with a clearer view of life-balance implications in treatment choices. This work provides a benchmark of machine learning (ML) approaches to predict radiation-induced toxicities in LC patients built upon a real-world health dataset based on a generalizable methodology for their implementation and external validation.

Materials and Methods

Ten feature selection (FS) methods were combined with five ML-based classifiers to predict six RT-induced toxicities (acute esophagitis, acute cough, acute dyspnea, acute pneumonitis, chronic dyspnea, and chronic pneumonitis). A real-world health dataset (RWHD) built from 875 consecutive LC patients was used to train and validate the resulting 300 predictive models. Internal and external accuracy was calculated in terms of AUC per clinical endpoint, FS method, and ML-based classifier under analysis.

Results

Best performing predictive models obtained per clinical endpoint achieved comparable performances to methods from state-of-the-art at internal validation (AUC ≥ 0.81 in all cases) and at external validation (AUC ≥ 0.73 in 5 out of 6 cases).

Conclusion

A benchmark of 300 different ML-based approaches has been tested against a RWHD achieving satisfactory results following a generalizable methodology. The outcomes suggest potential relationships between underrecognized clinical factors and the onset of acute esophagitis or chronic dyspnea, thus demonstrating the potential that ML-based approaches have to generate novel data-driven hypotheses in the field.

Multiple regression analysis of risk factors related to radiation pneumonitis

BACKGROUND

Radiation pneumonitis (RP) is a severe complication of thoracic radiotherapy that may lead to dyspnea and lung fibrosis, and negatively affects patients’ quality of life.

AIM

To carry out multiple regression analysis on the influencing factors of radiation pneumonitis.

METHODS

Records of 234 patients receiving chest radiotherapy in Huzhou Central Hospital (Huzhou, Zhejiang Province, China) from January 2018 to February 2021, and the patients were divided into either a study group or a control group based on the presence of radiation pneumonitis or not. Among them, 93 patients with radiation pneumonitis were included in the study group and 141 without radiation pneumonitis were included in the control group. General characteristics, and radiation and imaging examination data of the two groups were collected and compared. Due to the statistical significance observed, multiple regression analysis was performed on age, tumor type, chemotherapy history, forced vital capacity (FVC), forced expiratory volume in the first second (FEV1), carbon monoxide diffusion volume (DLCO), FEV1/FVC ratio, planned target area (PTV), mean lung dose (MLD), total number of radiation fields, percentage of lung tissue in total lung volume (vdose), probability of normal tissue complications (NTCP), and other factors.

RESULTS

The proportions of patients aged ≥ 60 years and those with the diagnosis of lung cancer and a history of chemotherapy in the study group were higher than those in the control group (P < 0.05); FEV1, DLCO, and FEV1/FVC ratio in the study group were lower than those in the control group (P < 0.05), while PTV, MLD, total field number, vdose, and NTCP were higher than in the control group (P < 0.05). Logistic regression analysis showed that age, lung cancer diagnosis, chemotherapy history, FEV1, FEV1/FVC ratio, PTV, MLD, total number of radiation fields, vdose, and NTCP were risk factors for radiation pneumonitis.

CONCLUSION

We have identified patient age, type of lung cancer, history of chemotherapy, lung function, and radiotherapy parameters as risk factors for radiation pneumonitis. Comprehensive evaluation and examination should be carried out before radiotherapy to effectively prevent radiation pneumonitis.

