What are Pulmonary Nodules?
A pulmonary nodule is a small, roundish growth on the lung—sometimes called a spot on the lung—that is easy to find and hard to diagnose. Pulmonary nodules turn up in about one of every 500 chest x-rays. But because they can be a form of early-stage cancer, it’s important to distinguish a benign nodule from a cancerous nodule as early as possible. Therefore, doctors approach every pulmonary nodule as cancerous until they can prove otherwise.
If a spot on the lung has a diameter of three centimeters or less, it’s called a nodule. If it’s bigger than that, it’s called a mass and undergoes a different evaluation process. About 40 percent of pulmonary nodules turn out to be cancerous. Half of all patients treated for a cancerous pulmonary nodule live at least five years past the diagnosis. But if the nodule is one centimeter across or smaller, survival after five years rises to 80 percent. That’s why early detection is critical.
The Mechanics of Pulmonary Nodules
Benign pulmonary nodules are just that—benign. There is very little growth or change, if there’s any at all. Cancerous pulmonary nodules, however, are known to grow relatively quickly—usually doubling in size every four months but sometimes as fast as every 25 days.
A cancerous nodule is a lesion or “sore” that steadily engulfs more and more of the structures of the lung. Over time the patient will experience shortness of breath, fatigue, and chest pain.
Symptoms of Pulmonary Nodules
The challenge in trying to identify pulmonary nodules before they become masses is that there are few, if any, symptoms to indicate a nodule might be present. The vast majority of pulmonary nodules—more than 90%—are discovered essentially by accident. They’re spotted incidentally in a chest x-ray or CT (computed tomography) scan performed for other purposes. If any symptoms do appear they tend to imitate characteristics common to a chest cold or a mild flu.
Causes of Pulmonary Nodules
Benign nodules are almost always healed over “wounds” on the lung left from tuberculosis or a fungal infection, although there are other, less common causes.
Cancerous nodules can be the first stage of a primary lung cancer, brought on by smoking or any other common cause of lung cancer. They also can be a secondary cancer that metastasized in the lungs from a primary cancer elsewhere in the body.
Diagnosing Pulmonary Nodules
The diagnostic process focuses on determining whether a pulmonary nodule is cancerous or benign.
The most sure-fire way to make the distinction is by examining the growth rate of the nodule. Benign nodules do not grow much if at all. Cancerous nodules, on the other hand, can double in size on average every four months (some as quickly as 25 days, some as slowly as 15 months). Growth can be evaluated through a series of x-rays or CT (computed tomography) scans over a period of time.
The second most sure-fire way to distinguish a cancerous nodule from a benign nodule is to evaluate its calcification—that is, its development based on its shape and surface. Benign nodules tend to be smoother and more regularly shaped, with more even color throughout. Cancerous nodules are more likely to have irregular shapes, rougher surfaces, and color variations or speckled patterns.
In most cases, x-rays or CT scans provide enough information to make a reliable diagnosis. Doctors might choose to retrieve cells from the nodule for a biopsy. Cells are collected using a needle or performing localized surgery. In addition, an analysis of the patient’s sputum can provide diagnostic information.
Treating Pulmonary Nodules
In almost every case, benign pulmonary nodules require no treatment. Cancerous nodules, however, usually are treated by removing them surgically. Several surgical procedures are used, depending on the size, condition and location of the nodule:
thorocoscopic surgeryis a procedure similar to “scoping” an injured knee. The surgeon inserts the thorascopic device into the lung and withdraws the offending nodule tissue.
mini-thoracotomyis a minimally invasive surgical procedure that zeros in on the nodule. It is chosen instead of a full thoracotomy whenever possible.
thoracotomyis a comprehensive, invasive procedure whose goal is removal of the diseased portion of the lung—sometime a sizeable “wedge” of the organ.
ABCs of Nodules
Concerned about pulmonary nodules? Follow these ABCs: A is for
Age—few cases before 35, most cases after 45. B is for
Before—compare today’s x-rays with those taken before for any change. C is for
Calcium—nodules get their revealing shapes as a result of calcification. And S is for
Smoking—if you smoke, quit and get checked.