Patient-reported outcomes after personalised dose-escalation for stage II-III non-small-cell lung cancer patients: Results from the randomised ARTFORCE PET-Boost trial.

BACKGROUND AND PURPOSE: The ultimate challenge in dose-escalation trials lies in finding the balance between benefit and toxicity. We examined patient-reported outcomes (PROs), including health-related quality of life (HRQoL) in patients with locally advanced non-small cell lung cancer (LA-NSCLC), treated with dose-escalated radiotherapy. MATERIALS AND METHODS: The international, randomised, phase 2 ARTFORCE PET-Boost study (NCT01024829) aimed to improve 1-year freedom from local failure rates in patients with stage II-III NSCLC, with a ≥ 4 cm primary tumour. Treatment consisted of an individualised, escalated fraction dose, either to the primary tumour as a whole or to its most FDG-avid subvolume (24 x 3.0-5.4 Gy). Patients received sequential or concurrent chemoradiotherapy, or radiotherapy only. Patients were asked to complete the EORTC QLQ-C30, QLQ-LC13, and the EuroQol-5D at eight timepoints. We assessed the effect of dose-escalation on C30 sum score through mixed-modelling and evaluated clinically meaningful changes for all outcomes. RESULTS: Between Apr-2010 and Sep-2017, 107 patients were randomised; 102 were included in the current analysis. Compliance rates: baseline 86.3%, 3-months 85.3%, 12-months 80.3%; lowest during radiation treatment 35.0%. A linear mixed-effect (LME) model revealed no significant change in overall HRQoL over time, and no significant difference between the two treatment groups. Physical functioning showed a gradual decline in both groups during treatment and at 18-months follow-up, while clinically meaningful worsening of dyspnoea was seen mainly at 3- and 6-months. CONCLUSION: In patients with LA-NSCLC treated with two dose-escalation strategies, the average patient-reported HRQoL remained stable in both groups, despite frequent patient-reported symptoms, including dyspnoea, dysphagia, and fatigue.

Severe radiation-induced lymphopenia during concurrent chemoradiotherapy for stage III non-small cell lung cancer: external validation of two prediction models.

Background: Severe radiation-induced lymphopenia (RIL) in patients undergoing chemoradiotherapy (CRT) for non-small cell lung cancer (NSCLC) is associated with decreased immunotherapy efficacy and survival. At The Christie and MD Anderson Cancer Center (MDACC), prediction models for lymphopenia were developed in lung and esophageal cancer patients, respectively. The aim of this study was to externally validate both models in patients with stage III NSCLC. Methods: Patients who underwent concurrent CRT for stage III NSCLC in 2019-2021 were studied. Outcomes were grade ≥3 and grade 4 lymphopenia during CRT. The Christie model predictors for grade ≥3 lymphopenia included age, baseline lymphocyte count, radiotherapy duration, chemotherapy, mean heart and lung doses, and thoracic vertebrae V20Gy. MDACC predictors for grade 4 lymphopenia were age, baseline lymphocyte count, planning target volume (PTV), and BMI. The external performance of both models was assessed. Results: Among 100 patients, 78 patients (78%) developed grade ≥3 lymphopenia, with grade 4 lymphopenia in 17 (17%). For predicting grade ≥3 lymphopenia, the Christie and MDACC models yielded c-statistics of 0.77 and 0.79, respectively. For predicting grade 4 lymphopenia, c-statistics were 0.69 and 0.80, respectively. Calibration for the Christie and MDACC models demonstrated moderate and good agreement, respectively. Conclusion: The PTV-based MDACC prediction model for severe RIL demonstrated superior external performance in NSCLC patients compared to the dosimetry-based Christie model. As such, the MDACC model can aid in identifying patients at high risk for severe lymphopenia. However, to optimize radiotherapy planning, further improvement and external validation of dosimetry-based models is desired.

Self-Reported Cognitive Function and Quality of Life in Patients With SCLC in the Hippocampal Avoidance Prophylactic Cranial Irradiation Versus Prophylactic Cranial Irradiation Randomized Phase 3 Trial (NCT01780675).

