Screening

The perfect screening test should be inexpensive, easy to do, with no risk involved and readily available for everyone who needs it.

Preventing illness and disease with a good diet, exercise, immunizations and avoidance of harmful habits is always our most powerful strategy for good health—but things happen. Much of what we think of as “prevention” in health care is really early detection, or “screening,” our attempt to find threats before they compromise our health or life, while they can be effectively treated. I’ll outline the most important, evidence-based screening recommendations here. You can find the most complete list of screening recommendations at the U.S. Preventive Services Task Force website.

The perfect screening test would yield a positive test every time the condition is present (very “sensitive”) and never yield a positive test when the condition is absent (very “specific”). In identifying ideal screening tests, we look for a balance between those competing goals. We don’t ever want to miss something, but there can be harms associated with incorrectly suspecting that a condition is present: Expense, anxiety and additional testing that could be potentially harmful are all risks of screening. Oh, by the way, the perfect screening test should be inexpensive, easy to do, with no risk involved and readily available for everyone who needs it.

Then, there are the characteristics of the condition for which we’re screening. The perfect condition for screening is one that’s fairly common, has serious implications if not found, has a fairly predictable time in life of occurrence, is slow to progress, easy to find and, if found, has an effective treatment.

Colon cancer is the perfect example of a condition that’s ideal for screening. Except in unusual circumstances, colon cancer risk starts to increase after the age of 50, can be life threatening, takes many years to develop and has curative treatment if identified early. Colonoscopy, done at 10-year intervals (unless there are precancerous polyps present) is almost 100 percent sensitive at finding cancer when it’s present and, when done regularly at that interval, it’s very unlikely that someone would develop a colon cancer that couldn’t be treated in a curative manner. Almost as effective is to have a yearly stool test that’s very effective at identifying early warning signs of hidden blood in the stool. When this test is positive, colonoscopy is necessary to make a definitive diagnosis. The stool test is highly sensitive (doesn’t miss many) but not completely specific (some that are suspected aren’t actually present).

Some other conditions, like pancreatic cancer and ovarian cancer, aren’t ideal for general screening, even though they’re devastating when they occur. They aren’t highly common, they develop quickly, and the treatment is seldom “curative” even when the disease is found early.

So, given all that background, what health screening is worthwhile and recommended?

• An annual “check-up” to review your history, update immunizations and plan any screening tests you may need. The traditional cornerstone of this visit, the “complete physical exam,” has very little scientific evidence to support its value.

• Blood pressure check at least yearly. Blood pressure control is critically important in preventing heart disease and stroke.

• Cervical cancer screening. This includes a Pap test every three years for women 21 to 29 years old or, for women 30 to 65, a Pap and HPV (human papilloma virus) test every five years if both are negative. There’s no screening after 65 if previous screening has been negative.

• Colon cancer screening with colonoscopy every 10 years or yearly fecal occult blood test and colonoscopy if positive.

• Diabetes screening. Fasting blood sugar every two to three years.

• Cholesterol screening every five years if the patient is at normal or low risk, more often if elevated.

• Breast cancer screening in women with mammography. U.S. Preventive Health Screening Taskforce recommends every two years from age 50 to 74. Screening between age 40 to 50 is based on personal preference and any possible increased risks.

• Lung cancer screening yearly with a low dose CT scan for anyone 55 to 80 years old with a greater than 30-pack-per-year smoking history.

• Abdominal aortic aneurysm screening with ultrasound once for men older than 65 who’ve ever smoked.

• Testing for chlamydia and gonorrhea in women 20 to 24 years old.

• Hepatitis C testing once for those born 1945 to 1965.

• HIV testing once for those 15 to 65 years of age.

• For prostate cancer, discussion with your physician about your risks and preferences about screening is recommended. Routine screening is no longer recommended.

Many other screening tests exist for particular conditions in particular populations. If you haven’t had these important tests, please visit your doctor and discuss what’s best for your own needs.