What organ would you point out as the most important in the body? It is probably the heart because it only takes a few minutes without a heartbeat to diagnose clinical death. But what about the lungs?
Interestingly, our whole conception of life has to do with the lungs and the function of breathing. Religious people associate breathing with the soul and life itself. Medically, the lungs can’t function without the heart, and the heart is useless without the lungs. That’s why lung cancer is one of the most life-threatening and aggressive diseases a person can have.
Lung cancer is a progressive and uncontrolled growth of lung tissue. This new lung tissue is not useful for breathing and creates an obstruction and then a significant problem for the rest of the body. Since lung cancer is in close contact with blood vessels to exchange blood gasses, the tumor is always in danger of dislodging cells and sending them through the bloodstream. Many patients are detected when lung cancer has already spread to other body parts, which is not a sign of a good prognosis.
Lung cancer divides into two types. They are small cell lung cancer and non-small cell lung cancer. Small cell lung cancer is a type of lung cancer that spreads very rapidly and is very dangerous. Non-small cell lung cancer is a subgroup that includes plenty of lung cancer types. The most common is squamous cell lung cancer. This type of cancer is not as aggressive as small cell lung cancer, but it can also spread if we don’t treat it appropriately.
Like other types of cancer, the signs and symptoms of lung cancer can be arranged into different stages. First, we have the early symptoms that correspond to encapsulated cancer. Then, we have other symptoms that arise when cancer grows very large. In another stage, we have signs of metastasis, which can be divided according to the area where cancer spreads.
Initial symptoms of lung cancer
The initial symptoms of lung cancer can last a few weeks in small cell carcinoma or several months in non-small cell carcinoma. It depends on the aggressiveness of the tumor and the overall health of the patient. The initial symptoms are maintained throughout the course of the disease because they are caused by the tumor, regardless of the size. They are usually more severe as the disease progresses.
We can have the following signs and symptoms:
1. Shortness of breath
The lungs are essential for gas exchange. This is where oxygen enters the blood, and we take out carbon dioxide. For this exchange to occur, we need a constant flow of air coming in and out. The problem here is that tumors in the lungs create an obstacle to gas exchange. This obstacle can be very small and difficult to perceive. In advanced cancer, the tumor grows very large, and this symptom is very severe. Additionally, cancer prompts an inflammatory response, affects respiratory muscles, and creates the sensation of running out of breath.
2. Cough
This is also one of the most critical symptoms of lung cancer. Cough is a reflex and serves the purpose of clearing the airways out of microbes and obstructions. The tumor is perceived as a constant obstruction of the airways, and a cough reflex is elicited to try to remove this obstacle. Additionally, the inflammatory cytokines released by cancer cells affect the airway linings and create a reaction similar to respiratory infections. The airways respond by creating mucus and coughing to clear it out, even if there’s no actual infection.
3. Chest pain
This is sometimes the first symptom patients perceive as different and disturbing, especially if they have COPD and other respiratory diseases that cause cough and shortness of breath. Chest pain can be mild or very severe, depending on the size of the tumor and the inflammatory response it is causing. Chest pain increases during exercise or periods of intense stress. It happens because cancer activates nerve terminals in the lungs. The inflammatory cytokines are substances that also prompt a pain reaction when they are close to nerve terminals.
4. Tiredness
This is a common symptom in patients with lung cancer, and it has many reasons. Firstly, and depending on the size and location of the lesion, gas exchange can be compromised. Secondly, the tumor takes or robs energy from the body to feed and keep growing rapidly. This changes our metabolism and reduces the available energy.
5. Loss of appetite
Some patients experience a sensation of malaise and loss of appetite. It is even more common in patients with a tumor in the midline, close to the esophagus. As we will see below, a tumor in the midline may sometimes block the passage of foods, causing an uncomfortable sensation when the patient is swallowing.
6. Weight loss
Cancer is almost invariably associated with weight loss, especially in an advanced stage of the disease. It is caused by increased metabolic requirements that are not met by the intake of calories. This symptom can be found throughout the condition, but it is more common in the late stage.
