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July 2001. Review Article.
The introduction of Siewert classification, which has a direct impact on the surgical treatment, diminished the difficulties deriving from an inappropriate classification of carcinomas of the esophagogastric junction.
Piso affirms that there is not a significant difference between the rates of R0 resections for patients with PGC or DGC (rate of R0 resections of 78%-81%) . He finds a high resectability of primary gastric carcinoma. This can be explained by the development of surgical technique and anesthesia and by improved patient selection for laparotomy due to preoperative investigations ( 1 ).
The long term survival of patients with proximal gastric third carcinoma is worse than that for patients with distal gastric carcinoma due to more advanced tumor stages (particularly after reclassification of T2 type II carcinoma).
For DGC, patients with no lymph node metastases have a long term prognosis similar to those with a maximum of 20% lymph node metastases ( In ratio < 0.2) suggesting a benefit after D2 lymphadenectomy. In patients with PGC and an In ratio < 0.2, prognosis is much worse than that of those without lymph node metastases. Probably because of the inadequate extent of systemic lymphadenectomy. Left retroperitoneal lymphadenectomy (including the left renal hilus where extraperitoneal areas of the proximal gastric third drain) may be necessary ( 1, 2, 3 ).
In fact the long-term outcome of patients in the German Gastric Carcinoma Study identifies the lymph node ratio (the ratio of positive to removed nodes) and the residual tumor ( R ) category as the major indipendent prognostic factors in patients with resected gastric cancer. In addition the extended lymph node dissection is the most important factor determinig long-term survival in patients with stage II gastric cancer ( 4 ).
The high prevalence of "intestinal type" tumours allows a limited extent of luminal resection margins. Consequently total gastrectomy with transhiatal resection of the distal esopahgus is usually sufficient to achieve complete tumour removal at the oral margin, in the PGC ( 1, 3 ).
Among proximal tumors type II has a favourable prognosis in comparison to type III and other proximal carcinomas, mainly due to diagnosis in earlier stages. The late diagnosis of type III is due to late symptoms( in contrast to earlier dysphagia in cardia tumours) and more difficult endoscopic exploration of the gastric fundus ( 1, 3 ).
Sakaguchi et al affirm that the relatively poor prognosis associated with PGC is mainly from advanced tumor stages of esophageal invasion. Early detection is the most important strategy to improve the survival of patients with PGC. In addition aggressive lymph node dissection and chemotherapy for esophageal invasion should be considered even if the tumour invasion is moderate (T2 tumour), and a tumor free margin is important
( 5 ).
Harrison et al define a subset of PGC resected using an transabdominal-only approach, to discriminate true PGC from distal esophageal adenocarcinoma.
It appears that PGCs are inherently more aggressive than are DGCs.
This opinion is partially different from Piso's opinion who affirms that after stratification into less and more advanced tumor stages, tumor site has no statistically significant influence on the prognosis of patients with stage I and II of disease, showing that proximal and more distal gastric carcinomas are not different tumor entities. However for patients with advanced disease, tumor site is an indipendent prognostic factor with negative influence on the prognosis of patients with proximal tumors, suggesting that left retroperitoneal lymphadenectomy should be considered in these patients ( 1 ).
1) P Piso et al. Proximal versus distal gastric carcinoma- What are the differences? Annals of Surgical oncology, 7 (7) : 520-525, 2000.
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