Body Radiation Therapy For Lung Cancer Research Articles

Tracheal necrosis after sandwich immunotherapy and stereotactic body radiotherapy for lung cancer

Tracheal necrosis after sandwich immunotherapy and stereotactic body radiotherapy for lung cancer

Stereotactic body radiotherapy in lung cancer: a contemporary review.

The treatment of early stage non-small cell lung cancer (NSCLC) has improved enormously in the last two decades. Although surgery is not the only choice, lobectomy is still the gold standard treatment type for operable patients. For inoperable patients stereotactic body radiotherapy (SBRT) should be offered, reaching very high local control and overall survival rates. With SBRT we can precisely irradiate small, well-defined lesions with high doses. To select the appropriate fractionation schedule it is important to determine the size, localization and extent of the lung tumor. The introduction of novel and further developed planning (contouring guidelines, diagnostic image application, planning systems) and delivery techniques (motion management, image guided radiotherapy) led to lower rates of side effects and more conformal target volume coverage. The purpose of this study is to summarize the current developments, randomised studies, guidelines about lung SBRT, with emphasis on the possibility of increasing local control and overall rates in "fit," operable patients as well, so SBRT would be eligible in place of surgery.

PO-1341 Failure patterns after stereotactic body radiotherapy for lung cancer according to the T stage

PO-1341 Failure patterns after stereotactic body radiotherapy for lung cancer according to the T stage

Difference in target dose distributions between Acuros XB and collapsed cone convolution/superposition and the impact of the tumor locations in clinical cases of stereotactic ablative body radiotherapy for lung cancer.

The objective of the study is to analyze the difference in target dose distributions between Acuros XB (AXB) and collapsed cone convolution (CCC)/superposition and the impact of the tumor locations in clinical cases of stereotactic ablative body radiotherapy (SABR) for lung cancer. Ninety-six patients underwent SABR for lung cancers Kyushu University Hospital from 2014 to 2017. We recalculated clinical plans originally calculated by AXB using CCC with the identical monitor units (MUs) and beam arrangements. We calculated the following dosimetric parameters: maximum dose (Dmax), minimum dose (Dmin), homogeneity index (HI), conformity index (CI), and D95 of the planning target volume (PTV). We investigated the difference between the results of two calculations and examined the impact of tumor location. Moreover, we determined the target central dose using a thorax phantom and assessed the calculation accuracy of the two algorithms for each fraction. CCC significantly overestimated the dose to PTV, compared to AXB (P < 0.05). The mean differences of Dmax, Dmin, and D95 were 1.17, 1.95, and 1.85 Gy, respectively. The mean differences of HI and CI were 0.02 and - 0.06. Dmin, HI, and D95 had significant correlations with the tumor location, and the difference was greater when the PTV was included the chest wall (P < 0.05). The discrepancy between the calculated and irradiated dose was 2.48% for CCC, whereas it was 0.14% for AXB. We demonstrated that CCC significantly overestimated the dose to PTV relative to AXB in clinical cases of lung SABR.

Difference in failure patterns after stereotactic body radiotherapy for lung cancer according to clinical Tstage based on 4D computed tomography.

Stereotactic body radiotherapy (SBRT) is atreatment option for early-stage lung cancer. We aimed to examine the differences in failure patterns after SBRT according to the clinical Tstage. Atotal of 120 patients with early-stage lung cancer (T1-3N0M0) who underwent SBRT were analysed. The clinical stage in patients whose tumours were in contact with the chest wall was confirmed using four-dimensional computed tomography (4D-CT). Local failure, regional node metastasis, and distant metastasis were confirmed from clinical charts. Median follow-up time was 27.5months (range 7-122) after SBRT. Thirteen patients were restaged from clinical T2 with visceral pleural invasion to T3 with chest wall invasion using 4D-CT analysis. Thirty-seven patients developed recurrences. The median progression-free survival (PFS) and overall survival (OS) were 38.1 and 53.8months, respectively. The 3‑year PFS and OS rates were 50.7% and 60.3%, respectively. Asignificant difference was observed in PFS according to the clinical Tstage (p = 0.001). No significant differences were observed in OS according to the clinical Tstage (p = 0.213). The proportion of locoregional failures relative to distant metastasis decreased with progression from T1 to T3. The pleural dissemination rate was significantly higher in T3 tumours than in T1 and T2 tumours (p = 0.010). Clinical Tstage is associated with PFS after SBRT for lung cancer. There were differences in the failure patterns according to Tstage. 4D-CT might provide significant information for assessing chest wall invasion associated with unfavourable PFS.

