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Colon cancer

Approximately 100,000 cases detected annually in the U.S.

30-40% of newly diagnosed patients have stage III disease, i.e. they have lymph node metastases.

15-20% have T3 or T4 lesions at presentation.

More than 60,000 patients are eligible for adjuvant chemotherapy.

Colon carcinoma overall mortality 50%.

Recurrent cancer of the colon and rectum is diagnosed during follow-up in up to 50% of patients operated on for cure.

Rapid changes in the risk of colon cancer in individuals who migrate from one area to another indicate that exposure to diet changes during adult life has an important role in carcinogenesis.

An elevated CEA may herald a recurrence by 2 to 18 months before diagnosis is made by other means, with an average lead-time of 4-8 months.

Frequency of synchronous liver metastases ranges from 15%-30%.

With liver metastases 3-year survival rate of 20% and fewer than 3% survive 5 years.

Following resection of liver metastases the recurrence rate is about 71% at 13 months.

At postmortem examination 95% of patients dying with colorectal cancer have liver metastases, and in up to 50% of these patients the liver is the only site of dissemination.

Third most common cause of cancer deaths in women.

Screening recommended at age 50 years with one of the following: annual fecal occult blood testing, flexible sigmoidoscopy every 5 years, double contrast barium enema every 5-10 years or colonoscopy every 10 years.

Fewer than 30% of persons who should be screened have been.

Second most common malignant disease in developed countries and second leading cause of death in North America.

Almost all colorectal cancers arise from adenomatous polyps that develop over a period of years.

Chromosomal instability and usually multiple allelic deletions account for roughly 85% of colorectal carcinomas. The remainder are caused by defective DNA mismatch repair mechanisms allowing mutations to be accumulated many times the normal rate.

5% of patients have synchronous colonic cancers.

Approximately 5% of patients develop metachronous cancers at a later point in time.

Screening with stool guaiac (43%) and multiple fecal occult blood testing (1.6%) by gynecologists is greatly underutilized.

A lack of physical activity is the risk factor most consistently shown to be associated with an increased risk of colon cancer.

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