Checkpoint inhibitor induced colitis | |
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Specialty | Gastroenterology |
Symptoms | Diarrhea, abdominal pain, rectal bleeding |
Complications | Perforation, toxic megacolon |
Usual onset | ~6-7 weeks after starting checkpoint inhibitor [1] |
Causes | Cancer immunotherapy treatment |
Risk factors | Caucasian, NSAID use, anti-CTLA4 treatment, melanoma, history of prior checkpoint inhibitor induced colitis, Faecalibacterium in fecal microbiota |
Diagnostic method | Colonoscopy, stool tests for infection |
Differential diagnosis | Infectious colitis, gastrointestinal metastases (rare) |
Prevention | None |
Treatment | Corticosteroids, infliximab, vedolizumab |
Prognosis | Associated with improved overall survival |
Frequency | 0.7 – 1.6% (anti-PD1) 5.7 – 9.1% (anti-CTLA-4) 13.6% (combination therapy) |
Checkpoint inhibitor induced colitis is an inflammatory condition affecting the colon (colitis), which is caused by cancer immunotherapy (checkpoint inhibitor therapy). Symptoms typically consist of diarrhea, abdominal pain and rectal bleeding. Less commonly, nausea and vomiting may occur, which may suggest the present of gastroenteritis. The severity of diarrhea and colitis are graded based on the frequency of bowel movements and symptoms of colitis, respectively.
The gold standard for the diagnosis of checkpoint inhibitor induced colitis is colonoscopy with evaluation of the terminal ileum. However, in most cases, a flexible sigmoidoscopy is sufficient. Infection should be ruled out with stool studies, including Clostridioides difficile, bacterial culture, ova and parasites. Symptoms of upper abdominal pain, nausea or vomiting warrant evaluation with upper endoscopy.
Treatment of immune checkpoint inhibitor colitis is based on severity, as defined by the grade of diarrhea and colitis. Mild cases by managed with temporary interruption of immune checkpoint inhibitor therapy, dietary modification (low residue), and/or loperamide. More severe cases require immune suppression with corticosteroid therapy. If steroids are ineffective, infliximab may be considered. If colitis fails to improve with infliximab, then vedolizumab may be effective.
The most common symptom is diarrhea, which occurs in 92 percent of cases, followed by abdominal pain (82%) and rectal bleeding (64%). [2] About 46% of cases include fever and 36% involve nausea and vomiting. [2] Less often, nausea and vomiting may be present. Weight loss has been reported. [1] Onset of diarrhea generally occurs about 6–7 weeks after starting immune checkpoint inhibitor therapy. [1]
The extent of diarrhea is graded based on severity, from 1 to 5. Grade 1 diarrhea is defined by an increase in the number of stools below four per day (compared with baseline). Grade 2 diarrhea is defined by an increase of 4–6 bowel movements per day. Grade 3 diarrhea is defined by an increase by 7 or more bowel movements per day. Grade 4 diarrhea involves life-threatening consequences, such as shock, whereas grade 5 results in death.
The extent of colitis is also graded based on severity, from 1 to 5. Grade 1 colitis does not result in any symptoms, while grade 2 colitis leads to abdominal pain, mucous and blood in the stools. Grade 3 colitis is defined by severe pain, peritoneal signs and ileus. Grade 4 colitis is defined by life-threatening consequences, including perforation, ischemia, necrosis, bleeding, or toxic megacolon. Grade 5 colitis results in death.
