Colorectal cancer

Colorectal cancer (CRC), also known as bowel cancer, colon cancer, or rectal cancer, is the development of cancer from the colon or rectum (parts of the large intestine).

Early detection through screening is useful for cervical and colorectal cancer.

Another risk factor is inflammatory bowel disease, which includes Crohn's disease and ulcerative colitis.

Bowel obstruction may occur as a complication of chronic inflammation, and those with the disease are at greater risk of bowel cancer.

Another risk factor is inflammatory bowel disease, which includes Crohn's disease and ulcerative colitis.

Complications may include megacolon, inflammation of the eye, joints, or liver, and colon cancer.

Some of the inherited genetic disorders that can cause colorectal cancer include familial adenomatous polyposis and hereditary non-polyposis colon cancer; however, these represent less than 5% of cases. Other syndromes that are strongly associated with colorectal cancer include Gardner syndrome and familial adenomatous polyposis (FAP).

While these polyps start out benign, malignant transformation into colon cancer occurs when they are left untreated.

It typically starts as a benign tumor, often in the form of a polyp, which over time becomes cancerous.

Untreated colorectal polyps can develop into colorectal cancer.

Aspirin and other non-steroidal anti-inflammatory drugs decrease the risk.

It may also decrease the risk of certain types of cancer, particularly colorectal cancer.

Treatments used for colorectal cancer may include some combination of surgery, radiation therapy, chemotherapy and targeted therapy.

Other risk factors include diet, obesity, smoking, and lack of physical activity.

Some of the inherited genetic disorders that can cause colorectal cancer include familial adenomatous polyposis and hereditary non-polyposis colon cancer; however, these represent less than 5% of cases.

Hereditary nonpolyposis colorectal cancer (HNPCC) or Lynch syndrome is an autosomal dominant genetic condition that is associated with a high risk of colon cancer as well as other cancers including endometrial cancer (second most common), ovary, stomach, small intestine, hepatobiliary tract, upper urinary tract, brain, and skin.

The classic warning signs include: worsening constipation, blood in the stool, decrease in stool caliber (thickness), loss of appetite, loss of weight, and nausea or vomiting in someone over 50 years old.

Underlying associated diseases include hypothyroidism, diabetes, Parkinson's disease, celiac disease, non-celiac gluten sensitivity, colon cancer, diverticulitis, and inflammatory bowel disease.

Treatments used for colorectal cancer may include some combination of surgery, radiation therapy, chemotherapy and targeted therapy.

There are targeted therapies for lung cancer, colorectal cancer, head and neck cancer, breast cancer, multiple myeloma, lymphoma, prostate cancer, melanoma and other cancers.

Bowel cancer may be diagnosed by obtaining a sample of the colon during a sigmoidoscopy or colonoscopy.

It can provide a visual diagnosis (e.g., ulceration, polyps) and grants the opportunity for biopsy or removal of suspected colorectal cancer lesions.

Signs and symptoms may include blood in the stool, a change in bowel movements, weight loss, and feeling tired all the time.

The history in these patients should focus on factors that could be associated with potential causes: blood coating the stool suggests hemorrhoidal bleeding while blood mixed in the stool implies a more proximal source; bloody diarrhea and tenesmus is associated with inflammatory bowel disease while bloody diarrhea with fever and abdominal pain especially with recent travel history suggests infectious colitis; pain with defecation occurs with hemorrhoids and anal fissure; change in stool caliber and weight loss is concerning for colon cancer; abdominal pain can be associated with inflammatory bowel disease, infectious colitis, or ischemic colitis; painless bleeding is characteristic of diverticular bleeding, arteriovenous malformation (AVM), and radiation proctitis; nonsteroidal anti-inflammatory drug (NSAID) use is a risk factor for diverticular bleeding and NSAID-induced colonic ulcer; and recent colonoscopy with polypectomy suggests postpolypectomy bleeding.

Another risk factor is inflammatory bowel disease, which includes Crohn's disease and ulcerative colitis.

Conditions with similar symptoms as ulcerative colitis includes acute self-limiting colitis, amebic colitis, schistosomiasis, Crohn's disease, colon cancer, irritable bowel syndrome, intestinal tuberculosis and nonsteroidal anti-inflammatory drug enteropathy.

Screening is effective for preventing and decreasing deaths from colorectal cancer.

Screening for colorectal cancer, if done early enough, is preventive because almost all colorectal cancers originate from benign growths called polyps, which can be located and removed during a colonoscopy (see colonic polypectomy).

This is then followed by medical imaging to determine if the disease has spread.

Dietary factors that increase the risk include red meat, processed meat, and alcohol.

In 2015, the International Agency for Research on Cancer of the World Health Organization (WHO) classified processed meat (bacon, ham, hot dogs, sausages) as carcinogenic to humans (Group 1), based on "sufficient evidence in humans that the consumption of processed meat causes colorectal cancer."

Other proteins responsible for programmed cell death that are commonly deactivated in colorectal cancers are TGF-β and DCC (Deleted in Colorectal Cancer).

DCC has long been implicated in colorectal cancer.

Ashkenazi Jews have a 6% higher risk rate of getting adenomas and then colon cancer due to APC gene being more common.

Mutations in the APC gene may result in colorectal cancer.

The APC protein prevents the accumulation of β-catenin protein.

Mutations and overexpression of β-catenin are associated with many cancers, including hepatocellular carcinoma, colorectal carcinoma, lung cancer, malignant breast tumors, ovarian and endometrial cancer.

Colorectal cancer (CRC), also known as bowel cancer, colon cancer, or rectal cancer, is the development of cancer from the colon or rectum (parts of the large intestine).

Dietary factors that increase the risk include red meat, processed meat, and alcohol.

The International Agency for Research on Cancer at the World Health Organization classifies processed meat as Group 1 (carcinogenic to humans), because the IARC has found sufficient evidence that consumption of processed meat by humans causes colorectal cancer.

Cancers that are confined within the wall of the colon may be curable with surgery, while cancer that has spread widely is usually not curable, with management being directed towards improving quality of life and symptoms.

For example, colorectal cancer spreads primarily through the portal vein to the liver.

Other syndromes that are strongly associated with colorectal cancer include Gardner syndrome and familial adenomatous polyposis (FAP).

The countless polyps in the colon predispose to the development of colon cancer; if the colon is not removed, the chance of colon cancer is considered to be very significant.

Colorectal cancer (CRC), also known as bowel cancer, colon cancer, or rectal cancer, is the development of cancer from the colon or rectum (parts of the large intestine).

Bacteroides are implicated in the initiation of colitis and colon cancer.