What Is Metastatic Lung Cancer?

Metastatic lung cancer, also called advanced lung cancer, means cancer that starts in the lungs and spreads to other parts of the body. The word “metastatic” means cells from the cancerous tumor have separated from its initial site of development and spread to other parts of the body via the blood or lymphatic system.

Lung cancer often goes undetected in the early stage as it is usually asymptomatic. Even when symptoms are present, they are typically mild, with most patients not seeing them as enough reason to see a doctor. This results in most people receiving a diagnosis of the condition at stage IV when the cancer has already spread to other organs and parts of the body.

“Lung cancer most commonly metastasizes to bones, brain, liver, and adrenal glands,” said Wael Harb, MD, board-certified hematologist and medical oncologist at MemorialCare Cancer Institute at Orange Coast Medical Center in Fountain Valley and Saddleback Medical Center in Laguna Hills, CA. And in its advanced stage, lung cancer is complicated to treat. However, the outcomes vary for different people.

If you are diagnosed with the condition, your doctor will recommend treatment to help manage your symptoms and help you live longer.

A number of things can increase your risk of developing lung cancer. But according to the American Lung Association (ALA), tobacco smoking is the number one cause of lung cancer. Health experts attribute this habit to about 90% of lung cancer cases. The chemicals in tobacco can cause permanent changes, called mutations, in the DNA sequence of a gene.

Mutations in the DNA of your lung cells can cause the cells to behave atypically – they begin to grow and multiply uncontrollably without dying, forming a tumor. As the tumor keeps increasing in size, some of the tumor cells can break away and spread to other parts of the body, where they form new malignant tumors. The lung cancer cells spread by traveling through the bloodstream or lymphatic system or invading nearby tissues.

Health experts are unsure what exactly causes cancer to metastasize. As Dr. Harb said, “Genetic mutations and expression of specific proteins may influence the tendency of cancer to spread to particular organs.”

While no risk factor is particularly attributed to metastatic lung cancer, the following factors can increase your risk of lung cancer in general, which can lead to metastatic lung cancer:

• Smoking

• Exposure to hazardous chemicals like arsenic, asbestos, uranium, and chromium

• Exposure to radon, an odorless colorless radioactive gas that exists in the soil

• Radiation therapy to the chest

• Genes/family history of lung cancer

• A medical history of lung cancer (a lung cancer survivor exposed to the risk factors can develop another lung cancer)

• Taking beta-carotene supplements

Just as lung cancer can spread to other body parts, some cancers can also travel from other parts of the body to the lungs. The lung is, in fact, one of the common sites for cancer metastasis.

Common cancers that can metastasize to the lungs include:

• Colorectal cancer

• Breast cancer

• Renal cancer

• Lymphomas

• Osteosarcoma (a type of bone cancer)

• Head/neck squamous cell carcinomas

• Uterine leiomyosarcoma (a rare cancerous tumor that occurs in the smooth muscle lining of the uterus)

In addition to those cancers listed above, thyroid cancer, adrenal cancer, and choriocarcinoma (a fast-growing cancer that occurs in the uterus) are rare cancers that can also metastasize to the lungs.

Lung cancer symptoms can vary from person to person, typically depending on where the cancer has spread to and which organs are affected.

The symptoms may include:

• Pain in the chest area

• Persistent cough

• Coughing up blood

• Blood in spit

• Weakness

• Difficulty breathing

• Wheezing

• Unintended and unexplained weight loss

• Nausea and vomiting

• Increased risk of fractures (when the cancer has spread to the bones)

• Headache and confusion (e.g., when cancer has spread to the brain)

• Abdominal pain and jaundice (e.g., when cancer has metastasized to the liver)

“Metastatic lung cancer is unlikely to be cured,” said Suresh Mukkamala, MD, medical oncologist and hematologist at Arizona Oncology. However, systemic treatment can help alleviate some of these symptoms and prolong survival.

To diagnose metastatic lung cancer, healthcare professionals use different examinations, tests, and procedures, such as:

Biopsy

This is the standard test for diagnosing cancers. If your doctor suspects you have cancer, they may suggest a biopsy immediately or after a series of other tests. During a lung biopsy, they will use a special biopsy needle to remove samples of your lung tissue and take it to the lab to test for cancer.

Computed tomography (CT) scans

This scan uses X-rays to show images of the body and may be used to find out if a cancerous tumor from the lungs has spread to other parts of the body.

Magnetic resonance imaging (MRI)

Similar to CT scans, MRI scans can show detailed images of the body. However, MRI uses strong magnetic fields and radiowaves. MRI scans can be used to check for signs of lung cancer spread to parts of the body like the brain, breasts, and blood vessels.

Bone scans

A doctor can order this test to check whether lung cancer has spread to the bones.