Introduction: In the randomized controlled trial in patients with SCLC comparing standard prophylactic cranial irradiation (PCI) with hippocampal avoidance PCI (HA-PCI), we did not observe beneficial effects of HA-PCI on tested cognition. Here, we report findings on self-reported cognitive functioning (SRCF) and quality of life (QoL). Methods: Patients with SCLC were randomized to receive PCI with or without HA (NCT01780675) and assessed at baseline (82 HA-PCI and 79 PCI patients) and at 4, 8, 12, 18, and 24 months of follow-up, using the European Organization for the Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ-C30) and EORTC QLQ-brain cancer module (BN20). SRCF was assessed with the cognitive functioning scale of the EORTC QLQ-C30 and the Medical Outcomes Study questionnaire. A change of 10 points was used for minimal clinically important differences. Percentages of patients classified with having improved, stable, or deteriorated SRCF were compared between groups using chi-square tests. Changes in mean scores were analyzed using linear mixed models. Results: There was no significant difference in the percentage of patients with deteriorated, stable, or improved SRCF between the treatment arms. Depending on the evaluated time point, 31% to 46% and 29% to 43% of patients in the HA-PCI and PCI arm, respectively, reported a deteriorated SRCF on the basis of the EORTC QLQ-C30 and Medical Outcomes Study. QoL outcomes were not significantly different between the study arms, except for physical functioning at 12 months (p = 0.019) and motor dysfunction at 24 months (p = 0.020). Conclusions: Our trial did not find beneficial effects of HA-PCI over PCI on SRCF and QoL. The cognitive benefit of sparing the hippocampus in the context of PCI is still a subject of debate.

18F-FDG-PET guided vs whole tumour radiotherapy dose escalation in patients with locally advanced non-small cell lung cancer (PET-Boost): Results from a randomised clinical trial.

BACKGROUND AND PURPOSE: We aimed to assess if radiation dose escalation to either the whole primary tumour, or to an 18F-FDG-PET defined subvolume within the primary tumour known to be at high risk of local relapse, could improve local control in patients with locally advanced non-small-cell lung cancer. MATERIALS AND METHODS: Patients with inoperable, stage II-III NSCLC were randomised (1:1) to receive dose-escalated radiotherapy to the whole primary tumour or a PET-defined subvolume, in 24 fractions. The primary endpoint was freedom from local failure (FFLF), assessed by central review of CT-imaging. A phase II 'pick-the-winner' design (alpha = 0.05; beta = 0.80) was applied to detect a 15 % increase in FFLF at 1-year. CLINICALTRIALS: gov:NCT01024829. RESULTS: 150 patients were enrolled. 54 patients were randomised to the whole tumour group and 53 to the PET-subvolume group. The trial was closed early due to slow accrual. Median dose/fraction to the boosted volume was 3.30 Gy in the whole tumour group, and 3.50 Gy in the PET-subvolume group. The 1-year FFLF rate was 97 % (95 %CI 91-100) in whole tumour group, and 91 % (95 %CI 82-100) in the PET-subvolume group. Acute grade ≥ 3 adverse events occurred in 23 (43 %) and 20 (38 %) patients, and late grade ≥ 3 in 12 (22 %) and 17 (32 %), respectively. Grade 5 events occurred in 19 (18 %) patients in total, of which before disease progression in 4 (7 %) in the whole tumour group, and 5 (9 %) in the PET-subvolume group. CONCLUSION: Both strategies met the primary objective to improve local control with 1-year rates. However, both strategies led to unexpected high rates of grade 5 toxicity. Dose differentiation, improved patient selection and better sparing of central structures are proposed to improve dose-escalation strategies.

Investigation of the added value of CT-based radiomics in predicting the development of brain metastases in patients with radically treated stage III NSCLC.

