eContour

66 y/o M with cT3N1 SCC of the upper esophagus

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TECHNIQUE: The patient was treated definitively with VMAT with concurrent weekly carboplatin and paclitaxel.

DOSE: He received 50.4Gy in 28 fractions to the esophagus and nodal station 2-4 (per Rusch et al. J Thorac Oncol 2019) as well as level IVb and VIb (per Gregoire et al. Radiother Oncol 2014).

SIMULATION:

  • Immobilization with an all-in-one board with arms up.
  • IV contrast, oral contrast (45 minutes prior to CT), and barium (just prior to CT) were used to aid in target delineation.
  • A 4D-CT was obtained and used to assess internal motion. 
  • Daily imaging with CBCT.

IMRT Contours for Esophagus (per Consensus Guideline 2015)
  • GTV: Tumor and involved lymph nodes were delineated per CT, PET/CT, and EGD/EUS. 
  • CTV:
    • Esophageal GTV + 1cm radial margin and 4cm sup-inf margin following the mucosa, but limited superiorly to not extend above the inferior portion of the cricoid.
    • Involved node GTV + 1cm margin. 
    • Vertebral bodies and heart were carved out of the CTV, while the trachea and great vessels were not. 
  • PTV: CTV + 1cm
    • NOTE: 0.5 – 1cm margin may be used
  • OARs: Heart, Lungs, Cord, Esophagus, Brachial plexus, Thyroid, Larynx
 

IASLC Lymph Node Stations (per Rusch et al. J Thorac Oncol 2019)
Station 4: Paratracheal Nodes
Superior: Top of aortic arch 
Inferior: Right pulmonary artery crosses midline or upper lobe bronchus
Lateral (Right): Pleural envelope (upper), medial to SVC and azygos (intermediate), and right upper lobe pulmonary vein (caudal). 
Lateral (Left): Aortic arch (upper), pulmonary trunk/aortic arch (intermediate), and pulmonary trunk/left pulmonary artery (lower)
Anterior: Right brachiocephalic vein & SVC or arch of ascending aorta
Posterior: Posterior wall of trachea 
 
Station 3A: Prevascular nodes
Superior: Upper border of sternal notch
Inferior: Carina
Lateral: Pleural envelope
Anterior: Sternum/clavicular heads, ribs
Posterior: anterior border of station 1-4 or SVC, exclude great arteries, include left brachiocephalic vein
 
Station 3P: Retrotracheal nodes
Superior & Inferior: Same as 3A
Anterior: P. trachea
Lateral: Air/soft tissue interface or aorta
Posterior: Vertebral body or 1 cm posterior to an imaginary line at the anterior border of vertebral body
 
Station 1-2: High mediastinum and upper paratracheal
Superior: Upper border of sternal notch
Inferior: Aortic arch/level 4
Lateral: Pleural envelope
Anterior: Vessels (subclavian vein, brachiocephalic, subclavian artery, common carotid, brachiocephalic trunk)
Posterior: Posterior wall of trachea
 
*In our case the aortic arch was higher than typical and thus station 1-2 were not present/contoured and rather station 4 covered this area.*
 
Station IVb: Medial supraclavicular group
Superior: 2 cm superior to sternal notch
Inferior: Sternal notch
Anterior: P. sternocleidomastoid muscle or clavicle
Posterior: A. edge of scalene (superior), apex of lung/brachiocephalic vein or trunk, and common carotid/subclavian artery (inferior)
 
Station VIb: Prelaryngeal, pretracheal, paratracheal-recurrent laryngeal nerve nodes
Superior: Inferior edge of thyroid cartilage
Inferior: Sternal notch
Anterior: Posterior edge of infrahyoid muscle
Posterior: Anterior larynx, thyroid gland, and trachea/pre-vertebral muscle (L)/esophagus (R)
Medial: Lateral aspects of trachea and esophagus 
Lateral: Common carotid artery