Lung cancer, one of the most common cancers in the world, is a leading cause of cancer-related death in men and women in the United States. Smoking cigarettes is usually the cause of lung cancer, but far from the only one. Risk factors also include exposure to asbestos, radiation and pollution, or a family history of the condition. Non-small cell lung cancer (NSCLC) accounts for about 80 to 85 percent of all lung cancer diagnoses, with small cell lung cancer (SCLC) comprising the remaining 15 to 20 percent.
Yale Medicine's pathologists at are highly specialized—some specialize in bone and soft tissue pathology, related to the ribs, sternum and vertebral column, as well as hematologic conditions involving white cells that can form masses, particularly in the lymph nodes in the middle of the chest.
What happens if lung cancer is suspected?
The doctor may order tests to look for cancer cells and to rule out other conditions. If symptoms suggest lung cancer, a chest X-ray or computerized tomography (CT) scan is the next step. Other tests include sputum cytology, which checks sputum (phlegm) for cancer cells, or a bronchoscopy, in which the doctor checks for abnormalities through a tube inserted down the throat to the lung. Depending on the results, a biopsy or surgery may be performed for further testing.
“Ultimately, looking at and analyzing lung tissue with a biopsy is an important step in diagnosing lung cancer,” says Yale Medicine pathologist Robert Homer, MD.
How is lung cancer diagnosed?
Doctors combine findings from:
A physical exam, which includes a discussion of patient and family history
Imaging tests, such as an X-ray, to see whether a nodule or abnormal mass is present in the lungs, and a CT scan, which can reveal small lesions
Lab tests, such as a sputum cytology, in which sputum produced by a cough will be collected and analyzed.
While the results of different tests may be considered, the formal diagnosis is based on analysis of lung cells under a microscope after a biopsy.
What are the different types of biopsies used when lung cancer is suspected?
There are several different ways to obtain tissue for diagnosis:
Bronchoscopy, in which a fiber-optic tube with a light is inserted through the throat and into the lungs to examine suspicious areas, or nodules. A bronchoscope, a small needle on the end of the tube, takes a sample of tissue from the nodule.
Mediastinoscopy, in which an incision is made at the base of the neck, and surgical tools are inserted behind the breastbone to obtain tissue samples from the lymph nodes.
Needle biopsy, in which CT scan and x-ray images map a path for a needle to penetrate the chest wall to extract abnormal tissue cells from the outer edges of the lung. “Pathologists will cut a number of slides from the sample,” says Homer, "and skill is required to know how to get the most information from a very small piece of tissue.”
Cryobiopsy. “This is an alternative type of biopsy that allows you to get more tissue out of the lung to sample,” Dr. Homer says.
A biopsy may also be obtained from the lymph nodes, or such areas as the liver, where the cancer may have spread. “Ultimately, we are trying to see whether cancer is present, and if it is, decide how extensive the cancer is,“ Dr. Homer says. “It is common to sample lymph nodes in the center of the chest even if there is no radiologic evidence.”
A diagnosis, which explains the results of the biopsy in a pathology report, is typically available within a week of the procedure. If the patient desires a second opinion, tissue samples can be sent to a different lab.
How is sample tissue analyzed?
Samples collected during a biopsy are sent to a pathology lab to be studied under the microscope. “We check for various proteins expressed by the tumor cells,” says Homer. The pathologists may do additional tests to classify the cancer.
Analysis is also important to determine where the cancer originated, because that can help determine treatment options. A handful of conditions may look like lung cancer, but on closer examination, are not, and tumors that look like primary lung cancer may have started growing elsewhere in the body, Dr. Homer says.
How long does it typically take to get a diagnosis?
The pathologist will explain the results of the biopsy in a pathology report. This is typically available within a week of the procedure. Tissue samples can always be sent to an additional pathology lab if the patient desires a second opinion.
What makes Yale Medicine’s approach to diagnosing lung cancer unique?
“Like most areas of medicine, our high volume means that we have experience in specimens that other pathologists rarely see,” says Dr. Homer.
Pathologists at Yale Medicine are highly specialized – our team includes some who specialize in bone and soft tissue pathology, related to the ribs, sternum and vertebral column, as well as hematologic conditions involving white cells that can form masses, particularly in the lymph nodes in the middle of the chest.
“Our ability to work as a team is what makes us special,” says Dr. Homer.