Pre-Existing Interstitial Lung Abnormalities Are Independent Risk Factors for Interstitial Lung Disease during Durvalumab Treatment after Chemoradiotherapy in Patients with Locally Advanced Non-Small-Cell Lung Cancer

Introduction/Background: Chemoradiotherapy (CRT) followed by durvalumab, an immune checkpoint inhibitor, is the standard treatment for locally advanced non-small-cell lung cancer (NSCLC). Interstitial lung disease (ILD) is a life-threatening toxicity caused by these treatments; however, risk factors for the ILD have not yet been established. Interstitial lung abnormalities (ILAs) are computed tomography (CT) findings which manifest as minor interstitial shadows. We aimed to investigate whether ILAs could be risk factors for grade-two or higher ILD during durvalumab therapy. Patients and Methods: Patients with NSCLC who received durvalumab after CRT from July 2018 to June 2021 were retrospectively enrolled. We obtained patient characteristics, laboratory data, radiotherapeutic parameters, and chest CT findings before durvalumab therapy. Results: A total of 148 patients were enrolled. The prevalence of ILAs before durvalumab treatment was 37.8%. Among 148 patients, 63.5% developed ILD during durvalumab therapy. The proportion of patients with grade-two or higher ILD was 33.8%. The univariate logistic regression analysis revealed that older age, high dose-volume histogram parameters, and the presence of ILAs were significant risk factors for grade-two or higher ILD. The multivariate analysis showed that ILAs were independent risk factors for grade-two or higher ILD (odds ratio, 3.70; 95% confidence interval, 1.69−7.72; p < 0.001). Conclusions: We showed that pre-existing ILAs are risk factors for ILD during durvalumab treatment after CRT. We should pay attention to the development of grade-two or higher ILD during durvalumab treatment in patients with ILAs.

Radiation pneumonitis prediction after stereotactic body radiation therapy based on 3D dose distribution: dosiomics and/or deep learning-based radiomics features

Background

This study was designed to establish radiation pneumonitis (RP) prediction models using dosiomics and/or deep learning-based radiomics (DLR) features based on 3D dose distribution.

Methods

A total of 140 patients with non-small cell lung cancer who received stereotactic body radiation therapy (SBRT) were retrospectively included in this study. These patients were randomly divided into the training (n = 112) and test (n = 28) sets. Besides, 107 dosiomics features were extracted by Pyradiomics, and 1316 DLR features were extracted by ResNet50. Feature visualization was performed based on Spearman’s correlation coefficients, and feature selection was performed based on the least absolute shrinkage and selection operator. Three different models were constructed based on random forest, including (1) a dosiomics model (a model constructed based on dosiomics features), (2) a DLR model (a model constructed based on DLR features), and (3) a hybrid model (a model constructed based on dosiomics and DLR features). Subsequently, the performance of these three models was compared with receiver operating characteristic curves. Finally, these dosiomics and DLR features were analyzed with Spearman’s correlation coefficients.

Results

In the training set, the area under the curve (AUC) of the dosiomics, DLR, and hybrid models was 0.9986, 0.9992, and 0.9993, respectively; the accuracy of these three models was 0.9643, 0.9464, and 0.9642, respectively. In the test set, the AUC of these three models was 0.8462, 0.8750, and 0.9000, respectively; the accuracy of these three models was 0.8214, 0.7857, and 0.8571, respectively. The hybrid model based on dosiomics and DLR features outperformed other two models. Correlation analysis between dosiomics features and DLR features showed weak correlations. The dosiomics features that correlated DLR features with the Spearman’s rho |ρ| ≥ 0.8 were all first-order features.

Conclusion

The hybrid features based on dosiomics and DLR features from 3D dose distribution could improve the performance of RP prediction after SBRT.

Treatment plan comparison of volumetric-modulated arc therapy to intensity-modulated radiotherapy in lung stereotactic body radiotherapy using either 6- or 10-MV photon energies

Purpose

The aim of this study was to dosimetrically compare volumetric‐modulated arc therapy (VMAT) with intensity‐modulated radiotherapy (IMRT) techniques using either 6‐ or 10‐MV photon beam energies in lung stereotactic body radiation therapy (SBRT) plans.

Methods

Thirty patients with primary or metastatic lung tumors eligible for SBRT were randomly selected. VMAT and IMRT treatment plans using either 6‐ or 10‐MV photon energies were generated through automatic SBRT planning software in the RayStation treatment planning system.

