Intensity-modulated Radiotherapy For Lung Cancer Research Articles

Esophagitis Following Intensity-Modulated Radiotherapy for Lung Cancer

Esophagitis Following Intensity-Modulated Radiotherapy for Lung Cancer

Impact of pretreatment clinical factors and DVH parameters on radiation pneumonitis and survival after intensity-modulated radiotherapy for lung cancer.

e20571 Background: The aim of this study was to investigate the relationship between clinical factors and dose-volume histogram parameters regarding Overall Survival (OS) and Radiation-Pneumonitis-Free Survival (RPFS) in lung cancer patients. Methods: We retrospectively reviewed clinical data of lung cancer patients from 2018 to 2020. Demographic, clinical, and treatment-related data were collected for all patients. OS was defined as the duration from pathological diagnosis to death or last follow-up. RPFS was defined as the duration from the start of radiation therapy to occurrence of grade≥3 Radiation-Pneumonitis, or final follow-up. RPFS and OS rates were estimated with the Kaplan-Meier method and compared using the log-rank test. The Cox regression model was used to estimate the hazard ratio (HR) and the corresponding 95% confidence interval (CI) for univariate and multivariate analysis. Results: A-hundred patients were included in this study. The median follow-up period after completion of radiotherapy was 42.9months (range: 2.0–152.1). In multivariate study, low serum sodium after RT, V5ipsi≥51%, V20ipsi≥28%, V30ipsi≥22% and MLDipsi≥15.99 Gy were independent predictive factors for poor OS, respectively ( p ＜0.05). MLD≥10.20 Gy suggested a poorer RPFS ( p ＜0.1) in this cohort. Conclusions: The independent significant risk factors of radiation pneumonitis were V20, V5 and MLD. In addition, the V20 and V5 of the ipsilateral lung should be more strictly limited to less than 28% and 51% when determining radiotherapy especially in this era of immunotherapy. Some blood indexes of low nutritional status were very important to determine the occurrence of high-risk radiation pneumonitis.

Comparison of combinations of irradiation techniques and jaw conditions in intensity-modulated radiotherapy for lung cancer.

PurposeTo assist in the selection of a suitable combination of an irradiation technique and jaw condition in intensity‐modulated radiotherapy (IMRT) and volumetric‐modulated arc radiotherapy (VMAT) for lung cancer treatment plans.Materials and methodsThirty patients with lung cancer who underwent radiotherapy were enrolled retrospectively. They were categorized as having central lung cancer, peripheral lung cancer with mediastinal lymph node metastasis (peripheral E lung cancer), and peripheral lung cancer without mediastinal lymph node metastasis (peripheral N lung cancer). Four treatment plans were designed for each patient: fixed jaw and adaptive jaw IMRT technique (FJ‐IMRT and JA‐IMRT), and fixed jaw and jaw tracking VMAT technique (FJ‐VMAT and JT‐VMAT). The dose parameters of the four group plans were compared and analyzed.ResultsCompared to FJ‐IMRT, JA‐IMRT significantly reduced the mean dose (Dmean) and volume percentage of 5 Gy (V5Gy) of the total lung in central and peripheral N lung cancer. Similarly, compared to FJ‐VMAT, JT‐VMAT provided better protection to most organs at risk (OARs), particularly for total lung and heart. In comparison with IMRT, VMAT significantly improved the conformity index (CI) of the planning target volume for the three lung cancer classifications, and it reduced the dose of almost all OARs except V5Gy and Dmean of the total lung. Moreover, the mean monitor units of the VMAT groups were far lower than the IMRT groups.ConclusionBased on the dosimetric findings and considering clinical data published on lung and heart side effects, we propose recommendations on the preferred treatment technique based on tumor location and pulmonary function. For central lung cancer with normal pulmonary function, we advise JT‐VMAT techniques. Conversely, for central lung cancer with poor pulmonary function, we recommend JA‐IMRT techniques. We advocate JA‐IMRT for peripheral E lung cancer. For peripheral N lung cancer, JT‐VMAT techniques are strongly recommended.

