US provides information regarding tissue characterization, anatomic delineation, and intralesional vascular pattern via Doppler technique. Additionally, nodal involvement may also be established by US, and this modality may serve as guidance for fine-needle aspiration. However, some caveats exist. US may be insufficient in the detection and characterization of masses located in the deep lobe of the parotid gland [107,112]. Additional limitations of US include the inability to appropriately assess deep compartment extension, perineural tumor spread, bone invasion, and oropharyngeal/retropharyngeal nodal involvement [112]. Variant 5: Treated cancer of the oral cavity or oropharynx or hypopharynx or larynx or cancer of unknown primary of the head and neck. Surveillance imaging or follow-up imaging for suspected or known recurrence. Tumors of the oral cavity, oropharynx, hypopharynx, and larynx as well as tumors in which a primary site is not identified but the patient presents with metastatic cervical adenopathy are generally treated with a combination of surgery, chemotherapy, and/or radiation therapy [117]. This represents a heterogeneous group of tumors with posttreatment prognosis dependent on the site of origin and histology, although the majority of tumors are squamous cell carcinomas. As many as 40% of patients suffer recurrence after therapy, and up to 25% of patients will develop distant metastases [118,119], with the majority of recurrences occurring in the first 2 years following treatment [16]. Rate of recurrence and distant metastatic disease is directly linked to advanced stage of disease before treatment. The early detection of residual disease and recurrence, diagnosis of distant metastases, and differentiation from posttreatment changes is vital in the follow-up imaging in order to offer salvage therapy and improved survival. The exact delineation of recurrence is crucial in determining the type of salvage therapy offered.
Staging and Post Therapy Assessment of Head and Neck Cancer. US provides information regarding tissue characterization, anatomic delineation, and intralesional vascular pattern via Doppler technique. Additionally, nodal involvement may also be established by US, and this modality may serve as guidance for fine-needle aspiration. However, some caveats exist. US may be insufficient in the detection and characterization of masses located in the deep lobe of the parotid gland [107,112]. Additional limitations of US include the inability to appropriately assess deep compartment extension, perineural tumor spread, bone invasion, and oropharyngeal/retropharyngeal nodal involvement [112]. Variant 5: Treated cancer of the oral cavity or oropharynx or hypopharynx or larynx or cancer of unknown primary of the head and neck. Surveillance imaging or follow-up imaging for suspected or known recurrence. Tumors of the oral cavity, oropharynx, hypopharynx, and larynx as well as tumors in which a primary site is not identified but the patient presents with metastatic cervical adenopathy are generally treated with a combination of surgery, chemotherapy, and/or radiation therapy [117]. This represents a heterogeneous group of tumors with posttreatment prognosis dependent on the site of origin and histology, although the majority of tumors are squamous cell carcinomas. As many as 40% of patients suffer recurrence after therapy, and up to 25% of patients will develop distant metastases [118,119], with the majority of recurrences occurring in the first 2 years following treatment [16]. Rate of recurrence and distant metastatic disease is directly linked to advanced stage of disease before treatment. The early detection of residual disease and recurrence, diagnosis of distant metastases, and differentiation from posttreatment changes is vital in the follow-up imaging in order to offer salvage therapy and improved survival. The exact delineation of recurrence is crucial in determining the type of salvage therapy offered.