Monday, August 4, 2014
What’s in my lung?
by: Karl Schroeder MD
Pulmonary/Critical Care Physician Pulmonary Associates of the Southeast PC
After the discovery of a pulmonary nodule, the first question a patient asks is, ‘what is a pulmonary nodule?’ This is actually a hard question to answer. The simple answer is a nodule is a lump of tissue in the lung that is less than 3 cm seen on a radiographic study. If it is larger than 3 cm, then it is classified as a lung mass. This usually leads to their next question, ‘what caused it?’. This question is actually much harder to answer and probably the most frustrating to both the physician and the patient.
A pulmonary nodule can represent many things with most of them being benign. These include cancer (both metastic lesions and primary lung cancer), granulomas, harmartomas, and chondromas, among others.
All of these reasons are important but most of these are benign lesions. It is very important to rule out cancer from any source as the cause of the nodule. Lung cancer, like breast, colon, and other types of cancer, is very important to diagnosis at its earliest stage possible. Lung cancer remains the leading cause of death by cancer in both men and women. This is because the overwhelming majority of lung cancer cases are discovered as either stage 3 or stage 4. When discovered at these stages, they are usually not respectable and carry a low survival rate. Stage 3 and 4 has survival rate of 15% at 5 years where as stage 1 and 2 has a 92% survival rate at 5 years. Unfortunately, pulmonary nodules are usually asymptomatic or produce common symptoms like cough, chest congestion. It is not till it becomes much larger that it produces symptoms that prompt investigation like hemoptysis, weight loss and chest pain.
Therefore, the strategy to monitor these small lumps of tissue is to catch them at the earliest stage IF THEY ARE CANCER. Most of these nodules are benign. There are some common strategies used to monitor the nodules. The most common is to get repeated CT scans to monitor for changes in size. These CT scans are usually at 3-6 month intervals. If the nodules grow, then the nodule should either be biopsied or resected. Unfortunately, over that same timeframe, some of these nodules will grow significantly or even metastasis to a distant site. These events can change the diagnosis from a potentially curable disease to a disease that can only be managed.
Because of this, new techniques and technology is being developed to biopsy these nodules even at a small size. Electromagnetic Navigational Bronchoscopy (ENB) is one of these techniques. ENB allows physicians to biopsy lung nodules at small sizes (greater than 6 mm). This allows patients and physicians to know what actually caused the nodule. Most nodules less than 10mm will not show up on PET scan imaging. ENB has increased the yield of trans bronchial biopsy from 20-30% to 70-90%. If non-diagnostic, then the nodules should still be monitored with serial CT scans.
Most recently, there is a study that tried to identify nodules early-- even before they become symptomatic. These studies focused on screening people who smoked for a significant amount of time (30 pack years), are between the ages of 55-74, and they quit smoking less than 15 years prior. The study showed that by screening these people with a yearly CT scan, the mortality from lung cancer could be decreased. Unfortunately, most insurance companies are not paying for screening lung CTs.
With this in mind, there are some facilities in the United States that are utilizing nodule clinics, lung cancer screening programs, and ENB to significantly increase the number of stage 1 and 2 lung cancer in the populations they access. Trinity Hospital and Pulmonary Associates of Southeast are working together to implement this type of program in Birmingham to help affect an earlier stage which lung cancer is diagnosed.