SOURCE: American Lung Association
The diagnosis and treatment of non small cell lung cancer has changed dramatically in the past 50 years since the Surgeon General’s report on smoking and lung cancer. Early detection is now a reality for lung cancer.
A large clinical trial called the National Lung Screening Trial (NLST) found that spiral CT scans in people at high risk of lung cancer (due to smoking history) lower the risk of death from lung cancer, when compared to chest x-rays. This finding has led to the development of screening guidelines for lung cancer.
Another approach now being studied uses newer, more sensitive tests to look for cancer cells in sputum samples. Researchers have found several changes often seen in the DNA of lung cancer cells. Current studies are looking at new tests that can spot these DNA changes to see if they can find lung cancers at an earlier stage.
Also known as autofluorescence bronchoscopy, this technique may help doctors find some lung cancers earlier, when they may be easier to treat. For this test, the doctor inserts a bronchoscope through the mouth or nose and into the lungs. The end of the bronchoscope has a special fluorescent light on it, instead of a normal (white) light.
The fluorescent light causes abnormal areas in the airways to show up in a different color than healthy parts of the airway. Some of these areas might not be visible under white light, so the color difference may help doctors find these areas sooner. Some cancer centers now use this technique to look for early lung cancers, especially if there are no obvious tumors seen with normal bronchoscopy.
This imaging test uses CT scans to create detailed 3-dimensional pictures of the airways in the lungs. The images can be viewed as if the doctor were actually using a bronchoscope.
Virtual bronchoscopy has some possible advantages over standard bronchoscopy. First, it is non-invasive and doesn’t require anesthesia. It also helps doctors view some airways that might not be seen with standard bronchoscopy, such as those being blocked by a tumor. But it has some drawbacks as well. For example, it doesn’t show color changes in the airways that might indicate a problem. It also doesn’t let a doctor take samples of suspicious areas like bronchoscopy does. Still, it can be a useful tool in some situations, such as in people who might be too sick to get a standard bronchoscopy.
This test will likely become more available as the technology improves.
Electromagnetic navigation bronchoscopy
Lung tumors near the center of the chest can be biopsied during bronchoscopy, but bronchoscopes have trouble reaching the outer parts of the lungs, so tumors in that part of the lung often need to have a needle biopsy. This test can be a way to use a bronchoscope to biopsy a tumor in the outer part of the lung.
First, CT scans are used to create a virtual bronchoscopy. The abnormal area is identified, and a computer helps guide a bronchoscope to the area so that it can be biopsied. The bronchoscope used has some special attachments that allow it to reach further than a regular bronchoscope.
This takes extra equipment and training for the doctor, and is not widely available.
Doctors now use video-assisted thoracic surgery (VATS) to treat some small lung tumors. It lets doctors remove parts of the lung through smaller incisions, which can result in shorter hospital stays and less pain for patients. Doctors are now studying whether it can be used for larger lung tumors.
In a newer approach to this type of operation, the doctor sits at a specially designed control panel inside the operating room to maneuver long surgical instruments using robotic arms. This approach, known as robotic-assisted surgery, is now being tested in some larger cancer centers.
Real-time tumor imaging
Researchers are looking to use new imaging techniques, such as four-dimensional computed tomography (4DCT), to help improve treatment. In this technique, the CT machine scans the chest continuously for about 30 seconds. It shows where the tumor is in relation to other structures as a person breathes, as opposed to just giving a ‘snapshot’ of a point in time, like a standard CT does.
4DCT can be used to determine exactly where the tumor is during each part of the breathing cycle, which can help doctors deliver radiation to a tumor more precisely. This technique might also be used to help show if a tumor is attached to or invading important structures in the chest, which could help doctors determine if a patient might be eligible for surgery.
A decade ago, chemotherapy was the only drug doctors could prescribe to someone with non-small-cell lung cancer (NSCLC). Not only does today’s chemotherapy work better than past versions, but there are also two new kinds of medications to treat this disease.
