Salivary gland tumors

Epidemiology
5% of all head and neck cancers in the US
1) Parotid: 70% of salivary gland tumors; 25% of parotid tumors are malignant; muco-epidermoid is the most common histology
2) Submandibular: 8% of salivary gland tumors; 40% are malignant
3) Minor salivary glands: 22% of tumors; 65% are malignant; adenoid cystic is the most common histology

Pathology
1) Pleomorphic adenoma: low malignant potential; RT used for recurrent tumors
2) Low grade tumors: acinic cell carcinoma, low grade mucoepidermoid
3) High grade tumors: adenoid cystic, high grade mucoepidermoid, undifferentiated

Clinical
Features associated with malignant salivary gland mass: short duration of symptoms, pain, facial nerve weakness, enlarged neck nodes, children, skin involvement

Prognostic factors
T/N stage, histology, age (older is worse), facial nerve involvement, surgical margin status

RT doses
Pleomorphic adenoma: 60Gy
Malignant tumors: 60-66Gy depending on margins; cranial nerve should be treated if clinically involved; lesions involving the minor salivary glands of the palate and paranasal sinus may have a higher rate of cranial nerve invasion

Outcome	Parotid	Submandibular	Minor
LC	60-90%	40-80%	60-80%
OS 5/10 yrs	50-80%/40-60%	30-60%/20-50%	50-80/40-60%