Lung Cancer Diagnosis
What You Need to Know
- Lung cancer is diagnosed through imaging tools, including computed tomography (CT), magnetic resonance imaging (MRI) and positron emission tomography (PET) scans.
- Once a doctor determines that there is reason to suspect that there may be cancer, he or she may use additional testing, including a biopsy, ultrasound, mediastinoscopy, thoracoscopy or wedge resection.
Lung cancer is a complex disease, with a number of causes, several types of tumors and various symptoms, which means that an accurate diagnosis is critical for the best possible prognosis. A medical center with experience in diagnosing and treating lung cancer is more likely to accurately diagnose the cause of symptoms.
Once cancer has been diagnosed, it is staged, which tells the patient and doctors how large the tumor is and where is has progressed beyond the initial site.
The first step in diagnosing lung cancer is through the use of imaging tools, including:
CT scans, which use X-rays to create cross-sectional images of the chest.
MRI scans, which use radio waves and strong magnets to create detailed images of soft tissue. Like CT scans, they can produce detailed images of the tissue in the chest cavity. They are most often used to see if lung cancer has spread beyond its initial site.
PET scans, which use fluorodeoxyglucose (FDG) injected into the body to illuminate cancer cells. It’s also useful in determining if cancer has spread beyond the initial site.
PET/CT scans, which combine the technology of both to give the doctor an even more detailed image.
Once a doctor determines that there is reason to suspect that there may be cancer (or some other condition), he or she will order further testing, which may include one or more of the following procedures.
Biopsies are the most common tool to obtain tissue for diagnosing lung cancer. Depending on where the nodule is located and the patient’s physical condition, the doctor will do either a needle biopsy or a bronchoscopy.
During a needle biopsy, the surgeon uses a syringe to remove tissue from the nodule. A CT scan guides the surgeon to the nodule. This type of test is usually done under sedation rather than under general anesthesia so that it can be done as an outpatient procedure without a hospital stay.
Bronchoscopy is a biopsy done by passing a tube called a bronchoscope through the patient’s mouth or nose, down into the trachea (windpipe) and then into the lungs where the suspicious nodule is located. Tissue is then obtained via needle, which the patient does not feel, from the bronchoscope. Depending on whether a flexible or rigid bronchoscope is used, the procedure will be done under sedation or general anesthesia. The advantage of a bronchoscopy is that the surgeon can evaluate the airways at the same time. At Hopkins, surgeons have the option of using ultrasound-guided or navigational bronchoscopies. A navigational bronchoscopy uses electromagnetic technology to guide the bronchoscope.
Endobronchial ultrasound (EBUS) is a kind of bronchoscopy with an ultrasound probe that can send sound waves throughout the chest cavity, allowing doctors to look at the area on an ultrasound monitor. The doctor can then take tissue samples from a nodule or other areas that may look suspicious.
Mediastinoscopy is a surgical procedure that requires general anesthesia. An incision is made in the neck so that a lighted instrument called a mediastinoscope can be inserted to examine the area between the lungs known as the mediastinum. Biopsies of the mediastinal lymph nodes are taken for cancer staging.
Video-assisted thoracoscopy (VAT) allows the doctor to see where the nodule is located, as well as the surrounding area. For this diagnostic procedure, a tiny camera is inserted through the airway on a thin, tube-like instrument. Using surgical instruments, the surgeon can remove as much tissue as is necessary for testing. A pathologist can test the nodule while the patient is still under anesthesia so that the surgeon can clear the section around the nodule if it is cancerous.
Wedge resection is surgery is used to remove a triangular section of tissue, including a nodule or tumor. It may be used as a diagnostic procedure to determine if a suspicious nodule is cancerous. A wedge resection removes the smallest possible amount of tissue. If tissue is found to be cancerous on a wedge resection, additional surgery may be required.