Oral cavity cancer is primarily a surgical disease: most patients have their tumor removed and receive radiotherapy afterward when the pathology shows risk features. Definitive radiotherapy is reserved for tumors that cannot be removed. Either way, the oral cavity itself and the mandible sit in or near the target, and a bite block is part of the setup.
Setup, dose levels and organ limits follow Head & Neck Planning Essentials. What is specific to the oral cavity — the oral tongue, floor of mouth, buccal mucosa, alveolar ridge, retromolar trigone and hard palate:
Added to the standard mask setup.
A device held between the teeth during simulation and every treatment. More →
It opens the mouth and pushes the tongue or palate away from the target, and makes the jaw and tongue position the same each day.
Wax held against the inside of the cheek.
Separates the cheek from the rest of the oral cavity when treating buccal mucosa tumors, so less of the mouth receives the target dose.
For definitive treatment. Post-operative volumes are on the post-operative page. Expansions come only from your protocol.
The high-dose CTV surrounds the gross disease. An optional intermediate-dose CTV covers high-risk tissue around the primary, including the entire base of tongue when involved and sites of possible contiguous spread.
Tongue and floor-of-mouth tumors can extend deep into muscle and toward the mandible, which is often why the mandible ends up partly inside the target.
Levels I, II, III and IV on the side of the tumor. Both sides are treated for tumors approaching the midline, near the tip of the tongue, or involving the base of tongue. Level V and the retrostyloid nodes may be added with bulky level IIa disease.
Including level Ib means the submandibular gland on that side usually cannot be spared.
Uses the shared head and neck constraint table. What changes for oral cavity cancer:
RTOG/Intergroup phase 3 trial of post-operative radiotherapy with or without concurrent cisplatin. Citation checked against Crossref; content not yet reviewed by DoseLab.
EORTC phase 3 trial of post-operative radiotherapy with or without concurrent cisplatin. Citation checked against Crossref; content not yet reviewed by DoseLab.
Consensus guidelines from multiple international groups for delineating the primary-tumor CTV in definitive radiotherapy of squamous cell carcinoma of the larynx, hypopharynx, oropharynx and oral cavity. Citation checked against Crossref; content not yet reviewed by DoseLab.
Updated consensus on selecting elective nodal levels for definitive radiotherapy of oral cavity, oropharynx, hypopharynx, larynx, nasopharynx, sinonasal and unknown-primary cancers. Citation checked against Crossref; content not yet reviewed by DoseLab.
NRG Oncology's page for RTOG 0920, a phase 3 trial of post-operative IMRT with or without cetuximab for intermediate-risk resected head and neck cancer. The protocol prescribes 60 Gy in 2 Gy fractions (optional 66 Gy high-risk and 56 Gy at-risk levels) and lists IMRT planning goals for the cord and brainstem planning risk volumes, lips, oral cavity, parotids, pharynx, cervical esophagus, larynx and mandible, with a planning priority order. DoseLab read section 6.5.4 of the version dated 25 January 2016 (copy hosted by the University of Cincinnati) for the oral cavity, lip and cervical esophagus values in the head and neck table.
Endorsed eviQ protocol for oral cavity squamous cell carcinoma treated with radiotherapy instead of surgery — for example when the tumor is unresectable or the patient is medically inoperable. It notes that surgery, with or without post-operative radiotherapy, remains the standard for most oral cavity cancers.
Endorsed eviQ protocol for adjuvant radiotherapy after resection of squamous cell carcinoma of the oral cavity, oropharynx, larynx or hypopharynx. It covers the risk features that prompt post-operative treatment, the added very-high-dose level for positive margins and extracapsular extension, and timing after surgery.