Investigation of four-dimensional (4D) Monte Carlo dose calculation in real-time tumor tracking stereotatic body radiotherapy for lung cancers.

To investigate the dosimetric variations and radiobiological impacts as a consequence of delivering treatment plans of 3D nature in 4D manner based on the 4D Monte Carlo treatment planning framework implemented on Cyberknife. Dose distributions were optimized on reference 3D images at end of exhale phase of a 4DCT dataset for twenty-five lung cancer patients treated with 60 Gy / 3Fx or 48 Gy / 4Fx. Deformable image registrations (DIR) between individual 3DCT images to the reference 3DCT image in the 4DCT study were performed to interpolate doses calculated on multiple anatomical geometries back on to the reference geometry to compose a 4D dose distribution that included the tracking beam motion and organ deformation. The 3D and 4D dose distributions that were initially calculated with the equivalent path-length (EPL) algorithm (3DEPL dose and 4DEPL dose) were recalculated with the Monte Carlo algorithm (3DMC dose and 4DMC dose). Dosimetric variations of V60Gy / 48Gy and D99 of GTV, mean doses to the lung and the heart and maximum dose (D1 ) of the spinal cord as a consequence of tracking beam motion in deforming anatomy, dose calculation algorithm, and both were quantified by the relative change from 4DMC to 3DMC doses, from 4DMC to 4DEPL doses, and from 4DMC to 3DEPL doses, respectively. Comparing 4DMC to 3DEPL plans, V60Gy / 48Gy and D99 of GTV decreased considerably by 13 ± 22% (mean ± 1SD) and 9.2 ± 5.5 Gy but changes of normal tissue doses were not more than 0.5 Gy on average. The generalized equivalent uniform dose (gEUD) and tumor control probability (TCP) were reduced by 14.3 ± 8.8 Gy and 7.5 ± 5.2%, and normal tissue complication probability (NTCP) for myelopathy and pericarditis were close to zero and NTCP for radiation pneumonitis was reduced by 2.5 ± 4.1%. Comparing 4DMC to 4DEPL plans found decreased V60Gy / 48Gy and D99 by 12.3 ± 21.6% and 7.3 ± 5.3 Gy, the normal tissues doses by 0.5 Gy on average, gEUD and TCP by 13.0 ± 8.6 Gy and 7.1 ± 5.1%. Comparing 4DMC to 3DMC doses, V60Gy / 48Gy and D99 of GTV was reduced by 5.2 ± 8.8 %and 2.6 ± 3.3 Gy, and normal tissues hardly changed from 4DMC to 3DMC doses. The corresponding decreases of gEUD and TCP were 2.8 ± 4.0 Gy and 1.6 ± 2.4%. The large discrepancy between original 3DEPL plan and benchmarking 4DMC plan is predominately due to dose calculation algorithms as the tracking beam motion and organ deformation hardly influenced doses of normal tissues and moderately decreased V60Gy / 48Gy and D99 of GTV. It is worth to make a thoughtful weight of the benefits of full 4D MC dose calculation and consider 3D MC dose calculation as a compromise of 4D MC dose calculation considering the multifold computation time. This article is protected by copyright. All rights reserved.

