Salivary gland cancer

Disease Description (Causes and Symptoms)

• Definition summary: Salivary gland cancer is a malignant tumor that develops in the salivary glands (major salivary glands: parotid, submandibular, and sublingual glands; minor salivary glands: small salivary glands in the oral cavity, nasal cavity, and other areas). It accounts for approximately 3–6% of head and neck cancers.
• Causes and pathophysiology: The exact cause is unclear, but previous radiation exposure is known to be a risk factor, and some types may be associated with smoking. The risk may increase in people with a history of chronic inflammation or sialoliths (stones). Benign tumors are more common in the parotid gland but may become malignant, while the proportion of malignant tumors is relatively higher in the submandibular and minor salivary glands.
• Main symptoms:
  • A painless or painful lump/swelling felt in front of the ear (parotid gland), under the jaw (submandibular gland), or in the floor of the mouth or beneath the mucosa (minor salivary glands)
  • A mass that gradually enlarges and localized swelling
  • Facial paralysis when the facial nerve is involved (a major warning sign)
  • Enlarged cervical lymph nodes (in cases of metastasis)
  • With progression, difficulty breathing, speaking, or swallowing; pain; and symptoms caused by bone involvement
• Pattern of metastasis: Lung metastasis is most common, followed by bone metastasis.

Treatment Methods (Standard Treatment · Medications · Procedures/Surgery · Lifestyle Management · Precautions)

• Basic principles: The treatment plan is determined according to the stage, histologic type (histologic grade), and whether the facial nerve is involved.
• Surgery
  • Radical resection (wide excision): Complete removal of the primary tumor when possible (e.g., partial or total parotidectomy).
  • Facial nerve preservation: If there is no nerve involvement before or during surgery, preservation is considered first. If nerve involvement is clear, nerve resection and reconstruction may be performed.
  • If there is cervical lymph node metastasis or a high risk of it, neck dissection (cervical lymph node removal) is performed.
• Radiation therapy
  • Adjuvant radiation therapy is recommended in cases of residual disease after surgery, histologically high-risk features (positive resection margins, high grade, perineural invasion, nerve involvement, etc.), recurrence, or a history of systemic metastasis.
  • Radiation therapy alone or in combination may be used when surgery is not possible or when systemic treatment is also needed.
• Chemotherapy
  • Mainly used as an adjunct in advanced or metastatic cases, or when the disease cannot be controlled with surgery or radiation therapy. There is no single standardized regimen, and the regimen is selected according to the pathological type.
• Rehabilitation and conservative management
  • If facial paralysis occurs, symptom-relieving treatments such as physical therapy (facial muscle exercises), electrical stimulation therapy, and, when necessary, nerve reconstruction surgery or Botox may be used.
  • Pain and oral hygiene management, and nutritional management (nutritional support when eating, chewing, or swallowing is difficult).
• Complications and precautions
  • Facial nerve paralysis (temporary or permanent), wound infection, salivary leakage (fistula), changes in voice or swallowing, recurrence, and distant metastasis.
  • Skin changes, reduced salivary gland function (dry mouth), and dental damage may occur after radiation therapy.
  • Early diagnosis and determination of an appropriate extent of surgery are important for prognosis.

Checklist Before an Outpatient Visit (Including What to Bring · Recording Symptoms for the Visit · Example Questions)

• What to bring
  • A list of medications currently being taken (including prescription drugs, over-the-counter drugs, and supplements)
  • Previous medical certificates, surgical records, biopsy or fine-needle aspiration results, and pathology reports
  • Recent imaging (CT/MRI/PET) or image files (if possible, the original CD/DVD or electronic files)
  • A record of when symptoms began and how they have changed (changes in size, pain, presence or absence of paralysis, etc.)
  • A record of smoking, alcohol use, and occupational history (including radiation exposure), as well as other underlying diseases and surgical history
• Key items to record for the doctor to check during the outpatient visit
  • The size and growth rate of the mass, presence or absence of pain, facial paralysis or sensory abnormalities, changes in swallowing or speech, and whether lymph nodes are palpable
• Example questions (to think about in advance of the visit)
  • When did the symptoms begin? Has the lump increased in size rapidly?
  • Have you had radiation therapy or surgery involving the head and neck in the past?
  • Is there a family history or exposure to harmful substances through smoking or work?

General Example Questions to Ask the Doctor

• "What is the histologic type and grade of my biopsy (or fine-needle aspiration) result? What is the prognosis?"
• "How likely is it that the facial nerve can be preserved during surgery? If preservation is not possible, what rehabilitation methods are available?"
• "Will additional treatment after surgery (radiation therapy or chemotherapy) be necessary, and what are the reasons and expected side effects?"
• "What follow-up tests (frequency and types of tests) will be used to monitor recurrence or metastasis?"
• "What lifestyle precautions should I take (such as smoking and oral hygiene)?"

Examples of Disease-Specific Questions (1–2 Specific Questions)

• "Is neck lymph node removal (neck dissection) necessary in my case? If so, what will be the extent of the dissection?"
• "What tests will be used to evaluate facial nerve function before and after surgery, and what treatment options (such as nerve reconstruction or physical therapy) are available if paralysis occurs?"

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Note: Diagnosis and treatment decisions vary depending on the stage, histologic findings, and the patient's overall condition. Please consult your treating medical team to finalize a specific diagnosis and treatment plan.