In the oesophagus, endoscopic therapies can be used for high-grade dysplasia and selected cases of early cancer (T1a) as a less morbid and potentially equally effective treatment option in comparison with oesophagectomy (Cancer Council Australia Barrett’s Oesophagus and Early Oesophageal Adenocarcinoma Working Party 2014; Uedo et al. 2012).

Endoscopic en-bloc resection is recommended for superficial oesophageal SCCs, excluding those with obvious deep submucosal involvement. Endoscopic mucosal resection may be considered in lesions smaller than 10 mm if en-bloc resection can be assured (Pimentel-Nunes et al. 2015). However, endoscopic submucosal dissection is recommended as the first option for mucosal SCCs larger than 10 mm in size, mainly to provide an en-bloc resection for accurate pathology staging and to avoid missing important histological features (Pimentel-Nunes et al. 2015).

Submucosal invasion caries an increased risk of lymph node metastasis and the need for further management should be discussed in an MDM (Draganov et al. 2019; Pimentel-Nunes et al. 2015; Rizvi et al. 2017).

In Barrett’s oesophagus, complete resection (R0) of a superficial lesion with mucosal adenocarcinoma is considered curative (Pimentel-Nunes et al. 2015). Complete resection (R0) of a sm1 lesion (≤ 500 μm) with a low risk profile (well or moderately differentiated, no lymphovascular invasion) is potentially curative but can also be associated with a risk of lymph node metastasis. This should be discussed in an MDM where the risk of surgery should be balanced against the risk of lymph node metastasis (Pimentel-Nunes et al. 2015).

Surgery for Barrett’s oesophagus is recommended in the following instances:

• lymphovascular invasion
• poorly differentiated tumour
• deeper infiltration into sm1 and beyond (> 500 μm), or
• where positive deep resection margins are diagnosed. If only the lateral margin is positive or there is piecemeal resection with no other high-risk criteria, endoscopic surveillance/re-treatment is recommended rather than surgery (Pimentel-Nunes et al. 2015).

For oesophageal cancers, following endoscopic resection the remaining Barrett’s mucosa should be eradicated (Cancer Council Australia Barrett’s Oesophagus and Early Oesophageal Adenocarcinoma Working Party 2014). Further treatment to the remaining non-dysplastic epithelium is necessary using either the endoscopic mucosal resection technique or radiofrequency ablation.

Endoscopic treatment is also feasible for selected high-grade dysplasia of the stomach and early gastric cancers confined to the mucosa (T1a). Not dissimilar to the oesophagus, there are two sets of indications for endoscopic management in the stomach: an absolute set of criteria and an expanded criteria. In relation to the absolute indications, the tumour must meet all the following criteria:

• well-differentiated adenocarcinoma
• no ulceration
• stage T1a
• have a diameter of less than 2 cm (Rizvi et al. 2017).

The expanded criteria has been modified to account for tumours that have a very low probability of lymph node metastasis. This includes tumours clinically diagnosed as T1a and are:

• well-differentiated type without ulceration, however, greater than 2 cm in diameter
• differentiated type with ulceration and less than 3 cm in diameter, or
• undifferentiated type without ulceration and less than 2 cm in diameter (Rizvi et al. 2017).

Tumours extending up to 500 μm into the submucosa can also be considered. The risk of lymph node metastasis when endoscopic submucosal dissection is performed for the expanded indication is higher than when it is performed for absolute indications but remains low and should be balanced against the risks versus benefits of surgical resection (Draganov et al. 2019; Ono et al. 2016; Pimentel-Nunes et al. 2015; Rizvi et al. 2017).