PO-1186 Treatment outcomes of stereotactic body radiotherapy for lung cancer according to tumor appearances

PO-1186 Treatment outcomes of stereotactic body radiotherapy for lung cancer according to tumor appearances

Radiomics for prediction of radiation-induced lung injury and oncologic outcome after robotic stereotactic body radiotherapy of lung cancer: results from two independent institutions

ObjectivesTo generate and validate state-of-the-art radiomics models for prediction of radiation-induced lung injury and oncologic outcome in non-small cell lung cancer (NSCLC) patients treated with robotic stereotactic body radiation therapy (SBRT).MethodsRadiomics models were generated from the planning CT images of 110 patients with primary, inoperable stage I/IIa NSCLC who were treated with robotic SBRT using a risk-adapted fractionation scheme at the University Hospital Cologne (training cohort). In total, 199 uncorrelated radiomic features fulfilling the standards of the Image Biomarker Standardization Initiative (IBSI) were extracted from the outlined gross tumor volume (GTV). Regularized models (Coxnet and Gradient Boost) for the development of local lung fibrosis (LF), local tumor control (LC), disease-free survival (DFS) and overall survival (OS) were built from either clinical/ dosimetric variables, radiomics features or a combination thereof and validated in a comparable cohort of 71 patients treated by robotic SBRT at the Radiosurgery Center in Northern Germany (test cohort).ResultsOncologic outcome did not differ significantly between the two cohorts (OS at 36 months 56% vs. 43%, p = 0.065; median DFS 25 months vs. 23 months, p = 0.43; LC at 36 months 90% vs. 93%, p = 0.197). Local lung fibrosis developed in 33% vs. 35% of the patients (p = 0.75), all events were observed within 36 months. In the training cohort, radiomics models were able to predict OS, DFS and LC (concordance index 0.77–0.99, p < 0.005), but failed to generalize to the test cohort. In opposite, models for the development of lung fibrosis could be generated from both clinical/dosimetric factors and radiomic features or combinations thereof, which were both predictive in the training set (concordance index 0.71– 0.79, p < 0.005) and in the test set (concordance index 0.59–0.66, p < 0.05). The best performing model included 4 clinical/dosimetric variables (GTV-Dmean, PTV-D95%, Lung-D1ml, age) and 7 radiomic features (concordance index 0.66, p < 0.03).ConclusionDespite the obvious difficulties in generalizing predictive models for oncologic outcome and toxicity, this analysis shows that carefully designed radiomics models for prediction of local lung fibrosis after SBRT of early stage lung cancer perform well across different institutions.

Changes in pulmonary function and their correlation with dose-volume parameters in patients undergoing stereotactic body radiotherapy for lung cancer.

It is desirable to estimate the degree of the decrease in pulmonary function before lung stereotactic body radiation therapy (SBRT) especially for patients with poor pulmonary function. The purpose of this study was to investigate whether decreases in pulmonary function after SBRT may be predicted from radiation dose–volume parameters.A total of 70 patients undergoing SBRT were evaluated for changes in pulmonary function. Of these, 67 had primary lung cancer and 3 had lung metastasis. Twenty-six (37%) patients had chronic obstructive pulmonary disease. Pulmonary function tests (PFTs) were performed shortly before and at 18–24 months after SBRT. Radiation pneumonitis was Grade 2 in 10 patients and Grade 3 in 1. Mean forced vital capacity (FVC) decreased from 2.67 to 2.51 L (P < 0.01) and mean forced expiratory volume in 1 s (FEV1) decreased from 1.80 to 1.72 L (P < 0.01). Planning target volume (PTV) was correlated with changes in FVC. Changes in percent predicted FVC were correlated with %V5Gy (% of lung volume receiving > 5 Gy) and %V40Gy. Although the correlation was not significant, the %V20Gy value was the closest to the percent reduction in predicted FVC; %V20Gy of 10% tended to be associated with ~10% reduction in predicted FVC. Patients with poor pulmonary function did not necessarily show greater decreases in each PFT parameter. Decreases in FVC and FEV1 were within previously reported ranges. PTV was associated with decreases in FVC. The %V20Gy value was closest to the percentage decrease in predicted FVC.

Dosimetric Evaluation of Simplified Knowledge-Based Plan with an Extensive Stepping Validation Approach in Volumetric-Modulated Arc Therapy-Stereotactic Body Radiotherapy for Lung Cancer.

