Lung cancer is the most common type of cancer and the leading cause of cancerous deaths among males and females in the United States and across the globe. According to the American Cancer Association, approximately 234,030 new cases of lung cancer are being diagnosed every year and about 154,050 deaths occur due to lung cancer. Interestingly, lung cancer causes more deaths per year compared to those caused by prostate, ovarian, colon, and breast cancers collectively.
Lung cancer begins in the lungs and either involves lung parenchyma (the functional part) or coverings. According to the type of tissue involved, the lung cancers are further divided into;
- Adenocarcinoma (40 percent of lung cancers)
- Squamous Cell Carcinoma (25 and 30 percent of lung cancers)
- Large cell carcinomas
- Non-Small Cell Lung Carcinoma
Active smoking (people who actually smoke) and passive smoking (people who have never smoked, but remain in the company of smokers for a long period or a considerable time) are the two major risk factors for lung cancer. When it comes to signs and symptoms, most lung cancers are asymptomatic especially in the initial stages and only show symptoms after they spread to involve other body tissues.
However, a few signs and symptoms may indicate the development of lung cancer in the early or middle stages. These include;
1) Sudden onset or change in cough
The majority of people ignore a new onset of cough and put off investigations, considering it may be due to simple flu or cold. Your cough could be harmless when it is short-lived and resolve spontaneously or with over-the-counter medications within several days to one week. However, a recent attack of cough episodes that persist for more than 3 weeks or a change in a pre-existing cough (e.g., smoker’s cough) can be warning signs of lung cancer.
It is of special importance when your cough is associated with fluid, a change in color of the sputum or presence of blood (a sign medically known as “hemoptysis”). Hemoptysis is considered a red flag sign for the presence of lung cancer, especially if it is associated with other risk factors like active or passive smoking. You should immediately consult your health care provider in case you experience new and persistent episodes of cough or any change in chronic cough for evaluation of the underlying cause.
2) Breathing changes
As the lungs are associated with breathing, any pathology occurring in the lungs may cause certain changes in the breathing pattern. If you are exerting yourself or exercising, you will naturally become short of breath. However, a positive sign of lung cancer could be shortness of breath or gasping breathing pattern (one that you experience after running or heavy exercise), especially after performing activities you normally perform every day such as doing one flight of stairs or just walking from one room to another. This indicates that something is wrong with your functional part of the lungs.
Of note, the change in the breathing pattern could be due to multiple other reasons such as severe anemia, pregnancy, ischemic heart diseases, or non-cancerous causes of the lungs, e.g., asthma, pulmonary embolism, chronic bronchitis, bronchiolitis, pulmonary tuberculosis, infections of the respiratory tract, or inhalation of foreign bodies into the lungs. Therefore, it is important to have a proper checkup from pulmonologists or cardiologist to investigate and exclude the non-cancerous causes.
3) Wheezing
Wheeze is a typical whistling sound that produces when air passes through congested, inflamed or blocked airways. The most common cause of wheeze is asthma or pneumonia followed by some other benign conditions of the lungs that are easily treatable.
However, wheezing can be due to the presence of cancer in the lungs as the cancerous mass can put pressure on the lung tissues and cause congestion or blockage of the airways. So don’t assume that your whistling sounds are due to allergies or asthma and let your doctor evaluate the root cause.
4) Chronic Mucus Production
Also called phlegm or sputum, mucus is produced by a special type of tissues in the lungs, and it serves as a defense against irritants, dust particle, and pathogens. Although mucus production is a normal and healthy process, excessive production lasting a month or longer can possibly be a sign of lung cancer.
The hallmark of lung cancer is the production of red or rusty sputum (due to the presence of blood in it). If you are experiencing excessive mucus production along with other symptoms of lung disease, don’t waste your time to get yourself checked by a physician.
5) Weight changes
A significant amount of unexplained weight loss in the short time could be a warning sign of lung cancer, especially when it is associated with other signs and symptoms such as chronic cough and wheeze.
A similar type of weight changes occurs in pulmonary tuberculosis, an infectious disease caused by a bacterium. So if you experience certain weight changes without trying, bring them to your physician’s attention immediately.
6) Pain
Pain is a non-specific symptom and can come in various forms and due to various inflammatory, infectious, traumatic reasons. However, a characteristic pattern of pain that includes a new and persistent pain in your chest that radiates towards your shoulders or back can be a warning sign of lung cancer.
Chest pain is a symptom that indicates that something is wrong with your lungs and your body is trying to overcome this issue. Even if your pain is non-radiating and confined to the chest, you should consult your doctor to evaluate the underlying cause.
7) Loss of Appetite
Loss of appetite or anorexia is a common sign in lung cancer patients. It occurs due to release of chemicals and hormones in the body that suppress the hunger center in the brain. Loss of appetite could be the main reason behind a sudden weight loss and also be associated with some other things such as jaw pain, dry mouth, or mouth sores.
8) Bone and Muscle Pains
One may wonder what is the relationship between lung cancer and bone pain. Well, it is true that the majority of lung cancers can cause bone and muscle pains, especially in the back, shoulder, and muscles of limbs.