Results

For planning target volume, there was no difference in D_95% for all plans, whereas D_2% and D_50% were significantly increased by 5.22%–5.98% and 2.47%–2.59%, respectively, using VMAT_6/10‐MV plans compared to IMRT_6/10‐MV plans. When comparing the D_max of organs at risk (OARs), VMAT_6/10‐MV was 18.32%–47.95% lower than IMRT_6/10‐MV for almost all OARs. VMAT_6/10‐MV obviously decreased D_mean, V_5Gy, V_10Gy, and V_20Gy of whole lung by 9.68%–20.92% than IMRT_6/10‐MV. Similar results were found when comparing VMAT_6‐MV with IMRT_10‐MV or VMAT_10‐MV with IMRT_6‐MV. The differences in the D_2%, heterogeneity index, and conformity index between 6‐ and 10‐MV plans are not statistically significant. Plans using 6‐MV performed 4.68%–8.91% lower levels of D_max of spinal cord, esophagus, great vessels, and trachea and proximal bronchial tree than those using 10‐MV plans. Similarly, D_mean, V_5Gy, V_10Gy, and V_20Gy of whole lung were also reduced by 2.79%–5.25% using 6‐MV. For dose fall‐off analysis, the D_2cm and R_50% of VMAT_6/10‐MV were lower than those of IMRT_6/10‐MV. Dose fall‐off curve based on 10 rings was steeper for VMAT plans than IMRT plans regardless of the energy used.

Conclusions

For lung SBRT plans, VMAT‐based plans significantly reduced OARs dose and steepened dose fall‐off curves compared to IMRT‐based plans. A 6‐MV energy level was a better choice than 10‐MV for lung SBRT. In addition, the dose differences between different techniques were more obvious than those between different energy levels.

Evaluation of the relationship between the range of radiation-induced lung injury on CT images after IMRT for stage I lung cancer and dosimetric parameters

BACKGROUND

This study evaluated the correlation between radiation-induced lung injury (RILI) and dosimetric parameters on computed tomography (CT) images of stage I non-small cell lung cancer (NSCLC) patients undergoing intensity-modulated radiotherapy (IMRT).

MATERIALS AND METHODS

Sixty-three stage I NSLC patients who underwent IMRT were enrolled in the study. The patients underwent CT within 6 months (acute phase) and 1.5 years (late phase) after radiotherapy. These were fused with the planned irradiation CT. The range of RILI was measured from 10% to 100%, with an IC in 10% increments.

RESULTS

The median interval from completion of radiotherapy to acute and late phase CT was 92 and 440 days, respectively. The median RILI ranges of the acute and late phases were in the 80% (20-100%) and 70% dose regions (20-100%), respectively. The significantly narrower range of RILI when lung V20 in the acute phase was less than 19.2% and that of V5 in the late phase was less than 27.6% at the time of treatment planning.

CONCLUSIONS

This study showed that RILI occurred in a localized range in stage I NSCLC patients who underwent IMRT. The range of RILI was correlated with V20 in the acute phase and V5 in the late phase. KEY MESSAGES RILI correlated with V20 in acute and V5 in late phase. The shadow of RILI occurred in 80% dose region in acute and 70% in late phase. No relationship exists between radiographic changes in RILI and PTV volume.

Computed tomography guided interstitial percutaneous high-dose-rate brachytherapy in the management of lung malignancies. A review of the literature

A growing number of patients with lung cancer are not amenable to surgery due to their age or comorbidities. For this reason, local ablative techniques have gained increasing interest recently in the management of inoperable lung tumors. High-dose-rate percutaneous interstitial brachytherapy, performed under CT-guidance, is a newer form of brachytherapy and is a highly conformal radiotherapy technique. The aim of this study was to describe this method and review the existing literature. Eight articles comprising 234 patients reported toxicity and clinical outcome. The follow-up ranged from 6 to 28 months. Diverse fractionation schemes were reported, with 20 Gy in a single fraction being the most frequently utilized. Toxicity was limited; major pneumothoraces occurred after only 8% of the interventions. Local control rates at one year ranged between 37% and 91%. In conclusion, high-dose-rate percutaneous interstitial brachytherapy is a safe, fast, and efficient treatment option for inoperable lung tumors.

