Lung Neoplasm Malignant

Lung cancer is one of the most common and serious types of cancer, caused by harmful cells in your lungs growing unchecked. While it remains a leading cause of cancer-related deaths, advances in treatments have caused a significant decline in lung cancer deaths in recent years, offering new hope to patients and their families.

Table of contents

• What is lung cancer?
• Types of lung cancer
• Stages of lung cancer
• Causes and risk factors
• Signs and symptoms
• Diagnosis
• Treatment options
• Screening recommendations
• Living with lung cancer
• Prevention

What is lung cancer?

Lung cancer is a disease caused by uncontrolled cell division in your lungs^[1]. Your cells normally divide and make more copies of themselves as part of their natural function. However, sometimes they get changes called mutations (permanent changes in the cell’s genetic material) that cause them to keep making more of themselves when they shouldn’t. These damaged cells dividing uncontrollably create masses, or tumors (abnormal growths of tissue), that eventually keep your organs from working properly^[1].

Lung cancer usually starts in the airways called bronchi (the large tubes that carry air into your lungs) or bronchioles (smaller branches of airways), or in small air sacs called alveoli (tiny air-filled pockets where oxygen enters your blood)^[1]. The lungs are two spongy organs in the chest that control breathing^[2]. Cancer that starts in the lungs can then spread to other organs^[1].

A cancerous tumor of the lung can grow into nearby tissue and destroy it. The tumor can also spread to other parts of the body through a process called metastasis (when cancer cells travel from the original tumor to other parts of the body)^[3].

• Lungs
• Bronchi
• Bronchioles
• Alveoli
• Trachea

Types of lung cancer

There are many cancers that affect the lungs, but the term “lung cancer” is usually used for two main kinds: non-small cell lung cancer and small cell lung cancer^[1]. These categories refer to what the cancer cells look like under a microscope^[9].

Non-small cell lung cancer (NSCLC)

Non-small cell lung cancer is the most common type of lung cancer. It accounts for over 80% of lung cancer cases^[1]. About 80 to 85 out of 100 lung cancers are non-small cell lung cancer^[3]. There are several different subtypes that start in different types of cells and tissues of the lung^[3].

The main types of non-small cell lung cancer include:

• Adenocarcinoma: This is the most common type of non-small cell lung cancer. It starts in the lung cells that make mucus. These tumors are often found in the outer edges of the lungs and are more likely to be found before they have started to spread to other parts of the body^[3].
• Squamous cell carcinoma: This is the second most common type of non-small cell lung cancer. It starts in the flat cells that line the airway tubes of the lung^[3].
• Large cell carcinoma: This type has tumors with cells that look very large and round when examined under a microscope. It is a very rare type of non-small cell lung cancer and can grow and spread very quickly^[3].

Less common types of non-small cell lung cancer include adenosquamous carcinoma and sarcomatoid carcinoma^[1].

Small cell lung cancer (SCLC)

Small cell lung cancer grows more quickly and is harder to treat than non-small cell lung cancer^[1]. It is called small cell because the cancer cells look small when they are examined under a microscope^[3]. This type is usually found in the center of a lung and is the most aggressive type of lung cancer^[3].

Small cell lung cancer is often found as a relatively small lung tumor that has already spread to other parts of the body. In many cases, it has already spread to other parts of the body when it is diagnosed^[1][3]. Specific types of small cell lung cancer include small cell carcinoma (also called oat cell carcinoma) and combined small cell carcinoma^[1].

Other types of cancer in the lungs

Other types of cancer can start in or around your lungs, including lymphomas (cancer in your lymph nodes), sarcomas (cancer in your bones or soft tissue), and pleural mesothelioma (cancer in the lining of your lungs). These are treated differently and usually aren’t referred to as lung cancer^[1].

Stages of lung cancer

Cancer is usually staged based on the size of the initial tumor, how far or deep into the surrounding tissue it goes, and whether it has spread to lymph nodes or other organs. Each type of cancer has its own guidelines for staging^[1].

The general staging for lung cancer is^[1]:

• Stage 0 (in-situ): Cancer is in the top lining of the lung or bronchus. It hasn’t spread to other parts of the lung or outside of the lung.
• Stage I: Cancer hasn’t spread outside the lung.
• Stage II: Cancer is larger than Stage I, has spread to lymph nodes inside the lung, or there’s more than one tumor in the same lobe of the lung.
• Stage III: Cancer is larger than Stage II, has spread to nearby lymph nodes or structures, or there’s more than one tumor in a different lobe of the same lung.
• Stage IV: Cancer has spread to the other lung, the fluid around the lung, the fluid around the heart, or distant organs.