Comparaison dosimétrique et de la toxicité de la radiothérapie conformationnelle avec modulation d’intensité et de la radiothérapie conformationnelle tridimensionnelle des carcinomes bronchiques non à petites cellules

PurposeAlthough three-dimensional conformal radiotherapy (3D-CRT) remains the gold standard as a curative treatment for NSCLC when surgery is not possible, intensity modulated radiotherapy (IMRT) is increasingly used routinely. The purpose of this study was to assess the clinical (immediate toxicities) and dosimetric impact of IMRT compared to 3D-CRT in the treatment of locally advanced (stages IIIA to IIIC) non-small cell lung cancer (NSCLC) treated with concomitant radiochemotherapy, while IMRT in lung cancer was implemented in the radiotherapy department of the Jean-Perrin Center. Patients and methodsBetween March 2015 and October 2019, 64 patients treated with concomitant radiochemotherapy were retrospectively included. Thirty-two received 3D-CRT and 32 IMRT. The radiotherapy prescription was 66Gy in 33 fractions of 2Gy. ResultsIMRT has improved coverage of target volumes (V95 increased by 14.81% in IMRT; P<0.001) without increasing doses to OARs and reducing dysphagia (RR=0.67; P=0.027). Low doses to the lung were not significantly increased in IMRT (pulmonary V5 increased by 7.46% in IMRT). ConclusionIntensity modulated radiotherapy, compared with the standard RC3D technique, improve the coverage of target volumes without increasing the dose to the OARs. It also improves the immediate tolerance of the treatment by reducing the number of dysphagia.

FDG and FMISO PET-guided dose escalation with intensity-modulated radiotherapy in lung cancer

BackgroundConcomitant chemo-radiotherapy is the reference treatment for non-resectable locally-advanced Non-Small Cell Lung Cancer (NSCLC). Increasing radiotherapy total dose in the whole tumour volume has been shown to be deleterious. Functional imaging with positron emission tomography (PET/CT) offers the potential to identify smaller and biologically meaningful target volumes that could be irradiated with larger doses without compromising Organs At Risk (OAR) tolerance. This study investigated four scenarios, based on 18FDG and 18F-miso PET/CT, to delineate the target volumes and derive radiotherapy plans delivering up to 74Gy.MethodTwenty-one NSCLC patients, selected from a prospective phase II trial, had 18FDG- and 18F-miso PET/CT before the start of radiotherapy and 18FDG PET/CT during the radiotherapy (42Gy). The plans were based planned on a standard plan delivering 66 Gy (plan 1) and on three different boost strategies to deliver 74Gy total dose in pre-treatment 18FDG hotspot (70% of SUVmax) (plan 2), pre-treatment 18F-miso target (SUVmax > 1.4) (plan 3) and per-treatment 18FDG residual (40% of SUVmax). (plan 4).ResultsThe mean target volumes were 4.8 cc (± 1.1) for 18FDG hotspot, 38.9 cc (± 14.5) for 18F-miso and 36.0 cc (± 10.1) for per-treatment 18FDG. In standard plan (66 Gy), the mean dose covering 95% of the PTV (D95%) were 66.5 (± 0.33), 66.1 (± 0.32) and 66.1 (± 0.32) Gy for 18FDG hotspot, 18F-miso and per-treatment 18FDG. In scenario 2, the mean D95% was 72.5 (± 0.25) Gy in 18FDG hotspot versus 67.9 (± 0.49) and 67.9 Gy (± 0.52) in 18F-miso and per-treatment 18FDG, respectively. In scenario 3, the mean D95% was 72.2 (± 0.27) Gy to 18F-miso versus 70.4 (± 0.74) and 69.5Gy (± 0.74) for 18FDG hotspot and per-treatment 18FDG, respectively. In scenario 4, the mean D95% was 73.1 (± 0.3) Gy to 18FDG per-treatment versus 71.9 (± 0.61) and 69.8 (± 0.61) Gy for 18FDG hotspot and 18F-miso, respectively. The dose/volume constraints to OARs were matched in all scenarios.ConclusionEscalated doses can be selectively planned in NSCLC target volumes delineated on 18FDG and 18F-miso PET/CT functional images. The most relevant strategy should be investigated in clinical trials.Trial registration(RTEP5, NCT01576796, registered 15 june 2012)

Association between absolute volumes of lung spared from low-dose irradiation and radiation-induced lung injury after intensity-modulated radiotherapy in lung cancer: a retrospective analysis.

