**8. Tumour volume**

116 Carcinogenesis, Diagnosis, and Molecular Targeted Treatment for Nasopharyngeal Carcinoma

The most commonly affected regions are the bone, lung and liver (Chiesa & De Paoli, 2001) (**Figure 20)**. Thus, bones and lung apices should be evaluated for tumour involvement in head and neck MRI studies, especially in patients with risk factors such as metastatic

Fig. 20. A and B 20A is a sagittal T1 weighted exam of the spine showing multiple areas of abnormal intermediate signal within vertebral bodies in the lower thoracic and lumbar spine -bony metastases. 20B is a contrast CT of the abdomen that shows the presence of

The presence of M1 disease is associated with shorter survival rates (Teo *et al.*, 1996) and significantly alters patient management, as such patients are generally considered to be incurable. Median survival is under four months and approximately 90% of patients with distant metastases pass away within a year (Goh & Lim, 2009; Khor *et al.,* 1978). The goal of treatment in such instances will be palliation with therapy being applied for locoregional

The exact method for the evaluation of distant metastasis will vary from institution to institution. Imaging options include bone scintigraphy, chest x-ray, CT of the thorax, abdomen and pelvis, and PET/CT. Studies have shown fluorodeoxyglucose PET/CT imaging to have a higher sensitivity and specificity in detecting distant metastases (Chen *et al.,* 2006; Chua *et al.*, 2009; Comoretto *et al.,* 2008; King *et al.,* 2008; Lin *et al.*, 2008; Liu *et al.*,

multiple liver metastases.

symptom control.

2007; Ng *et al.*, 2009; Wang *et al.*, 2007; Yu *et al.,* 2010).

cervical nodes which extend to the supraclavicular fossa (stage N3b).

Tumour volume has also been reported to have significant prognostic relevance outside of the TNM classification system (Wei & Sham, 2005). There is an estimated 1% increase risk of local control failure with every 1 cm3 increase in tumour volume. The increased risk is attributed to factors such as increase number of tumour clonogens, tumor hypoxia and relative radioresistance, etc (Bentzen *et al.*, 1991; Johnston *et al.,* 1995; Lartigau *et al.*, 1993; Sze *et al.*, 2004). However, issues with standardized methods of volume measurement, the intraand interobserver reliability due to operator-dependent tracing, as well as the technical challenges associated with implementing this in the clinical setting – including the time it takes to perform this tedious task – have prevented it from being routinely used in daily practice.