High grade colitis may lead to severe complications, including perforation, toxic megacolon and death. Bleeding may occur due to colitis. Treatment with corticosteroids may lead to infectious complications, including: urinary tract infections, C. difficile infection, and pneumonia. [3]
Immune checkpoints are important for the normal development of T regulatory cells (Tregs) in the intestine. Mice with the CTLA-4 gene removed (e.g. CTLA-4 knockout) develop severe autoimmune disease, with diffuse infiltration of T cells in multiple organs and fatal enterocolitis. [2]
Immune checkpoint inhibitor colitis is typically characterized by either diffuse mucosal inflammation or focal active colitis with patchy crypt abscesses. [4] Common findings of acute colitis include: intraepithelial neutrophilic infiltrates, crypt abscesses, and increased apoptotic cells within crypts. However, the histologic appearance varies, and evidence of chronic inflammation is seen in some cases, including intraepithelial lymphocytes or basal lymphocytes and crypt architecture distortion. [4] Histologic inflammation may occur as early as 1–2 weeks after immune checkpoint inhibitor therapy, well before the onset of symptoms. [4]
Anti-PD-1 induced colitis may lead to more CD8+ T cell inflammation, whereas Anti-CTLA4 induced colitis may involve more CD4+ T cell infiltration and higher mucosal levels of the inflammatory molecule TNF alpha.
Amongst people treated with immune checkpoint inhibitors, those with Faecalibacterium genus and other Bacillota present in the colonic flora have longer progression-free survival and overall survival. In addition, a higher rate of checkpoint inhibitor induced colitis is associated with the presence of Faecalibacterium in the fecal microbiota. [5]
Colonoscopy with evaluation of the terminal ileum is the gold standard in the diagnosis of checkpoint inhibitor induced colitis. [4] [2] However, in most cases, a limited evaluation of the distal colon with flexible sigmoidoscopy is sufficient. [4] [2] [6] Endoscopic findings may include loss of vascular pattern, erythema, edema, erosions, ulcers, exudates, granularity, and bleeding. [1] [7] Biopsies should be taken even in endoscopic findings are normal, as inflammation may not be immediately apparent and may only be seen on histology (microscopic colitis). [4]
Symptoms of nausea, vomiting and epigastric pain may suggest involvement of the upper gastrointestinal tract. If present, evaluation with upper endoscopy is warranted. [4]
There are no stool tests or blood tests specific for checkpoint inhibitor induced colitis. [1] However, diagnostic evaluation should include ruling out infectious causes for diarrhea and colitis. [4] Stool studies should include: Clostridioides difficile toxin, bacterial culture, ova and parasites. Testing for CMV infection should be considered. [4] Fecal calprotectin may be helpful, and is very sensitive and specific for inflammation in the intestines. [4] Elevations in fecal calprotectin correlate with the extent of intestinal inflammation. [2]
Computed tomography (CT) imaging may show evidence of colitis, though the sensitivity is relatively low (50%). [1] Free air in the peritoneum indicates bowel perforation. [1] Abdominal imaging may be necessary to rule out toxic megacolon or perforation. [1]
Though rare, gastrointestinal metastases (rare) should be considered as a cause of symptoms. [4]
Treatment varies depending on the severity of disease. For mild disease, supportive care may be sufficient, including loperamide and a low residue or bland diet. For more severe disease, the immune checkpoint inhibitor should be discontinued. Corticosteroid therapy is used to decrease inflammation, at a dose of roughly prednisone 1–2 mg per kg of body weight per day. In cases that do not respond to corticosteroid therapy, infliximab may be used. For cases that fail to respond to infliximab, or where infliximab is contraindicated, vedolizumab may be used. [8] Overall, response rates from treatment are 59% for corticosteroids, 81% for infliximab, and 85% for vedolizumab. [9]
Surgery with resection of the colon (colectomy) is necessary in some instances, [10] particularly if severe complications occur, such as perforation [1] or toxic megacolon.
Fecal calprotectin, a stool test and marker of inflammation, may be used to follow improvement in colitis. [8]
The prevalence of checkpoint inhibitor induced colitis varies depending on the regimen of immunotherapy. The incidence is 0.7 – 1.6% for anti-programmed cell death protein 1 (PD1) agents, 5.7 – 9.1% for anti-cytotoxic T-lymphocyte associated protein 4 (CTLA-4), and about 13.6% for combination therapy. [2] The risk associated with ipilimumab is dose dependent, such that higher doses are associated with higher rates of colitis. [11] However, other agents (nivolumab and pembrolizumab) are not associated with a dose dependent effect on the risk of immune mediated colitis. [11]
Risk factors for immune mediated colitis include Caucasian race, treatment with an anti-CTLA4 based regimen, melanoma as cancer type, [3] nonsteroidal anti-inflammatory drug (NSAID) use, [8] and a prior history of checkpoint inhibitor induced colitis.
