Lisa Van den Bosch1, Gilles Defraene2, Stéphanie Peeters1, Christophe Dooms3, Walter De Wever4, Christophe Deroose5, Dirk De Ruysscher1,6. 1. a Department of Radiation Oncology , University Hospitals Leuven , Leuven , Belgium. 2. b Experimental Radiation Oncology, Department of Oncology , KU Leuven , Leuven , Belgium. 3. c Department of Respiratory Oncology , University Hospitals Leuven , Leuven , Belgium. 4. d Department of Radiology , University Hospitals Leuven , Leuven , Belgium. 5. e Department of Nuclear Medicine , University Hospitals Leuven , Leuven , Belgium. 6. f Department of Radiation Oncology (Maastro Clinic) , GROW Research Institute, Maastricht University Medical Center , Maastricht , The Netherlands.
Abstract
PURPOSE: It is unknown whether the dose-response relation of the primary tumor in NSCLC is different from that of the involved lymph nodes (LN). As the recurrence rate is much lower in LN, we hypothesized that LN need a lower radiation dose. MATERIAL AND METHODS: A retrospective analysis of prospective data was performed on patients with locally advanced NSCLC treated with (chemo)radiotherapy. The impact of EQD2,T prescription dose on relapse was analyzed using Cox regression modeling correcting for baseline diameter. RESULTS: From 2006 to 2010, 75 consecutive patients were included, resulting in 142 lymph nodes in the analysis. Any relapse (locoregional/distant) occurred in 58 patients (77%), while involved nodal relapse (INR) was observed in 13% of patients. No dose-response relationship was observed for INR (p = .22). Primary tumor progression was seen in 40% of patients together with a significant dose-response relationship (p = .033). Baseline nodal diameter was not associated with INR (p = .76), while primary tumor diameter was a highly significant predictor for relapse (p = .0031). CONCLUSIONS: These results suggest that LN control may be achieved at lower radiation doses than needed for the primary tumor. Prospective dose de-escalation studies on LN are warranted to decrease the incidence of severe esophagitis without compromising local tumor control.
PURPOSE: It is unknown whether the dose-response relation of the primary tumor in NSCLC is different from that of the involved lymph nodes (LN). As the recurrence rate is much lower in LN, we hypothesized that LN need a lower radiation dose. MATERIAL AND METHODS: A retrospective analysis of prospective data was performed on patients with locally advanced NSCLC treated with (chemo)radiotherapy. The impact of EQD2,T prescription dose on relapse was analyzed using Cox regression modeling correcting for baseline diameter. RESULTS: From 2006 to 2010, 75 consecutive patients were included, resulting in 142 lymph nodes in the analysis. Any relapse (locoregional/distant) occurred in 58 patients (77%), while involved nodal relapse (INR) was observed in 13% of patients. No dose-response relationship was observed for INR (p = .22). Primary tumor progression was seen in 40% of patients together with a significant dose-response relationship (p = .033). Baseline nodal diameter was not associated with INR (p = .76), while primary tumor diameter was a highly significant predictor for relapse (p = .0031). CONCLUSIONS: These results suggest that LN control may be achieved at lower radiation doses than needed for the primary tumor. Prospective dose de-escalation studies on LN are warranted to decrease the incidence of severe esophagitis without compromising local tumor control.