Each stage has several combinations of size and spread that can fall into that category. For instance, the primary tumor in a Stage III cancer could be smaller than in a Stage II cancer, but other factors put it at a more advanced stage^[1].

Causes and risk factors

Smoking is the most common cause of lung cancer. It is estimated that 90% of lung cancer cases are attributable to smoking^[4]. Cigarette smoking causes about 80% to 90% of lung cancer deaths in the United States^[22]. People who smoke have the greatest risk of lung cancer. The risk of lung cancer increases with the length of time and number of cigarettes smoked^[2].

The risk is highest in males who smoke. The risk is further compounded with exposure to other carcinogens, such as asbestos^[4]. The risk of lung cancer secondary to passive smoking (breathing in smoke from other people’s cigarettes) increases by 20 to 30%^[4]. Smoke from other people’s cigarettes, cigars, or pipes is called secondhand smoke^[22].

However, lung cancer can also happen in people who have never smoked^[2]. Quitting smoking, even after smoking for many years, significantly lowers the chances of developing lung cancer^[2].

Other risk factors for lung cancer include^[4]:

• Radiation for non-lung cancer treatment, especially non-Hodgkins lymphoma and breast cancer
• Exposure to metals such as chromium, nickel, arsenic, and polycyclic aromatic hydrocarbons
• Lung diseases like idiopathic pulmonary fibrosis
• Asbestos exposure, particularly occupational exposure
• Radon exposure

Asbestos exposure increases the risk for lung cancer in a dose-dependent manner but varies according to the type of asbestos fiber^[4]. Radon exposure is a leading cause of nonsmoking-related lung cancer^[4].

Signs and symptoms

Lung cancer typically doesn’t cause symptoms early on. There are usually no signs or symptoms in the early stages of lung cancer^[2][6]. Symptoms of lung cancer usually happen when the disease is advanced^[2].

The most common but nonspecific symptom of lung cancer is cough^[12]. Many people with the condition eventually develop symptoms including^[6]:

• A persistent cough (a new cough that doesn’t go away)
• Coughing up blood, even a small amount
• Persistent breathlessness (shortness of breath)
• Chest pain
• Hoarseness
• Wheezing
• Unexplained tiredness and weight loss
• An ache or pain when breathing or coughing

Signs and symptoms that happen when lung cancer spreads to other parts of the body may include^[2]:

• Bone pain
• Headache
• Losing weight without trying
• Loss of appetite
• Swelling in the face or neck

Associated symptoms, including coughing up blood or shortness of breath, or systemic symptoms, including loss of appetite or weight loss, greatly increase the likelihood of having lung cancer^[12].

Diagnosis

If your healthcare professional thinks you may have lung cancer, a number of tests can be used to look for cancerous cells and to rule out other conditions^[7]. When evaluating a patient for lung cancer, a detailed history and physical examination should be performed, including environmental and work exposures^[12].

The initial evaluation for lung cancer begins with laboratory testing, including a complete blood count, serum chemistries, calcium levels, liver function tests, and chest radiography^[12]. Lung cancer diagnosis often starts with an imaging test to look at the lungs. If you have symptoms that worry you, a healthcare professional might start with an X-ray^[7].

CT of the chest with intravenous contrast media should be performed when there is a high level of suspicion, even if radiographic results are normal^[12].

Tests may include^[7]:

• Imaging tests: These tests make pictures of the body. They can show the location and size of the lung cancer. Tests might include X-ray, MRI, CT and positron emission tomography (also called a PET scan).
• Sputum cytology: Sputum is the mucus that is coughed up from the lungs. If you are coughing up sputum, it can be looked at under a microscope. The sputum can sometimes show lung cancer cells.
• Biopsy: A biopsy is a procedure to remove a sample of tissue for testing in a lab.

Referral to a multidisciplinary lung cancer team, imaging, and confirmation through sputum cytology, thoracentesis, fine-needle aspiration, or mediastinoscopy are recommended^[12].

If lung cancer is confirmed, other tests are done to find out how far it has spread through the lungs, lymph nodes, and the rest of the body. This process is called staging^[9]. The type and stage of lung cancer tell doctors what kind of treatment you need^[9].

Treatment options

If lung cancer is confirmed, treatment options vary based on staging, histology, immunotherapy biomarker testing, and patient health status^[12]. Lung cancer is treated in several ways, depending on the type of lung cancer and how far it has spread^[9].