Symptoms of advanced lung cancer:
In advanced disease, we have a larger tumor that starts causing more severe symptoms. Besides the symptoms we already described, the patient can also begin to experience the following:
7. Cachexia
We have already mentioned weight loss and tiredness. Cachexia is one step forward and features more severe weight loss. It is a wasting syndrome found in most types of cancer where patients have a conglomerate of symptoms, including loss of appetite, weight loss, muscle weakness, and fatigue.
8. Fatigue
This symptom can be found in patients with lung cancer with or without cachexia. As the disease becomes severe, they feel exhausted, but tiredness turns into fatigue, which is much more severe. Fatigue does not improve, even when patients sleep tight or take a nap. It happens because there’s metabolic stress in the organism, and it burns extra energy, emptying the reserves very rapidly.
9. Airflow obstruction
When patients have a growing tumor, there’s always a certain degree of airway obstruction, depending on where it is located. However, the tumor grows very large in advanced lung cancer, and the obstacle becomes more evident. Patients usually have a more severe sensation of running out of breath, and they may even find it harder to breathe. This mainly happens when tumors are located in the midline and close to the central airways. It may also occur when tumors invade lymph nodes in the midline area.
10. Hemoptysis
It means coughing up blood, and it is an advanced symptom in lung cancer because plenty of blood vessels are being formed to help the tumor grow larger. These new blood vessels created around cancer have a fragile lining that breaks very easily. Cough is usually what damages the blood vessels, and patients stain their tissue in the blood.
11. Irritation of the airways
Even if there is no blood, patients can have a persistent irritation of the airways. This is more evident around the tumor because it prompts a localized inflammatory response. But as the disease progresses, the inflammation can take a larger area of the lungs and irritate the airways.
12. Airway collapse
A distinct feature of the lungs is that they are made up of empty spaces that should remain empty for air to pass through. This is true in the airways and the bronchioles/alveoli. When the airways or the bronchioles/alveoli collapse, the walls come close together or stick to one another, compromising the airflow. The inflammatory response and the tumor itself can cause a collapse of the airways, the bronchioles, or the alveoli.
13. Higher risk of infectious diseases
Patients with lung cancer have an immunity problem because the immune system is overwhelmed by the tumor and the metabolic issues caused by cancer cells. Thus, patients with lung cancer are more commonly affected by viral and bacterial infections of the respiratory tract.
Symptoms of lung cancer metastasis into the thoracic cavity
Lung cancer can spread to nearby or distant organs in late-stage disease. In the case of small cell lung cancer, metastasis is much more common and aggressive. But even in these cases, the thoracic cavity is usually the most compromised. Lung cancer starts to spread to nearby tissues and will begin to give out symptoms depending on the structures it comes across.
The most important signs and symptoms include:
14. Hoarseness
This happens in patients with lung cancer in the midline or very close to the midline. They have changes in their voice tone and can complain of hoarseness. This is because the laryngeal nerve is compressed. This nerve comes from the vagus nerve and runs very low to go back up and reach the larynx. The left recurrent laryngeal nerve is more susceptible to compression because it is further down in the thorax.
15. Breathing muscle paralysis
Another nerve that can be affected by the growth of lung cancer is the phrenic nerve. This nerve is born further down and mediates the function of the diaphragm. This is the most important breathing muscle. When the phrenic nerve is affected, weakness of the diaphragm muscle can cause severe breathing difficulties.
16. Dysphagia
It means difficulty or pain when trying to swallow food. In more severe cases, even drinking water can be uncomfortable. This happens because very large tumors located on the midline compress the esophagus. This is the part of the digestive tube that connects the mouth and the stomach. Other causes of dysphagia, such as GERD, should be excluded, but a simple radiograph can be enough to see the lesion and diagnose the disease.
17. Stridor
This is a characteristic breathing sound in patients with a large tumor in the midline. It is a high-pitched sound produced when the major airways are compressed. It can also be made by another type of airway obstruction or a clog of secretions produced by patients with COPD.
