Lung Cancer And Physical Activity

Introduction

Lung cancer is a severe disease that affects your lungs. According to the Global Cancer Observatory 2022 data report, lung cancer is the no.1 most common cancer type with around 2,480,000 cases reported annually worldwide. It also ranks as the most deadly cancer with around 1,817,000 deaths reported globally in 2022.

Unfortunately, lung cancer is often diagnosed when it is already in its advanced stage, limiting treatment options. Exploring different non-clinical ways to prevent and better manage lung cancer is one way to improve patient outcomes and quality of life. Here, we will examine the benefits of physical activity for preventing and managing lung cancer.

What is lung cancer?

As part of the normal functioning of your body, your cells constantly divide. However, on some occasions, the DNA in these cells can mutate, changing the DNA sequence. This can lead to uncontrolled cell proliferation and eventually, the formation of a mass, or a tumour. Lung cancer occurs when cells divide in an uncontrolled manner in the lungs. Lung cancer usually starts developing in your airways, bronchi or bronchioles, or your small air sacs known as alveoli (see Figure 1). However, it can also start in another organ and then spread to the lungs or metastasise.

There are two major types of lung cancer:

1.) Small cell lung cancer (SCLC)

SCLC accounts for around 15% of lung cancers. This is a fast-growing cancer that can affect anyone, however, it often affects people who use tobacco products, in particular, cigarettes. SCLC can be further divided into two types:

• Small cell carcinoma - the most common form of SCLC
• Combined small cell carcinoma - around 2% to 5% of all SCLC. This type of cancer is a combination of non-small cell and small cell lung cancer cells

2.) Non-small cell lung cancer (NSCLC)

The most common lung cancer type. It accounts for around 85% of all lung cancer cases. NSCLC grows slower compared to SCLC, however, it has often metastasised to other parts of the body by the time of diagnosis, making treatment more difficult. NSCLC can also be further divided into three major categories:

• Adenocarcinoma – this type of cancer develops from the cells that secrete mucus and other liquids. It usually affects people who are either current smokers or people who used to smoke
• Squamous cell carcinoma – this type forms in the squamous cells (flat cells that line the inside of your airways). It is also associated with tobacco use
• Large cell carcinoma – also known as undifferentiated carcinoma. This type of cancer can form in any portion of the lung. This type of cancer grows and spreads rapidly making it harder to treat

What is the difference between SCLC and NSCLC?

SCLC and NSCLC cells differ in the way they look under the microscope. SCLC cells look small and round, while NSCLC cells look larger. In general, SCLC cells tend to grow faster than NSCLC cells.

What are the risk factors for lung cancer?

Around 79% of lung cancer cases in the UK are preventable. The biggest risk factor for developing lung cancer is smoking, which is responsible for around 85% of all cases. Not using tobacco is the best way to prevent lung cancer. It is also important that you avoid secondhand smoke.

Other risk factors for developing lung cancer include:¹

• Exposure to ionising radiation, such as previous radiation treatment affecting your chest area, for example, treatment for breast cancer. Atomic bomb survivors are at an increased risk of lung cancer
• Family history of lung cancer
• Chronic inflammation from infections and other medical conditions – for instance, people with chronic obstructive pulmonary disease or tuberculosis are at an increased risk
• Exposure to harmful substances, such as air pollution, radon, asbestos, silica, heavy metals, diesel and polycyclic aromatic hydrocarbons (occur naturally in coal, crude oil, and gasoline)

What are the symptoms of lung cancer?

Lung cancer can cause many different symptoms. The main symptoms (and percentage of people with these symptoms at the time of diagnosis) are:²

• Cough (33.9%)
• Dyspnoea (shortness of breath) (26.7%)
• Pain (23.8%)
• Weight loss (21%)
• Haemoptysis (coughing up blood) (11.3%)
• Anorexia (loss of appetite) (6.1%)
• Physical weakness, fatigue (10%)
• Superior vena cava syndrome (can cause swelling in your upper body, shortness of breath and other symptoms) (0.5%)
• Aphonia (loss of voice) or voice alterations (3.2%)

However, around 31.5% of people have no symptoms at diagnosis.² Additionally, these symptoms, such as cough, can be a sign of another disease or infection, which is why it is important to see your doctor so that you can be properly diagnosed.

