What is the risk of nodal metastasis from superficial adenocarcinoma arising in Barrett's esophagus?
R.C. Haggitt (Seattle)
Superficial adenocarcinoma arising in Barrett's esophagus is defined herein as adenocarcinoma with invasion limited to the mucosa (intramucosal carcinoma) or to the mucosa and submucosa (submucosal carcinoma). Determining the risk of nodal metastasis when carcinoma is limited to the mucosa or mucosa and submucosa serves as an important surrogate marker for prognosis because it is well established that nodal metastasis is one of the most important independent prognostic indicators. Relatively few studies have been published in which the data are presented in a manner that allows determination of the prevalence of nodal metastasis with carcinoma limited to the mucosa and submucosa.
Table I summarizes data published in five different papers in which it was possible to determine the number of cases of intramucosal and submucosal carcinoma, respectively, with positive nodes. Note that none of 40 patients with intramucosal carcinoma alone had positive lymph nodes. Three of the patients with submucosal carcinoma had positive nodes, and one had distant metastasis at the time of the surgical resection; however, this patient had a poorly differentiated tumor with lymphatic invasion [5]. Thus, if one summarizes all cases of superficial adenocarcinoma in Barrett's esophagus, i.e. intra- and submucosal carcinomas, 4 of 67 (6%) had either positive lymph nodes or distant metastasis at the time of surgical resection.
Insufficient data exist to determine if the patients with invasion limited to the submucosa, but who had positive nodes or distant metastasis at the time of diagnosis, had other pathologic risk factors predictive of an adverse outcome. For example, one cannot determine whether the patients with positive nodes had poorly differentiated tumors or lymphatic invasion, findings that are associated with an increased risk of an adverse outcome.
The reason so few studies provide data that permit the analysis shown in Table I is that most report survival rates for T, N and M stages or stage groupings (0-IV), which does not permit determination of the prevalence of positive lymph nodes with invasion limited to the mucosa or mucosa and submucosa.
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