Diagnosing Lung Cancer: The Pathologist’s Role
November is National Lung Cancer Awareness Month. Lung cancer is the second most common cancer in both women and men, accounting for 13% of all new cancers. The American Cancer Society estimates that in 2015 in the United States there will be about 221,200 new cases of lung cancer with an estimated 158,040 deaths. The pathologist is a key member of the care team. All treatment begins with a diagnosis.
How is lung cancer diagnosed?
55 to 74 years old
In fairly good health
Have at least a 30 pack-year smoking history
Are either still smoking or have quit smoking within the last 15 years
Patients might present with symptoms due to lung cancer that then lead to its discovery. Such symptoms can include cough, shortness of breath, weight loss, among others. Lung cancer might incidentally be found during imaging for another reason. An important consideration to keep in mind is that lung cancer incidence is increasing in non-smokers. No longer is it a disease of smokers alone.
Once an abnormality has been found, it must be sampled. There are a variety of approaches to obtain tissue for diagnosis. A pathologist plays a crucial role in each, ensuring the tissue is adequate for both diagnosis and testing for precision medicine targets (“actionable mutations”).
A tumor can be sampled by an interventional radiologist using CT. A pathologist will be there to assess the tissue.
Bronchoscopy is another important technique to obtain tissue, often combined with ultrasound (EBUS). Again a pathologist will be present to ensure adequate sampling.
Another option is through a surgical approach in the operating room. A wedge biopsy of lung or sampling of mediastinal lymph nodes can often yield a diagnosis. During this procedure, the surgeon will call a pathologist for a frozen section of the tissue.
Upon reaching the lab, the tissue is carefully examined and described by a pathologist or pathologist assistant.
The biopsy is placed into a cassette then processed in an instrument to prepare it for cutting.
Next, the specimen is embedded into paraffin, cut and placed on a slide.
This is stained, cover slipped and delivered to the pathologist.
In the lab, pathologists examine tissues under the microscope using various stains to make a diagnosis.
Often the case will be presented at a tumor board or multidisciplinary conference. The team typically includes oncology, radiology, surgery, pathology, radiation oncology, nursing, patient navigators, social workers and a genetic counselor. Tumor board begins with the patient’s oncologist or surgeon giving a short history. Next, a radiologist will show pertinent imaging. The entire meeting room sees the films. Then a pathologist will present the biopsy results. These are either projected directly from a microscope or prepared beforehand. The pathologist explains the diagnosis and the important prognostic features. An open discussion then ensues regarding management and next steps, i.e. surgery, chemotherapy, radiation, etc.
The value of a team approach to patient care assures the best care possible. Each member of the team is important. As a pathologist, I know all treatment begins with a diagnosis.
When appropriate, a tumor is tested for the presence of “actionable mutations”. If discovered, the patient may be eligible for targeted therapy. The success of precision medicine depends on pathologists. Mutations in such genes as EGFR, RAS, ALK, ROS1 and MET are searched for by the pathologist.
The advent of precision medicine has ushered in a new way of battling cancer. With an understanding of the genetics of cancer, treatment is now personalized specific to a patient's unique tumor characteristics. However, one of the limitations of precision medicine is the inevitable development of treatment resistance by the tumor. The vast majority of patients, after experiencing clinical benefit, will require a change in treatment as their tumor mutates. As a cancer changes, so must our response. In this perennial "cat and mouse" game, new approaches must be developed to keep up.
Instead of always playing "catch up" with a tumor, immunotherapy offers the greatest hope in our search for a cancer cure. By harnessing the power of the immune system, the body can keep up with new mutations. What is cancer immunotherapy?
Lung cancer immunotherapy
Nivolumab (Opdivo) and pembrolizumab (Keytruda) target PD-1, a protein on T cells that is important in recognizing other cells. When PD-1 is blocked, the immune system “brakes” are released and the T cell response against cancer is boosted. These drugs have been shown to shrink some tumors or slow their growth. Both drugs have been approved for patients with non-small cell lung cancer as a second line treatment after tumor begins to grow after standard chemotherapy. The pathologist will examine the tumor and test it for the presence of such actionable targets.
What can patients do?
Get a copy of the pathology report
Make sure you understand everything in the report
The College of American Pathologists provides a helpful resource to understand the details behind your pathology report to help make informed decisions about your health. Path Report also provides a video.
Ask if your case has been presented at tumor board or an interdepartmental specialty conference, if so, find out the recommendations.
Consider a second opinion if there is no specialty program or conference
Ask if your tumor has been profiled
Ask to meet with your pathologist
A pathologist is there at the beginning and throughout a patient’s journey. Follow Path Report during November as we celebrate National Lung Cancer Awareness. See how pathologists are crucial members of the care team. To learn more about the vital role of the pathologist, visit cap.org. Get the facts about your health. Get a copy of your pathology report. Understand it and ask questions. Discover the other member of your care team, the pathologist.