Robotic total mesorectal excision for rectal cancer: it may improve survival as well as quality of life

Abstract

I read with great interest the letter by Ziogas et al. [1]. Their first question is why the da Vinci system in rectal cancer surgery may provide a survival benefit and the second is why this benefit cannot occur for other cancer sites in the gastrointestinal tract. For the first question, the answer lies with the technological advantages of the da Vinci system. In rectal cancer surgery, total mesorectal excision (TME) has become the surgical treatment of choice [2]. However, TME is a technically demanding procedure since it is performed in a narrow pelvic cavity. Therefore, macroscopic completeness of a resected rectal specimen is variable according to the patient’s anatomic factors and the type of surgical procedures. The macroscopic completeness of a resected rectal specimen is a predictive factor of a patient’s prognosis [3]. In my experience of robotic TME, pathologic results with macroscopic grading were excellent [4]. I postulate that these pathologic results account for improving long-term survival even though there is, as of yet, no study about long-term survival in robotic rectal cancer surgery. The second question can be similarly answered when one reflects on the specific technological advantage of the da Vinci system. Except the rectum, surgical view is excellent in the rest of the gastrointestinal tract and the concept of macroscopic completeness of a resected specimen does not exist in gastrointestinal tract surgeries other than rectal surgery. The important thing for a better survival is en bloc and proper lymph node dissection. Thus, the technical advantage of the da Vinci system does not contribute to a better survival benefit compared to the open procedures in the era of proper lymph node dissection in gastrointestinal tract cancer surgeries beyond quality of life. The general advantages of da Vinci robotic system are a three-dimensional view, hand-tremor filtering, fine dexterity, and motion scaling. These advantages are more helpful for secure dissection in a narrow surgical field. Therefore, da Vinci system may provide a greater advantage in rectal cancer surgery than other gastrointestinal tract surgeries. However, further large-scale prospective studies to evaluate these issues would be helpful.