This is due to the spread of cancerous cells to the bones and muscles. The characteristic pattern of bone pains due to lung cancer is that it gets worse with movement and at night.
9) Headaches
This is not an early sign of lung cancer. In this cancer, headache often appears when there is already metastasis of cancer to the brain. According to recent clinical trials, pulmonologists have found that not all headaches are due to the spread of cancer to the brain. Some are due to the continuous build-up of pressure on the neck and chest veins, especially an external jugular vein and superior cava.
These are large blood vessels that transport blood from the upper body (skull, face, and neck) to the heart. A specific type of lung cancer called non-small cell carcinoma is associated with causing migraines.
10) Nervous system problems
Some type of lung cancers can cause problems in the nervous system by attacking the body’s own immune system. This can lead to weakness of the muscle groups, numbness in the extremities, tingling sensations over the body, and in severe cases, paralysis.
A characteristic example of a nervous system attack on lung cancer is Lambert-Eaton syndrome, which typically involves the muscles of the hips and causes weakness and muscle wasting. In this syndrome, one of the first signs is the loss of balance and unsteadiness in the arm and legs that causes trouble getting up from the sitting position. Later, the group of muscles around the shoulder and back may become week followed by the weakness of facial muscles.
11) Hypercalcemia
It means the presence of high calcium levels in the blood. It happens in lung cancer when it spreads to the bones, thus causing the breaking of the bones and bone resorption. Hypercalcemia, when developed, may cause nausea, vomiting, belly pain, frequent urination, thirst, constipation, fatigue, weakness, confusion, dizziness, and other nervous system problems.
One important point related to hypercalcemia is that it is associated with poor prognosis (the survival rate) of lung cancer as it interferes with body metabolism and chemotherapy drugs.
12) Blood Clots
Formation of blood clots in the lung vessels is not a specific symptom of lung cancer. It’s rather a complication that can further lead to various health problems. The clot can transfer into an embolus and travel from the lungs to other parts of the body such as heart, brain and blood vessels of the lower extremities.
The site where blood clot travels and blocks the blood vessels can cause severe problems like a heart attack, stroke, pulmonary embolism or deep venous thrombosis. These are potentially life-threatening conditions and may cause death or permanent disability.
13) Horner syndrome
Pancoast tumors (cancers that affect the upper area of the lungs) can affect specific nerves in the neck, eyes, and other parts of the face and thus leads to Horner syndrome. This syndrome is characterized by
- A smaller pupil in the same eye
- Drooping or weakness of one eyelid
- Severe neck and shoulder pain
- Reduced or absent sweating on the same side of the face
This syndrome may also cause weakness of the facial muscles that results in drooping of saliva from the mouth, inability to speak and difficulty in swallowing food.
14) Superior Vena Cava Syndrome
The superior vena cava (SVC) is the major blood vessel that receives blood from the upper part of the body and drains directly into the heart (right atrium). As it passes next to the lymph nodes in the chest and apices (upper part) of the right lung, the lung tumors in the apical area (such as Pancoast tumors) can put pressure on it and leads to the accumulation of backflow of blood in the vein. This backflow of the blood causes swelling and cyanosis (bluish discoloration) in the neck, face, upper chest, and arms.
In severe cases, the SVC syndrome may also cause dizziness, headaches, migraines, and a change in the conscious level. While this syndrome develops gradually over time, in some cases it may become severe and life-threatening much earlier than expected and thus needs immediate medical attention to be treated right away.
15) Paraneoplastic Syndromes
Other than physical and pressure symptoms discussed ahead, some types of lung cancers also cause problems with distant tissues and organs due to the production of certain hormone-like substances that enter the bloodstream.
These remote signs and symptoms due to these chemicals are collectively called paraneoplastic syndrome. According to some experts, paraneoplastic symptoms could be the first symptoms that appear in lung cancer patients because it affects organs other than the lungs. The two most common paraneoplastic syndromes associated with lung cancer include;
1. Cushing Syndrome
This syndrome occurs due to the presence of excess ACTH (adrenocorticotropic hormone) in the blood. ACTH further increases the production of cortisol, a hormone that acts on the adrenal glands and causes Cushing syndrome. This syndrome is characterized by multiple symptoms that can affect your body from head to toe.
Its most common symptoms are weight gain, muscle weakness, easy bruising, moon-like face, a collection of fat at the back (buffalo hump), coarse hair, restlessness, confusion, dizziness, and fatigue. The most troublesome symptoms of Cushing syndrome include high blood sugar levels and high blood pressure.
2. SIADH (syndrome of inappropriate anti-diuretic hormone)
The cause of this syndrome is similar to the Cushing syndrome, i.e., cancerous cells in the lungs produce certain hormone-like substances that further act on distant tissues to cause problems. The hormone-like substance in this syndrome is ADH (anti-diuretic hormone), which affects the kidneys. ADH causes kidneys to retain water in the body that leads to an increase in blood volume as well as a decrease in salt levels in the body.
This metabolic shift in the body is called SIADH. The common symptoms of this syndrome include loss of appetite, fatigue, muscle weakness and cramps, nausea, vomiting, and diarrhea. If left untreated, it may lead to seizures, coma, and death.