SURGERY IN RECTAL CANCER
The rectum, final segment of the digestive tube, is located in a bone tunnel, and is difficult to access, with anatomic connections to the bladder, the prostate in men, and the uterus and vagina in women. Furthermore, it is close to local nerves.
Therefore, in rectal cancer surgery, those aspects concerning the preservation of urinary and sexual functions must also be considered.
Rectal cancer surgery can be performed via transanal (through the anus) or via abdominal.
When performed via abdominal, a single large incision (open surgery) or several small incisions can be made, through which gas is inflated and a light lens connected to a camera is introduced in order to visualize the surgical operations (minimally invasive or laparoscopic surgery). Thus, the laparoscopic approach can be assisted by robotic surgery. Transanal resection can also be supported by endoscopic techniques, then designated endoscopic transanal microsurgery.
The transanal approach allows the local treatment of rectal lesions, avoiding incisions and the impact of abdominal surgery, but has significant oncologic limitations. Originally, it was applied to lesions of the last 5 cm of the rectum. Presently, it is applied to higher lesions using specific instrumentation.
These techniques do not allow removal of perirectal lymphatic tissue, their application being limited to very early and superficial lesions or to cases where patients do not meet health conditions allowing abdominal resection surgery. It can also be an option to consider in cases of refusal of any type of stoma, providing that the patient understands and accepts the therapeutic limitations of these techniques.
Typically, abdominal surgery of rectal tumors consisted in abdominoperineal resection, that is, removal of the rectum, anal canal and anus, with subsequent execution of a permanent colostomy (permanent installation of the intestine at skin surface for discharge of its content into a pouch through the abdominal wall).
The advance of oncologic staging, the development of radiotherapy and chemotherapy protocols, and the improvement of automated suture equipment resulted in the progress of rectum anterior resection. In this case, there is removal of the rectum and anal canal up to a distal level free of lesions, and subsequent anastomosis (connection) of the colon to the remnant segment of the rectum or the anus.
This surgery has oncologic results similar to the previous procedure, but allows the preservation of the anal sphincter.
However, in some cases, even in rectum anterior resection, stoma is indicated (colostomy in the case of the large intestine or ileostomy in the case of the small intestine):
- When lesions are adjacent to the anus
- In perforated or occlusive tumors
- When the intestine condition does not allow safe anastomosis
- In cases of significant coexistent disease that excludes prolonged surgery
- In cases where anastomosis presents high risk of dehiscence (poor cicatrization of the intestinal connection with consequent leak of the intestinal content into the abdomen).
It has been proven that the application of minimally invasive techniques in colorectal surgery allows a quicker recovery and better quality of life, with oncologic results similar to those obtained by open surgery.
Abdominal surgery with robotic support
The complexity of rectal cancer surgery, combined with the anatomic particularities of that organ, make its removal by minimally invasive surgery (laparoscopy) with robotic support a particular case.
In rectal cancer surgery, the aim is to obtain a good oncologic result (that is, the cure of the cancer), but also a good functional result, which means to avoid fecal and urinary incontinence, erectile dysfunction (both frequent after rectal cancer surgery), and to reduce the necessity of permanent ostomy in the case of tumors close to the anus.
The attainment of these purposes depends on the preservation of pelvic nerve plexuses. Due to their location, these plexuses are hard to visualize, identify and preserve, in conventional open surgery, as in laparoscopic surgery.
Robotic surgery, allowing tridimensional vision, has great amplification capacity maintaining definition and uses surgical equipment for minimally invasive surgery technologically more advanced than that available for conventional laparoscopic surgery, allowing lower dissection and facilitating the identification and preservation of the referred nerve plexuses.
Therefore, robotic surgery plays a determinant role in the reduction of incontinence and erectile dysfunction risk and reduction of the necessity of permanent ostomy.