DEAR DR. DONOHUE: What is a lung nodule? My lung doctor has taken a series of CT scans and X-rays since November 2004, when it was first discovered. He tells me it has not grown and says not to worry. I still worry about lung cancer. – H.G.

A lung nodule is a spot, usually round, seen on a chest X-ray or a scan. It could be an old infection, one that doesn’t deserve any further investigation. And some people with rheumatoid arthritis often have one or more lung nodules. Or it could represent an aberrant blood vessel, something that isn’t usually worrisome. It might be an old, healed injury. Or it could be lung cancer.

It’s the cancer possibility that worries everyone, patient and doctor. Size is an important criterion in distinguishing between innocent spots and possible cancers. If the diameter of the spot is less than 2 centimeters (four-fifths of an inch), the likelihood of cancer is not great. Any nodule that stays the same size, as yours has, for two years is almost never cancer. Cancer nodules tend to double in size in much shorter intervals. The possibility that your nodule is cancerous is most remote.

Additional signs help distinguish cancerous from benign nodules – pattern of calcification is one example.

If there’s any doubt about the nature of a nodule, retrieving a sample of tissue for microscopic inspection settles the issue definitely. The sample can sometimes be obtained with a needle if the nodule is close to the surface. At other times, it can often be gotten during a bronchoscopic examination. A bronchoscope is a viewing device that is inserted into the lungs through the airways.

I’ll get to your other questions, H.G., soon.

DEAR DR. DONOHUE: I am a woman who will be 87 in a few weeks. I am in fairly good health. Do I still need to go for mammograms every year? – S.P.

Experts can’t agree on the answer to your question. Some background information on breast cancer shows the difficulty of being dogmatic about this matter. Close to 50 percent of new breast cancers occur in women 65 and older. About two-thirds of breast-cancer deaths happen in these women. So advanced age shouldn’t be an absolute reason for stopping mammograms. Most authorities say that women older than 70 should continue with mammograms if they have a life expectancy of at least five years. Furthermore, the number of birthdays doesn’t correlate well with a person’s age in health years. Some 87-year-olds are as vigorous as 57-year-olds. The decision to continue with mammograms is one that should be made by the patient with her physician.

On the other side of the debate are those who say women can stop mammograms at 70. Some take a slightly different tack. They say that women older than 75 should continue with mammograms but can do so at less-frequent intervals – intervals of two to three years. Cancers if older women tend to grow more slowly than those in younger women.

There is a downside to mammograms. False-positive reports require women to undergo further tests, including biopsies. During the time that the mammogram result is being checked, women are in a state of high anxiety.

The breast-cancer report explains the details of this common cancer. Readers can order a copy by writing: Dr. Donohue – No. 1101, Box 536475, Orlando, FL 32853-6475. Enclose a check or money order (no cash) for $4.75 U.S./$6.75 Can. with the recipient’s printed name and address. Please allow four weeks for delivery.

DEAR DR. DONOHUE: Is there any relation between blood cholesterol and blood pressure? Both of mine are high. – F.K.

Blood cholesterol doesn’t affect blood pressure, or vice versa.

However, both work in concert to damage the heart and arteries. They encourage the formation of plaque, the buildup of cholesterol, fat, blood cells and blood protein, on artery walls. High blood pressure stresses the heart.

DEAR DR. DONOHUE: Will you kindly answer a question about a lab test? The nurse from my doctor’s office called me with the results of some lab tests I had done. All were good, but she mentioned that one of my tests turned out positive. It was called the ANA test.

I asked her what this was, and she was evasive about it. She says it doesn’t call for any action now, but I would still like to know what it is. – R.C.

ANA is antinuclear antibody. It’s an antibody in the blood that’s directed against the nucleus of some body cells. Antibodies are the body’s ammunition against troublemakers.

Positive ANA tests are found in people with lupus, scleroderma and rheumatoid arthritis. I take it you have no symptoms. A positive ANA test in a person with no symptoms of illness generally isn’t a sign of anything bad. Sometimes age turns the test positive.

Dr. Donohue regrets that he is unable to answer individual letters, but he will incorporate them in his column whenever possible. Readers may write him or request an order form of available health newsletters at P.O. Box 536475, Orlando, FL 32853-6475. Readers may also order health newsletters from

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