Clinical and dosimetric predictors of radiation pneumonitis in early-stage lung cancer treated with Stereotactic Ablative radiotherapy (SABR) - An analysis of UK's largest cohort of lung SABR patients

BACKGROUND

Stereotactic Ablative Radiotherapy (SABR) is the standard treatment for early-stage medically inoperable lung cancer. Predictors of radiation pneumonitis (RP) in patients treated with SABR are poorly defined. In this study, we investigate clinical and dosimetric parameters, which can predict symptomatic RP in early-stage lung cancer patients treated with SABR.

MATERIALS AND METHODS

Patients treated with lung SABR between May 2009 and August 2018, in a single United Kingdom (UK) radiotherapy center were included. The patient's baseline characteristics, treatment details, and toxicity were retrieved from the electronic medical record. Dosimetric data was extracted from Xio and Monaco treatment planning systems. Patients were treated according to the UK SABR consortium guidelines. RP was graded retrospectively using Common Terminology Criteria for Adverse Events (CTCAE) version 4.0, based on available clinical and imaging information. Univariate and multivariate binary logistic regression was performed to determine predictive factors for grade ≥ 2 radiation pneumonitis, using Statistical Package for the Social Sciences (SPSS) statistics version 21 software. The goodness of fit was assessed using the Hosmer and Lemeshow test. The optimal diagnostic threshold was tested using the Receiver operating characteristics (ROC) curve. The chi-square test was carried out to test the different risk factors against the likelihood of developing grade ≥ 2 pneumonitis.

RESULTS

A total of 1266 patients included in the analysis. The median age of patients was 75 years. Six hundred sixty-six patients (52.6%) were female. Median follow up was 56 months. Sixty-five percent of patients received 55 Gy in 5 fractions. Forty-three percent of patients had Eastern Cooperative Oncology Group (ECOG) performance status (PS) of 2 and 16.2% had PS of 3. The Median Charlson comorbidity index was 6 (range 2-11). Median Standardized Uptake Value (SUV) max of the tumor was 6.5. Four hundred two patients (31.8%) had confirmed histological diagnosis; other patients were treated based on a radiological diagnosis. The median tumor size was 20 mm (range 4 mm-63 mm). Median Planning Target Volume (PTV) was 30.3 cc. Median values of R100, R50, and D2cm were 1.1, 5.6, 32.8 Gy. The median value of mean lung dose, V20, and V12.5 were 3.9 Gy, 5 %and 9.3% respectively. Eighty-five (6.7%) patients developed symptomatic RP (grade ≥ 2) with only 5(0.4%) developing grade 3 RP. Five percent of patients developed rib fractures but only 28% of these were symptomatic. On univariate analysis lower lobe tumor location, larger tumor size, PTV, mean lung dose, lung V20Gy, and V12.5 Gy were significantly associated with grade ≥ 2 RP. On multivariate analysis, only mean lung dose was associated with grade ≥ 2 pneumonitis. ROC curve analysis showed optimal diagnostic threshold for tumour size, PTV, mean lung dose, V20 and V12.5; are 22.5 mm ((Area Under Curve (AUC)-0.565)), 27.15 cc (AUC-0.58), 3.7 Gy (AUC-0.633), 4.6% (AUC-0.597), 9.5% (AUC-0.616). The incidence of ≥grade 2 RP was significantly high for values higher than the ROC threshold.

CONCLUSION

SABR treatment resulted in a very low rate of grade 3 pneumonitis. Lower lobe tumor location, larger tumor size, PTV, mean lung dose, V20, and V12.5 were found to be significant predictors of symptomatic radiation pneumonitis.

