Low Anterior Resection Syndrome

Overview

Low anterior resection syndrome, or LARS, is a group of bowel symptoms that can happen after an operation called a low anterior resection. In that operation, part of the rectum (the last part of the large bowel, just above the anus) is removed, and the healthy bowel is joined back to the anus. The rectum normally works as a storage pouch and as a sensor that tells you when you need the toilet. When it is removed or changed, your bowel can behave differently. LARS is not a disease and it is not a sign that the cancer has come back. It is the name for the changes in how your bowel works after this kind of surgery.

Yes, it is very common. Most people who have a low join after rectal surgery will notice some change in their bowel habit, and a large number have symptoms strong enough to affect daily life. Hearing this can be a relief — it means what you are experiencing is a recognised pattern, not something unusual or your fault.

It affects people who have had surgery to remove part of the rectum, most often as treatment for rectal cancer. It is more likely when the join between the bowel and the anus is very low, and when radiotherapy (x-ray treatment) to the pelvis has also been given. It can also happen after surgery for other rectal problems. It affects adults of all ages, and a small number of children who have had similar surgery.

Symptoms

Common symptoms

• Needing to open your bowels very often — sometimes many times a day
• Urgency: a sudden, strong need to go, with little warning
• Clustering: passing stool several times within a short period, often feeling you have not quite finished
• Accidental leaks of wind, liquid, or solid stool (incontinence)
• Soiling of underwear, or needing to wipe many times
• A feeling of not emptying your bowel completely
• Loose or watery stools, or a mix of loose stools and constipation
• Wind, bloating, and gurgling
• Soreness or irritation of the skin around the anus from frequent wiping

Symptoms in children

• LARS is uncommon in children because this surgery is rare in childhood, but the symptoms are similar to those in adults
• Young children may find it harder to describe urgency or a feeling of not finishing, so behaviour changes or toilet accidents may be the main clue
• Children need extra attention to staying hydrated and to skin care, and their growth and eating should be checked regularly
• A children's bowel or surgical team should guide any changes to diet, toilet training, or treatment

Symptoms in older adults

• Urgency can be harder to manage if walking is slow or if arthritis makes getting to the toilet difficult
• There is a higher risk of dehydration from frequent loose stools, especially in hot weather or during illness
• Rushing to the toilet raises the risk of falls, so planning a clear, safe route to the bathroom matters
• Other conditions and other medicines can affect the bowel, so a medication review with your doctor or pharmacist can be helpful
• Skin in older adults is more fragile, so protection against soreness is important

Causes

Main causes

• Removal of the rectum, which normally stores stool and senses when you need the toilet
• The new join sitting very low, close to the anus, so there is less storage space
• Changes to the nerves and muscles that control the bowel and the anal sphincter (the ring of muscle that holds stool in)
• Radiotherapy to the pelvis, which can make the bowel and surrounding tissues less stretchy
• Faster movement of stool through the remaining bowel, leading to loose stools and urgency
• Changes in the bacteria and function of the bowel after surgery

Risk factors

• A very low join between the bowel and the anus
• Radiotherapy to the pelvis before or after surgery
• A leak at the join after surgery, or a temporary stoma
• Removal of a large part of the rectum
• Having irritable bowel syndrome or other bowel problems before surgery
• Emergency rather than planned surgery

When to see a doctor

See a doctor urgently if:

• Severe tummy pain with vomiting or a swollen abdomen
• Heavy bleeding from your bottom
• A fever with feeling very unwell
• Signs of dehydration such as dizziness, very dark urine, or passing very little urine
• A sudden, major worsening of symptoms, or being unable to pass stool or wind at all

Book a routine appointment if:

• Symptoms that are affecting your work, sleep, travel, or social life
• Symptoms that are not improving after a few weeks of simple changes
• Sore skin around the bottom that is not healing
• Losing weight without trying, or feeling very tired
• Any new blood in your stool that lasts more than a few days
• Feeling low, anxious, or avoiding going out because of your bowels

Diagnosis

LARS is usually diagnosed from your story rather than from a single test. Your doctor or specialist nurse will ask about how often you go, how urgent it feels, whether you leak, and how much this affects your life. A simple questionnaire called the LARS score is often used to grade symptoms as mild, moderate, or severe. They will also check that nothing else — such as an infection or a narrowing at the join — is causing your symptoms.

Tests that may be done

• A detailed conversation about your bowel habit and your surgery
• A symptom questionnaire (the LARS score) to measure how much symptoms affect you
• A physical examination, which may include a gentle rectal examination
• Blood tests to check for anaemia, low salts, or dehydration
• A stool sample if infection is suspected
• A flexible sigmoidoscopy or colonoscopy (a camera test of the bowel) if there is bleeding or a change in symptoms
• Scans such as CT or MRI if your team needs to look at the join or the surrounding area
• Specialist bowel function tests, such as anorectal manometry, which measures the pressure and squeeze of the anal muscles, or a balloon test to see how much your bowel can hold

What to expect at your appointment

The first appointment is usually a relaxed conversation, and you can bring a written diary of your bowel habits for a few days beforehand — that helps a lot. You may be asked some personal questions, but they are asked to help you, and you can bring someone with you if that feels easier. Tests are only arranged if they are needed, and most people do not need many. You should leave with a clear plan and a follow-up.

Treatment

LARS is managed step by step, starting with simple changes and adding specialist help if needed. Most people improve with a combination of diet adjustments, pelvic floor (kegel) exercises, good toilet habits, and sometimes medicines prescribed by your doctor. Specialist services such as a colorectal nurse, a pelvic floor physiotherapist, or a bowel function clinic can offer more advanced options. Treatment is tailored to your symptoms, your life, and what matters most to you.