Introduction: Despite radical intent therapy for patients with stage III non-small-cell lung cancer (NSCLC), cumulative incidence of brain metastases (BM) reaches 30%. Current risk stratification methods fail to accurately identify these patients. As radiomics features have been shown to have predictive value, this study aims to develop a model combining clinical risk factors with radiomics features for BM development in patients with radically treated stage III NSCLC. Methods: Retrospective analysis of two prospective multicentre studies. Inclusion criteria: adequately staged [18F-fluorodeoxyglucose positron emission tomography-computed tomography (18-FDG-PET-CT), contrast-enhanced chest CT, contrast-enhanced brain magnetic resonance imaging/CT] and radically treated stage III NSCLC, exclusion criteria: second primary within 2 years of NSCLC diagnosis and prior prophylactic cranial irradiation. Primary endpoint was BM development any time during follow-up (FU). CT-based radiomics features (N = 530) were extracted from the primary lung tumour on 18-FDG-PET-CT images, and a list of clinical features (N = 8) was collected. Univariate feature selection based on the area under the curve (AUC) of the receiver operating characteristic was performed to identify relevant features. Generalized linear models were trained using the selected features, and multivariate predictive performance was assessed through the AUC. Results: In total, 219 patients were eligible for analysis. Median FU was 59.4 months for the training cohort and 67.3 months for the validation cohort; 21 (15%) and 17 (22%) patients developed BM in the training and validation cohort, respectively. Two relevant clinical features (age and adenocarcinoma histology) and four relevant radiomics features were identified as predictive. The clinical model yielded the highest AUC value of 0.71 (95% CI: 0.58-0.84), better than radiomics or a combination of clinical parameters and radiomics (both an AUC of 0.62, 95% CIs of 0.47-076 and 0.48-0.76, respectively). Conclusion: CT-based radiomics features of primary NSCLC in the current setup could not improve on a model based on clinical predictors (age and adenocarcinoma histology) of BM development in radically treated stage III NSCLC patients.

Bronchial Stenosis in Central Pulmonary Tumors Treated With Stereotactic Body Radiation Therapy.

PURPOSE: Stereotactic body radiation therapy (SBRT) in lung tumors has an excellent local control due to the high delivered dose. Proximity of the proximal bronchial tree (PBT) to the high dose area may result in pulmonary toxicity. Bronchial stenosis is an adverse event that can occur after high dose to the PBT. Literature on the risk of developing bronchial stenosis is limited. We therefore evaluated the risk of bronchial stenosis for tumors central to the PBT and correlated the dose to the bronchi. METHODS AND MATERIALS: Patients with a planning tumor volume (PTV) ≤2 cm from PBT receiving SBRT (8 × 7.5 Gy) between 2015 to 2019 were retrospectively reviewed. Main bronchi and lobar bronchi were manually delineated. Follow-up computed tomography scans were analyzed for bronchial stenosis and atelectasis. Bronchial stenosis was assessed using Common Terminology Criteria for Adverse Events Version 4.0 (CTCAEv4). Patient, tumor, dosimetric factors and survival were evaluated between patients with and without stenosis using uni- and multivariate and Kaplan-Meier analysis. RESULTS: Fifty-one patients were analyzed with a median age of 70 years and World Health Organization (WHO) performance status ≤1 in 92.2%. Median follow-up was 36 months (interquartile range [IQR], 19.6-45.4) and median overall survival 48 months (IQR 21.5-59.3). In 15 patients (29.4%) bronchial stenosis was observed on follow-up computed tomography scan. Grade 1 stenosis was seen in 21.6% (n = 11), grade 2 in 7.8% (n = 4). No grade ≥3 stenosis was observed. Median time to stenosis was 9.6 months (IQR 4.4-19.2). Patients who developed stenosis had significantly larger gross tumor volume with a median of 19 cm3(IQR 7.7-63.2) versus 5.2 cm3 (IQR 1.7-11.3, P <.01). Prognostic factors in multivariate analysis for stenosis were age (P = .03; odds ratio [OR] 1.1), baseline dyspnea (P = .02 OR 7.7), and the mean lobar bronchus dose (P = .01; OR 1.1). CONCLUSIONS: Low-grade (≤2) lobar bronchial stenosis is a complication in approximately one-third of patients after SBRT for lung tumors with a PTV ≤2 cm from PBT. Prognostic risk factors were age, baseline dyspnea and mean dose on a lobar bronchus.

