ProCaLung - Peer review in stage III, mediastinal node-positive, non-small-cell lung cancer: How to benchmark clinical practice of nodal target volume definition and delineation in Belgium☆.

BACKGROUND AND PURPOSE: The Quality Assurance project for stage III non-small cell lung cancer radiotherapy ProCaLung performed a multicentric two-step exercise evaluating mediastinal nodal Target Volume Definition and Delineation (TVD) variability and the opportunity for standardization. The TVD variability before and after providing detailed guidelines and the value of qualitative contour reviewing before applying quantitative measures were investigated. MATERIALS AND METHODS: The case of a patient with stage III NSCLC and involved mediastinal lymph nodes was used as a basis for this study. Twenty-two radiation oncologists from nineteen centers in Belgium and Luxembourg participated in at least one of two phases of the project (before and after introduction of ProCaLung contouring guidelines). The resulting thirty-three mediastinal nodal GTV and CTV contours were then evaluated using a qualitative-before-quantitative (QBQ) approach. First, a qualitative analysis was performed, evaluating adherence to most recent guidelines. From this, a list of observed deviations was created and these were used to evaluate contour conformity. The second analysis was quantitative, using overlap and surface distance measures to compare contours within qualitative groups and between phases. A 'most robust' reference volume for these analyses was created using the STAPLE-algorithm and an averaging method. RESULTS: Five GTV and seven CTV qualitative groups were identified. Second step contours were more often in higher-conformity groups (p = 0.012 for GTV and p = 0.024 for CTV). Median Residual Mean Square Distances improved from 2.34 mm to 1.36 mm for GTV (p = 0.01) and from 4.53 mm to 1.58 mm for CTV (p < 0.0001). Median Dice coefficients increased from 0.81 to 0.84 for GTV (p = 0.07) and from 0.82 to 0.89 for CTV (p ≤ 0.001). Using HC-contours only to generate references translated in more robust quantitative evaluations. CONCLUSION: Variability of mediastinal nodal TVD was reduced after providing the ProCaLung consensus guidelines. A qualitative review was essential for providing meaningful quantitative measures.

Clinical Outcomes After Proton Beam Therapy for Locally Advanced Non-Small Cell Lung Cancer: Analysis of a Multi-institutional Prospective Registry.

PURPOSE: For most disease sites, level 1 evidence is lacking for proton beam therapy (PBT). By identifying target populations that would benefit most from PBT, prospective registries could overcome many of the challenges in clinical trial enrollment. Herein, we report clinical outcomes of patients treated with PBT for locally advanced non-small cell lung cancer (LA-NSCLC). METHODS AND MATERIALS: Data were obtained from the multi-institutional prospective database of the Proton Collaborative Group (PCG). Inclusion criteria of our study were stage III de novo or recurrent LA-NSCLC, use of PBT, and availability of follow-up data. Overall survival (OS) time was calculated from the start of treatment until death or last follow-up. Kaplan-Meier curves were generated for groups of interest and compared with log-rank tests. Cox regression modeling was used to evaluate the multivariate association between selected covariates and OS. RESULTS: A total of 195 patients were included in the analysis. PBT was given with a median equivalent dose in 2 Gy fractions (EQD2) of 63.8 Gy (relative biological effectiveness). Pencil beam scanning was used in 20% of treatments. Treatment-related grade 3 adverse events were rare: 1 pneumonitis, 2 dermatitis, and 3 esophagitis. No grade 4 events were reported. Two cardiac-related grade 5 events occurred in patients with multiple risk factors. The median follow-up time for living patients was 37.1 months and the median OS was 19.0 months. On multivariate analysis, good performance status (hazard ratio, 0.27; [95% confidence interval, 0.15-0.46]; P < .0001), pencil beam scanning use (0.55; [0.31-0.97]; P = .04), and increased EQD2 (0.80; [0.71-0.90] - per 10 Gy increase; P = .0002) were associated with decreased mortality. CONCLUSIONS: PBT appears to yield low rates of adverse events with an OS similar to other retrospective studies on PBT for LA-NSCLC. PBS use and increased EQD2 can potentially improve OS.

Preoperative and postoperative radiotherapy (RT) for non-small cell lung cancer: still an open question.

Preoperative and postoperative radiotherapy (PORT) with or without chemotherapy has been used in non-small cell lung cancer (NSCLC) for decades. Numerous trials have investigated the potential survival benefit of this strategy, but despite greater knowledge of the disease, considerable technological developments in imaging and radiotherapy, and significant progress in surgery, many questions remain unsolved. In this review, we summarize the current knowledge on this problem and discuss issues which still require elucidation.