Purpose:We investigated the performance of the simplified knowledge-based plans (KBPs) in stereotactic body radiotherapy (SBRT) with volumetric-modulated arc therapy (VMAT) for lung cancer.Materials and Methods:For 50 cases who underwent SBRT, only three structures were registered into knowledge-based model: total lung, spinal cord, and planning target volume. We performed single auto-optimization on VMAT plans in two steps: 19 cases used for the model training (closed-loop validation) and 16 new cases outside of training set (open-loop validation) for TrueBeam (TB) and Halcyon (Hal) linacs. The dosimetric parameters were compared between clinical plans (CLPs) and KBPs: CLPclosed, KBPclosed-TB and KBPclosed-Hal in closed-loop validation, CLPopen, KBPopen-TB and KBPopen-Hal in open-loop validation.Results:All organs at risk were comparable between CLPs and KBPs except for contralateral lung: V5 of KBPs was approximately 3%–7% higher than that of CLPs. V20 of total lung for KBPs showed comparable to CLPs; CLPclosed vs. KBPclosed-TB and CLPclosed vs. KBPclosed-Hal: 4.36% ± 2.87% vs. 3.54% ± 1.95% and 4.36 ± 2.87% vs. 3.54% ± 1.94% (P = 0.54 and 0.54); CLPopen vs. KBPopen-TB and CLPopen vs. KBPopen-Hal: 4.18% ± 1.57% vs. 3.55% ± 1.27% and 4.18% ± 1.57% vs. 3.67% ± 1.26% (P = 0.19 and 0.27). CI95 of KBPs with both linacs was superior to that of the CLP in closed-loop validation: CLPclosed vs. KBPclosed-TB vs. KBPclosed-Hal: 1.32% ± 0.12% vs. 1.18% ± 0.09% vs. 1.17% ± 0.06% (P < 0.01); and open-loop validation: CLPopen vs. KBPopen-TB vs. KBPopen-Hal: 1.22% ± 0.09% vs. 1.14% ± 0.04% vs. 1.16% ± 0.05% (P ≤ 0.01).Conclusions:The simplified KBPs with limited number of structures and without planner intervention were clinically acceptable in the dosimetric parameters for lung VMAT-SBRT planning.

Investigation of approaches for internal target volume definition using 4-dimensional computed tomography in stereotactic body radiotherapy of lung cancer

The present study was undertaken to investigate the suitability of alternative internal target volume (ITV) delineation strategies based on maximum intensity projection (MIP), average intensity projection (AIP), 2 extreme phases and 4 phases images relative to the ITV10phase in stereotactic body radiation therapy (SBRT) for lung cancer. The 4-dimensional computed tomography (4DCT) data of 15 lung cancer patients treated with SBRT in our clinic were used. Five different ITVs were generated as follows: merging GTVs from 10 phases (ITV10Phase); merging GTVs from 2 extreme phases (0%, 50%) (ITV2Phase); merging GTVs from 4 phases (0%, 20%, 50%, and 70%) (ITV4Phase); delineating GTV on MIP (ITVMIP), and delineating GTV on AIP (ITVAIP). PTV10Phase, PTV2Phase, PTV4Phase, PTVMIP, and PTVAIP were generated by adding a 5-mm margin around the related ITV. Volumetric analyses were performed for 4 ITVs and PTVs relative to ITV10phase and PTV10phase. SBRT plans made for all PTVs were evaluated for dosimetric effect of alternative ITV delineation strategies. The mean percentage overlap volume (POV) for PTV2phase, PTV4phase, PTVMIP, and PTVAIP relative to PTV10phase were 84.2 ± 5.4%, 92.0 ± 2.9%, 82.2 ± 5.7%, and 73.8 ± 9.3%, for lower-lobe tumors, respectively. The mean POV for PTV2phase, PTV4phase, PTVMIP, and PTVAIP relative to PTV10phase were 93.2 ± 2.5%, 95.9 ± 1.0%, 87.5 ± 6.7%, and 83.3 ± 6.8% for upper-lobe, respectively. For lower-lobe tumors the mean differences in V20 and MLD for plans based on PTV2phase and PTV4phase were <0.5% and <10 cGy, compared with a plan based on PTV10phase. The use of PTV based on 4 respiratory phases and a 5-mm margin is a safe approach to reduce the workload of target delineation for tumors located in both lower and upper lobes.

The impact of 4DCT-ventilation imaging-guided proton therapy on stereotactic body radiotherapy for lung cancer.

