Head & Neck Cancers – General Introduction

Fast Facts:

• 3% of all cancers
• Males > females
• ≈ 90% squamous cell carcinoma
• Strong association with tobacco & alcohol use – not uncommon to have synchronous primary elsewhere (e.g. lung cancer).

General Indications for PET/CT in Head & Neck Cancers:    

Initial Staging:  PET/CT has proved valuable in the assessment of:

• Primary: Size, location and extent.
• Regional metastatic adenopathy (> 50% of patients).
• Distant metastatic disease (> 10% of patients) – most commonly to the lungs, liver & skeleton.
• Metastatic Cancer of Unknown Primary:  In the setting of a positive nodal biopsy demonstrating SCCA, a clinical search for the patient’s primary lesion will be unsuccessful in ≈ 10% of patients. PET/CT imaging can be helpful in locating the primary lesion in many of these cases, dramatically improving clinical treatment and outcome.
• Assist in accurate delineation of radiation portal for radiotherapy.
• Baseline exam for follow-up assessment.

Assessing Response to Therapy & Prognosis: 

• Early Response: Non-responders can be offered alternative therapy.
• Late Response: Assess success or failure of therapy, and ultimate outcome.

Recurrence, Restaging, & Surveillance: 

• Excellent surveillance tool for SCCA patients.
• Restaging known recurrence, especially if further surgery and/or radiation are contemplated.
• Distinguishing recurrence from post-therapeutic inflammation/scarring.

Head & Neck Imaging Protocol:

While the vast majority of PET/CT scans are performed without intravenous contrast, some centers do administer IV contrast for their head and neck cancer patients (as nearly all of these patients will require a contrast exam to fully evaluate both tumor size and invasion).

A Common Protocol:

Step 1: Whole body imaging from the thoracic inlet to mid-thighs.

• Arms positioned above the head. 
• 80-cc non-ionic contrast administered.

Step 2: Dedicated neck imaging from the skull base to the aortic arch.

• Arms positioned along the patient’s side. 
• 60-cc non-ionic contrast administered.
• Thinner CT sections performed.