Ulcerative colitis (UC) is one of the two types of inflammatory bowel disease (IBD), with the other type being Crohn's disease. It is a long-term condition that results in inflammation and ulcers of the colon and rectum. The primary symptoms of active disease are abdominal pain and diarrhea mixed with blood (hematochezia). Weight loss, fever, and anemia may also occur. Often, symptoms come on slowly and can range from mild to severe. Symptoms typically occur intermittently with periods of no symptoms between flares. Complications may include abnormal dilation of the colon (megacolon), inflammation of the eye, joints, or liver, and colon cancer.
Infliximab, a chimeric monoclonal antibody, sold under the brand name Remicade among others, is a medication used to treat a number of autoimmune diseases. This includes Crohn's disease, ulcerative colitis, rheumatoid arthritis, ankylosing spondylitis, psoriasis, psoriatic arthritis, and Behçet's disease. It is given by slow injection into a vein, typically at six- to eight-week intervals.
Enteritis is inflammation of the small intestine. It is most commonly caused by food or drink contaminated with pathogenic microbes, such as Serratia, but may have other causes such as NSAIDs, radiation therapy as well as autoimmune conditions like coeliac disease. Symptoms include abdominal pain, cramping, diarrhoea, dehydration, and fever. Related diseases of the gastrointestinal system involve inflammation of the stomach and large intestine.
Gastrointestinal diseases refer to diseases involving the gastrointestinal tract, namely the esophagus, stomach, small intestine, large intestine and rectum; and the accessory organs of digestion, the liver, gallbladder, and pancreas.
Colitis is swelling or inflammation of the large intestine (colon). Colitis may be acute and self-limited or long-term. It broadly fits into the category of digestive diseases.
Toxic megacolon is an acute form of colonic distension. It is characterized by a very dilated colon (megacolon), accompanied by abdominal distension (bloating), and sometimes fever, abdominal pain, or shock.
Diverticular disease is when problems occur due to diverticulosis, a benign condition defined by the formation of pouches (diverticula) from weak spots in the wall of the large intestine. This disease spectrum includes diverticulitis, symptomatic uncomplicated diverticular disease (SUDD), and segmental colitis associated with diverticulosis (SCAD). The most common symptoms across the disease spectrum are abdominal pain and bowel habit changes such as diarrhea or constipation. Otherwise, diverticulitis presents with systemic symptoms such as fever and elevated white blood cell count whereas SUDD and SCAD do not. Treatment ranges from conservative bowel rest to medications such as antibiotics, antispasmodics, acetaminophen, mesalamine, rifaximin, and corticosteroids depending on the specific conditions.
Megacolon is an abnormal dilation of the colon. This leads to hypertrophy of the colon. The dilation is often accompanied by a paralysis of the peristaltic movements of the bowel. In more extreme cases, the feces consolidate into hard masses inside the colon, called fecalomas, which can require surgery to be removed.
Radiation proctitis or radiation proctopathy is a condition characterized by damage to the rectum after exposure to x-rays or other ionizing radiation as a part of radiation therapy. Radiation proctopathy may occur as acute inflammation called "acute radiation proctitis" or with chronic changes characterized by radiation associated vascular ectasiae (RAVE) and chronic radiation proctopathy. Radiation proctitis most commonly occurs after pelvic radiation treatment for cancers such as cervical cancer, prostate cancer, bladder cancer, and rectal cancer. RAVE and chronic radiation proctopathy involves the lower intestine, primarily the sigmoid colon and the rectum, and was previously called chronic radiation proctitis, pelvic radiation disease and radiation enteropathy.
Neutropenic enterocolitis, also known as typhlitis, is an inflammation of the cecum that may be associated with infection. It is particularly associated with neutropenia, a low level of neutrophil granulocytes in the blood.
