PET/CT in head and neck cancer

Abstract

Head and neck cancer is the third most frequent cancer worldwide, with 500,000 new cases every year [1]. It is a heterogeneous group of neoplasms arising in the upper aerodigestive tract with different pathophysiologies, histologies and staging paradigms [2]. PET/CT is emerging as the “method of choice” for diagnosis in head and neck cancer [3], and nuclear medicine physicians may regard this diagnostic entity as a rather simple challenge: the cancer, the large nodes and the metastases are often clearly visible on FDG PET/CT and we can just describe what we see and regard the case as closed. But we could also try to obtain a thorough knowledge of this complex and intriguing heterogeneous disease entity. We could aspire to learn more about the different types of head and neck cancer and their pathogenesis, to improve staging paradigms, to refine strategies for diagnosis and treatment, and to clarify the strengths and weaknesses of PET/CT for each type. Such an approach would facilitate better, more professional and closer collaboration with the surgeons, oncologists and radiation oncologists who are responsible for patients’ treatment. Furthermore, only through this approach, whereby we accept responsibility as clinicians ourselves, can we exploit fully the advantages of PET/CT to achieve optimal diagnosis and treatment guidance in head and neck cancer. Head and neck cancer is more common in males than in females. It is found most frequently in middle-aged and elderly patients, and smoking and alcohol consumption are involved in the pathogenesis of some of the most frequent types. Overall, head and neck cancer patients have a 5-year survival rate of only 50%, though the rate varies widely depending on the type and extent of disease, and an improved effort with regard to both diagnosis and treatment is warranted. Head and neck cancer may arise in the nose and paranasal sinuses, the lips and oral cavity, the naso-, oroand hypopharynx, and the salivary glands. Malignant melanomas and invasive skin cancers can arise in the head and neck region. Head and neck sarcomas are seen in children, most frequently as soft tissue sarcomas (rhabdomyosarcomas), and in adults as osteosarcomas. Osteosarcomas of the head and neck region are seen in a slightly older age group than the more common osteosarcomas of the extremities, and they have a lower potential for metastatic spread. In the head and neck region, rarer nerve and vessel cancers can also be found. The neck also houses the thyroid and parathyroid glands, which give rise to neoplastic diseases well known in nuclear medicine. A thorough knowledge of these cancers and their mode of local invasion and spread will lead to better and more useful PET/CT interpretation. The histological type is most often a squamous cell carcinoma owing to the site of origin, but adenocarcinomas and many other rarer histologies are found. The special non-keratinized and undifferentiated carcinomas of the nasopharynx are especially frequent in Asia, China and Japan and among the circumpolar Inuit population (owing to a combination of genetic predisposition, Epstein-Barr virus infection and environmental co-factors). Our institution (Rigshospitalet, the National University Hospital in Copenhagen) is the referral hospital for Greenland, with its Eur J Nucl Med Mol Imaging (2007) 34:1329–1333 DOI 10.1007/s00259-007-0373-x