by Mona Jhaveri - October 1, 2021

Lung cancer is the most common type of cancer globally; unfortunately, it’s also one that’s difficult to detect early. The most recent statistics report that over 2.21 million people live with lung cancer worldwide, and more than 1.8 million deaths each year due to this form of cancer.

However, survival rates for lung cancer have been steadily increasing over time thanks to improved treatments such as targeted therapy, immunotherapy, and new surgical techniques.

In this blog post, we will discuss what causes lung cancer and how it can be detected so you can take steps now to lower your risk of developing it later on!

About Lung Cancer

The definition of this disease is the abnormal and uncontrolled growth of cells in any part of a person’s lungs. Cells become cancerous when they lose their normal functions, which then leads to them multiplying uncontrollably. Cancer can affect almost any type of cell within the body, but lung cancer is one that you want to be especially wary about since early detection is so difficult and it has a high rate of mortality.

The two main subtypes are non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC). NSCLC is the most common type at about 80% to 85%, according to American Cancer Society statistics. It is further broken down into squamous cell carcinoma, adenocarcinoma (the most common type), and large cell carcinoma.

SCLC is the second most common type of lung cancer, making up about 10% to 15%. Compared to NSCLC, it has a much higher mortality rate because it grows, spreads, and develops faster.

Statistics

When it comes to both sexes, lung cancer is one of the most common types of cancer worldwide. In men, it is only surpassed by prostate cancer, while in women, it comes second to breast cancer as the most common form of the disease.

The average age at diagnosis is about 70 years. Lung cancer is rarely found in those under 40 and rarer still in children. Lung cancer is most commonly found in men, and it’s also more likely to affect Black men than other racial groups. However, despite their overall lung cancer risk being higher, Black men are less likely to develop SCLC than white men.

The latest news from organizations such as the American Cancer Society is that survival rates for lung cancer patients have been steadily increasing over time thanks to improved treatments such as targeted therapy, immunotherapy, and new surgical techniques.

The awareness of risk factors for lung cancer is also increasing, and as a result, lung cancer survival rates are likely to continue improving.

Risk Factors

Lung cancer risk factors can be divided into two categories:

  • Controllable risk factors – those you can change.
  • Noncontrollable risk factors – those you have no effect over.

Controllable Risk Factors

  • Smoking

The most controllable risk factor for lung cancer is smoking. Smokers are 23 times more likely to develop lung cancer than nonsmokers, and the earlier they started, the worse the disease.

This doesn’t mean that smokers who quit are in the clear. The risk for lung cancer is still high because of damage done to the lungs due to smoking, even if it has been 20 or 30 years since you quit.

  • Second-hand smoke exposure

Exposure to second-hand smoke also increases the risk of developing lung cancer, primarily when this occurs at an early age.

  • Asbestos exposure

Asbestos is a known carcinogen that’s been linked to lung cancer. Exposure can occur in the workplace or through household exposure when people live in a home with asbestos in the walls or ceilings.

  • Radon exposure

Radon is a naturally occurring radioactive gas that seeps into homes, especially located below ground level, and it’s been linked to lung cancer. Radon levels are highest during winter months when windows tend to be closed more often due to heating needs, hence increasing risk for exposure.

  • Exposure to other cancer-inducing agents

Being exposed to substances like silica, uranium, beryllium, cadmium, arsenic, and chromium and nickel compounds also increases lung cancer risk. Workplace exposure to these substances in certain professions has been predominantly linked to lung cancer in the past.

Noncontrollable Risk Factors

  • Family or personal history of lung cancer

If you have a family member with the disease, your chances of developing it are also increased. If there is more than one first-degree relative who has lung cancer, your risk is further increased.

Similarly, if you have been diagnosed with lung cancer before, your risk for developing it again is higher than the average person.

  • Air pollution

Low-quality air can be a lung cancer risk factor, especially if you live in an area with heavy pollution. While poor quality air is nowhere near as great as the risk from smoking, it is still a factor to consider.

Potential Risk Factors

  • Cannabis smoking

Smoking marijuana can increase lung cancer risk, but this is more likely to occur when combined with tobacco.

