When breast cancer moves into the lung, it often doesn’t cause symptoms. Instead, a tumor might be first discovered on an imaging study done as part of treatment follow-up, such as a chest CT (computed tomography) scan.
If a lung metastasis does cause symptoms, they may include:
- pain or discomfort in the lung
- shortness of breath
- persistent cough
- coughing up blood and mucus
It can be difficult to tell the difference between symptoms of lung metastasis and symptoms of the common cold or upper respiratory conditions — especially if it’s cold and flu season, or you have a history of respiratory problems. Many doctors recommend that any unusual symptoms persisting for more than a week or two should be checked out.
If your doctor suspects lung metastasis, he or she is likely to order imaging tests such as a chest CT or a PET (positron emission tomography) scan.
If a tumor is found, it’s important to make sure that the tumor isn’t actually a primary lung cancer — cancer that first started growing in the lung — as opposed to breast cancer spread. If you’re a past or present smoker, this is especially critical. A true lung cancer would require different types of treatment than breast cancer does.
Your doctor can order additional tests to confirm a diagnosis. For procedures involving the lungs, your doctor will involve a thoracic surgeon, pulmonologist, or interventional radiologist who specializes in the diagnosis and treatment of lung conditions. Tests may include:
- Examination of a sample of your mucus under a microscope
- Bronchoscopy: This involves inserting a flexible, lighted tube down your airways and into the lung(s) to examine the tissue and possibly sample any suspicious areas.
- Lung needle biopsy: Guided by imaging scans of the suspicious area, a doctor inserts a needle through the skin and into the lung to remove a small sample of tissue.
- Surgery: The doctor performs surgery to remove the area of concern for examination.
If a tissue sample is removed, your doctor will not only confirm that it is breast cancer in the lung, but also can have it tested for other characteristics that may influence treatment choices, such as HER2 status and hormone receptor status. Remember that metastatic breast cancer isn’t always exactly the same as the original breast cancer.
The most common treatments for metastatic breast cancer in any location (bone, brain, lung, or liver) are systemic medications, which treat cancer throughout the entire body. Systemic medications include chemotherapy, hormonal therapy, targeted therapies, and bone-strengthening medication.
Local treatments — therapies directed specifically to the new locations of the breast cancer — aren’t usually the first choice for metastases. Still, local treatments are recommended under certain circumstances. Local treatments include surgery and radiation therapy.
You can read about systemic and local treatments for metastasis in the Recurrent and Metastatic Breast Cancer Treatment Choices section.
Sometimes, breast cancer cells can collect in the fluid that surrounds the lungs. The lungs are inside a thin sac of tissue known as the pleura, which separates them from the chest wall. As a result of breast cancer spread, extra fluid can build up inside the pleura, a condition known as pleural effusion. For more information about this condition, see Local Treatments for Fluid around the Lungs or in the Abdomen.