Stercoral perforation is the perforation or rupture of the intestine's walls by its internal contents, such as hardened feces or foreign objects. Hardened stools may form in prolonged constipation or other diseases which cause obstruction of transit, such as Chagas disease, Hirschprung's disease, toxic colitis, hypercalcemia, and megacolon.
In the anatomy of humans and homologous primates, the descending colon is the part of the colon extending from the left colic flexure to the level of the iliac crest. The function of the descending colon in the digestive system is to store the remains of digested food that will be emptied into the rectum.
Management of ulcerative colitis involves first treating the acute symptoms of the disease, then maintaining remission. Ulcerative colitis is a form of colitis, a disease of the intestine, specifically the large intestine or colon, that includes characteristic ulcers, or open sores, in the colon. The main symptom of active disease is usually diarrhea mixed with blood, of gradual onset which often leads to anaemia. Ulcerative colitis is, however, a systemic disease that affects many parts of the body outside the intestine.
Biological therapy, the use of medications called biopharmaceuticals or biologics that are tailored to specifically target an immune or genetic mediator of disease, plays a major role in the treatment of inflammatory bowel disease. Even for diseases of unknown cause, molecules that are involved in the disease process have been identified, and can be targeted for biological therapy. Many of these molecules, which are mainly cytokines, are directly involved in the immune system. Biological therapy has found a niche in the management of cancer, autoimmune diseases, and diseases of unknown cause that result in symptoms due to immune related mechanisms.
Stercoral ulcer is an ulcer of the colon due to pressure and irritation resulting from severe, prolonged constipation due to a large bowel obstruction, damage to the autonomic nervous system, or stercoral colitis. It is most commonly located in the sigmoid colon and rectum. Prolonged constipation leads to production of fecaliths, leading to possible progression into a fecaloma. These hard lumps irritate the rectum and lead to the formation of these ulcers. It results in fresh bleeding per rectum. These ulcers may be seen on imaging, such as a CT scan but are more commonly identified using endoscopy, usually a colonoscopy. Treatment modalities can include both surgical and non-surgical techniques.
Radiation enteropathy is a syndrome that may develop following abdominal or pelvic radiation therapy for cancer. Many affected people are cancer survivors who had treatment for cervical cancer or prostate cancer; it has also been termed pelvic radiation disease with radiation proctitis being one of the principal features.
Vedolizumab, sold under the brand name Entyvio, is a monoclonal antibody medication developed by Takeda Oncology for the treatment of ulcerative colitis and Crohn's disease. It binds to integrin α4β7, blocking the α4β7 integrin results in gut-selective anti-inflammatory activity.
Amoebiasis, or amoebic dysentery, is an infection of the intestines caused by a parasitic amoeba Entamoeba histolytica. Amoebiasis can be present with no, mild, or severe symptoms. Symptoms may include lethargy, loss of weight, colonic ulcerations, abdominal pain, diarrhea, or bloody diarrhea. Complications can include inflammation and ulceration of the colon with tissue death or perforation, which may result in peritonitis. Anemia may develop due to prolonged gastric bleeding.
Antimotility agents are drugs used to alleviate the symptoms of diarrhea. These include loperamide (Imodium), bismuth subsalicylate (Pepto-Bismol), diphenoxylate with atropine (Lomotil), and opiates such as paregoric, tincture of opium, codeine, and morphine. In diarrhea caused by invasive pathogens such as Salmonella, Shigella, and Campylobacter, the use of such agents has generally been strongly discouraged, though evidence is lacking that they are harmful when administered in combination with antibiotics in Clostridium difficile cases. Use of antimotility agents in children and the elderly has also been discouraged in treatment of EHEC due to an increased rate of hemolytic uremic syndrome.
Segmental colitis associated with diverticulosis (SCAD) is a condition characterized by localized inflammation in the colon, which spares the rectum and is associated with multiple sac-like protrusions or pouches in the wall of the colon (diverticulosis). Unlike diverticulitis, SCAD involves inflammation of the colon between diverticula, while sparing the diverticular orifices. SCAD may lead to abdominal pain, especially in the left lower quadrant, intermittent rectal bleeding and chronic diarrhea.