What are the potential complications of Low Anterior Resection (LAR) for rectal cancer?

Complications of Low Anterior Resection (LAR)

Anastomotic leakage is the most severe and common complication after LAR, occurring in 2.0% to 25% of patients, with most series reporting 8-10%, and represents the primary driver of morbidity and mortality following rectal cancer surgery. 1

Major Complications

Anastomotic Leakage (AL)

• Incidence ranges from 2.0% to 10.3%, with peaks up to 25% in high-risk populations 1
• Risk factors in elderly patients (>80 years) include ≥3 stapler firings and coronary artery disease as independent predictors 1
• Clinical presentation includes fever, tachycardia, abdominal pain, and peritoneal signs 2
• Symptomatic leaks occur in approximately 78% of cases, requiring intervention 3

Management approach:

• Proximal diversion (temporary ileostomy) should be performed at index surgery for high-risk anastomoses to decrease severity of septic complications and reduce reoperation rates 1
• Conservative management with percutaneous drainage is successful in 55.6% of cases, requiring an average of 4.4 procedures 3
• Reoperation is needed in 55.6% of patients with AL, though most can be managed electively rather than emergently 3
• Restoration of intestinal continuity is achievable in 63% of patients after successful leak management 3

Low Anterior Resection Syndrome (LARS)

• Affects up to 73% of patients and includes at least one of eight bowel symptoms: variable/unpredictable bowel function, urgency, frequency, and emptying difficulties 1, 2
• Symptoms rarely improve spontaneously after 3 months without intervention 1
• The British Society of Gastroenterology emphasizes that early active case finding is required rather than waiting for spontaneous improvement 1

Management algorithm:

1. Assess LARS risk preoperatively using formal scoring tools and discuss with patients 1
2. Offer supported self-management interventions to all patients immediately after surgery 1
3. If symptoms persist beyond 3 months despite self-management, refer to specialist services 1
4. Exclude contributing conditions: bile acid diarrhea (BAD), pancreatic exocrine insufficiency (PEI), and small intestinal bacterial overgrowth (SIBO) 1
5. Consider pelvic floor exercises, bulking agents for stool consistency, and transanal irrigation 1

Diverting Ileostomy-Related Complications

Stoma-Related Morbidity

• DI-related morbidity rates range from 2.9% to 62.2%, with median 14.3% 1
• Complications include skin irritation, parastomal hernias, stomal prolapse/retraction, and decreased quality of life 1
• Morbidity rates increase with time to ileostomy closure 1

Metabolic Complications

• DI formation in elderly patients is independently associated with kidney injury, with increased risk persisting after stoma closure 1
• Dehydration or renal failure is common in elderly patients with metabolic disorders, leading to 17% to 30% readmission rate 1

Impact on Adjuvant Therapy

• DI during adjuvant chemotherapy predicts severe chemotherapy-induced diarrhea and need for regimen modifications, potentially affecting long-term survival 1

Optimal timing for ileostomy closure:

• In selected fit elderly patients, early closure within 2 weeks is recommended (weak recommendation, moderate quality evidence) 1, 2
• Early closure associated with lower incidence of postoperative small bowel obstruction, stoma-related complications, and better functional outcomes 1, 2
• Trade-off: relatively higher surgical site infection rate (2-18%) compared with late closure 2
• Traditional approach of 8-12 weeks closure remains standard when early closure is not feasible 1, 2
• Reversal before 6 weeks carries increased complication risk and should only be performed in carefully selected patients 2

Other Significant Complications

Surgical and Technical

• Anastomotic hemorrhage occurs in 5.3% of laparoscopic LAR cases 4
• Small bowel obstruction risk increases with delayed ileostomy closure 1
• Tumor size, location, and pathological staging are independent risk factors for complications 4

Long-Term Functional Issues

• Chronic pain, fecal incontinence, and sexual difficulties affect both sexes 1
• Constipation and evacuation difficulties including straining, incomplete evacuation, tenesmus, bloating, and flatulence 1
• Patients describe "living in limbo" due to incontinence and unpredictable bowel function 1

Critical Pitfalls to Avoid

• Do not assume spontaneous improvement after 3 months—active intervention is required 1
• Do not delay ileostomy closure beyond necessary as morbidity increases with time 1
• Do not perform objective testing to diagnose LARS—clinical assessment is sufficient 1
• Do not overlook metabolic complications in elderly patients with ileostomies, particularly dehydration and renal dysfunction 1