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April 2002. Review Article.
We report an interpretation of the biological significance of lymphadenectomy, by Gervasoni et al. This article underlines a different philosophy from that of other US Professors about the theme of lymphadenectomy. This different approach is interesting because it shows the importance of philosophy in Science. For this reason we propose at the bottom of our home page a link to the philosophy journal "The New Era".
In virtually all malignant solid tumors, except for low-risk differentiated thyroid cancers and carcinoid tumors, it is accepted that lymph node status is one of the most important prognostic indicators of poor survival. What remains debatable is if lymph node metastases govern or only indicate poor survival and whether lymphadenectomy of varying extents can offer these patients a survival advantage.
Gervasoni et al argue that controlled clinical trials have demonstrated that radical lymph node resection offered no survival benefit over routine lymph node dissection in melanoma, breast, colorectal, gastric and other cancers. Today, this has resulted in a trend toward "minimally invasive surgery" for staging the regional nodes in breast cancer and melanoma.
Today with recent developments in molecular biology, they affirm that we can now better understand the "seed and soil" theory of Paget. Lymph nodes are not sieves or millipore filters that function to cull out tumor cells or foreign agents. It is recognized that multiple cellular events have to occur for the development of regional lymph node metatases. These events include detachment of a malignant cell from the primary tumor, invasion of the lymphatic space, and attachment, implantation, and progressive growth in the regional lymph node. These latter events require appropriate receptors on the cancer cells and in the lymph node cells or stroma themselves, secretion of appropriate paracrine growth factors, and the development of angiogenesis. The development of lymph node metastases is therefore not a simple mechanical event but one that requires multiple cellular and molecular steps.
Therefore the authors conclude that lymph node metastases functions as an indicator of prognosis, not the controlling or determining factor of prognosis. Thus, varying degrees of treatment of regional lymph nodes and metastases do not seem to be controlling factors in the outcome of cancer ( 1 ). .
1) James E Gervasoni, Jr, Charu Taneja, Maureen A Chung, and Blake Cady. Biologic and clinical significance of lymphadenectomy. Surgical Clinics of North America. Volume 80, number 6, December 2000, 1631-1675.
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