Local Excision of Rectal Neoplasia
Anuradha R. Bhama
David Maron
Scott R. Steele
Perioperative Considerations
Indications for Surgical Treatment
Goal of treatment is to completely remove the pathology en bloc with negative margins.
Curative for benign lesions
Can be diagnostic for what may be more advanced lesions without clear preoperative staging, with the understanding that formal proctectomy may still be necessary
Appropriate staging of the lesion
Prior to the operation, a full colonoscopy should be performed to
rule out synchronous lesions
document the location and extent of lesion in question
biopsy the lesion of question to confirm pathology
Obtain further staging workup as indicated (magnetic resonance imaging for local staging and computed tomography of the chest/abdomen/pelvis for distant staging, if indicated).
Traditional guidelines for standard transanal excision
<8 cm from anal verge (at or below the first rectal valve)
Note that higher lesions are still possible but need to have adequate exposure.
Need to intussuscept the rectum down toward the verge.
Be prepared for full-thickness entry into the peritoneum that may require a laparoscopy/laparotomy to repair.
≤3 cm in size
≤40% of circumference of the lumen of the rectum
All of these are guidelines, and more extensive lesions are still able to be removed via the transanal approach.
Transanal minimally invasive surgery (TAMIS)
Proximal extent higher up in the rectum is more easily attained up to the second or third rectal valve.
Need to consider the bulk of the mass to allow for appropriate visualization of the proximal margin.
Larger lesions can be removed if the mucosal defect can be closed without creating an iatrogenic stenosis.
With higher lesions, peritoneal entry remains a possibility.
Benign versus malignant pathology
Benign lesions are candidates for transanal excision if size permits.
T1 lesions can be resected locally if:
Favorable histology with low risk of metastasis (low grade, no neurovascular invasion, no lymphovascular invasion), or
Patient cannot tolerate radical excision.
T2 or T3 lesions in patients who are unable to tolerate radical excision, with the understanding that this is not curative in nature.
Higher local recurrence exists with >T1 lesions.
The addition of radiation or chemotherapy will not “bail out” positive margins.
All patients with proven adenocarcinoma should be counseled of the risk of preexisting lymph node metastases and the potential for false-negative lymph node involvement on local staging studies.
These patients should be counseled that they may still require a formal radical proctectomy and understand that transanal excision in these circumstances is not curative in nature.
Limitations
Standard transanal excision
Cannot typically reach lesions higher than 8 cm from the anal verge
May have limited exposure and visibility due to body habitus and extent of anal retractors (eg, large buttocks with a long anal canal)
TAMIS
Requires advanced laparoscopic skills
Potential to enter peritoneal cavity for higher lesions or vagina for anterior lesions in women
Preoperative Preparation
Standard transanal excision
Rectum should be cleared with either enemas morning of the operation or a full bowel preparation the day prior.
Preoperative antibiotics should be administered as with traditional colon surgery.
Venous thromboembolism prophylaxis should be administered.
TAMIS
Full mechanical bowel preparation should be given.
Preoperative antibiotics should be administered as with traditional colon surgery.
Venous thromboembolism prophylaxis should be administered.
Foley catheter should be placed in the bladder.
Patient Positioning
The location of the lesion should be identified and documented during the full colonoscopy or during a flexible sigmoidoscopy done during clinic as this will determine the ideal positioning of the patient.
When possible, the patient should be positioned such that the lesion is located in the inferior quadrant.
For all of these positions, it is imperative to ensure that all pressure points are padded appropriately and there is no pressure or strain on the joints.
Lesions in the posterior rectum can be performed in modified lithotomy position.
Lesions in the anterior rectum can be performed in prone for standard transanal excision (prone jackknife or Kraske positioning) or in prone split leg for TAMIS.
For TAMIS, lesions located laterally can be approached with the patient in a right or left lateral decubitus position with the lesion downward and the legs bent at the hip and knee.
Ensure that padding is placed between the legs and also under the inferior axilla. Ensure that all bony prominences are padded appropriately.
The buttocks should be taped apart to aid in visualization.
STANDARD TRANSANAL EXCISION
Technique
A Lone Star retractor (Cooper-Surgical) can be utilized to evert the anus. Alternatively, anal eversion sutures (#0 Vicryl) can be used.
Various retractors can be used to expose the rectum: Hill-Ferguson, Pratt bivalve, Fansler, and so on.
Deavers or Wiley retractors may be helpful to expose more proximal lesions.
The use of a headlight or lighted retractors (or both) will aid in visualization of the lesion.
Start by marking the incision line with electrocautery. A 1-cm margin should be marked circumferentially around the lesion (Fig. 29-1).
FIGURE 29-1 ▪ Marking the lesion with 1-cm margins. (Reprinted with permission, Cleveland Clinic Center for Medical Art & Photography © 2019. All Rights Reserved.)
Stay sutures can be placed proximal and lateral to the lesion to help pull the tumor down toward the anal canal.
Local anesthetic with epinephrine (or dilute epinephrine alone) can be infiltrated to assist in hemostasis.
Using the marked intended incision, a full-thickness excision should be performed, starting proximally and working distally toward the anal canal, although a submucosal excision can be performed for benign lesions, similar to an endoscopic removal (Fig. 29-2).
For malignant lesions, the deep margin should extend into the mesorectum (Fig. 29-3). Ensure that the dissection is perpendicular as to not compromise the oncologic margins.
FIGURE 29-2 ▪ Full-thickness excision of the lesion. (Reprinted with permission, Cleveland Clinic Center for Medical Art & Photography © 2019. All Rights Reserved.)
FIGURE 29-3 ▪ Defect created after removal. Note the fat. (Reprinted with permission, Cleveland Clinic Center for Medical Art & Photography © 2019. All Rights Reserved.)
The specimen should be pinned down onto Styrofoam and oriented for pathologic evaluation (Fig. 29-4).Related posts:
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