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Things to Know About Lung Cancer Symptoms vs. Asthma
Lung cancer includes a group of diseases in which lung cells exhibit abnormal and uncontrolled growth starting the lungs, while asthma is a disease caused by inflammation and/or mucus that decreases or blocks the breathing passages (bronchioles) of the lungs.
Asthma is usually an acute problem triggered by many different substances, mainly affecting the lungs. Lung cancer is an ongoing disease that can metastasize (spread) to other organs like the liver, bones or the brain. Asthma is considered a part of a lung condition termed chronic obstructive pulmonary disease (COPD), while lung cancer is not considered a part of COPD.
Both lung cancers and asthma can have symptoms of cough and shortness of breath; wheezing usually is associated with asthma, while chest pain and coughing up blood are more associated with lung cancers.
About 90% of lung cancers are associated with smoking, while causes or triggers of asthma vary from individual to individual (for example, exercise-induced asthma, chemical-induced asthma, and many others). The exact cause of asthma is not known.
Many asthma attacks can self-resolve or resolve with medication (inhalers); lung cancers do not resolve and require extensive medical treatments and/or surgery. Severe lung cancers (especially those that metastasize or are stages III and IV) can be fatal.
The main risk factor for developing lung cancer is smoking. In contrast, the risk factors for developing asthma include any allergies (for example, eczema or hay fever) and genetic disposition (family members with asthma).
Life expectancy is reduced in individuals with late-stage lung cancers. Depending upon the type of lung cancer, about 15% may survive 5 or more years after diagnosis. Patients with mild to moderate asthma attacks, on the other hand, usually have a normal life expectancy with treatment.
What Is Lung Cancer?
Lung cancer is a group of diseases characterized by abnormal growths (cancers) that started in the lungs.
Lung cancer is the leading cause of cancer deaths in women and men both in the United States and throughout the world. Lung cancer has surpassed breast cancer as the leading cause of cancer deaths in women for the past 25 years. In the United States, there are more deaths due to lung cancer than the number of deaths from colon and rectal, breast, and prostate cancer combined.
If lung cancer is found at an early stage, at least half of such patients will be alive and free of recurrent cancer five years later. Once lung cancer has metastasized, that is, spread to other distant organs, the five-year overall survival is less than 5%.
Cancer occurs when normal cells undergo a transformation that causes them to grow abnormally and multiply without control and potentially spread to other parts of the body. The cells form a mass or tumor that differs from the surrounding tissues from which it arises. Cancers are also called malignant tumors. Such tumors are dangerous because they take oxygen, nutrients, and space from healthy cells and because they invade and destroy or reduce the ability of normal tissues to function.
Most lung tumors are malignant. This means that they invade and destroy the healthy tissues around them and can spread throughout the body. The lung is a bad place for a cancer to arise because it contains a very rich network of both blood vessels and lymphatic channels through which cancer cells can spread.
The specific types of primary lung cancers are as follows:
- Adenocarcinoma (an NSCLC) is the most common type of lung cancer, making up 30%-40% of all cases. A subtype of adenocarcinoma is called bronchoalveolar cell carcinoma, which creates a pneumonia-like appearance on chest X-rays.
- Squamous cell carcinoma (an NSCLC) is the second most common type of lung cancer, making up about 30% of all cases.
- Large cell cancer (another NSCLC) makes up 10% of all cases.
- SCLC makes up 20% of all cases.
- Carcinoid tumors account for 1% of all cases.
What Is Asthma?
Asthma is a disease that affects the breathing passages of the lungs (bronchioles). Asthma is caused by chronic (ongoing, long-term) inflammation of these passages. This makes the breathing tubes, or airways, of the person with asthma highly sensitive to various "triggers."
- When the inflammation is "triggered" by any number of external and internal factors, the walls of the passages swell, and the openings fill with mucus.
- Muscles within the breathing passages contract (bronchospasm), causing even further narrowing of the airways.
- This narrowing makes it difficult for air to be breathed out (exhaled) from the lungs.
- This resistance to exhaling leads to the typical symptoms of an asthma attack.
Because asthma causes resistance, or obstruction, to exhaled air, it is called an obstructive lung disease. The medical term for such lung conditions is chronic obstructive pulmonary disease or COPD. COPD is actually a group of diseases that includes not only asthma but also chronic bronchitis and emphysema. Some people with asthma do not have COPD. These are the individuals whose lung function returns to normal when they are not having an attack. Others will have a process of lung airway remodeling from chronic, long-standing inflammation, usually untreated. This results in permanent abnormalities of their lung function with symptoms of obstructive lung disease occurring all the time. These people are categorized as having one of the class of diseases known as COPD.
Like any other chronic disease, asthma is a condition you live with every day of your life. You can have an attack any time you are exposed to one of your triggers. Unlike other chronic obstructive lung diseases, asthma is reversible.
What Are the Symptoms of Lung Cancer?
Up to one-fourth of all people with lung cancer may have no symptoms when the cancer is diagnosed. These cancers usually are identified incidentally when a chest X-ray is performed for another reason. The majority of people, however, develop symptoms. The symptoms are due to direct effects of the primary tumor, to effects of metastatic tumors in other parts of the body, or to disturbances of hormones, blood, or other systems caused by the cancer.
Symptoms of primary lung cancers include cough, coughing up blood, chest pain, and shortness of breath.
- A new cough in a smoker or a former smoker should raise concern for lung cancer.
- A cough that does not go away or gets worse over time should be evaluated by a health care professional.
