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Where Does This Myth Come From?
Why Does it Matter?
The Bottom Line

"If lung cancer is exposed to the air during surgery, the cancer will spread."

This is one myth I hadn't heard. But according to a survey published in the Annals of Internal Medicine in 2003, it's a common belief, especially among middle-aged and elderly men who have lung cancer or are at risk for it. Nearly 40% of those surveyed believed the above statement was true, though they couldn't remember if the source was one they trusted. This myth is a good example of how a misconception or faulty assumption can lead not only to the spread of misinformation, but also to bad medical decisions as well.

Where Does This Myth Come From?

Those who believed the myth about how lung cancer spreads during surgery couldn't remember where they had heard it when asked by the researchers. My guess is that it evolved through a confusion of cause and effect and a misunderstanding about how tumors spread. It's common for people with lung cancer to have surgery (especially for non-small-cell types). At the time of surgery or even weeks to months later, it's discovered that the cancer spread. The first event (surgery) may be assumed to have caused the second event (spread or cancer) because of the timing.

What Is Lung Cancer?

Smoking cigarettes is by far the most common cause of lung cancer. Cancerous cells multiply out of control and eventually form a mass called a tumor. As the tumor grows, it destroys nearby areas of the lung.

Lung cancers are divided into two basic groups, non-small cell and small cell, based on the microscopic appearance of the tumor cells. Some are more responsive to treatment than others and the choice of therapy often depends, at least in part, on the type of lung cancer that is present. For example, small-cell lung cancer tends to spread early, so surgery is rarely helpful. This type of lung cancer is usually treated with a combination of chemotherapy and radiation. Even so, only 6% of patients are still alive 5 years after diagnosis.

Non-small-cell lung cancer, on the other hand, is more likely to be localized when it's diagnosed and be treatable with surgery. The most common type of lung cancer, adenocarcinoma, is primarily treated with surgery. Up to 20% of patients are alive five years after the diagnosis. (Adenocarcinoma of the lung is the most common form among nonsmokers.)

There are several other types of non-small-cell lung cancer: large cell, squamous cell, adenosquamous, undifferentiated and bronchioloalveolar carcinoma. Lung cancer is difficult to cure because so often it spreads before it's detected. It usually spreads to surrounding lung tissue first, causing breathing problems, cough, or chest pain. Other nearby structures — including lymph nodes, the lining of the heart, and blood vessels — can be involved as the tumor enlarges. Tumor cells can travel far from the lungs to form tumors in other organs, such as the brain or bones.

The best way to prevent the spread of lung cancer is to detect and treat it early, before it spreads. Unfortunately, there are no reliable screening tests, though studies are underway to determine whether CT (computed tomography)scanning in people at high risk for lung cancer (including heavy smokers) is effective.

Just as humans need air to live, it may be assumed (wrongly) that exposing a tumor to air will allow it to grow more quickly. It may also be true that people don't want surgery and look for any reason to avoid it. That could be why this myth is more appealing than it might otherwise be. Although the overall cure rate in lung cancer is not high, long-term survival is generally highest for those who have their tumor surgically removed.

Why Does it Matter?

Some myths don't matter much. After all, if a parent believes that wearing a jacket on a cool day will prevent pneumonia and encourages his or her child to wear a jacket, no harm is done and the child will probably be more comfortable. If you believe surgery will make your cancer spread, however, you may be inclined to refuse surgery. In fact, that's just what researchers found. Among those who believed in this misconception, nearly 25% stated that they would turn down surgery. Nearly as many said that even faced with scientific evidence to the contrary, they would still turn down surgery.

Perhaps when faced with the decision in real life, most people would have surgery. But this study is a chilling reminder of how difficult it is to change people's beliefs, even when they're give compelling evidence to the contrary.

A mistaken belief about how lung cancer spreads during surgery could deny a person the most effective treatment or even cure.

The Bottom Line

There are times when a person who's ill doesn't follow the advice or recommendations of a doctor. Sometimes the person's reasons are based on previous experience, fear, advice from friends or family, religious beliefs or cultural traditions. Sometimes they're based on misinformation. In my view, each person should make their own medical decisions but only after they have considered the best information given to them by healthcare professionals they trust. When someone makes a decision that differs from their doctor's advice, it's important to ask why. There will always be times when people don't follow a doctor's advice — but it should not be because of belief in a medical myth.

Robert H. Shmerling, M.D. is associate physician at Beth Israel Deaconess Medical Center and associate professor at Harvard Medical School. He has been a practicing rheumatologist for over 20 years at Beth Israel Deaconess Medical Center. He is an active teacher in the Internal Medicine Residency Program, serving as the Robinson Firm Chief. He is also a teacher in the Rheumatology Fellowship Program.

Airing Out a Lung Cancer Myth