Siewert III adenocarcinoma: treatment update.

Siewert III cancer, although representing around 40% of EGJ cancers and being the EGJ cancer with worst prognosis, does not have a homogenous treatment, has few dedicated studies, and is often not considered in study protocols. Although staged as an esophageal cancer by the TNM 7th ed., it is considered a gastric cancer by new TNM 8th ed. Our aim was to consolidate the current literature on the indications and treatment options for Siewert III adenocarcinoma. A review of the literature was performed to better delineate treatment indications (according to stage, surgical margins, type of lymphatic spread and lymphadenectomy) and treatment strategy. The treatment approach is strictly dependent on cancer site and nodal diffusion. T1m cancers have insignificant risk of nodal metastases and can be safely treated with endoscopic resections. The risk of nodal metastases increases markedly starting from T1sm cancers and requires surgery with lymphadenectomy. The site of this type of cancer and the nodal diffusion require a total gastrectomy and distal esophagectomy, with 5 cm of clear proximal and distal margins and a D2 abdominal and inferior mediastinal lymphadenectomy. Multimodal treatments are indicated in all locally advanced and node positive cancers. Siewert III cancers are gastric cancers with some peculiarities and require dedicated studies and deserve more consideration in the current literature, especially because their treatment is particularly challenging.