Adoption of Biologically Effective Dose of the Non-Target Lung Volume to Predict Symptomatic Radiation Pneumonitis After Stereotactic Body Radiation Therapy With Variable Fractionations for Lung Cancer

Background: This study aims to establish lung biologically effective dose (BED)–based uniform dosimetric constraints for minimizing the risk of symptomatic radiation pneumonitis (SRP) from stereotactic body radiation therapy (SBRT) using variable fractionations in patients with lung tumors.

Materials and Methods: A total of 102 patients with primary or oligometastatic lung tumors treated with SBRT in our institution were enrolled into this study. The associations between the clinical and dosimetric parameters and the incidences of SRP were analyzed using univariate and multivariate Cox regression hazard models. The receiver operating characteristic (ROC) curve was generated to evaluate the predictive performance of lung BED on the SRP risk compared with the physical dose.

Results: SRP occurred in 11 patients (10.8%). In univariate analysis, the mean lung dose (p = 0.002), V₅ (p = 0.005), V₂₀ (p < 0.001), and the percentage of non-target normal lung volume receiving more than a BED of 5–170 Gy (V_BED5−170, p < 0.05) were associated with SRP. Multivariate logistic regression analysis showed that there existed a significant statistical correlation between SRP and V_BED70 (p < 0.001), which performed better than V₅ or V₂₀ on the ROC curves, resulting in an optimal cut-off value of lung V_BED70 of 2.22%.

Conclusions: This retrospective study indicated that non-target lung BED may better predict SRP from patients with SBRT-treated lung cancer. Limiting the lung V_BED70 below 2.22% may be favorable to reduce the incidence of SRP, which warranted further prospective validation.

Significant Correlation Between Overall Survival and Mean Lung Dose in Lung Stereotactic Body Radiation Therapy (SBRT)

Background

After stereotactic body radiation therapy (SBRT) for medically inoperable stage I non-small-cell lung cancer (NSCLC), more patients die of comorbidities, particularly severe pulmonary insufficiency, than of tumor progression. The aim of this study was to evaluate correlation between lung biologically effective dose (BED) with an α/β ratio of 3 Gy (BED₃) and overall survival (OS) for these patients.

Methods

From 2012 to 2017, we have developed a prospectively updated institutional database for all first 100 consecutively treated patients with inoperable Stage 1 (T1T2N0M0) NSCLC. All SBRT were conducted on a Novalis Tx^® LINAC with two coplanar dynamic conformal arcs (84%) or with coplanar volumetric modulated arc therapy (VMAT) (16%). Mean GTV and PTV were 8.6 cc and 50.8 cc, respectively. The marginal dose prescribed to the PTV was the 80% isodose line (IDL), i.e., 54 Gy in 3 fractions for 76 patients (BED₁₀ = 126 Gy) and 50 Gy in 5 fractions for 24 patients (BED₁₀ = 83.3 Gy). Pulmonary heterogeneity has been taken into account by using Monte Carlo or AAA algorithms. Median follow-up was 25 months.

Results

At 1, 2, 3 and 5 years, local control (LC) was respectively 100, 98.2, 98.2, and 77.7%, and OS was respectively 83, 71.2, 58.1, and 33.2% (median OS was 49 months). Significant OS prognostic factors in univariate and multivariate analysis were mean lung BED₃ (HR = 1.14, p = 0.01) and PTV volume (HR = 1.01, p = 0.004). A mean lung BED₃ ≤ 5 Gy was significantly associated with a doubling of median OS from 29 months to more than 60 months (not achieved, p = 0.0068). For patients with a forced expiratory volume in 1 second (FEV1) ≤ 40%, a mean lung BED₃ ≤ 4 Gy was significantly associated with a doubling of median OS from 23 to 46 months (p = 0.019).

