The evaluation of a patient with a suspected head and neck malignancy begins with a full history and examination. A head and neck data sheet (Figure 1) and detailed
diagrams are essential. A comprehensive head and neck examination covers an area equivalent to 13% of the total body surface (Browne, 1986), and takes approximately ten minutes to perform properly. It is unnecessary to discuss methods of head and neck examination, details of which are available in standard textbooks (Million et al, 1982;
Browne, 1986). However, where appropriate, pertinent
comments are made in each section regarding the examination of any one site or sub-site.
Following the initial clinical examination, the
physician will proceed with pre-treatment evaluation which will include, in the first instance, full b l o o d count and
sedimentation rate, urea and electrolytes, s erum calcium and liver function, treponemal serology and a chest
radiograph (Swann and Blakeslee, 1988). Many substances have been evaluated as tumour-markers in head and neck squamous carcinoma. These include serum carcinoembryonic antigen (CEA) (Silverman et al, 1976), serum ferritin
(Maxim and Veltri, 1986) , serum B 2-microglobulin
(Wennerberg et al, 1984) , serum vitamin A (Mugliston and Coe, 1986) and the serum enzymes phosphohexose isomerase, aliesterase, adenosine deaminase and 5-nucleotidase
(Goel et al, 1986? Lai et al, 1987a? Lai et al, 1987b? Lai et al, 1989). However, none of these have any proven use and, as such, there is no reliable tumour marker with any practical value in the diagnosis and management of head and neck squamous carcinoma.
Histological diagnosis is a pre-requisite to the treatment of head and neck cancer and biopsy (under local or general anaesthetic) is mandatory. Aspiration biopsy
(fine needle or tru-cut) has added a new dimension to the pre-treatment eval u a t i o n of patients with tumours of the
head and neck. It is a safe technique with a high diagnostic accuracy, minimal complication rate'and may be performed
in the clinic or at endoscopy (Wilson et al, 1985? Shaha et al, 1986? Siodlak et al, 1986). Diagnostic
sensitivity can b e increased by using CAT, MRI or ultrasound guided probes (Gatenby et al, 1984? Lufkin et al, 1987? Baatenburg De Jong, 1988). Following initial assessment and preliminary investigations, the surgeon will proceed to endoscopy (fibreoptic and/or rigid) and biopsy, so as to
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confirm or refute his, or her, suspicions of malignancy, obtain a histological diagnosis and stage the cancer (s). Histological diagnostic sensitivity is increased by using
immunocytochemistry (Shi et al, 1984; Cortesina et al, 1988), Accurate staging is facilitated by pre-treatment imaging
to include CAT, M R I , ultrasound and radionuclide scanning. Imaging should be performed before endoscopy and only as appropriate, since it is neither necessary or financially feasible in all cases and should only be carried out if it will significantly alter patient management
(Cantrell, 1984? Stell, 1987).
Such imaging techniques are of value not only in the e valuation of the primary , occult primary and local and distant metastases, b u t also in assessing the second primary and residual and recurrent disease following surgery and irradiation. The merits of each investigation in evaluating these conditions at each of the head and neck sites and sub sites are discussed in the subsequent sub-sections
(1.3.3.-1.3.7.).
Computerised axial tomography was introduced in the early 1970's, beginning with first generation head scanners
otolaryngological applications by the presence of a water bag between the head and the scanning gantry. The water bag was essential for accurate density measurements but limited the range of the study to the orbits and the brain.
These problems were resolved by the development of second generation scanners which then began to make important contributions to the diagnosis and management of
otolaryngological problems (Mancuso et al, 1977;
Wortzman et al, 1978) . Continued development has provided third (Sagerman and Chung, 1981) and fourth generation scanners (Smith and Noyek, 1988) w i t h improved resolution, decreased scanning time and applicability to all parts of
the body.
Computed tomography of the head and neck provides
two- and three- dimensional information and allows a visual scaled demonstration of normal anatomical structures and their geometrical relationships. It can also locate and demonstrate tumour masses and, so long as the mass is w i t h i n the resolution of the unit and other technical factors are controlled, tumour size and extension,
encroachment onto major vessels, the aero-digestive passages and soft tissues and attachment to, and invasion of, bone and cartilage can all be demonstrated. In addition,
distant metastases in organs such as the lung and liver can be accurately evaluated.
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Computerised tomography does have distinct
disadvantages. It involves X-ray irradiation, is operator and observer dependent and is expensive. In addition, it only provides anatomical, and not physiological
information. The CT signal intensity is dependent on a single variable (attenuation coefficient) and streaking artefacts often exist due to bone, metal dental fillings and motion abnormalities related to respiration and
deglutition. The subsequent reconstruction of coronal and sagittal images from the transverse sections results in a prolonged imaging time (Kean and Smith, 1986) , and although direct coronal and sagittal CT images can now be performed this is not always possible due to technical limitations, or an unco-operative or unfit patient. Also, the low c ontrast levels in CAT means that iodinated contrast
materials are often used which subsequently block the thyroid gland and this can preclude radionuclide thyroid imaging
for up to six months.
However, CAT is the most v aluable of the imaging
modalities currently available to investigate the head and neck and, in appropriate cases, has revolutionised the
work up and staging of patients w ith head and neck squamous carcinoma (Sagerman and Chung, 1981; Muraki et al, 1983; Mancuso and Hanafee, 1985; Schaeffer et al, 1985a).
Magnetic resonance imaging was first discovered in 1946 by Bloch and Purcell for which they received the Nobel Prize in 1952 (Wilhelm, 1983, p 89). Over the next