Physical activity and lung cancer

Physical activity can affect lung cancer in a few ways. It helps by potentially reducing the risk of cancer development as well as improving your overall well-being during treatment and post-treatment. Multiple studies have shown that physical activity before, during, and after treatment is safe and beneficial.³

Physical activity and cancer prevention

Firstly, what is physical activity? Physical activity is defined as any movement involving the use of skeletal muscles which needs more energy than resting. It can be high-intensity exercise or sports, or any everyday activity, such as walking or doing household chores.

Physical activity is associated with reduced risk of lung cancer by around 21-25%.⁴ Physical activity improves lung function and reduces the risk of infections and respiratory diseases. It can reduce your risk of lung cancer by reducing insulin in your blood, reduce chronic inflammation, both of which are associated with an increased risk of cancer. It also improves immune function, meaning that your body can be better prepared to fight cancer.³

Physical activity can also reduce cancer risk which is associated with obesity as multiple cancers have an increased risk of development in people with a high body mass index.⁵

However, it is worth noting that it might be whether people smoke or not that reduces the risk of developing lung cancer, and not physical activity. It has been observed that physical activity correlated with reduced risk of lung cancer for former and current smokers but, there was no difference in the risk of lung cancer among those who have never smoked.⁶

How can physical activity help lung cancer patients during and after treatment?

Engaging in light exercise can help a person undergoing treatment to feel better. Physical activity can improve multiple symptoms associated with lung cancer, such as fatigue, shortness of breath, muscle atrophy (wasting of muscle mass), pain, loss of appetite, and a decline in physical fitness.³

During the treatment, physical activity can be seen as a non-pharmacological intervention used alongside chemotherapy, radiotherapy, and surgical treatment. It can reduce inflammation associated with cancer and improve metabolic and immune functions, which can improve treatment outcomes.⁷ Additionally, exercise before surgery can improve outcomes after surgery and reduce the time spent in the hospital.⁸ It can also improve quality of life by improving lung function, mental wellbeing and sleep quality, while reducing fatigue.⁷

Challenges for patients

In some studies more than 50% of participants with lung cancer were unable to complete an exercise study.⁸ Many barriers exist that can limit a person’s ability to stay physically active. Some of them are general, like lack of access to services or lack of interest, however, others are specifically due to their health status. These include symptoms they are experiencing, advancement of cancer, treatment strategy, and side effects associated with that treatment.⁷

It is also worth noting that not all types of exercise are suitable for every person. Some people may need to be more cautious when it comes to exercising. These include patients with:

• Severe anaemia
• A compromised immune system – you may need to avoid public spaces, such as gyms
• Severe fatigue
• Balance issues or weakness – should not exercise alone in case of fall or injury

It is important to identify what types of physical activities work for you.

Getting started with exercise

You should start gently and progress slowly, especially if you have not been active before diagnosis. You should consult your doctor before you begin an exercise programme, they may be able to advise you on what types of exercises are most suitable for you. Additionally, you might want to consider starting by working with a physical therapist, kinesiologist, or cancer exercise specialist.⁷

Many lung cancer patients suffer from shortness of breath and struggle with breathing, so starting with some breathing exercises might be preferred. Improving breathing will improve endurance and quality of life, and will make everyday activities easier.⁹ Relaxation breathing can be useful in reducing stress and anxiety. You should try using the full capacity of your lungs during relaxation breathing, and breathe slowly and deeply.⁹

In particular, diaphragmatic breathing can be useful for lung cancer patients. It improves the strength of the diaphragm and the abdominal muscles. If the diaphragm becomes weak, the person starts using their shoulders and other muscles to help them breathe. Diaphragmatic breathing allows more air to enter and exit your lungs with less tiring of the chest muscles, which can help with shortness of breath.⁹

Additionally, based on your fitness, you might start with other light exercises, such as stretching and walking. You can slowly progress to more intensive exercises based on your health and your doctor’s advice.

Summary

Lung cancer is the most common and the most deadly cancer in the world. It is a very serious disease which can result in multiple symptoms, such as coughing, dyspnoea, and fatigue. There is some evidence to suggest that physical activity may reduce your risk of getting lung cancer. Furthermore, exercise can help improve your physical and mental well-being during and after cancer treatment. It is important to listen to your doctor’s advice and find the right types of exercises to suit you and your current health status.