The aim of this study was to investigate the association between absolute volumes of lung spared from low-dose irradiation and radiation-induced lung injury (RILI) after intensity-modulated radiotherapy (IMRT) for lung cancer. The normal lung relative volumes receiving greater than 5, 10, 20 and 30 Gy (V5–30) mean lung dose (MLD), and absolute volumes spared from greater than 5, 10, 20 and 30 Gy (AVS5–30) for the bilateral and ipsilateral lungs of 83 patients were recorded. Any association of clinical factors and dose–volume parameters with Grade ≥2 RILI was analyzed. The median follow-up was 12.3 months; 18 (21.7%) cases of Grade 2 RILI, seven (8.4%) of Grade 3 and two (2.4%) of Grade 4 were observed. Univariate analysis revealed the located lobe of the primary tumor. V5, V10, V20, MLD of the ipsilateral lung, V5, V10, V20, V30 and MLD of the bilateral lung, and AVS5 and AVS10 of the ipsilateral lung were associated with Grade ≥2 RILI (P < 0.05). Multivariate analysis indicated AVS5 of the ipsilateral lung was prognostic for Grade ≥2 RILI (P = 0.010, OR = 0.272, 95% CI: 0.102–0.729). Receiver operating characteristic curves indicated Grade ≥2 RILI could be predicted using AVS5 of the ipsilateral lung (area under curve, 0.668; cutoff value, 564.9 cm3; sensitivity, 60.7%; specificity, 70.4%). The incidence of Grade ≥2 RILI was significantly lower with AVS5 of the ipsilateral lung ≥564.9 cm3 than with AVS5 < 564.9 cm3 (P = 0.008). Low-dose irradiation relative volumes and MLD of the bilateral or ipsilateral lung were associated with Grade ≥2 RILI, and AVS5 of the ipsilateral lung was prognostic for Grade ≥2 RILI for lung cancer after IMRT.

Application of ExacTrac and cone-beam computed tomography image-guided radiotherapy in intensity-modulated radiotherapy for lung cancer

Objective To compare set-up error and the positioning and error correction time between the infrared markers automatic positioning+ ExacTrac (A) and the manual positioning+ cone-beam computed tomography (CBCT) image-guided radiotherapy (IGRT)(B) in intensity-modulated radiotherapy (IMRT) for lung cancer. Methods A total of 20 patients with lung cancer were randomly divided into Group A and Group B. In Group A, after automatic positioning, a group of orthogonal X-rays images were taken using kV X-rays, which matched digitally reconstructed radiographs to obtain errors before correction. In group B, after manual positioning, images were taken using CBCT, which matched reference computed tomography images to obtain errors before correction. The positioning and error correction time was recorded in both groups. After error correction, errors after correction were obtained in each group using IGRT. Between-group comparison was made using the paired t test. Results The errors in lateral, longitudinal, vertical, and spinning vertical directions were significantly reduced after correction in both Group A and B (A: 1.8±1.3 vs. 0.4±0.1, P=0.000; 2.7±1.9 vs. 0.5±0.1, P=0.000; 2.8±1.7 vs. 0.4±0.1, P=0.000; 1.6±1.0 vs. 0.3±0.9, P=0.000; B: 2.6±1.9 vs. 0.5±0.5, P=0.000; 3.1±2.5 vs. 0.6±0.6, P=0.000; 2.1±1.8 vs. 0.5±0.5, P=0.000; 0.9±0.7 vs. 0.3±0.1, P=0.000). There were no significant differences in errors after correction between Group A and Group B (0.4±0.1 vs. 0.5±0.5, P=0.204; 0.5±0.1 vs. 0.6±0.6, P=0.257; 0.4±0.1 vs. 0.5±0.5, P=0.518; 0.3±0.9 vs. 0.3±0.1, P=0.755). However, the positioning and error correction time in Group A was significantly shorter than that in Group B (199.1±16.2 vs. 315.2±13.7, P=0.000). Conclusions The application of ExacTrac or CBCT IGRT can substantially reduce set-up errors and improve set-up accuracy in IMRT. In addition, the application of the ExacTrac system can substantially shorten the positioning and error correction time. Key words: Lung neoplasms/intensity-modulated radiotherapy; ExacTrac; CBCT; Set-up errors; Positioning and error correction time

Pitfalls and Challenges to Consider before Setting up a Lung Cancer Intensity-modulated Radiotherapy Service: A Review of the Reported Clinical Experience

Intensity-modulated radiotherapy (IMRT) is being increasingly used for the treatment of non-small cell lung cancer (NSCLC), despite the absence of published randomised controlled trials. Planning studies and retrospective series have shown a decrease in known predictors of lung toxicity (V20 and mean lung dose) and the maximum spinal cord dose. Potential dosimetric advantages, accessibility of technology, a desire to escalate dose or a need to meet normal organ dose constraints are some of the factors recognised as supporting the use of IMRT. However, IMRT may not be appropriate for all patients being treated with radical radiotherapy. Unique problems with using IMRT for NSCLC include organ and tumour motion because of breathing and the potential toxicity from low doses of radiotherapy to larger amounts of lung tissue. Caution should be exercised as there is a paucity of prospective data regarding the efficacy and safety of IMRT in lung cancer when compared with three-dimensional conformal radiotherapy and IMRT data from other cancer sites should not be extrapolated. This review looks at the use of IMRT in NSCLC, addresses the challenges and highlights the potential benefits of using this complex radiotherapy technique.

