Disease staging

Disease staging

Careful disease staging is essential to guide therapy . Current staging classification according to the American Joint Commit tee on Cancer (AJCC)/Union for International Cancer Control (UICC) (8th edition) is shown in Table 66.4 . The T stage advances as the tumour invades from mucosa deep to muscle, adventitia and beyond the oesophagus . Regional nodes -

Figure 66.48 Bronchoscopic picture of airway in /f_i ltration by oesophageal cancer. TABLE 66.4 TNM classi /f_i cation of oesophageal cancer. T: Primary tumour Tx Tumour cannot be assessed T0 No evidence of primary tumour Tis High-grade dysplasia, de /f_i ned as malignant cells con /f_i ned to the epithelium by the basement membrane T1 Tumour invades the lamina propria, muscularis mucosae or submucosa T1a: Tumour invades the lamina propria or muscularis mucosae T1b: Tumour invades submucosa T2 Tumour invades the muscularis propria T3 Tumour invades adventitia T4 Tumour invades the adjacent structures T4a: Tumour invades the pleura, pericardium, azygos vein, diaphragm or peritoneum T4b: Tumour invades other adjacent structures, such as the aorta, vertebral body or airway a N: Regional lymph nodes Nx Regional nodal status cannot be assessed N0 No regional lymph node metastasis N1 Metastasis in one or two regional lymph nodes N2 Metastasis in three to six regional lymph nodes N3 Metastasis in seven or more regional lymph nodes M: Distant metastases M0 No distant metastasis M1 Distant metastasis a Regional nodes extend from the paratracheal/oesophageal nodes in the neck to the coeliac nodes.

encompass the paratracheal nodes from the neck, through the mediastinum to the upper abdomen, including the coeliac nodes. The segregation of N1 to N3 is by the number of involved lymph nodes. Location is defined by the position of the epicentre of the tumour in the oesophagus ( Figure 66.1 Stage groupings di ff er among squamous and adenocarcino mas. Separate groupings are assigned for clinical (cTNM), pathological (pTNM) and post-neoadjuvant (ypTNM) systems. Because of the complexity , these are not reproduced in this chapter b ut readers can refer to the staging manual. Controversy exists as to whether adenocarcinoma of the OGJ should be staged as oesophageal or gastric cancer. According to the latest staging definitions, a tumour involving the OGJ with its epicentre no more than 2 /uni00A0 cm into the gastric cardia is staged as adenocarcinoma of the oesophagus, while those with a centre located at more than 2 /uni00A0 cm distal to the anatomical OGJ are staged as gastric cancer. Endoscopic and percutaneous ultrasonography The cT stage and paraoesophageal nodes are best staged using EUS. EUS is the only imaging modality able to distinguish the various layers of the oesophageal wall, usually seen as five alter nating hyper- and hypoechoic layers using 12-MHz ultrasound ( Figure 66.49 ). Infiltration to adjacent structures (cT4) is most accurately assessed. The accuracy of EUS for tumour and nodal staging averages 85% and 75%, respectively . T he draw back is that many advanced cancers do not permit passage of a conventional echoendoscope, though most non-traversable tumours are likely to be at least cT3. Miniaturised ultrasonog raphy catheter probes can be used to pass through the working channel of a conventional endoscope. EUS-guided FNA can be used to obtain cytological proof of involved lymph nodes Bronchoscopic examination can assess airway involvement by the tumour. Percutaneous ultrasonography of cervical nodes is useful, as FNA can be obtained in the same setting. In diagnosing possible T4 cancer by CT scan, obliteration of the fat plane between the oesophagus and the aorta, trachea and bronchi, and pericardium is suggestive of invasion, but the paucity of fat in cachectic patients makes this criterion unreliable. Diagnosis of paraoesophageal nodes is less accurate than with EUS, but distant nodes are better assessed by CT scan. Fluorodeoxyglucose–positron emission tomography scans Squamous cell cancers are usually fluorodeoxyglucose (FDG) avid ( Figure 66.50 ). Detection of the primary tumour is useful. Adenocarcinomas of the OGJ sometimes show limited or absent FDG accumulation regardless of tumour volume (FDG non-avidity). Positron emission tomography (PET) does not define the oesophageal wall and thus has no value in cT staging. Its spatial resolution is also insu ffi cient to separate the primary tumour with juxtatumoral nodes because of interfer - ence from the primary cancer. It is mostly used for detecting regional and non-regional nodes, as well as distant metastases. The uptake by the tumour may have some prognostic value, and c hange in uptake after neoadjuvant treatment is similarly useful in predicting histological response and outcome. Laparoscopy Laparoscopic staging is useful in adenocarcinomas, especially ). those of the OGJ, but not for squamous cell cancer. Laparos - - copy should be reserved for patients in whom confirmation of metastatic disease that is not otherwise obtainable is essential in deciding on treatment.

Figure 66.49 Endoscopic ultrasonography (EUS) picture of an oesophageal tumour. The layers of the oesophageal wall on EUS are obliterated. The tumour appears eccentric with extraoesophageal invasion (6 o’clock to 9 o’clock).