Functional lung avoidance during radiotherapy can help reduce pulmonary toxicity. This study assessed the potential impact of four-dimensional computed tomography (4DCT)-ventilation imaging-guided proton radiotherapy (PT) on stereotactic body radiotherapy (SBRT) by comparing it with three-dimensional conformal radiotherapy (3D-CRT) and volumetric modulated arc therapy (VMAT), which employ photon beams. Thirteen lung cancer patients who received SBRT with 3D-CRT were included in the study. 4DCT ventilation was calculated using the patients' 4DCT data, deformable image registration, and a density-change-based algorithm. Three functional treatment plans sparing the functional lung regions were developed for each patient using 3D-CRT, VMAT, and PT. The prescribed doses and dose constraints were based on the Radiation Therapy Oncology Group 0618 protocol. We evaluated the region of interest (ROI) and functional map-based dose-function metrics for 4DCT ventilation and the irradiated dose. Using 3D-CRT, VMAT, and PT, the percentages of the functional lung regions that received ≥ 5Gy (fV5) were 26.0%, 21.9%, and 10.7%, respectively; the fV10 were 14.4%, 11.4%, and 9.0%, respectively; and fV20 were 6.5%, 6.4%, and 6.6%, respectively, and the functional mean lung doses (fMLD) were 5.6Gy, 5.2Gy, and 3.8Gy, respectively. These results indicated that PT resulted in a significant reduction in fMLD, fV5, and fV10, but not fV20. The use of PT reduced the radiation to highly functional lung regions compared with those for 3D-CRT and VMAT while meeting all dose constraints.

Evaluation of the target dose coverage of stereotactic body radiotherapy for lung cancer using helical tomotherapy: A dynamic phantom study.

To evaluate the target dose coverage for lung stereotactic body radiotherapy (SBRT) using helical tomotherapy (HT) with the internal tumor volume (ITV) margin settings adjusted according to the degree of tumor motion. Lung SBRT with HT may cause a dosimetric error when the target motion is large. Two lung SBRT plans were created using a tomotherapy planning station. Using these original plans, five plans with different ITV margins (4.0-20.0mm for superior-inferior [SI] dimension) were generated. To evaluate the effects of respiratory motion on HT, an original dynamic motion phantom was developed. The respiratory wave of a healthy volunteer was used for dynamic motion as the typical tumor respiratory motion. Five patterns of motion amplitude that corresponded to five ITV margin sizes and three breathing cycles of 7, 14, and 28 breaths per minute were used. We evaluated the target dose change between a static delivery and a dynamic delivery with each motion pattern. The target dose difference increased as the tumor size decreased and as the tumor motion increased. Although a target dose difference of <5 % was observed at ≤10mm of tumor motion for each condition, a maximum difference of -9.94 % ± 7.10 % was observed in cases of small tumors with 20mm of tumor motion under slow respiration. Minimizing respiratory movement is recommended as much as possible for lung SBRT with HT, especially for cases involving small tumors.

Comparison of setup accuracy between Catalyst HD and skin markers in stereotactic body radiotherapy of lung cancer

Objective To compare the setup accuracy between Catalyst HD and skin markers in stereotactic body radiotherapy (SBRT) of lung cancer. Methods A total of 24 cases treated with SBRT were selected and all patients were fixed with vacuum pad in the supine position. Patients in group A were positioned by Catalyst HD and those in group B were positioned by shin markers. All patients were matched with the CT images after CBCT scan by rigid registration and the setup errors in six directions (x-, y-, z-axis, Rtn, Pitch and Roll) were obtained. Results The mean±SD in group A and B in the six directions were as follows: (0.13±0.12) cm, (0.25± 0.19) cm; (0.26±0.15) cm, (0.13±0.11) cm; (0.23±0.19) cm, (0.35±0.29) cm; (0.43°±0.40°), (0.80°±0.69°); (0.48°±0.47°), (0.79°±0.64°); (0.62°±0.60°) and (0.88°±0.70°), respectively. Except the x-axis data in group B, all the data in the six directions were not normally distributed. The obtained data significantly differed between two groups (all P 0.5 cm/2°) also significantly differed between two groups (P<0.05). Conclusions The setup errors of Catalyst HD are less than those of the skin markers (except the y-axis). The setup accuracy of Catalyst HD is superior to that of traditional skin markers, which is worthy of application in clinical practice. Key words: Stereotactic body radiotherapy; Catalyst HD system; Setup error

Questionnaire survey comparing surgery and stereotactic body radiotherapy for lung cancer: lessons from patients with experience of both modalities.