The overall survival impact of prophylactic cranial irradiation in limited-stage small-cell lung cancer: A systematic review and meta-analysis.

BACKGROUND: Prophylactic cranial irradiation (PCI) for limited-stage small-cell lung cancer (LS-SCLC) patients has become more controversial. Since the publication of the systematic review by Aupérin et al. in 1999, no randomized controlled trials regarding PCI in LS-SCLC have been completed. The aim of this study was to systematically review and meta-analyze the effect of PCI on overall survival (OS) in patients with LS-SCLC. METHODS: A systematic search was conducted in the databases of MEDLINE (PubMed), Embase and the Cochrane library. Only studies that reported an adjusted hazard ratio (aHR), indicating the effect of PCI versus no PCI on OS (adjusted for confounders) in patients with LS-SCLC were included for critical appraisal and meta-analysis. A pooled aHR estimate was calculated using a random-effects model. RESULTS: Pooling of 28 retrospective studies including a total of 18,575 patients demonstrated a significant beneficial effect of PCI versus no PCI on OS with a pooled aHR of 0.62 (95% CI: 0.57-0.69). Substantial heterogeneity of reported aHRs among studies was observed (I2 = 65.9%). Subgroup analyses revealed that this heterogeneity could partly be explained by study sample size. The pooled aHR among 7 versus 21 studies with a sample size of > 300 versus ≤ 300 patients was 0.79 (95% CI: 0.64-0.97) versus 0.56 (95% CI: 0.46-0.69; p < 0.001), respectively. CONCLUSIONS: This meta-analysis demonstrates a significant beneficial effect of PCI on OS in patients with LS-SCLC. Larger studies reported a milder beneficial effect, possibly due to a decreased risk of model overfitting. Serious risk of selection and confounding bias were of concern due to the lack of prospective trials. These results support the role of PCI in standard clinical practice in patients with LS-SCLC while awaiting results of prospective trials on alternative strategies.

Importance of tumour volume and histology in trimodality treatment of patients with Stage IIIA non-small cell lung cancer-results from a retrospective analysis.

OBJECTIVES: Chemoradiotherapy (CRT) has been the backbone of guideline-recommended treatment for Stage IIIA non-small cell lung cancer (NSCLC). However, in selected operable patients with a resectable tumour, good results have been achieved with trimodality treatment (TT). The objective of this bi-institutional analysis of outcomes in patients treated for Stage IIIA NSCLC was to identify particular factors supporting the role of surgery after CRT. METHODS: In a 2-centre retrospective cohort study, patients with Stage III NSCLC (seventh edition TNM) were identified and those patients with Stage IIIA who were treated with CRT or TT between January 2007 and December 2013 were selected. Patient characteristics as well as tumour parameters were evaluated in relation to outcome and whether or not these variables were predictive for the influence of treatment (TT or CRT) on outcome [overall survival (OS) or progression-free survival (PFS)]. Estimation of treatment effect on PFS and OS was performed using propensity-weighted cox regression analysis based on inverse probability weighting. RESULTS: From a database of 725 Stage III NSCLC patients, 257 Stage IIIA NSCLC patients, treated with curative intent, were analysed; 186 (72%) with cIIIA-N2 and 71 (28%) with cT3N1/cT4N0 disease. One hundred and ninety-six (76.3%) patients were treated by CRT alone (high-dose radiation with daily low-dose cisplatin) and 61 (23.7%) by TT. The unweighted data showed that TT resulted in better PFS and OS. After weighting for factors predictive of treatment assignment, patients with a large gross tumour volume (>120 cc) had better PFS when treated with TT, and patients with an adenocarcinoma treated with TT had better OS, regardless of tumour volume. CONCLUSIONS: Patients with Stage IIIA NSCLC and large tumour volume, as well as patients with adenocarcinoma, who were selected for TT, had favourable outcome compared to patients receiving CRT. This information can be used to assist multidisciplinary team decision-making and for stratifying patients in studies comparing TT and definitive CRT.

