Low anterior resection syndrome (LARS) is frequent after treatment for low rectal cancer. Increased bowel frequency and urgency with rectal spasms and incontinence have deleterious impacts on quality of life in a third of the cases.

One possible physiopathology hypothesis suggests an ongoing spastic process; different mechanisms have been postulated. These include alteration of normal anorectal sensation with loss of the recto-anal inhibitory reflex (RAIR), decreased rectal compliance and reduced rectal capacity as well as sphincter damage secondary to preoperative chemoradiation therapy or during surgery.

Current available treatments are often ineffective, highlighting the need for more successful management. Botulinum toxin A (BTX-A) is a neurotoxin inhibiting acetylcholine release at the neuromuscular junction. It is currently used for the treatment of various smooth muscle spastic diseases.

The hypothesis of this study is that intra-rectal BTX-A injections could represent a medical treatment alternative for LARS. The goal of this study is to document the effects of intra-rectal BTX-A injections on sphincter function and quality of life of patients with LARS.

No more information desired

Inclusion Criteria:

• Age 18 years or older
• Aptitude to sign informed consent
• Diagnosis of low anterior resection syndrome (LARS) : More than 12 months after sphincter-preserving surgery for treatment of locally advanced rectal cancer, Mild to moderate underwear soiling, Baseline Wexner score ranging from 0-16 (moderate symptoms, and Patient-reported imperious defecation or Patient-reported incomplete stool evacuation
• Digital rectal exam (by surgeon) demonstrating satisfying anorectal tonus considering prior radical rectal surgery.
• Willingness to complete questionnaires and manometric studies before and after Botox-A administration
• Prior failed medical treatment, at least one attempt (narcotics, loperamide, cholestyramine, fibers)

Exclusion Criteria:

• Inability to sign informed consent
• Counter-indication to Botox-A administration : Allergy to Botox-A or its ingredients (Clostridium botulinum type A neurotoxin complex, human albumin and sodium chloride, Allergy to other forms of botulinum toxin (Dysport, Xeomin or Myobloc, Myasthenia gravis, Eaton-Lambert syndrome, lateral amyotrophic sclerosis or any other neurological disease which might interfere with neuromuscular function
• Prior use of any form of botulinum toxin A, for any indication
• Infection at proposed Botox-A injection site
• Personal or family history of bleeding diathesis
• Pregnancy or breastfeeding
• Severe incontinence (Wexner score ≥ 17 or daily use of diapers)
• Patient taking anticoagulant. ASA ( acetylsalicylic acid) allowed