Selective mediastinal node irradiation in non-small cell lung cancer in the IMRT/VMAT era: How to use E(B)US-NA information in addition to PET-CT for delineation?
FDG-PET-CT-based selective lymph node (LN) irradiation is standard using 3D-conformal techniques for locally advanced NSCLC. With newer techniques (intensity-modulated/volumetric-arc therapy (IMRT/VMAT)), the dose to non-involved adjacent LN decreases, which raises the question whether FDG-PET-CT-delineation is still safe. We therefore evaluated the impact of adding linear endosonography with needle aspiration (E(B)US-NA) to FDG-PET-CT in selective nodal irradiation.



Based on literature data on sensitivity and specificity of E(B)US-NA in FDG-PET-CT-staged NSCLC, false negative (FN) rates for different constellations of CT, PET and E(B)US-NA were calculated. The algorithm was tested on consecutive patients with N2/N3 disease referred for radiotherapy in Leuven and Maastricht.



An algorithm determining when to include LN in the GTV is proposed, based on data from 5 meta-analyses. Adding E(B)US-NA to FDG-PET-CT decreases the FN-rate, but for PET-positive and E(B)US-negative LN, FN rates are still 14-16%. In Leuven 520 LN were analyzed, in Maastricht 364 LN; with E(B)US-NA a geographical miss was avoided in 2 (2/40=5%) and 1 (1/28=4%) patients, respectively.



E(B)US-NA in addition to FDG-PET-CT for mediastinal staging decreases the risk of a geographical miss with 4-5%. The impact of this small decrease on survival is unknown. The proposed algorithm may guide the radiation oncologist when to include LN in the nodal GTV.
Radiation Oncology, University Hospitals Leuven/KU Leuven, Belgium.
Stephanie T
ST
Peeters
Respiratory Oncology (Pneumology), University Hospitals Leuven/KU Leuven, Belgium.
Christophe
C
Dooms
Radiation Oncology (MAASTRO Clinic), GROW, Maastricht University Medical Center, The Netherlands.
Angela
A
Van Baardwijk
Pulmonology, Maastricht University Medical Center, The Netherlands.
Anne-Marie C
AM
Dingemans
Pulmonology, Maastricht University Medical Center, The Netherlands.
Hanneke
H
Martinussen
Respiratory Oncology (Pneumology), University Hospitals Leuven/KU Leuven, Belgium.
Johan
J
Vansteenkiste
Thoracic Surgery, University Hospitals Leuven/KU Leuven, Belgium.
Herbert
H
Decaluwé
Thoracic Surgery, University Hospitals Leuven/KU Leuven, Belgium.
Paul
P
De Leyn
Respiratory Oncology (Pneumology), University Hospitals Leuven/KU Leuven, Belgium.
Jonas
J
Yserbyt
Respiratory Oncology (Pneumology), University Hospitals Leuven/KU Leuven, Belgium.
Kristiaan
K
Nackaerts
Radiology, University Hospitals Leuven/KU Leuven, Belgium.
Walter
W
De Wever
Nuclear Medicine, University Hospitals Leuven/KU Leuven, Belgium.
Christophe M
CM
Deroose
Radiation Oncology, University Hospitals Leuven/KU Leuven, Belgium; Radiation Oncology (MAASTRO Clinic), GROW, Maastricht University Medical Center, The Netherlands. Electronic address: dirk.deruysscher@maastro.nl.
Dirk
D
De Ruysscher
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D001707:Biopsy, Needle; D002289:Carcinoma, Non-Small-Cell Lung / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy*; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy*; D008198:Lymph Nodes / Q000000981:diagnostic imaging / Q000473:pathology / Q000528:radiation effects*; D008297:Male; D008482:Mediastinum / Q000473:pathology; D008875:Middle Aged; D000072078:Positron Emission Tomography Computed Tomography / Q000379:methods; D019275:Radiopharmaceuticals; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18
Endobronchial ultrasound (EBUS); Intensity-modulated radiotherapy (IMRT); Non-small cell lung cancer (NSCLC); PET–CT based delineation; Radiotherapy; Volumetric arc therapy (VMAT)