Challenges in the target volume definition of lung cancer radiotherapy.

Radiotherapy, with or without systemic treatment has an important role in the management of lung cancer. In order to deliver the treatment accurately, the clinician must precisely outline the gross tumour volume (GTV), mostly on computed tomography (CT) images. However, due to the limited contrast between tumour and non-malignant changes in the lung tissue, it can be difficult to distinguish the tumour boundaries on CT images leading to large interobserver variation and differences in interpretation. Therefore the definition of the GTV has often been described as the weakest link in radiotherapy with its inaccuracy potentially leading to missing the tumour or unnecessarily irradiating normal tissue. In this article, we review the various techniques that can be used to reduce delineation uncertainties in lung cancer.

Phase 3 Randomized Trial of Prophylactic Cranial Irradiation With or Without Hippocampus Avoidance in SCLC (NCT01780675).

INTRODUCTION: To compare neurocognitive functioning in patients with SCLC who received prophylactic cranial irradiation (PCI) with or without hippocampus avoidance (HA). METHODS: In a multicenter, randomized phase 3 trial (NCT01780675), patients with SCLC were randomized to standard PCI or HA-PCI of 25 Gy in 10 fractions. Neuropsychological tests were performed at baseline and 4, 8, 12, 18, and 24 months after PCI. The primary end point was total recall on the Hopkins Verbal Learning Test-Revised at 4 months; a decline of at least five points from baseline was considered a failure. Secondary end points included other cognitive outcomes, evaluation of the incidence, location of brain metastases, and overall survival. RESULTS: From April 2013 to March 2018, a total of 168 patients were randomized. The median follow-up time was 26.6 months. In both treatment arms, 70% of the patients had limited disease and baseline characteristics were well balanced. Decline on the Hopkins Verbal Learning Test-Revised total recall score at 4 months was not significantly different between the arms: 29% of patients on PCI and 28% of patients on HA-PCI dropped greater than or equal to five points (p = 1.000). Performance on other cognitive tests measuring memory, executive function, attention, motor function, and processing speed did not change significantly different over time between the groups. The overall survival was not significantly different (p = 0.43). The cumulative incidence of brain metastases at 2 years was 20% (95% confidence interval: 12%-29%) for the PCI arm and 16% (95% confidence interval: 7%-24%) for the HA-PCI arm. CONCLUSIONS: This randomized phase 3 trial did not find a lower probability of cognitive decline in patients with SCLC receiving HA-PCI compared with conventional PCI. No increase in brain metastases at 2 years was observed in the HA-PCI arm.

Dutch translation and linguistic validation of the U.S. National Cancer Institute's Patient-Reported Outcomes version of the Common Terminology Criteria for Adverse Events (PRO-CTCAE™).

BACKGROUND: The U.S. National Cancer Institute's Patient-Reported Outcomes version of the Common Terminology Criteria for Adverse Events (PRO-CTCAE™) is a library of items for assessing symptomatic adverse events by patient self-report in oncology trials. The aim of this multi-site study was to generate and linguistically validate a Dutch language version of the U.S. PRO-CTCAE for use in the Netherlands and Dutch-speaking Belgium. METHODS: All 124 items in the PRO-CTCAE item library were translated into Dutch using established translation procedures, including dual forward translations, reconciliation, back-translation, reconciliation of the source with the back-translation, and expert reviews. Harmonization of the translation for use in both the Netherlands and Belgium was achieved via an iterative review process in which the translations were discussed and reconciled by consensus of PRO experts, clinicians and bilingual Dutch translators. The translated PRO-CTCAE™ items were completed by a geographically-diverse sample of Dutch speaking patients from the Netherlands (n = 40) and Belgium (n = 60), and who were currently receiving or who had recently completed cancer-directed therapy. Patients were diverse with respect to age, sex, educational attainment, and cancer diagnosis. Cognitive debriefing, using a semi-structured interview guide, probed for comprehension and clarity of PRO-CTCAE symptom terms, attributes (e.g. frequency, severity, interference), response choices, and understanding of 'at its worst' and 'in the last 7 days'. Items for which the patient data indicated possible difficulties were considered for revision. RESULTS: Three items underwent minor phrasing revision and retesting was not deemed necessary. The symptom term for stretch marks was poorly understood by 12.5% of participants, and this item was revised to include parenthetical phrasing. It was retested with 10 participants from Belgium (n = 5) and the Netherlands (n = 5) and demonstrated acceptable comprehension. CONCLUSIONS: The Dutch language version of PRO-CTCAE has been successfully developed and linguistically validated for use in oncology studies in the Netherlands and Dutch-speaking Belgium. Extending the availability of NCI PRO-CTCAE in languages beyond English increases international consistency in the capture of Patient-Reported outcomes in patients participating in cancer clinical trials.

