68 y/o M with stage I (T1N0M0) SCC of subglottic larynx.

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He was treated with definitive RT alone using IMRT. The primary tumor received 70 Gy in 35 fractions. Entire larynx and low risk neck including bilateral levels III-IV, VI and superior mediastinum received 56 Gy during that time.

  • For subglottic involvement, always treat level VI and consider superior mediastinum (Eisbruch et al Sem Rad Onc 2002)
  • Always cover LN levels III-IV bilaterally, and add level II for advanced T stage or N+.
  • Definitive RT dose and coverage (extrapolated from 3D-CRT* in Paisley et al IJROBP 2002):
    • CTV70 = GTV + 5-10mm, carving out bone/air.
    • CTV60-63 = high risk elective, consider N+ neck plus one level above/below
    • CTV54-56* = low risk elective, including entire larynx (top thyroid notch to bottom cricoid), paraglottic and pre-epiglottic space, pyriform sinuses, vallecula, as well as first echelon nodes (see above).

*This patient received fiberoptic laryngoscopy and proximal esophagogastroduodenoscopy confirming no hypopharyngeal involvement

*Paisley et al treated 42 patients (T1-T4N0) with 50-52Gy/20 to primary and first echelon nodes (EQD2 55Gy). Nodal involvement is low for subglottic primaries so 54-56Gy to N0 neck is reasonable.

  • Distribution of larynx cancer:
    • supraglottic = 30-35%
    • glottic = 60-65%
    • subglottic = <3%
  • Subglottis:
    • Inferior boundary: lower border of cricoid cartilage
    • Superior booundary: 5mm below free edge of TVCs (controversial)
  • Per NCCN (1.2015), "Subglottic cancer is not discussed because it is so uncommon."
  • Largest study for subglottic cancer is from SEER (Marchiano et al Otolaryngol Head Neck Surg 2016) which showed patients present with advanced local (58% T3-T4) but not regional (75% are N0) or distant (95% are M0) disease. Still 5-yr DSS is only 55% regardless of surgery, RT or both.
  • General management:
    • Stage I-II: RT alone for larynx preservation
    • Stage III-IV: Surgery +/- post-op RT (esp N+)