18. Swollen lymph nodes
We mentioned that some lymph nodes could be taken in advanced lung cancer as one of the first types of metastasis. These are the mediastinal lymph nodes, which are located in the midline. These lymph nodes are important to protect the lungs from infections, and that’s how they are invaded by cancer cells. You can’t see swollen lymph nodes, which can cause respiratory difficulty, stridor, or dysphagia. They can be seen in imaging tests because they are very deep inside the thorax.
19. Swelling of the arms
In some cases, there is also an obstruction of the venous or lymphatic flow. When this happens, the liquid can’t return to the heart and continue the normal flow. So, it accumulates in the arms or the face causing swelling and edema.
Symptoms of lung cancer metastasis outside of the thoracic cavity
Cancer can also spread outside the thoracic cavity in a more advanced stage of the disease. Metastasis to distant organs happens because the lungs are in contact with the bloodstream. Cancer cells dislodge from the primary tumor and travel via the blood vessels to other organs. Depending on each organ, there’s a higher or lower chance of receiving lung cancer cells like seeds of new tumors. The most likely organs that metastasize include the bone and the brain.
Depending on which organ is affected by the spread and how it happens, the symptoms of lung cancer metastasis can be highly variable. They may include:
20. Headache
In case of metastasis to the brain, headache is one of the leading symptoms. It can be located in a specific area or can be dull and difficult to identify.
21. Confusion
Patients may also have changes in their level of consciousness, mainly when metastasis is deeply rooted in the brain. It also depends on which area is taken by the disease. Patients can be lethargic, have a poor response, or become confused.
22. Photophobia
This is the clinical term to describe an increase in light sensitivity. Patients prefer a dark room because light makes them feel uncomfortable and sometimes prompts a headache.
23. Blurred vision
When the occipital area or the visual fields are affected by metastasis, patients may also report visual problems and blurred vision. In some cases, a portion of the visual field is gone.
24. Slurred speech
Patients may also have speech difficulties for many reasons. The motor area responsible for speech movements can be affected by metastasis. Also, the connections accountable for coordinating speech can be affected, causing disordered or incoherent speech.
25. Muscle weakness
The motor cortex in the brain is responsible for the movements of most parts of the body. Metastasis in this brain area can cause motor problems and muscle weakness. Similarly, metastasis in the spinal cord can lead to severe muscle weakness or complete paralysis, especially in the limbs.
26. Sensory abnormalities
There is also a sensory region of the brain that receives impulses from the skin. Metastasis in these areas causes sensory problems in a given area. The same happens with metastasis in the spinal cord. Sensory abnormalities can also include hypersensitivity, a burning sensation on the skin, among others.
27. Back pain
In the case of spinal cord compression, another important symptom is back pain. It is usually located in the lower back, and the motor or sensory function of the limbs can be affected, too.
28. Bone pain
The main symptom of metastasis in the bone is bone pain. It can be located in a single bone, and the most commonly affected areas are long bones, the spine, and the ribs. The pain can be dull and difficult to locate or sharp and very specific to a single location.
Conclusion
Lung cancer is not rare. It is actually one of the most common types of cancer in different parts of the world. But it is also a preventable cause of cancer when patients stop smoking.
Smoking is perhaps the most relevant risk factor for lung cancer because it causes inflammation and transports carcinogen substances to the lungs. That’s why on the second Wednesday of March, people celebrate a “no smoking day” in the United Kingdom and other parts of the world.
Besides not smoking, it is also essential to avoid passive smoking. It would help if you also avoided other environmental triggers, including smog and occupational exposure to carcinogens.
Treatment of lung cancer usually involves surgery to remove the tumor. But in most cases, this is done after chemotherapy or radiotherapy reduces the size of the tumor. Radiotherapy, chemotherapy, and immunotherapy can also help fight off advanced tumors which already spread to other tissues. In most cases, home remedies can also be used to reduce stress and anxiety.