| Schedule | Constraint | Source |
|---|---|---|
| Conventional fractionation 70 Gy / 35 fx definitive · 60–66 Gy / 30–33 fx post-op | Mean <20 Gy | RTOG 0920 |
| Max <30 Gy (non-oral cavity), <50 Gy (oral cavity) | RTOG 0920 |
Quoted from RTOG 0920, checked 2026-09-24. Full table with references →
The upper and lower lips, in front of the oral cavity.
The lips close the mouth, keep food and saliva in, and help with speech and facial expression.
The lips are contoured apart from the oral cavity because the goal is to keep them much lower — lip mucositis and cracking are painful and visible. They are easiest to spare when the target is posterior, as in larynx cancer, and hardest in anterior oral cavity cancer.
Brouwer 2015 runs the lip contour from the lower edge of the nose to the top of the mandibular body, and includes the inner surface of the lips (Table 1):
The mucosa in front of the jaws belongs to the lips; the mucosa to the side belongs to the buccal mucosa. RTOG 0920 asks for the lips and oral cavity as two separate structures.
Consensus CT delineation guidelines for head and neck organs at risk from eight cooperative groups, with anatomical descriptions and example images. Citation checked against Crossref; content not yet reviewed by DoseLab.