Conclusion

Mean lung BED₃ is strongly and significantly associated with OS in SBRT for inoperable Stage I NSCLC. For all treated patients, a mean lung BED₃ ≤ 5 Gy lead to a doubling of median OS. This threshold value should be reduced to 4 Gy for patients with FEV1 ≤ 40%.

Clinical Outcomes and Predictors of Lung Toxicity After Multiple Courses of Lung Stereotactic Body Radiotherapy for Early-Stage Non-Small Cell Lung Cancer

BACKGROUND

The clinical outcomes of multicourse lung stereotactic body radiotherapy (SBRT) have yet to be validated in a prospective study, and there are a lack of data on allowable composite dosimetry.

PATIENTS AND METHODS

Forty-four patients underwent multicourse lung SBRT for recurrent or metachronous NSCLC. The median biologically effective dose (BED₁₀) for the first course and subsequent courses were 132 and 100 Gy, respectively. Patient and treatment characteristics were evaluated to determine the correlation with the development of radiation pneumonitis (RP).

RESULTS

The local control rate was 91%. A total of 13.6% developed a grade 2+ RP, and 4.5% developed a grade 3+ RP, including one grade 5. On univariable analysis, multiple composite dosimetric factors (V₅ [proportion of lung structure receiving at least 5 Gy], V₁₀, V₂₀, V₄₀, and mean lung dose) were correlated with the development of RP. When comprised of the first and second course of SBRT, a composite lung V₅ of < 30% and > 50% was associated with a 0 and 75% incidence of grade 2+ RP, respectively. We identified no significant correlation on multivariable analysis but observed a strong trend between composite lung V₅ and the development of grade 2+ RP (hazard ratio, 1.157; P = .058). Evaluation of multiple clinical factors also identified a significant correlation between the timing of repeat lung SBRT and the development of grade 2+ RP after the second course (P = .0028).

CONCLUSION

Subsequent courses of lung SBRT, prescribed to a median BED₁₀ of 100 Gy, can provide a high rate of local control with a 4.5% incidence of grade 3+ toxicity. Composite lung V₅ and the timing of the second course of lung SBRT may be correlated to the development of RP.

X-rays induced IL-8 production in lung cancer cells via p38/MAPK and NF-κB pathway

PURPOSE

It is reported inflammatory cytokine interleukin-8 (IL-8) could predict radiation-induced lung toxicity (RILT). RILT is believed to be a consequence of a cascade of cytokine production. It is considered that vascular endothelial cell and macrophages are the mainly source of cytokines. This study was investigated the production of IL-8 from cancer cells induced by X-rays may involve in the radiation-induced inflammation.

MATERIALS AND METHODS

We analyzed IL-8 in human lung cancer cell lines after expose to X-rays, and we also detect IL-8 in HUVEC cells and THP1 cells as endothelial cell and macrophage model to identify the change in normal cells after expose. Furthermore, we added the inhibitors to the culture with or without radiation to identify the role of MAPK and NF-κB pathways on the radiation-induced secretion of IL-8.

RESULTS

Radiation could induce IL-8 production both in non-lung cancer cells (HUVECs and THP1 cells) and in lung cancer cells (A549 cells, H446 cells, PC-9 cells). Simultaneously, radiation activated p38/MAPK and NF-κB signal pathways in lung cancer cells. Moreover, p38/MAPK inhibitor SB203580 and NF-κB inhibitor BAY11-7082 could block the IL-8 up-regulated by X-rays but JNK inhibitor SP600125, ERK inhibitor U0126, ROS Scavenger NAC could not inhibit this phenomenon.

CONCLUSIONS

X-rays could induce IL-8 production in lung cancer cells, which may be related to the activation of p38/MAPK and NF-κB signaling pathway, providing a new point for elucidating the mechanism of radiation pneumonitis.