Most smoke inhaling can lead to respiratory problems and thus contribute to lung cancer risk, such as smoking pipes, cigars, low-tar cigarettes, and menthol cigarettes.

  • E-cigarettes

The FDA classifies e-cigarettes as “tobacco” products. However, studies have yet to confirm whether they increase lung cancer risk.

E-cigarettes do contribute to short-term lung problems, though, which increases the risk of developing lung cancer.

Lung Cancer Symptoms

Symptoms for lung cancer can be vague and hard to pinpoint. An individual may not even know he or she has lung cancer until it has reached advanced stages, when tumors are too big to ignore or if they start causing other serious problems.

Signs that indicate the need for medical attention include:

  • Persistent cough
  • Chest pain when breathing deeply or coughing up blood (or pink, rusty substances)
  • Shortness of breath that doesn’t go away after a few weeks
  • Hoarseness in the voice for more than three weeks or pain when swallowing food
  • Unexplained weight loss over several months even if you are eating normally and exercising regularly

If lung cancer is caught early enough, it is often easier to treat. This is why it’s essential for lung cancer patients and survivors to receive follow-up care after treatment. Healthcare providers need to track their condition, detect any recurrence of the disease, or a developing problem that may indicate complications from earlier treatments or delayed side effects. 

Lung Cancer Screening

Cancer screening is performed regularly on high-risk patients. Screening for lung cancer can be performed using a low-dose CT (LDCT) scan, a special type of computed tomography scan that uses low-dose X-rays to produce multiple images or pictures of the inside of your body.

Lung cancer screening with LDCT is recommended for people at high risk due to smoking or workplace hazards.

The benefits of LDCTs in detecting early lung cancers include saving people from having to undergo invasive procedures and surgeries, as well as making it possible for doctors to more accurately measure the severity of the disease and adjust treatments accordingly if needed.

The earlier you catch lung cancer, the more effectively it can be treated. It is highly recommended to go for screening if you are at risk due to smoking history or workplace hazards.

Lung Cancer Detection

While screening helps discover lung cancer early, before it even becomes noticeable, most cases are found after cancer has advanced to a more noticeable stage. That’s why it is essential for those at high risks, such as smokers, former smokers, and people exposed to hazardous substances on the job or in their environment, to regularly undergo lung cancer screening.

Imaging tests

Most common imaging tests used to detect lung cancer include X-rays (plain or CT), PET, and MRI scans. The doctor will use imaging tests to look at suspicious areas in the lungs, see how far cancer has spread, and whether surgery is feasible.

Different imaging tests utilize various methods of creating images. They often use other forms of radiation (such as X-rays or sound waves), which are emitted by machines called radiologic equipment, to make the images visible on film or digital screens.

After obtaining a scan of the lungs, the doctor may order a biopsy to confirm whether cancer cells are present.

  • Lung biopsy

A needle biopsy is a minimally invasive procedure involving inserting a needle into the suspected lung tumor and taking tissue samples for examination under the microscope.

Different types of biopsies can be performed when testing for lung cancer:

  • Fine needle aspiration (FNA) biopsy – a small fluid sample or tissue is taken out with a thin needle.
  • Core biopsy – in this procedure, the doctor removes larger pieces of tissue using a larger needle than in an FNA biopsy.
  • Transthoracic needle biopsy – for cancers located in the outer regions of the lung. The needle is inserted through the chest wall and into the tumor.

In the future, a liquid biopsy might be used to diagnose lung cancer. Liquid biopsies use blood tests and other methods such as tumor sequencing or genetic analysis, which can detect tiny amounts of cancer cells in the body fluids (such as urine, saliva, sweat).

  • Sputum cytology

For cancers that start in the central lung airways, such as squamous cell carcinoma, sputum cytology might help diagnose the disease. This involves testing the sputum (from a saliva or mucus sample) for abnormal cells.

Lung Cancer Treatment

If cancer is discovered, the next step is determining the stage and type of cancer and treating it accordingly. What treatment the doctor prescribes depends on the cancer stage, how much it has spread, and it’s kind. Treatments may include surgery, radiation therapy, or chemotherapy, among others.

Surgery

If lung cancer is considered operable (i.e. if a tumor can be physically removed), the doctor might recommend surgery to remove part or all of a lung.

