Mesothelioma vs. Lung Cancer: What to Know

Often times, people confuse mesothelioma for a form of lung cancer because the most common type, pleural mesothelioma, affects the lungs. Though at a glance it may seem like these cancers would be very similar, they have key differences in many aspects, like where and how they develop.

While mesothelioma on average is only diagnosed in about 3,000 new cases in the U.S. each year, the American Cancer Society estimated 222,500 new cases of lung cancer in 2017 alone. Lung cancer is one of the most common in the world, and though mesothelioma is rare, it is completely preventable and in need of better awareness, too. Both of these cancers often come with a rather poor prognosis and have led to many deaths around the globe. More education around the causes of these cancers, ways to prevent them, and common symptoms to keep in mind can help change these statistics and save lives.

In honor of Lung Cancer Awareness Month this November, we highlighted some of the overlap between the two and a few ways they differ to help bring more attention to these deadly, and often preventable cancers.

What They Have in Common

Lung cancer and pleural mesothelioma especially have some common aspects that can help account for the confusion around these cancers. Most notably, both cancers begin with similar symptoms, face a longer latency period, and are often treated with the same kinds of therapies like surgery.

Symptoms

In both cases, the symptoms that first start to present can come off as rather nonspecific and may be mistaken as a normal illness, like the flu. It’s easy for many patients to ignore any of the early symptoms for some time, thinking it’s nothing serious. Unfortunately, it’s also easy for doctors to sometimes confuse the early symptoms for other diseases as well.

Some of the common symptoms for both of these cancers include:

Patients may experience other symptoms depending on their individual case. But even for symptoms that may seem like nothing, like a persistent cough, it’s important for the public to pay attention to what they’re experiencing and seek a doctor’s help before it gets worse.

Latency Period

In addition to the lack of clear, decisive symptoms, the latency period associated with both mesothelioma and lung cancer can make it difficult for doctors to properly diagnose them early on. The only confirmed cause of mesothelioma is asbestos exposure. The asbestos fibers become lodged in the lining of the lungs (or in the other forms of mesothelioma, in the abdomen or heart) and slowly irritate the lungs over time. The irritation can lead to scarring and inflammation, which can in turn develop into tumors over the course of 10 to even 50 years.

For lung cancer, latency period really varies by patient depending on the cause. Lung cancer can also develop from asbestos exposure or other environmental toxins like radon, but is more often caused by smoking or secondhand smoke. Depending on the patient, it may take anywhere from months to 50 or more years to begin showing symptoms.

Because of the nonspecific symptoms and latency periods, both cancers are often misdiagnosed as other diseases. Pleural mesothelioma is often mistaken for common respiratory illnesses like the flu, chronic obstructive pulmonary disease (COPD) and lung cancers like adenocarcinoma. Lung cancer is also often misdiagnosed as the flu or other common illnesses, as well as other more serious diseases like lymphoma or thoracic hodgkin disease.

Treatment Plans

In general, both types of cancer rely on the standard treatment options of surgery, chemotherapy and radiation, and may also implement some emerging treatments like immunotherapy. In fact, Opdivo and Keytruda are two immunotherapy drugs that have been FDA approved to treat subtypes of non-small cell lung cancer, though they are not yet officially approved for the treatment of mesothelioma.

Because of the nature of these symptoms and latency period, both cancers are often not properly diagnosed until they have developed into a more advanced stage, which can limit some of the treatment options available for these patients.

How They Are Different

Though pleural mesothelioma and lung cancer have a lot of similarities, there are two key differences that really set them apart: the actual location of the cancer, and how these cancer cells continue to develop and grow in the body.

Though lung cancer and this form of mesothelioma both affect the lungs, just how they impact the lungs is very different. In general, mesothelioma forms in the lining of the lungs, while lung cancer develops in the lung tissue itself.

In any form of mesothelioma, the tumors develop over time because the asbestos fibers have become lodged in the lining of organs, whether the lungs, heart or abdomen. As such, the tumors present and spread very differently from tumors present in the lung tissue itself. As pleural mesothelioma becomes more advanced, the tumors may form a sheath-like formation across the lung cavity. These tumors may then spread quickly to other areas of the body, like the lymph nodes, abdomen, and diaphragm.

Lung cancer is usually caused by abnormal cell growth in one or both lungs. What part of the lung is affected will vary depending on the type of lung cancer, but can include the lining of the bronchial tubes, the lung’s air sacs, the mucus-producing glands, or on the lung surface. Because the majority of lung cancer cases aren’t really discovered until more advanced stages, the tumors may have spread from the lung tissue into the lymph nodes, the bloodstream and other organs. Rather than the sheath-like tumor mass in pleural mesothelioma, patients will likely have larger, wider spread masses.

Because of these key differences, how symptoms present, how these cancers are diagnosed, and the intent behind these common treatments will vary widely between lung cancer and mesothelioma patients.

Better Awareness, Prevention & More Research

At the end of the day, the world needs better education around all types of cancer. Better understanding of how some of these cases can be prevented on a widespread scale can save many lives. In addition to awareness and prevention, research is truly critical to improving treatments and survival. Clinical trials for both of these cancers have already seen some progress and success in finding new, effective treatments.

With these pillars in place, we’ll be that much closer to ending these cancers once and for all.