Optimal beam arrangement for pulmonary ventilation image-guided intensity-modulated radiotherapy for lung cancer.

BackgroundThe principal aim of this study was to evaluate the feasibility of incorporating four-dimensional (4D)-computed tomography (CT)-based functional information into treatment planning and to evaluate the potential benefits of individualized beam setups to better protect lung functionality in patients with non-small cell lung cancer (NSCLC).MethodsPeak-exhale and peak-inhale CT scans were carried out in 16 patients with NSCLC treated with intensity-modulated radiotherapy (IMRT). 4D-CT-based ventilation information was generated from the two sets of CT images using deformable image registration. Four kinds of IMRT plans were generated for each patient: two anatomic plans without incorporation of ventilation information, and two functional plans with ventilation information, using either five equally spaced beams (FESB) or five manually optimized beams (FMOB). The dosimetric parameters of the plans were compared in terms of target and normal tissue structures, with special focus on dose delivered to total lung and functional lung.ResultsIn both the anatomic and functional plans, the percentages of both the functional and total lung regions irradiated at V5, V10, and V20 (percentage volume irradiated to >5, >10 and >20 Gy, respectively) were significantly lower for FMOB compared with FESB (P < 0.05), but there was no significant difference for V30 (P > 0.05). Compared with FESB, a greater degree of sparing of the functional lung was achieved in functional IMRT plans with optimal beam arrangement, without compromising target volume coverage or the irradiated volume of organs at risk, such as the spinal cord, esophagus, and heart.ConclusionsPulmonary ventilation image-guided IMRT planning with further optimization of beam arrangements improves the preservation of functional lung in patients with NSCLC.

Fatal pneumonitis associated with postoperative intensity-modulated radiotherapy in lung cancer: Case report and review

Radiation pneumonitis (RP) is the most significant complication of acute treatment-related toxicities in lung cancer. Intensity-modulated radiotherapy (IMRT) with inverse planning enables us to achieve the desired dose distribution. However, there are many high-risk procedures associated with lung irradiation, including chemotherapy and surgery. We report a case of fatal treatment-related pneumonitis, where the patient had undergone postoperative IMRT for lung cancer. Following completion of radiotherapy, the patient developed progressive dyspnea. A chest computed tomography (CT) scan revealed the presence of diffuse reticular interstitial processes and honeycombing in both lungs. The fibrotic change in both lungs in a transverse view was compatible with low-dose irradiation of non-target organs at risk. Acute radiation pneumonitis was diagnosed. For patients receiving postoperative IMRT, low-dose irradiation volumes should be considered for lungs, as well as strict dose-volume histogram (DVH) parameters.

Intensity-modulated Radiotherapy in the Treatment of Lung Cancer

Intensity-modulated radiotherapy (IMRT) is an advancement in radiotherapy that uses intensity-modulated beams, which can provide multiple intensity levels for any single beam direction and any single source position, allowing shaped distributions and dose gradients with narrower margins than previously possible. IMRT is ideal for treating complex treatment volumes and avoiding close proximity organs at risk that may be dose limiting, allowing dose escalation (to improve tumour control) and/or reducing normal tissue complications (through organ at risk sparing). Given these potential advantages of IMRT and the availability of IMRT planning systems and linear accelerators, IMRT has been introduced in a number of disease sites. This systematic review examined the evidence for IMRT in the treatment of lung cancer in order to quantify the potential benefits and to make recommendations for radiation treatment programmes considering adopting IMRT. This review revealed two retrospective cohort studies reporting on cancer outcomes, which was considered insufficient on which to make evidence-based recommendations. However, due to the known dosimetric properties of IMRT and extrapolating from clinical outcomes from other disease sites, IMRT should be considered for lung cancer patients where the tumour is in close proximity to an organ at risk, where the target volume includes a large volume of an organ at risk, or in scenarios where dose escalation would be potentially beneficial while minimising normal tissue toxicity. Until randomised data are available, future research in IMRT for lung cancer should include a comprehensive prospective assessment of the relevant outcomes, including tumour control and normal tissue toxicity.