Kill the Cancer Do Screening now! Daniel M. Kruss, M.D.
Colon Cancer Screening Daniel M. Kruss, M.D.
Colon Cancer Screening • 130,200 new cases expected this year • 93% are over age 50 • 20% diagnosed at emergency surgery • 4th most common cancer • 2nd cause of cancer death
Colon Cancer Screening • 56,300 deaths expected this year • 6% Lifetime Risk • 62% Five-year survival 53% in African Americans
Colon Cancer Screening Because of these large numbers, even a small improvement in survival will save many lives!
Colon Cancer Screening • What is cancer? • abnormal growth of abnormal cells • growth out of control cells multiply too quickly cells form masses called tumors tumors invade other organs • malignant tumors spread distantly • (metastasize)
Colon Cancer Screening Symptoms occur only late in the course of the disease Survival is related to the amount of spread at the time of surgery Goal: Detect the cancer, or pre-cancerous polyp before it spreads
Colon Cancer Screening What do we know about colon cancer?
Colon Cancer Screening The cause of colon cancer is partly genetic. It is more common in certain settings: 1. Family history of colon cancer 2. Familial Polyposis syndromes 3. Ulcerative Colitis and Crohn's Disease patients 4. Cancer of breast, ovarian, uterus
General Population 6% One 1st-degree Relative 2 to 3X Two 1st-degree Relative 3 to 6X 1st-degree Relative <50 Yrs 3 to 6X One 2nd- or 3rd-degree Relative 1.5X One 1st-degree Relative & Polyp 2X Colon Cancer ScreeningFamilial Risk
Colon Cancer Screening colon cancer may also have environmental triggers such as diet, geography, ???
Colon Cancer Screening Over 90% of colorectal carcinomas develop from an adenomatous polyp.
Colon Cancer Screening • Epidemiologic studies suggest: • 1 of every 5 persons is at risk to develop adenomatous polyps • 5% of these may progress to colorectal cancer • Screening for polyps at a stage when they can be colonoscopically removed is shown to decrease colorectal cancer mortality
Colon Cancer Screening This guides our present strategy: • find polyps • remove polyps • prevent 90% of colon cancers The other 10% awaits new genetic tests for blood and/or stool
Colon Cancer Screening How can we detect Colon cancer? 1. Fecal Occult Blood
Colon Cancer Screening • What is fecal Occult Blood? • OB is blood mixed in stool which you cannot see • It may come from sources anywhere along the gut from mouth to rectum • It may be an early warning signal that a polyp or tumor is present
Colon Cancer ScreeningFecal Occult Blood Testing Three Prospective Randomized Trials
Colon Cancer Screening A polyp or a cancer in the colon may bleed, slowly, and cause tiny amounts of OB in the stool. Large studies show us that only 1/3 of polyps and 1/2 of cancers bleed, however!! Depending on the method used, between 1.5-8% of 'healthy' persons will have OB in the stool!!
Colon Cancer Screening If we make our OB tests too sensitive, we may find a few more cancers, but will detect a lot more false positives. There is no harm in finding a false positive, except in the obligation (cost?) of examining each one to see if there is a cancer.
Colon Cancer Screening If we make our OB tests less sensitive, we will have fewer false positives, but will miss a few real cancers. We can improve OB specificity by avoiding red meats, vitamin C, aspirin and arthritis medicines, and many fresh fruits and vegetables for three days before and during three days of stool collection.
Colon Cancer Screening There is a trade-off between compliance and false-positives. Screening does not change the incidence of new colon cancers, but affects the stage at which they are discovered. The mortality was reduced from 8.33 to 5.88 per 1000 in the Minnesota study of stool OB.
Colon Cancer Screening Fecal Occult blood testing performed as part of an in-office digital rectal exam failed to detect potentially cancerous colon growths 95 percent of the time!
Colon Cancer Screening It must be clearly understood that the OB test is only one of several methods of screening and that it is, at best, 50% predictive. Then why do it?
Colon Cancer Screening Early detection is still the only method to prevent deaths from colon cancer
Colon Cancer Screening How can we detect Colon cancer? 2. Sigmoidoscopy
Colon Cancer Screening The American Cancer Society previously recommended: Sigmoidoscopy this was based on data suggesting that half of the cancers will be seen in this area, and any patients who have polyps seen, will receive full colonoscopy
Colon Cancer Screening How can we detect Colon cancer? 3. Colonoscopy
Colon Cancer Screening • The case for screening colonoscopy* • Involves greater risk and inconvenience • however • few significant lesions are missed • entire colon is examined • screening interval of 10 years (few polyps become cancer in less time) • *or virtual colonoscopy when available or • air contrast barium enema and sigmoidoscopy
Colon Cancer Screening If you are positive on OB screening, what is needed? colonoscopy (full colon exam) if positive findings, act on them if negative, consider searching the remainder of the GI tract
Colon Cancer Screening If a polyp is found, what is needed? 1. Annual colonoscopy until the colon is 'clear' 2. then re-examine every 3-5 years
Colon Cancer Screening What are the risks of colonoscopy? bleeding and/or perforation occur in less than 1/500 patients When properly indicated, the procedure is very safe and very efficient
Colon Cancer Screening What should I do now?
Colon Cancer Screening If you are over 55: screening for OB every year, colonoscopy (or sigmoidoscopy) If you have polyps, tell your blood relatives to have screening and be sure you have regular tests If relatives had colon polyps or colon cancer, get your colonoscopy now!
Colon Cancer ScreeningFamilial Risk Screening • Any Family History • Same as Average Risk Screening, • begin at age 55 • Strong Family History -Definition: • 2 Affected First-degree Relatives • or • 1 First-degree Relative Diagnosed <60 • Colonoscopy every 5 years, • Start at age 40 Years
Colon Cancer Screening Screening is optional... Without screening a 50 year old at average risk, has 530/10,000 chance of invasive colon cancer and 250/10,000 risk of dying from it. Screening between ages 50-75 reduces this risk by 10-75%
Colon Cancer Screening Fewer than half of patients diagnosed with colorectal cancer had received a screening procedure at least six months prior to their diagnosis
Colon Cancer Screening 94 percent of colorectal cancer patients had either not undergone a colonoscopy at all, or not until having the procedure that led to their diagnosis
Colon Cancer Screening The prognosis of colon cancer is directly related to the extent of disease when first diagnosed!!