From the Guidelines
Rectal tumor excision should be performed using a total mesorectal surgical resection for most early-stage (T1-T2) rectal cancers, with transanal excision considered for carefully selected T1-stage patients. The surgical approach depends on the tumor location, size, and suspected pathology, with options including transanal excision, transanal endoscopic microsurgery (TEM), or formal resection via low anterior resection or abdominoperineal resection for larger or malignant masses 1.
Preoperative Evaluation
Before surgery, patients should undergo complete bowel preparation and receive prophylactic antibiotics. Preoperative imaging for local staging of rectal cancer is essential for determining the need for neoadjuvant therapy and surgical strategy 1. Neoadjuvant chemotherapy and radiation added to primary resection in patients with radiologically determined high-risk/locally advanced rectal cancer has been shown to decrease local recurrence and improve survival 1.
Surgical Technique
During surgery, a 1-2cm margin around the mass should be maintained when possible, with full-thickness excision extending to perirectal fat for adequate pathologic evaluation. The defect should be closed primarily in layers when feasible. The standard of care for surgery is total mesorectal excision (TME), implying that all of the mesorectal fat, including all lymph nodes, should be meticulously excised 1.
Postoperative Care
Postoperatively, patients require close monitoring for bleeding, infection, and urinary retention. Diet can be advanced as tolerated, and pain managed with scheduled acetaminophen and as-needed opioids. Follow-up should include examination at 2-4 weeks post-surgery and surveillance based on pathology results. For patients with locally advanced rectal cancer (LARC), postneoadjuvant “restaging” has become important to re-evaluate surgical approach, assess response to selected chemotherapy/radiation therapy, or to consider organ-sparing “conservative” nonoperative surveillance in carefully selected patients who may demonstrate complete or near-complete response to neoadjuvant therapy 1.
From the Research
Guidelines for Rectal Tumor Excision
- The decision to excise a rectal tumor depends on accurate preoperative staging, which can be achieved through various modalities such as digital rectal examination, computed tomography, magnetic resonance imaging (MRI), and endorectal ultrasound (ERUS) 2.
- Endorectal ultrasound has been shown to be an accurate method for determining the depth of wall penetration and is comparable to MRI for lymph node metastases 2.
- Total mesorectal excision (TME) and preoperative chemoradiation therapy (PCRT) are standard procedures for locoregional and locally advanced rectal cancer, respectively 3.
- For tumors located in the retrorectal space, transanal endoscopic microsurgery (TEM) can be used to achieve complete excision while minimizing trauma 4.
- The accuracy of preoperative ERUS/MRI staging for mid to distal cT3N0 rectal cancer is limited, and patients should continue to receive preoperative CMT to avoid understaging and ensure optimal treatment 5.
Diagnostic Modalities
- Endorectal ultrasound: accurate for determining depth of wall penetration and comparable to MRI for lymph node metastases 2.
- Magnetic Resonance Imaging (MRI): emerging as an essential imaging modality, especially in the assessment of tumor response and depiction of complete remission after PCRT 3.
- Computed Tomography (CT): accuracy varies for depth of penetration and lymph node metastases 2.
- Digital Rectal Examination (DRE): accuracy varies for depth of penetration 2.
Treatment Approaches
- Watch-and-wait approach: may not be a proper strategy compared to radical surgery after neoadjuvant therapy, as the accuracy of mucosal integrity, endorectal ultrasound, and MRI to predict clinical complete response is poor 6.
- Radical surgery: based on the principles of total mesorectal excision, is the standard treatment for rectal cancer 3, 5.