What Are the Main Features of a TME?
A. TME represents a classical milestone in the history of cancer surgery because it was the first tissue block to be defined for cancer whose boundaries are conceptually and practically founded in a basic science –embryology, and now its offspring–ontogen
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R. Heald
Q. What Are the Embryological or Ontogenetic Principles that Make TME a Classic in the History of Surgery for Cancer …? A. TME represents a classical milestone in the history of cancer surgery because it was the first tissue block to be defined for cancer whose boundaries are conceptually and practically founded in a basic science –embryology, and now its offspring–ontogenetics. Unexpectedly massive improvement in local recurrence rates followed the application of the mere idea of TME to surgical practice–albeit imperfectly implemented in the early stages. This pointed to a fundamental truth now recognized as relevant to all visceral cancers – that embryologically defined envelopes of tissue with surgical and MRI definable margins and recognizably shiny surfaces present the careful surgeon with particular opportunities for cure–implying that the primary spread of carcinoma is often contained within these envelopes. These same margins provide the basis for modern image guidance from MRI scanning, not only in planning for surgery, but in modern radiotherapy (RT) as well. (Image guided Intensity modulated and volume modulated arc therapy - IGIMRT & VMAT) Furthermore respect for the surrounding layers and the understanding of their anatomy, in R. Heald Pelican Cancer Foundation, The Ark, Dinwoodie Drive, Basingstoke RG24 9NN, UK e-mail: [email protected]
both surgery and radiotherapy, has a major potential, not only for more actual “cures” but also for the preservation of the important autonomic functions of the surrounding nerve plexuses. These can be grouped together as “Pelvic Happiness”–sexual functions, continence Etc. – without which quality of life becomes seriously diminished and which continue to be diminished by anything less than the highest standards of surgical technique. Ontogenetics and Embryology Understanding technical advances is made easier by the recent refinement of embryology called ontogenetics – a new word - but a concept which simplifies and explains a lot. During the early weeks of foetal development, the zygote evolves into the morula–most easily thought of as a “blackberry-like” structure. Primordia or anlagen, lobes of the blackberry, grow into developmental compartments. Cell mixing does not occur at compartment boundaries, which sets the scene for the fundamental importance of specimen audit and margins in cancer control. Each ontogenetic compartment is a differentiated tissue entity derived from a particular primordium: it contains not only functional organs and structures but also supporting tissues which are often omitted in embryology and anatomy descriptions. Traditional principles of cancer surgery are based on centrifugal local tumor spread irrespective of these more fundamental tissue boundaries. “Old anatomy”
© Springer-Verlag Berlin Heidelberg 2018 V. Valentini et al. (eds.), Multidisciplinary Management of Rectal Cancer, https://doi.org/10.1007/978-3-319-43217-5_46
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therefore often dictates unnecessarily wide tumor excision with metrically defined margin
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