Results of neoadjuvant chemo(radio)therapy and resection for stage IIIA non-small cell lung cancer in The Netherlands.

Introduction: Concurrent chemoradiotherapy remains the main treatment strategy for patients with stage IIIA non-small cell lung cancer (NSCLC); stage cT3N1 or cT4N0-1 may be eligible for surgery and potentially resectable stage IIIA (N2) NSCLC for neoadjuvant therapy followed by resection. We evaluated treatment patterns and outcomes of patients with stage IIIA NSCLC in The Netherlands.Material and Methods: Primary treatment data of patients with clinically staged IIIA NSCLC between 2010 and 2016 were extracted from The Netherlands Cancer Registry. Patient characteristics were tabulated and 5-year overall survival (OS) was calculated and reported.Results: In total, 9,591 patients were diagnosed with stage IIIA NSCLC. Of these patients, 41.3% were treated with chemoradiotherapy, 11.6% by upfront surgery and 428 patients (4.5%) received neoadjuvant treatment followed by resection. The 5-year OS was 26% after chemoradiotherapy, 40% after upfront surgery and 54% after neoadjuvant treatment followed by resection. Clinical over staging was seen in 42.3% of the patients that were operated without neoadjuvant therapy.Conclusion: In The Netherlands, between 2010 and 2016, 4.5% of patients with stage IIIA NSCLC were selected for treatment with neoadjuvant therapy followed by resection. The 5-year OS in these patients exceeded 50%. However, the outcome might be overestimated due to clinical over staging.

The use of real-world evidence to audit normal tissue complication probability models for acute esophageal toxicity in non-small cell lung cancer patients.

INTRODUCTION: The aim of this work is to assess the validity of real world data (RWD) derived from an electronic toxicity registration (ETR). As a showcase, the NTCP-models of acute esophageal toxicity (AET) for concurrent chemoradiation (CCRT) for NSCLC patients were used to validate the ETR of AET before/after dose de-escalation to the mediastinal lymph nodes. MATERIAL AND METHODS: One hundred and one patients received 24 × 2.75 Gy and 116 patients received de-escalated dose of 24 × 2.42 Gy to the mediastinal lymph nodes. The validity and completeness of the ETR was analyzed. The grade ≥2 AET probability was defined according the V50 Gy and V60 Gy NTCP-models from literature. Validity of the models was assessed by calibration and discrimination. Furthermore, sensitivity and specificity for different cut-off points were determined. RESULTS: The compliance of ETR was 73-80%, with sensitivity and specificity rates of 83% and 86% for grade ≥2 AET, respectively. Discrimination of both NTCP-models demonstrated a moderate accuracy (V50 model, AUC 0.71; V60-model, AUC 0.69). Dose de-escalation did not influence the accuracy of the V50-model; AUC before: 0.69, and AUC after: 0.71. For the V60-model the model-accuracy decreased after dose de-escalation; AUC before: 0.72 and AUC after: 0.62, respectively. CONCLUSION: RWD is a useful method to audit NTCP models in clinical practice. The NTCP models to predict AET in NSCLC patients showed moderate predictive accuracy. For clinical practice, the V50Gy seems to be most stable for dose de-escalation without compromising safety and efficacy.