Currently, there is some controversy regarding indications for stereotactic body radiotherapy (SBRT) for lung cancer patients. We investigated the treatment preferences of patients with experience of both surgery and SBRT using a questionnaire survey. Of lung cancer patients treated with SBRT between 2005 and 2017, we identified those who also previously underwent surgery for lung cancer. These patients were asked about their experiences of surgery and SBRT including perceived condition, distress, stress, convenience, adverse effects, and satisfaction during and after treatment. Participants were also asked about treatment decision-making for hypothetical scenarios. Of 653 lung cancer patients treated with SBRT, 149 also underwent surgery for lung cancer, 52 of whom participated in this questionnaire. The median age at the time of this survey was 76 years (range, 59-91 years). Significantly more participants had a favorable impression of SBRT during and after treatment (all question items; P<0.01). In terms of overall satisfaction, 27 patients preferred SBRT and three patients preferred surgery. In a hypothetical scenario (equivalent treatment outcomes) aged 70 years and faced with decision-making for first-time lung cancer treatment, significantly more patients selected SBRT (P<0.01): 38 patients selected SBRT. In a scenario with 20% better survivals for surgical resection, 14 patients selected SBRT, 12 selected surgery, and 26 were indecisive (P=0.47). In a scenario at age 80 years, significantly more patients selected SBRT (P<0.01). Most patients with experience of both surgery and SBRT for lung cancer prefer SBRT. This information would be helpful at treatment decision-making.

Evaluation of the robustness of 3-dimensional conformal technique with MLC position control into the planning target volume in stereotactic body radiotherapy for lung cancer

The purpose of this study was to evaluate the robustness of 3-dimensional conformal technique with MLC position control into the planning target volume (PTV) in stereotactic body radiotherapy for lung cancer. Two techniques using fixed beams were compared; one technique involved setting the MLC position outside the PTV and was referred to as Plan “O.” Another technique involved setting the MLC position inside the PTV and was referred to as Plan “I.” Two tumor motions were simulated: (1) tumor motion on the internal target volume (ITV) boundary and (2) tumor motion on the PTV boundary. Ten-phase CT images that captured the tumor in respiratory motion were generated for 2 simulations. Then, 4-dimensional (4D) treatment planning was performed by using deformable image registration. The gross tumor volume (GTV) dose changes between the 4D accumulated dose and treatment planning dose were evaluated for Plan “O” and Plan “I,” respectively. For the simulation of tumor motion on the ITV boundary, the changes in GTV D50% were −0.10 ± 0.31% and −0.22 ± 0.26% (p < 0.05) for Plan “O” and Plan “I,” respectively. In the same manner, for the simulation of tumor motion on the PTV boundary, the changes in GTV D50% were −3.37 ± 2.16% and −3.68 ± 1.71% (p < 0.05). Our result suggested that the dose change would be negligible in a clinical situation where the tumor moves within the ITV margin for both techniques, while Plan “O” showed better robustness.

Stereotactic body radiotherapy for lung cancer in patients with interstitial lung disease

Stereotactic body radiotherapy (SBRT) is a highly dose-concentrated radiotherapy that can spare damage to normal organs much more than conventional radiotherapy. Severe radiation pneumonitis (RP) after stereotactic SBRT for thoracic lesions is rare but sometimes gets severe. In this review, we presented the reported frequency of severe RP after SBRT for stage I NSCLC, its risk factors, and the attempts at clarifying individual predictive risk factors. The ratio of fatal RP after SBRT for lung tumor in patients with accompanying pulmonary interstitial changes is more than 5%, and overall survival is poor. The dose to the normal lung and interstitial changes in the background lung are important predictive factors of severe RP, with idiopathic pulmonary fibrosis (IPF) being the biggest risk factor for severe RP, but these interstitial lung diseases (ILDs) are not always a contraindication for thoracic SBRT. Based on the high fatality rate, it would be reasonable to avoid prompt SBRT by watchful waiting in cases of indolent or non-aggressive tumors, such as ground-glass tumors. It would be better to use or recommend more highly precise irradiation systems or particle therapy (PT) that can reduce radiation doses to the normal lung more, in particular for the cases with IPF. Identification of biomarkers indicating an individual’s risk level for severe RP, such as single nucleotide polymorphisms (SNPs), would be important in treatment decisions, but it needs further research. Though there are no reliable drugs for treating severe RP, anti-fibrotic agents, such as pirfenidone, might be effective in its prevention or alleviation.