Treatment depends on the type of lung cancer and how far it has spread^[9]. Treatments include^[1]:

• Surgery: An operation in which doctors cut out the cancer. If the condition is diagnosed early and the cancerous cells are confined to a small area, surgery to remove the affected area of lung may be recommended^[1][6].
• Chemotherapy: Use of special medicines to shrink or kill the cancer. The drugs can be pills you take or medicines given in your veins, or sometimes both^[9]. If the cancer has spread too far for surgery or radiotherapy to be effective, chemotherapy is usually used^[6].
• Radiation therapy: Use of high-energy rays (similar to x-rays) to kill the cancer^[9]. If surgery is unsuitable due to your general health, radiotherapy to destroy the cancerous cells may be recommended instead^[6].
• Immunotherapy: A treatment approach that helps your body’s immune system fight cancer^[1].
• Targeted therapy: Use of drugs to block the growth and spread of cancer cells. The drugs can be pills you take or medicines given in your veins. You will get tests to see if targeted therapy is right for your cancer type before this treatment is used^[9]. There are also a number of medicines known as targeted therapies that target a specific change in or around the cancer cells that is helping them to grow. Targeted therapies cannot cure lung cancer but they can slow its spread^[6].

People with non-small cell lung cancer can be treated with surgery, chemotherapy, radiation therapy, targeted therapy, or a combination of these treatments. People with small cell lung cancer are usually treated with radiation therapy and chemotherapy^[9].

If you have lung cancer (especially non-small cell lung cancer), your doctor may run tests to find out if you have a change in your genes (genetic mutation). The results of these tests help your doctor know which treatments will work best for you^[9].

Screening recommendations

Screening can help find lung cancer at an early stage, when treatment may work better^[9]. People with an increased risk of lung cancer may consider yearly lung cancer screening using low-dose CT scans^[1].

Lung cancer screening is generally offered to people 50 and older who smoked heavily for many years. Screening also is offered to people who have quit smoking in the past 15 years^[1]. As of 2021, annual lung cancer screening using low-dose computed tomography is recommended starting at 50 years of age in patients with a 20 pack-year history^[12].

Adults 50 to 80 years of age who have a 20 pack-year smoking history and currently smoke or have quit smoking within the past 15 years should undergo annual low-dose CT screening^[12]. You should discuss your lung cancer risk with your healthcare professional to decide whether lung cancer screening is right for you^[1].

Living with lung cancer

Lung cancer can affect your daily life in different ways, depending on what stage it’s at and the treatment you’re having^[17]. Although not all these things work for everybody, there are several ways you can find support to help you cope^[17].

Having cancer can lead to a range of emotions. These may include shock, anxiety, relief, sadness and depression. People deal with serious problems in different ways. It’s hard to predict how living with cancer will affect you^[17].

Finding support

You can find support by^[17]:

• Talking to your friends and family
• Talking to other people in the same situation
• Finding out about your condition
• Avoiding trying to do too much
• Making time for yourself

Your specialist team should have at least one lung cancer nurse specialist working with them. Ask your doctor to arrange for you to see a specialist nurse, who can support you and provide information about other sources of advice and support. They will also have a contact number so you can call them later if you have any questions^[17].

You may find it helpful to talk about your experience of lung cancer with others at a local support group. Patient organizations have local groups where you can meet other people who have been diagnosed with lung cancer and had treatment^[17].

Managing symptoms

Breathlessness is common in people who have lung cancer, whether it is a symptom of the condition or a side effect of treatment^[17]. In many cases, breathlessness can be improved with some simple measures such as breathing in slowly through your nose and out through your mouth, making daily activities easier, and using a fan to direct cool air towards your face^[17].

Some people with lung cancer have pain, while others never have any. Pain is not related to the severity of the cancer. What causes cancer pain is not very well understood, but there are ways of treating it so the pain can be controlled^[17].

Prevention

The most important thing you can do to prevent lung cancer is to not start smoking, or, if you smoke, to quit^[22]. Patients with lung cancer should be offered smoking cessation interventions^[12].

Steps you can take to reduce your risk include^[22]:

• Don’t smoke: Cigarette smoking causes about 80% to 90% of lung cancer deaths in the United States. The most important thing you can do to prevent lung cancer is to not start smoking, or, if you smoke, to quit.
• Avoid secondhand smoke: Make your home and car smoke-free.
• Reduce radon in your home if needed: Get your home tested for radon and take steps to reduce the radon level if it is high.
• Be careful at work: Follow health and safety guidelines to avoid carcinogens (things that can cause cancer).

Quitting smoking will also help you heal once lung cancer treatment is over. Avoiding secondhand smoke from others is also a good idea^[23].