Self-care at home

• Eat regular meals at similar times each day rather than one large meal
• Adjust fibre: soluble fibre (such as oats, bananas, and peeled fruit) often helps firm up stool, while very high-fibre or gas-producing foods can make things worse for some people
• Keep a food and symptom diary for two to three weeks to spot your own triggers
• Drink enough fluid through the day, especially if your stools are loose
• Try cutting down on caffeine, alcohol, fizzy drinks, very spicy food, and high-fat meals to see if it helps
• Do pelvic floor exercises daily — a physiotherapist can check you are doing them correctly
• Give yourself unhurried time on the toilet, and avoid straining or rushing
• Use a barrier cream to protect the skin around the bottom
• Plan ahead: know where toilets are, carry a small kit with wipes, pads, and a change of underwear
• Try to keep active — gentle walking helps the bowel settle

Medical treatments

Doctors can prescribe treatments that slow the bowel down, bulk up the stool, or reduce urgency, and these are adjusted to suit you. A pelvic floor physiotherapist can teach you muscle training and biofeedback, which uses gentle sensors to help you sense and control the muscles better. Some people are taught bowel irrigation, where warm water is gently passed into the bowel through the anus at planned times to empty it and reduce leaks between times. For symptoms that stay severe despite these steps, specialist teams may offer nerve stimulation techniques or referral to a dedicated bowel function clinic. Psychological support and practical advice from a specialist nurse are also an important part of treatment.

When is surgery considered?

Surgery is only considered when symptoms remain very troublesome despite trying the full range of non-surgical treatments, and when you and your specialist team agree it is the right choice. Options discussed may include a permanent stoma (a bag on the tummy that collects stool), which many people find gives them back control and freedom, or in selected cases further surgery to refashion the join. These are big decisions, and you should be given time, information, and the chance to talk them through with your team and the people close to you.

Living with this condition

Life with LARS usually means planning ahead a little more than before. Knowing where toilets are, carrying a small kit, and allowing extra time in the morning can take a lot of the worry out of the day. Many people find a pattern settles over time — for example, symptoms may be worse in the morning or after certain meals. Keeping a diary helps you learn your own pattern, and small adjustments often make a big difference to confidence.

Lifestyle tips

• Eat at regular times and avoid very large meals
• Stay physically active — walking, swimming, and gentle strength work all help
• Limit alcohol and caffeine if they make urgency worse
• Plan travel with toilet stops in mind, and ask about accessible facilities
• Talk to your employer or school if you need flexible toilet breaks — you are entitled to reasonable adjustments in many countries
• Carry a small kit with wipes, a spare pair of underwear, and pads
• Keep up pelvic floor exercises as part of your daily routine
• Protect your skin with a barrier cream and gentle cleaning

Diet and exercise

There is no single diet that works for everyone with LARS, so a personal trial-and-error approach works best. Start by eating three small, regular meals, chewing well, and drinking enough fluid. Soluble fibre — oats, bananas, peeled apples, and similar foods — helps some people firm up stool, while beans, onions, and very spicy or fatty foods cause problems for others. A dietitian can help you adjust safely without missing out on important nutrients. For exercise, aim for something most days: walking, cycling, swimming, or whatever you enjoy. Pelvic floor exercises are the most targeted form of exercise for LARS, and a physiotherapist can teach you the correct technique.

Mental health and emotional wellbeing

It is very common to feel embarrassed, anxious, or low when your bowels feel unpredictable. Many people start avoiding trips, meals out, or seeing friends, and that isolation can be as hard as the physical symptoms. These feelings are understandable and they are treatable. Talking to your GP, a specialist nurse, or a counsellor can help, and talking therapies such as cognitive behavioural therapy are effective. If you ever feel hopeless or have thoughts of harming yourself, please reach out for crisis support straight away — contact your local crisis line or emergency services, or speak to a trusted person who can stay with you. You do not have to cope alone.

Prevention

LARS cannot be completely prevented, because it is a direct result of removing part of the rectum — and that surgery is often life-saving. Some things may reduce how severe it is: careful, nerve-sparing surgical technique; avoiding radiotherapy when it is not clearly needed (a decision to discuss with your cancer team); treating any leak at the join promptly; and starting pelvic floor exercises before and after surgery. If you are due to have rectal surgery, ask your team about prehabilitation (getting fitter before surgery) and about early bowel rehabilitation afterwards.

Screening programmes

There is no screening test for LARS itself. What matters is regular follow-up after your surgery, when your team can ask about bowel symptoms and step in early. If you had surgery for cancer, keep to your scheduled surveillance appointments, and mention any new or worsening bowel symptoms at every visit.

Complications

If left untreated

• Sore, broken, or infected skin around the anus from frequent stools and wiping
• Dehydration and low salt levels from ongoing loose stools
• Anaemia or tiredness if there is ongoing slight bleeding
• Constipation and hard stools building up, sometimes causing overflow leaks
• Avoiding work, travel, exercise, and social life
• Anxiety, low mood, and loss of confidence
• Straining that can contribute to piles or a small tear at the anus

Long-term outlook

The outlook is genuinely encouraging. For most people, symptoms are at their worst in the first few months and improve steadily over one to two years as the bowel adapts. Some people continue to have symptoms long term, but the range of treatments available is wide, and many people find a combination that lets them live the life they want. If simple steps are not enough, ask to be referred to a specialist bowel function service — there is almost always something else to try.

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