OC-0199 Patient-reported outcomes after stereotactic body radiotherapy in lung cancer: The Lung PLUS study

OC-0199 Patient-reported outcomes after stereotactic body radiotherapy in lung cancer: The Lung PLUS study

Assessment and agreement of the CT appearance pattern and its severity grading of radiation-induced lung injury after stereotactic body radiotherapy for lung cancer.

PurposeRadiographic severity of radiation-induced lung injury (RILI) has not been well-studied. The goal of this study was to assess the CT appearance pattern and severity of RILI without consideration of the clinical presentation.Material and methodsA total of 49 patients, 41 with primary lung cancer and 8 with metastatic lung cancer, were treated by 4-fraction stereotactic body radiotherapy (SBRT). RILI after SBRT was separately assessed by two observers. The early and late CT appearance patterns and CT-based severity grading were explored.ResultsThe median follow-up period was 39.0 months. In the early CT findings of observers 1 and 2, there was diffuse consolidation in 15 and 8, diffuse ground glass opacity (GGO) in 0 and 0, patchy consolidation and GGO in 17 and 20, patchy GGO in 3 and 3, and no changes in 10 and 14, respectively (kappa = 0.61). In late CT findings of observer 1 and 2, there were modified conventional pattern in 28 and 24, mass-like pattern in 8 and 11, scar-like pattern in 12 and 12, and no changes in 1 and 2, respectively (kappa = 0.63). In the results of the CT-based grading by observers 1 and 2, there were grade 0 in 1 and 2, grade 1 in 10 and 14, grade 2 in 31 and 29, grade 3 in 7 and 4, and none of grade 4 or more, respectively (kappa = 0.66). According to multivariate analyses (MVA), the significant predicting factors of grade 2 or more CT-based RILI were age (p = 0.01), oxygen dependence (p = 0.03) and interstitial shadow (p = 0.03).ConclusionsThe agreement of the CT appearance and CT-based grading between two observers was good. These indicators may be able to provide us with more objective information and a better understanding of RILI.

A Systematic Literature Review on Salvage Radiotherapy for Local or Regional Recurrence After Previous Stereotactic Body Radiotherapy for Lung Cancer.

Purpose:The purpose of this review article was to summarize available data on the efficacy and safety of salvage radiotherapy for isolated local or regional recurrence after prior stereotactic body radiotherapy for lung cancer.Methods:Studies were systematically searched on PubMed, following which suitable papers were selected. Reported outcomes and toxicities were qualitatively reviewed.Results:Nineteen papers, which were retrospective studies based on single institution experiences, were selected. Sixteen papers were on salvage radiotherapy for local tumor recurrence, and the remaining 3 papers evaluated radiotherapy for regional failures after stereotactic body radiotherapy for lung cancer. Patient cohorts in the selected papers seemed very frail with 2-year survival of 30% to 40% after the salvage. Local control was reported to be approximately 60% to 70%, which is worse than that after primary stereotactic body radiotherapy. Reported rates of toxicity grade 3 or worse were considered acceptable. Larger target volume and central tumor localization were suggested as risk factors for severe toxicities. Dosimetric data on patients having toxicities were found to help with considering dose constraints for organs at risk.Conclusion:Based on data from a limited number of articles, salvage radiotherapy is a reasonable treatment option for select patients with local or regional tumor recurrence after prior stereotactic body radiotherapy for lung cancer. Optimal patient selection and dose prescription can be clarified with a larger study that include more data on experiences with salvage radiotherapy.