New combinations: Many clinical trials are looking at newer combinations of chemotherapy drugs to determine which are the safest and most effective. This is especially important in patients who are older and have other health problems. Doctors are also studying better ways to combine chemotherapy with radiation therapy and other treatments.
Lab tests to help predict if chemo will be helpful: Doctors know that adjuvant chemotherapy after surgery may be more helpful for some people with early (stage I or II) cancers than for others, but figuring out which patients to give it to is not easy. In early studies, newer lab tests that look at patterns of certain genes in the cancer cells have shown promise in telling which people might benefit most. Larger studies of these tests are now trying to confirm their usefulness.
Other lab tests may help predict whether a lung cancer will respond to particular chemo drugs. Doctors are now looking to see if tests for these markers can help guide the choice of treatment, so these are not a part of standard treatment.
Maintenance chemotherapy: For people with advanced lung cancers who can tolerate chemotherapy, combinations of 2 chemo drugs (sometimes along with a targeted drug) are typically given for about 4 to 6 cycles. Some recent studies have found that with cancers that have not progressed, continuing treatment beyond the 4 to 6 cycles with a single chemo drug may help some people live longer. This is known as maintenance therapy. A possible downside to this continued treatment is that people may not get a break from having side effects from chemotherapy. Some doctors now recommend maintenance therapy, while others await further research on this topic.
One group of drugs changes the way certain cancer cells grow or change in your body. This is called targeted therapy. Others boost your immune system to better fight cancer. This is called immunotherapy.
Researchers are learning more about the inner workings of lung cancer cells that control their growth and spread. This is being used to develop new targeted therapies. Some of these treatments are already being used to treat non-small cell lung cancer. Others are now being tested in clinical trials to see if they can help people with advanced lung cancer live longer or relieve their symptoms.
Other targeted drugs being studied include ganetespib, custirsen, and dacomitinib. Some targeted drugs already approved for use against other types of cancer, such as sorafenib (Nexavar) and sunitinib (Sutent), are also being tested for use against NSCLC.
Researchers are also working on lab tests to help predict which patients might be helped by which drugs. Studies have found that some patients do not benefit from certain targeted therapies, whereas others are more likely to have their tumors shrink. Similar gene tests for other treatments are now being studied. Predicting who might benefit could save some people from trying treatments that are unlikely to work for them and would probably cause unneeded side effects.
Researchers are hoping to develop drugs that can help the body’s immune system fight the cancer.
Drugs that block PD-1 and PD-L1: Cancer cells may use natural pathways in the body to help avoid detection and destruction by the immune system. For example, they often have a protein called PD-L1 on their surface that helps them evade the immune system. New drugs that block the PD-L1 protein, or the corresponding PD-1 protein on immune cells called T cells, can help the immune system recognize the cancer cells and attack them.
Nivolumab (Opdivo) and pembrolizumab (Keytruda) are anti-PD-1 drugs that have been shown to shrink or slow the growth of some tumors. They are now approved for use in advanced NSCLC, and are typically used after certain other treatments have been tried.
Other, similar drugs such as atezolizumab (MPDL3280A) and MEDI4736 might also shrink some lung cancer tumors. Larger studies of these new drugs are now being done.
Vaccines: Several types of vaccines for boosting the body’s immune response against lung cancer cells are being tested in clinical trials. Unlike vaccines against infections like measles or mumps, these vaccines are designed to help treat, not prevent, lung cancer. These types of treatments seem to have very limited side effects, so they might be useful in people who can’t tolerate other treatments.
Some vaccines are made up of lung cancer cells that have been grown in the lab, or even of cell components, such as parts of proteins found on cancer cells. A recent study compared combining the vaccine with chemotherapy to treatment with the same chemotherapy alone in patients with advanced lung cancer. The cancers in the group that got the vaccine were more likely to shrink or stop growing than the cancers in the group that just got chemo. More studies are planned to see if the vaccine will actually help patients live longer.
At this time, vaccines are only available in clinical trials.