Unknown Primary

Patterns of Spread

  • Squamous Cell Carcinoma
  • When only neck is treated by surgery the primary recurrence occurs 20% of the time. This number is low due to other deaths and metastatic disease

Site or Origin

Upper Neck node favors

  • Nasopharynx
  • Oropharynx
  • Occasionally melanoma
  • Oral cavity
  • Larynx
  • Hypopharynx

Mid Neck node favors

  • Larynx
  • Hypopharynx
  • Thyroid
  • Esophagus
  • Disease below the clavical

Lower Neck node favors

  • Chest
  • Abdomen
  • Esophagus

Diagnostic Evaluation

PET

  • FDG-PET was the sole procedure that correctly identified occult primary site in 4%. (UF data)

Biopsy Results

  • Patients with traditional Radiological exam (-) and PE (-) blind biopsy found the site of primary 17% of the time. (UF data)
  • Taking all comer 43% were able to have biopsy proven primary H&N cancers (UF data).

Treatment

Surgery

  • N1 disease w/o ECE surgery alone has local control rate of 75% to 85%.
  • N1 disease w/o ECE may be treated with a neck dissection alone provided that the neck was not violated with an open procedure prior to surgery.

Radiation Therapy

  • Bilateral neck
  • Entire oropharynx including the BOT and tonsils
  • Entire nasopharynx
  • UF does not radiate larynx and hypopharynx
  • No oral cavity unless submandibular adenopathy
  • UF does not radiate larynx and hypopharynx
  • Dose of 64.8 Gy in 1.8 Gy /fraction with AP S/C
  • Boost gross adenopathy to 70-75 Gy

Chemotherapy

  • Concomitant chemotherapy for advanced N2 and N3 neck
  • Cispaltin 30 mg/m2 weekly or Carboplatin and paclitaxel.

Results

  • OS-5 is about 48% (MDACC)
  • Cause-specific survival at 5 years is 74% (MDACC)
  • With surgery alone mucosal primary recurrence rate is 20%
  • With RT, mucosal primary occurrence is 10% with 1/3 located in unirradiated sites.
  • The incidence of subsequent primary is similar to known rate of secondary primary (ie. RT may completely eliminate primary)
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