Skip to main content
EN → RO

LARS syndrome after rectal cancer surgery: symptoms and treatment

by Dr. Cristi Blajut
LARSlars syndromerectal cancerrecoverybowel dysfunction

LARS syndrome after rectal cancer surgery

LARS syndrome (Low Anterior Resection Syndrome) is the most common functional consequence after sphincter-preserving rectal cancer surgery. It affects up to 80% of patients to varying degrees and can have a significant impact on quality of life. The good news is that symptoms improve over time and effective treatments are available.

What is LARS syndrome

LARS represents a set of bowel symptoms that occur after low anterior resection (the operation in which the rectum is removed and the colon is reconnected to the anal canal). The causes include:

  • Loss of the rectal reservoir — the normal rectum stores stool; after resection, the colon takes over this function but does not have the same capacity
  • Pelvic nerve injury — nerves controlling the sphincter and rectal sensation can be affected
  • Anal sphincter changes — especially after radiotherapy
  • Scarring and inflammation — at the anastomosis site

Main symptoms

Common symptoms

  • Urgency — sudden, imperative need to go to the toilet, sometimes with accidental stool loss
  • Stool fragmentation — instead of complete evacuation, the patient goes to the toilet many times a day in small amounts
  • Increased frequency — more than 4-5 stools per day
  • Incontinence — involuntary loss of gas or stool, especially at night
  • Incomplete evacuation — the feeling that the bowel hasn’t fully emptied
  • Difficulty distinguishing gas from stool
  • Nighttime symptoms — waking up to evacuate or leakage during sleep

Severity categories

LARS is assessed with a validated questionnaire — the LARS Score — which quantifies symptoms on a scale of 0-42:

  • No LARS (0-20): normal or near-normal bowel function
  • Minor LARS (21-29): symptoms present but manageable
  • Major LARS (30-42): severe symptoms significantly affecting quality of life

You can assess your score with the LARS Score Calculator on this site.

How LARS evolves over time

LARS improves significantly in the first year after surgery (or after stoma closure):

  • First 3 months: most intense symptoms — high frequency, severe urgency, incontinence
  • 3-6 months: progressive improvement, the patient learns to manage symptoms
  • 6-12 months: significant improvement, a new “normal” stabilizes
  • 1-2 years: maximum improvement; symptoms persisting beyond 2 years tend to become permanent

Treatment of LARS syndrome

1. Dietary modifications

  • Soluble fiber (psyllium/Metamucil) — thickens stool and reduces fragmentation
  • Avoiding trigger foods — caffeine, alcohol, spicy foods, dairy (varies between patients)
  • Small, frequent meals instead of 3 large meals
  • Food diary — track what you eat and how you feel to identify triggers

2. Medication

  • Loperamide (Imodium) — slows bowel transit, reduces urgency and frequency; can be taken preventively before going out
  • Cholestyramine — useful when diarrhea is caused by bile acid malabsorption
  • Suppositories or mini-enemas — to schedule evacuation at a convenient time

3. Biofeedback and pelvic floor rehabilitation

  • Biofeedback — sphincter muscle training with specialized equipment; studies show significant improvement in 60-70% of patients
  • Kegel exercises — strengthen pelvic floor muscles
  • Transanal irrigation (TAI) — washing out the colon with water through a special system; can completely eliminate incontinence and allow “scheduled” evacuation

4. Sacral neuromodulation

For severe cases that do not respond to other treatments, electrical stimulation of the sacral nerves can significantly improve continence and bowel function.

Adapting to life with LARS

Practical strategies

  • Locate toilets — before going somewhere new, know where the bathrooms are
  • Emergency kit — always carry spare clothes, wet wipes and bags
  • Schedule evacuation — try to go to the toilet at the same times, ideally in the morning after breakfast
  • Communicate — talk with close family and friends about your situation; their understanding reduces stress

Emotional support

LARS can affect mental health — social anxiety, embarrassment, isolation. It is important to:

  • Speak with a psychologist if symptoms affect you emotionally
  • Look for support groups for rectal cancer patients
  • Remember that symptoms improve with time

When to contact your doctor

See a doctor if:

  • Symptoms get worse instead of improving
  • New rectal bleeding appears
  • You have severe abdominal or rectal pain
  • You cannot maintain adequate nutrition because of diarrhea
  • Symptoms significantly affect your social and professional life — there are solutions

Assess your symptoms

Use the LARS Score Calculator to assess severity and the POLARS Calculator if you have not yet had surgery, to estimate your risk of developing LARS.

This article is for informational purposes only and does not replace medical consultation. Discuss with your doctor about the most appropriate treatment options.