Treatment of Rectal Cancer
The standard treatment for rectal cancer is surgical resection using the Total Mesorectal Excision (TME) technique, preceded by preoperative radiotherapy or chemoradiotherapy for locally advanced disease, with the goal of sphincter preservation whenever possible. 1
Initial Assessment and Staging
- Complete clinical evaluation including rectal examination, rigid proctoscopy with biopsy, complete blood count, liver and renal function tests, CEA, and imaging (chest X-ray, CT/MRI/ultrasound of liver) is essential 2
- Endoscopic ultrasound or rectal MRI is recommended to select patients for preoperative treatment 1, 2
- Complete colonoscopy should be performed either pre- or postoperatively 1
- TNM staging system should always be used for proper classification 1
Treatment Approach Based on Disease Stage
Early Stage Disease (cT1-T2, N0)
- For very early tumors (T1), local procedures such as transanal endoscopic microsurgery may be appropriate without radiation 1, 3
- For early favorable cases (cT1-2, some early cT3, N0), surgery alone using TME technique is appropriate 1
- At least 12 lymph nodes should be examined for proper staging 2
Locally Advanced Disease (Most cT3, cT4, N+)
- Preoperative radiotherapy is recommended followed by TME, as this reduces local recurrence rates 1
- Two main preoperative radiotherapy approaches:
- Preoperative chemoradiotherapy is preferred over postoperative treatment due to decreased toxicity and improved efficacy 1, 2
Fixed/Unresectable Tumors
- Preoperative chemoradiotherapy (50.4 Gy, 1.8 Gy/fraction with concomitant 5-FU-based therapy) followed by radical surgery 6-8 weeks later 1
- For very elderly patients (≥80-85 years) or those unfit for chemoradiotherapy, 5×5 Gy with a delay of 8 weeks before surgery can be an option 1
Surgical Approach
- Total Mesorectal Excision (TME) is the gold standard surgical technique, providing low local recurrence rates (<10%) and good quality of life 1, 3, 5
- TME involves sharp, meticulous dissection of the tumor and mesorectum with all associated lymph nodes through the avascular embryologic plane 3
- Whenever possible, sphincter-preserving surgery (low anterior resection) should be employed 1
- For tumors in the upper third of the rectum, a margin of at least 5 cm distally to the tumor on an unfixed specimen must be achieved 1
Chemotherapy Options
- Standard preoperative chemoradiotherapy includes 5-FU given as:
- Capecitabine (Xeloda) is an oral fluoropyrimidine that can replace bolus or continuous infusion 5-FU, offering simplified chemoradiation that is more appealing to patients 6, 7
- Combinations with oxaliplatin or irinotecan have shown higher pathologic complete response rates but also increased toxicity 1, 4
Management of Metastatic Disease
- For resectable metastases, simultaneous rectal and hepatic surgery (if hepatectomy involves 3 or less segments) is standard 1
- Options for resectable metastases include:
- For unresectable metastases, systemic palliative chemotherapy is the standard treatment 1
- Options include 5-FU-FA or combinations with oxaliplatin or irinotecan 1
Follow-up Protocol
- History and rectosigmoidoscopy every 6 months for 2 years 1
- History and colonoscopy with resection of colonic polyps every 5 years 1
- Clinical, laboratory, and radiological examinations should be restricted to patients with suspicious symptoms 1
Common Pitfalls and Caveats
- Preoperative treatment is strongly preferred over postoperative treatment due to decreased toxicity and improved efficacy 1, 2
- Proper TME technique is crucial - inadequate mesorectal excision leads to higher local recurrence rates 3, 5
- For patients taking blood thinners like warfarin, capecitabine may increase the effect of these medications, requiring more frequent monitoring and potential dose adjustments 6
- The role of TME in tumors situated in the upper third of the rectum has been debated, but a margin of at least 5 cm distally is recommended 1