Salivary Gland Cancer

Clinical evaluation

• Diagnosis begins with a thorough medical history and physical examination. The physician will palpate the salivary glands and lymph nodes of the neck and assess facial nerve function.
  
  

Imaging studies

• Imaging is used to characterize the tumor, determine its extent, and assess for lymph node involvement or distant spread:
  • • CT (Computed Tomography) evaluates tumor size, bony involvement, and regional lymph node status.
    • MRI (Magnetic Resonance Imaging) provides detailed assessment of soft tissue involvement, nerve involvement, and the relationship between the tumor and adjacent structures. It is particularly valuable for parotid tumors near the facial nerve.
    • PET-CT (Positron Emission Tomography – CT) is used in selected cases to identify distant metastases or assess response to treatment.
    • Ultrasound may be used for initial evaluation of superficial salivary gland masses and to guide needle biopsy.

Biopsy

• Tissue sampling is required for a definitive diagnosis:
  
  • • Fine needle aspiration (FNA) biopsy: A thin needle is inserted into the tumor to withdraw a small sample of cells for pathological analysis. This is the most commonly used initial biopsy technique for suspected salivary gland tumors. It is performed with local anesthesia and carries minimal risk.
    • Core needle biopsy: Provides a larger tissue sample and may be used when FNA results are inconclusive.
    • Surgical excision: In some cases, the physician may recommend proceeding directly to surgical removal of the tumor (particularly for well-defined parotid masses), with definitive pathological diagnosis made on the excised specimen.

Salivary gland cancer is staged using the TNM (Tumor-Node-Metastasis) system:

Stage I

• Tumor ≤ 2 cm; confined to the salivary gland; no lymph node involvement; no distant metastasis

Stage II

• Tumor > 2 cm but ≤ 4 cm; confined to the salivary gland; no lymph node involvement; no distant metastasis

Stage III

• Tumor > 4 cm; OR tumor with extraparenchymal extension; OR involvement of a single ipsilateral lymph node ≤ 3 cm

Stage IVA

• Moderately advanced local disease with invasion of skin, mandible, ear canal, or facial nerve; OR regional lymph node involvement

Stage IVB

• Very advanced disease with invasion of the skull base or carotid artery; OR lymph node > 6 cm

Stage IVC

• Distant metastasis

Treatment is individualized based on tumor type, grade, stage, location, and the patient’s overall health. A multidisciplinary team – including head and neck surgeons, radiation oncologists, medical oncologists, and reconstructive surgeons – collaborates to develop each patient’s treatment plan.

Surgery

• Surgery is the primary treatment for most salivary gland cancers. The extent of surgery depends on the location and size of the tumor:
  
  

Radiation therapy

• Radiation therapy is used in the following situations:
  • As post-operative (adjuvant) treatment when surgical margins are positive or close, when the tumor is high-grade, or when perineural or vascular invasion is present.
  • As the primary treatment when surgery is not feasible.
  • Certain subtypes – particularly adenoid cystic carcinoma – may benefit from neutron beam or proton beam radiation therapy, though availability varies by institution.

Chemotherapy

• Chemotherapy plays a limited role in salivary gland cancer compared to other head and neck cancers. It is used primarily for:
  • Locally advanced or unresectable disease (typically in combination with radiation therapy)
  • Recurrent or metastatic disease where local treatment options are exhausted.