Eating with Low Anterior Resection Syndrome (LARS) is a multifaceted, physical, and emotional topic. Skandan Shanmugan, MD, is an associate professor of surgery at the University of Pennsylvania, Perelman School of Medicine, Division of Colon and Rectal Surgery at PENN Presbyterian. 

We asked Dr. Shanmugan to share his surgical experience with LARS, and what he finds most common in patients:

What food should patients with LARS eat?

LARS is usually the consequence after radiation and surgery for removing the sigmoid or rectum, usually for cancer. This often results in new, altered anatomy with some sort of denervation of the remaining colon, combined with a decrease in the rectal reservoir and sometimes anal sphincter dysfunction in cases where surgery is performed low into the pelvis. As a result, most patients with LARS will have symptoms of fecal urgency, fecal incontinence or leakage, increased frequency of bowel movements, clustering of bowel movements, and emptying difficulties. Their stool consistency may alternate from diarrhea to constipation.

I tell my patients to tailor their diet based on their symptoms. In reality, patients could eat or drink what they want, but I emphasize chewing their food well and having smaller meals, especially immediately after surgery. However, sometimes their diets may need to be altered based on the symptoms they experience with LARS. Sometimes, regardless of their diets, patients may need to use medical management (anti-diarrheals, bile acid sequestrants, etc.), or pelvic floor rehabilitation exercises to manage their symptoms.

Are there any foods people should avoid? 

Since each patient may exhibit different symptoms based on the spectrum of LARS, foods they should avoid would be seen with a period of trial and error. For instance, if a patient exhibits an immense amount of gas and bloating, then they may need to avoid foods high in fiber. But if a patient exhibits diarrhea, then we would recommend bulking agents with fiber supplements to achieve some regularity.

Nutritionists will tell you some things; surgeons might tell you other things. I tell my patients they can eat or drink anything they want. However, I stress the need to chew food really well. Eating smaller meals is also important. In my opinion, it’s not so much what food someone is eating as it is about the consistency of the food that gets swallowed that can cause problems. 

Diet by itself will not be altered by LARS. How people chew their food and by eating smaller meals is what I’ve seen help people manage LARS the most.

Are there foods that sit or settle more comfortably with people with LARS?

In general, I would recommend foods high in fiber and/or fiber supplements. Fiber intake can improve stool constituency by absorbing water and acting as a bulking agent. However, some patients may experience increased bloating and abdominal pain with fiber. For excessive bloating and gas pain, we may recommend a course of antibiotics to re-establish the normal bacteria and flora within the gut. In addition to fiber, I also recommend daily hydration with at least 2 liters of water. Finally, the best solution to mild LARS is to give your newly constructed anatomy time to adapt and become more absorptive and accommodating.  

Are there supplements or medicines that can slow down the passage of food until the body becomes retrained?

Yes. In addition to fiber and bulking agents, several medications can be used to mediate the symptoms of LARS. Loperamide and other antimotility agents can be used to treat diarrhea. Postprandial urgency and incontinence can be treated with serotonin antagonist, such as Ramoseron to help control symptoms. Fecal soilage can be treated with pelvic floor physical therapy (biofeedback), and sometimes injectable bulking agents. Patients with severe refractory LARS may sometimes need colonic irrigation and sacral nerve stimulation. Finally, the last resort for intractable symptoms would be to consider an ostomy – although this is rare.

Can patients expect or hope for less frequency and urgency come over time? 

Yes. Over time the neo-colorectal anastomosis will adapt and become more adaptive and accommodating to stool and its transit. But perhaps more importantly, the patient will become somewhat accustomed to managing their symptoms.

Ultimately can the colon and rectum return to the same functioning a person had before surgery?

Surgery to remove the rectum and sigmoid colon alters the body’s natural anatomy, configuration, and nerves in the pelvis. This unfortunately cannot be restored, but in time the new anatomy will become more adaptive and the nerves become more responsive to the stimuli entering the pelvis – this combined with diet, behavior modification tools, and medical therapy will usually get patients through this period of adjustment.

Do you have any tips for people living with LARS who get so frustrated or defeated by it?

Patience. Do not let your frustrations get the better of you. There are many modalities to help you through this period of adjustment so please reach out to your provider for assistance. Also, remember that surgery for removal of your rectum is usually necessary to treat your cancer, so in that perspective, most patients remain cancer-free – perhaps that knowledge can provide hope and help get you through this difficult period.

Additional LARS Resources

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