Salivary Glands Cancers

Background

• Salivary gland cancers make up 6% of all head and neck tumors
• Most commonly arise in the parotid gland (80%)
• Among salivary gland neoplasms, 10-15% arise in the submandibular glands
• These tumors present usually in the 6th decade of life
• Salivary gland cancers are mostly benign
• Submandibular, sublingual and minor salivary gland tumors are more likely to be malignant

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Definition

Neoplasms arising from the major (parotid, submandibular, sublingual) or minor salivary glands, ranging from benign to malignant.

Epidemiology

• Incidence: 3-6% of all head and neck tumors
• Age: Peak incidence in 6th-7th decade
• Gender: Slight female predominance for benign tumors; equal distribution for malignant
• ★ Most common site: Parotid gland (80% of all salivary tumors)
• ★ Rule of 80s:
  • 80% of salivary tumors occur in parotid
  • 80% of parotid tumors are benign
  • 80% of benign parotid tumors are pleomorphic adenomas

Risk Factors

• Radiation exposure (latency period: 15-20 years)
• Prior head/neck radiation therapy
• Occupational exposure (rubber manufacturing, hairdressing)
• Viral infections (EBV, HIV)
• Genetic syndromes (Li-Fraumeni)

Types

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Clinical features

• Symptoms
  • Solitary, mobile slow growing painless mass (may be present for many years)
  • Dysphagia and hoarseness
  • Difficult chewing
• Physical exam
• Painless, mobile mass found at the angle of the jaw (usually pleomorphic adenoma)
• Disturbance to facial nerve function (most commonly associated with invasive malignancy)

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Classic Presentation

Symptoms (in order of frequency)

1. Palpable mass (>90%)
2. Pain (suggests malignancy or infection)
3. Facial nerve palsy 
4. Dysphagia/hoarseness (deep lobe involvement)
5. Trismus (advanced disease)

Physical Examination Findings

• Benign features:
  • Mobile, well-circumscribed
  • Soft to rubbery consistency
  • No facial nerve involvement
  • No skin changes
• ★ Malignant features (RED FLAGS):
  • Fixed to deep structures
  • Hard consistency
  • Facial nerve palsy (25% of malignant)
  • Skin ulceration
  • Cervical lymphadenopathy
  • Rapid growth (doubling <6 months)

Diagnosis

• Imaging
  • Ultrasound (hypoechoic mass)
  • CT/MRI (necrosis or calcification can be visualized)
• Serum labs
• Fine needle aspiration (to assess for malignancy)

Diagnostic Algorithm

Laboratory Studies

• Fine Needle Aspiration (FNA):
  • Sensitivity: 85-95%
  • Specificity: 95-98%
  • ★ Cannot distinguish follicular lesions
  • Core needle biopsy if FNA non-diagnostic

Imaging Studies

• Ultrasound:
  • First-line imaging
  • Guides FNA
  • Hypoechoic = suspicious
• MRI (preferred over CT):
  • Best for deep lobe tumors
  • Perineural spread assessment
  • T1: intermediate signal
  • T2: high signal (most tumors)
• CT scan:
  • Stone detection (sialolithiasis)
  • Bone involvement
• ★ Technetium-99m scan:
  • "Hot" = Warthin tumor
  • "Cold" = most others

Differential diagnosis

• Facial nerve schwannoma

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Treatment

• Surgical management
• Superficial or total parotidectomy (pleomorphic adenoma of the parotid gland)
• Tumor excision with preservation of nerve (pleomorphic adenoma of the submandibular and minor salivary glands)

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First-Line Treatment

Surgical Management

• Parotid tumors:
  • Superficial parotidectomy (lateral to facial nerve)
  • Total parotidectomy (if deep lobe involved)
  • ★ Facial nerve preservation unless invaded
• Submandibular tumors:
  • Excision of entire gland
  • Level I-II neck dissection if malignant
• Minor salivary gland tumors:
  • Wide local excision
  • Site-specific approach

Surgical complications

• Recurrence after resection
• Malignant transformation

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Most Common Complications

1. ★ Frey syndrome (gustatory sweating)
   • Incidence: 30-50% post-parotidectomy
   • Aberrant parasympathetic reinnervation
   • Treatment: Botulinum toxin
2. Facial nerve injury
   • Temporary: 20-30%
   • Permanent: <5% (if nerve preserved)
3. First bite syndrome
   • Severe pain with first bite
   • Sympathetic denervation

Surgical Complications Timeline

• Immediate: Hematoma, nerve injury
• Early: Salivary fistula, infection
• Late: Frey syndrome, numbness

Prognostic Factors

• Favorable: Small size, low grade, parotid location
• Poor: High grade, facial nerve involvement, distant mets

HIGH-YIELD FACTS