Colorectal cancer, or cancer involving the human large intestine, ranks second only to lung cancer as the cause of cancer-related death in the United States. Each year, approximately 130,000 Americans are diagnosed with colorectal cancer, and 56,000 people die from this disease. Colorectal cancer generally occurs in patients over 50. Routine screening for colorectal cancer is considered the best means of reducing the mortality and morbidity produced by this disease.
Colon cancer arises in polypoid lesions involving the large intestine’s inner wall. Over time, these lesions undergo malignant transformation and develop into cancer. As the cancer grows, it penetrates through the intestinal wall, spreads to adjacent lymph nodes, and eventually disseminates to other body organs (especially the liver). Unfortunately, once the disease spreads to distant organs, it effectively becomes incurable.
Epidemiologic investigations have identified several risk factors for colorectal cancer. These include diets high in animal fats, hereditary polypoid diseases of the large intestine, inflammatory bowel disease (especially ulcerative colitis), and, possibly, cigarette smoking.
Colon cancers typically grow for many years without producing symptoms. As the tumor grows, it begins to bleed and, in time, to obstruct the intestinal lumen. Symptoms produced by an enlarging colon tumor include abdominal pain, fatigue (caused by chronic blood loss), and a change in stool size or caliber.
Because colorectal cancer is generally incurable once the disease spreads to other body organs, and because these cancers produce few symptoms before the disease is far advanced, many authorities advocate active screening for colon cancer to identify small colonic tumors and to permit their removal before the cancer invades and metastasizes. Detecting and treating colon cancer before it has metastasized significantly improves a patient’s long-term prognosis. Cancers detected when confined to the superficial layers of the large intestine are associated with cure rates approaching 100 per cent.
Several health care organizations, including the United States Preventative Services Task Force, the American Cancer Society, and the World Health Organization, recommend routine screening for colorectal cancer. Patients at average risk for this disease should be screened beginning at age 50. Screening for colorectal cancer generally assumes one of three forms: (1) annual digital rectal examinations, supplemented by chemical testing for occult rectal bleeding; (2) flexible sigmoidoscopy; and (3) colonoscopy. The preferred mode of screening remains controversial. The patient’s physician is free to select whichever screening method he or she deems appropriate.
Digital rectal examination and chemical tests for occult rectal bleeding are generally performed on patients over forty. During the exam, the physician inserts a finger into the patient’s rectum. Unfortunately, this technique only detects cancer immediately adjacent to the patient’s anus. For this reason, rectal examination is usually supplemented by occult blood testing, in which a stool specimen is tested for admixed blood. If the test detects blood in the patient’s stool, his or her large intestine should be carefully examined (usually colonoscopically) for a hidden, colonic tumor.
An alternate approach to colon cancer screening utilizes flexible sigmoidoscopy. In this procedure, which is typically performed every three to five years beginning at age 50, the examining physician inserts a foot-long, flexible tube, or “scope,” into the patient’s anus and examines the patient’s terminal colon for mucosal lesions. The principal drawback to flexible sigmoidoscopy is the test’s inability to reach and detect tumors located farther up the patient’s gastrointestinal tract.
A final approach to colorectal cancer screening employs colonoscopy, in which a doctor, typically a gastroenterologist, advances a large, flexible scope, known as a “colonoscope,” into the patient’s large intestine. Colonoscopy permits the examining physician to visualize lesions throughout the large intestine. During the examination, the physician searches for polyps and other pre-cancerous lesions on the intestine’s inner wall. These lesions can often be removed using the colonoscope, without resorting to surgery. Colonoscopic screening for colorectal cancer is generally performed every ten years in asymptomatic individuals having no prior history of colonic polyps or neoplasms.
Note that colorectal cancer screening is generally performed on asymptomatic individuals. People experiencing symptoms possibly caused by a colonic tumor – such as rectal bleeding, chronic abdominal pain, or a change in bowel habits or stool caliber – should be immediately evaluated for a possible colonic neoplasm. In these individuals, the patient’s symptoms mandate additional diagnostic tests to uncover the root cause of the patient’s symptoms.
The above screening tests for colon cancer can detect cancers and pre-cancerous lesions of the large intestine before they metastasize to other parts of a patient’s body. For this reason, screening often unmasks cancer when the disease is readily curable. In general, colon cancers, once detected, are treated by surgically excising the involved segment of large intestine. During surgery, regional lymph nodes are sampled for lymph node metastases. In patients in whom the cancer has spread to regional lymph nodes or to the liver, post-operative radiation and chemotherapy are often employed to treat the disease.
Our law firm has handled numerous malpractice cases arising out of a doctor’s failure to diagnose colon cancer before the disease metastasized throughout the patient’s body. Not infrequently, a treating physician fails to properly evaluate a patient’s complaint of rectal bleeding. Rectal bleeding in such cases is frequently misattributed to hemorrhoidal bleeding. The current standard of care calls for a thorough diagnostic search for a colonic neoplasm in any patient presenting with rectal bleeding. It is a mistake to blindly attribute rectal bleeding to hemorrhoids without examining the patient’s large intestine.
In other cases, physicians fail to screen their patients for colorectal cancer. In many cases, physicians disregard published screening recommendations. Patients over 50 often see their physicians for years without being offered tests for occult rectal bleeding, flexible sigmoidoscopy, and/or colonoscopy.
Finally, our firm has also encountered cases in which a pathologist, charged with examining tissue removed from a patient’s large intestine during an endoscopic biopsy, mischaracterizes the resected tissue as benign, thereby missing an underlying cancer.All of the above errors can contribute to significant delays in diagnosing colorectal cancer, with the unfortunate consequence that these tumors, when ultimately diagnosed, have often metastasized to distant organs, making them incurable. These outcomes are unfortunate. Colorectal cancers, when detected via standard screening methodologies, are often small and confined to the patient’s large intestine. In these instances, the cancer can usually be totally excised, yielding a high probability of long-term cure.