Radiation-induced lung injury: latest molecular developments, therapeutic approaches, and clinical guidance

Cancer research has advanced throughout the years with respect to the personalization of the treatments and to targeting cancer-related molecular signatures on different organs. Still, the adverse events of the treatments such as radiotherapy are of high concern as they may increase the mortality rate due to their severity. With the improved efficiency of cancer treatments, patient survival has been increasing. Consequently, the number of patients with adverse effects from radiotherapy is also expected to increase in the forthcoming years. Therefore, approaches for personalized treatments include the elimination of adverse events and decreasing the toxicity in healthy tissues while increasing the efficiency of cancer cytotoxicity. In this context, this paper aims to discuss the recent advances in the field of thorax irradiation therapy and its related toxicities leading to radiation pneumonitis in cancer patients. Molecular mechanisms involved in the radiation-induced lung injury and approaches used to overcome this lung injury are discussed. The discourse covers approaches such as therapeutic administration of natural products, current and prospective radioprotective drugs, and applications of mesenchymal stem cells for radiation-induced lung injury.

Immune checkpoint-inhibitors and chemoradiation in stage III unresectable non-small cell lung cancer

Lung cancer resulted in an estimated 1.8 million deaths worldwide in 2018 and approximately 20% of patients with non-small cell lung cancer (NSCLC) are diagnosed with stage III unresectable disease. Phase III data from the PACIFIC trial show significantly improved progression-free survival for the checkpoint-inhibitor durvalumab given as consolidation following definitive chemoradiotherapy (cCRT). Overall survival results from this study have now been reported, along with outcomes from other phase II trials. A thorough review of the efficacy and safety of checkpoint-inhibitors used in conjunction with cCRT for stage III unresectable NSCLC is needed. Published and presented literature on phase II and III data was identified using the key search terms "non-small cell lung cancer" AND "checkpoint-inhibitors" (OR respective aliases). One randomized phase III clinical trial and three phase II trials reporting outcomes of checkpoint-inhibitors in conjunction with cCRT for stage III unresectable NSCLC were identified. PACIFIC reported significantly improved overall survival for consolidation durvalumab following cCRT compared with placebo. Although discontinuation due to adverse events (AEs) was higher with durvalumab, rates of grade 3/4 pneumonitis or radiation pneumonitis were low and comparable between arms. Results from phase II trials also show promising activity for other checkpoint-inhibitors and alternative sequencing strategies, although these need to be confirmed in a randomized context. Preliminary data suggest differences in the safety profiles between PD-1 and PD-L1 inhibitors. Currently, the role of PD-L1 expression levels for patient selection in this setting remains unclear, and durvalumab should be administered on an individual basis in patients with known driver mutations. Consolidation durvalumab following cCRT significantly improves overall survival with an acceptable safety profile in patients with stage III unresectable NSCLC, now representing a new standard of care.

Stereotactic body radiotherapy in patients with chronic obstructive pulmonary disease and interstitial pneumonia: a review

Stereotactic body radiation therapy (SBRT) can yield excellent local tumor control, as well as survival benefit comparable to that of surgery for early-stage lung cancer. However, in terms of toxicity, SBRT might lead to fatal radiation pneumonitis. Lung diseases, such as chronic obstructive pulmonary disease (COPD) and interstitial lung disease (ILD), are major risk factors for lung cancer. However, these patients are typically not candidates for the gold-standard treatment option, lobectomy, because of the perioperative risks. In addition, patients with poor respiratory function can be excluded in prospective clinical trials. Thus, SBRT for patients with pulmonary diseases is still challenging, but there appears to be a clinical role for this modality as an alternative treatment. However, there are few well-documented review articles on SBRT for patients with pulmonary diseases. Therefore, we aimed to review SBRT in the context of important patient-related factors, including COPD and ILD. SBRT is an acceptable alternative treatment option for patients with lung cancer who also have COPD with an equivalent risk of radiation pneumonitis to normal lung. However, latent ILD should be detected prior to treatment. The indication for SBRT should be decided by carefully considering the risks and benefit for patients with ILD.