The surgery depends on the stage and location of cancer and whether it has metastasized (spread to other areas of the body like lymph nodes).

Surgery may involve:

Lobectomy – removal of a lobe or section lung. This type is often used for early-stage cancers that have not spread beyond one lung lobe.

Pneumonectomy – removal of a lung or part of it (the whole upper, middle, or lower lobe). This type is used for more advanced stages where cancer has spread to other parts of the body and surgery can no longer be performed on just one lung.

New forms of surgery include video-assisted thoracic surgery (VATS) and robotically-assisted thoracic surgery (RATS). These are less invasive procedures that involve small incisions.

Radiation therapy

The doctor might recommend radiation treatment to help fight the cancer and ease symptoms of lung cancer, such as shortness of breath or coughing up blood. Radiation is often used in combination with surgery (so-called adjuvant radiotherapy). It’s also used before surgery to shrink cancer and make it easier to remove.

Radiation therapy might be given as external beam radiation. A machine is used to shoot beams of high-energy rays into the body from outside (external) or internally via radioactive seeds implanted in the tumor.

In some cases, brachytherapy can be used instead – this involves implanting radioactive materials directly into the tumor to deliver radiation.

Radiation side effects may include fatigue, skin irritation or dryness, nausea, and vomiting.

Chemotherapy

Chemotherapy involves administering anticancer drugs via an intravenous drip (IV) line to kill cancer cells throughout your body. Chemotherapy has various goals depending on the lung cancer stage, including shrinking the tumor before surgery or slowing down its growth so that other treatments can work better.

Chemotherapy drugs are usually fast-acting and target rapidly dividing cells. Unfortunately, chemo can affect not only cancer cells but also healthy cells in the body – including hair, skin, and nails.

Chemotherapy side effects are common and include nausea, vomiting, diarrhea or constipation, mouth sores (mucositis), fatigue, loss of appetite, or taste changes.

Immunotherapy

A form of cancer treatment that has been gaining traction in recent years, immunotherapy works by stimulating the body’s immune system to recognize and attack cancer cells.

This method is now being studied as a possible option for lung cancer treatment combined with chemotherapy or radiation therapy to help kill off remaining cancer cells after surgery/radiation has been completed.

Immunotherapy side effects may include fatigue and flu-like symptoms such as fever, chills, and sweats.

Targeted therapy

For NSCLC, targeted therapies work by blocking the growth and spread of cancer cells. They aim to interfere with specific proteins found in lung tumors that tell the cancer cells how to grow and divide.

Many targeted therapy drugs have been developed for lung cancer, including crizotinib, gefitinib, and sotorasib.

Targeted therapy side effects may include nausea and vomiting, diarrhea or constipation, fatigue.

As of yet, there is no evidence that targeted therapy works on a disease as widespread as SCLC.

Long-Term Effects of Treatment

Many people diagnosed with lung cancer experience a disease-free period of remission.

However, even when the cancer is no longer detectable in the body through imaging, and there is no sign it has spread to other parts of the body (locally advanced), many patients continue to suffer from long-term effects. These include reduced exercise capacity, respiratory problems such as shortness of breath, coughing, excess mucus, and fatigue.

In some cases, lung cancer can return after remission even if the disease was initially detected at an early stage. Depending on the extent of damage to healthy tissue from radiation therapy or surgery, this may significantly impact the quality of life – sufferers might experience reduced lung function, for example.

Lung cancer statistics indicate that lung cancer survivors have a higher risk of developing another type of lung tumor in the future than people who never had it before. This is true even if they were diagnosed at an early stage and successfully treated with surgery alone.

Conclusion

Lung cancer is a type of cancer that starts in the lung and can spread to other body parts.

It is one of the deadliest cancers worldwide because it spreads quickly, making early detection difficult. There are different types of lung cancer – including non-small cell lung cancer (NSCLC, which accounts for 80% or more cases) and small cell carcinoma (SCLC).

Chemotherapy is a common treatment option. Immunotherapy and targeted therapies are also being developed as possible lung cancer treatments, with promising results. New innovations are on the horizon for screening, diagnosing, and treatment. 

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