Positron emission tomography (PET)

This is a type of scan where a healthcare professional injects you with a radioactive substance meant to travel through your body. The substance settles in body areas with cancer cells, showing where the cells are located.

“Treatment in early-stage lung cancer patients primarily includes surgery, radiation therapy with or without systemic therapy, but treatment in more advanced lung cancer patients is primarily systemic therapy with or without radiation therapy,” according to Dr. Mukkamala.

The choice of treatment for metastatic lung cancer also depends on factors like the patient’s performance status, organ function, and molecular characteristics of the tumor. Doctors can combine two or more of the following treatment options:

Chemotherapy

Chemotherapy involves using drugs such as carboplatin, cisplatin, and docetaxel (Taxotere) to target and kill off cancer cells. Older adults or those who may not tolerate combination therapy may be treated with a single chemo medication.

Immunotherapy

Immunotherapy is the use of drugs like immune checkpoint inhibitors to treat cancer using the body’s own immune system. The drugs help the immune system's T-cells better recognize and fight cancer cells.

Targeted drug therapy

Oncologists now use targeted therapies, e.g., the ones that target HER2 lung cancers, to treat cancer of the lung. This therapeutic approach involves using drugs that target the specific proteins and genes that are helping cancers grow, divide, and spread.

Radiation therapy

Doctors can use radiation to kill cancers that have spread to specific sites. This reduces the risk of further cancer spread. This approach may also help to shrink the cancer tumors and help relieve symptoms in people with metastatic cancer.

Additionally, some people may choose to participate in clinical trials that experiment with new medications. Also, “lifestyle modifications, such as quitting smoking and maintaining an active lifestyle, are supportive measures,” Dr Harb noted, adding that palliative treatments can be employed to control symptoms and enhance the quality of life.

Receiving a diagnosis of metastatic cancer can be traumatizing, and the need for solid support and care at such a point cannot be overemphasized.

While treatments and lifestyle enhancement can improve your symptoms, support from family, friends, peer groups, and healthcare professionals can help with comfort, managing emotional effects, and dealing with the daily challenges of living with cancer.

If you’d like to join a support group, you can check out:

• ALA’s directory of support groups

• Lung Cancer Research Foundation’s resources for connecting with and supporting other lung cancer patients

• Lung Cancer Survivors, an online community supported by the ALA

• Cancer Hope Network, a support group with over 400 volunteers who want to help you navigate lung cancer diagnosis

• Cancer Survivors Network, a peer support community for cancer patients supported by the American Cancer Society

Organizations like the American Cancer Society (ACS) have estimated survival rates for lung cancer, but different factors, including overall health status, where the cancer has spread to, and age, can affect a person’s survival.

The five-year relative survival rate for people with advanced lung cancer is 9%, according to the ACS. This means that, on average, people with stage IV lung cancer are about 9% as likely as people who don’t have that cancer to live for at least five years after diagnosis.

“Metastatic Lung cancer patients with single (limited) metastasis have a two-year survival of around 20-25% and five-year survival of about 10%,” Dr Mukkamala added. “However, patients with metastatic lung cancer with several metastases in different organs have a two-year survival around 10%.”

Also, lung cancer mortality may differ across different races, age groups, races, and sexes. For instance, data from the ALA shows that lung cancer death rates between 2016 and 2020 were highest among Black males and lowest among Latino males and were also greater among men than women for all racial groups. These disparities may be due to factors like inequalities in healthcare and differences in lifestyle across people of different sexes.

Even though life expectancy for people with metastatic lung cancer is lower than for those with early-stage lung cancer, recent advancements in therapy may improve the outlook and help increase the quality of life for people with the condition.

While you cannot totally prevent lung cancer or keep it from spreading, science has shown that avoiding certain preventable risk factors can reduce your risk of developing this condition. So, to reduce your risk, you may want to quit smoking (if you smoke), avoid secondhand smoke, and avoid exposure to chemical carcinogens.

Going for regular screenings or getting medical attention as soon as you notice any symptoms is often beneficial, too. Doing these reduces the chances of receiving a diagnosis for advanced lung cancer and helps ensure you get treatment that may prevent the cancer from spreading.

It can be hard to tell when to contact a medical professional for health-related issues like lung cancer, especially since it doesn’t always cause symptoms. But consider getting regular screenings, especially if you have certain risk factors that increase your chance of developing it. Lung cancer screening is recommended for people age 50 or older who have a 20 pack-year smoking history (a pack a day for 20 years or more). If you have a family history of lung cancer, you may also be a good candidate for regular screening.

Also, see your doctor if you notice any symptom or change that is abnormal for you, such as pain in the chest, coughing up blood, and difficulty breathing. If the symptoms worsen, it will be ideal to see a doctor. Do not let the idea of a lung cancer stigma prevent you from seeking the help you may need.