Safety and efficacy of reduced dose and margins to involved lymph node metastases in locally advanced NSCLC patients.

BACKGROUND AND PURPOSE: (Chemo)Radiotherapy for locally advanced non-small lung cancer (LA-NSCLC) causes severe dysphagia due to the radiation dose to the mediastinal lymphadenopathy. Reducing the dose to the mediastinum and the margins to the planning target volume (PTV) might reduce severe toxicity rates. The results of both adaptations in LA-NSCLC patients receiving (chemo)radiotherapy were analysed. MATERIALS AND METHODS: 308 LA-NSCLC patients were included in an observational study. Both cohorts received hypofractionated RT (24 × 2.75 Gy) of 70 Gy (EQD210) to the primary tumour. The reference-cohort (N = 170) received the same dose of 70 Gy (EQD210) to the involved lymph nodes, while the reduction-cohort (N = 138) received 24 × 2.42 Gy, biologically equivalent to 60 Gy (EQD210). Furthermore, the patient-specific PTV-margins for both the primary tumour and lymph nodes were reduced by 2-3 mm in the reduction-cohort after implementing a carina based correction strategy. The effects on toxicity, regional failure and overall survival (OS) were assessed. RESULTS: The acute grade 3 (G3) dysphagia and G3 pulmonary toxicity decreased significantly from 12.9% to 3.6% and 4.1% versus 0%, respectively. The regional failures were comparable: 5.9% versus 4.3% (p = 0.546). The median OS was significantly different: 26 months (reference-cohort) versus 35 months (reduction-cohort). After correction for confounders, the association between the reduction-cohort and OS remained significant (HR 0.63 versus HR 0.70). CONCLUSION: A reduction in PTV-margins and dose from 70 Gy to 60 Gy to the involved lymph nodes in LA-NSCLC patients receiving (chemo)radiotherapy did not result in an increase in regional failures. Moreover, significantly lower acute toxicities and an improved OS were observed in the reduction-cohort.

Local and regional treatment response by 18FDG-PET-CT-scans 4 weeks after concurrent hypofractionated chemoradiotherapy in locally advanced NSCLC.

BACKGROUND AND PURPOSE: To investigate associations of early post-treatment 18Fluorodeoxyglucose-positron-emission-tomography (FDG-PET)-scans with local (LF), regional (RF), distant failure (DF) and overall survival (OS) in locally advanced non-small cell lung cancer (LA-NSCLC)-patients treated with concurrent chemoradiotherapy. MATERIALS AND METHODS: Forty-seven stage IIIA-B NSCLC-patients included in a randomized phase II-trial (NTR2230) received 66 Gy (24x2.75 Gy) with low dose Cisplatin +/- Cetuximab. FDG-PET-scans were performed at baseline and 4 weeks post-treatment (range, 1.6-10.1). SUVmax, SUVmean, metabolic tumor volume (MTV), total lesion glycolysis (TLG) and gross tumor volume were calculated separately for the primary tumor and the involved lymph nodes to generate baseline, post-treatment, and relative response metrics defined as (metricpre-metricpost)/metricpre. Univariable cox regression analyses were performed to investigate associations between PET-metrics and outcomes. RESULTS: Metrics resulted from the post-treatment scan and relative response were associated with outcome, but baseline metrics were not. Primary tumor metrics were stronger associated with all outcomes than lymph node metrics. Both the volumetric (TLG/MTV) and intensity (SUVmax/SUVmean) PET-metrics were associated with OS. The intensity metrics were associated with LF, while the volumetric PET-metrics were associated with RF/DF. This was in contrast to the nodal metrics, demonstrating only an association between RF and the relative response of TLG/MTV. No preference was found between PET volumetric and intensity metrics associated with outcome. CONCLUSION: Early post-treatment PET-metrics are associated with treatment outcome in LA-NSCLC patients treated with chemoradiotherapy. Both volumetric and intensity PET-metrics are useful, but more for the primary tumor than for lymph nodes.