- Coughing up blood (hemoptysis) occurs in a significant number of people who have lung cancer. Any amount of coughed-up blood is cause for concern.
- Chest pain is a symptom in about one-fourth of people with lung cancer. The pain is dull, aching, and persistent.
- Shortness of breath usually results from a blockage to the flow of air in part of the lung, collection of fluid around the lung (pleural effusion), or the spread of tumor throughout the lungs.
- Wheezing or hoarseness may signal blockage or inflammation in the lungs that may go along with cancer.
- Repeated respiratory infections, such as bronchitis or pneumonia, can be a sign of lung cancer.
Symptoms of metastatic lung tumors depend on the location and size. About 30%-40% of people with lung cancer have some symptoms or signs of metastatic disease.
- Lung cancer most often spreads to the liver, the adrenal glands, the bones, and the brain.
- Metastatic lung cancer in the liver may cause a loss of appetite, feeling full early on while eating, and otherwise unexplained weight loss.
- Metastatic lung cancer in the adrenal glands also typically causes no symptoms.
- Metastasis to the bones is most common with small cell cancers but also occurs with other lung cancer types. Lung cancer that has metastasized to the bone causes bone pain, usually in the backbone (vertebrae), the large bones of the thigh (the femurs), the pelvic bones, and the ribs.
- Lung cancer that spreads to the brain can cause difficulties with vision, weakness on one side of the body, and/or seizures.
- Paraneoplastic syndromes are the remote, indirect effects of cancer not related to direct invasion of an organ by tumor cells. Often they are caused by chemicals released from the cancers. Symptoms include the following:
- Clubbing of fingers -- the depositing of extra tissue under the fingernails
- New bone formation -- along the lower legs or arms
- Increased risk of blood clots in the arms, legs, or lungs
- Low sodium levels
- High calcium levels
- Low potassium levels
Degenerative conditions of the nervous system otherwise unexplained.
What Are the Symptoms of Asthma?
When the breathing passages become irritated or infected, an attack is triggered. The attack may come on suddenly or develop slowly over several days or hours. The main symptoms that signal an attack are as follows:
- chest tightness,
- coughing, and
- difficulty speaking.
Symptoms may occur during the day or at night. If they happen at night, they may disturb your sleep. Wheezing is the most common symptom of an asthma attack.
- Wheezing is a musical, whistling, or hissing sound with breathing.
- Wheezes are most often heard during exhalation, but they can occur during breathing in (inhaling).
- Not all asthmatics wheeze, and not all people who wheeze are asthmatics.
Current guidelines for the care of people with asthma include classifying the severity of asthma symptoms, as follows:
- Mild intermittent: This includes attacks no more than twice a week and nighttime attacks no more than twice a month. Attacks last no more than a few hours to days. Severity of attacks varies, but there are no symptoms between attacks.
- Mild persistent: This includes attacks more than twice a week, but not every day, and nighttime symptoms more than twice a month. Attacks are sometimes severe enough to interrupt regular activities.
- Moderate persistent: This includes daily attacks and nighttime symptoms more than once a week. More severe attacks occur at least twice a week and may last for days. Attacks require daily use of quick-relief (rescue) medication and changes in daily activities.
- Severe persistent: This includes frequent severe attacks, continual daytime symptoms, and frequent nighttime symptoms. Symptoms require limits on daily activities.
Just because a person has mild or moderate asthma does not mean that he or she cannot have a severe attack. The severity of asthma can change over time, either for better or for worse.
What Causes Lung Cancer?
Cigarette smoking is the most important cause of lung cancer. Research as far back as the 1950s clearly established this relationship.
- Cigarette smoke contains more than 4,000 chemicals, many of which have been identified as causing cancer.
- A person who smokes more than one pack of cigarettes per day has a 20-25 times greater risk of developing lung cancer than someone who has never smoked.
- Once a person quits smoking, his or her risk for lung cancer gradually decreases. About 15 years after quitting, the risk for lung cancer decreases to the level of someone who never smoked.
- Cigar and pipe smoking increases the risk of lung cancer but not as much as smoking cigarettes.
About 90% of lung cancers arise due to tobacco use. The risk of developing lung cancer is related to the following factors:
- The number of cigarettes smoked
- The age at which a person started smoking
- How long a person has smoked (or had smoked before quitting)
Other causes of lung cancer, including causes of lung cancer in nonsmokers, include the following:
- Passive smoking, or secondhand smoke, presents another risk for lung cancer. An estimated 3,000 lung cancer deaths occur each year in the U.S. that are attributable to passive smoking.
- Air pollution from motor vehicles, factories, and other sources probably increase the risk for lung cancer, and many experts believe that prolonged exposure to polluted air is similar to prolonged exposure to passive smoking in terms of risk for developing lung cancer.
- Asbestos exposure increases the risk of lung cancer nine times. A combination of asbestos exposure and cigarette smoking raises the risk to as much as 50 times.
Another cancer known as mesothelioma (a type of cancer of the inner lining of the chest cavity and the outer lining of the lung called the pleura, or of the lining of the abdominal cavity called the peritoneum) is also strongly associated with exposure to asbestos.
- Lung diseases, such as tuberculosis (TB) and chronic obstructive pulmonary disease (COPD), also create a risk for lung cancer. A person with COPD has a four to six times greater risk of lung cancer even when the effect of cigarette smoking is excluded.
- Radon exposure poses another risk.
- Radon is a byproduct of naturally occurring radium, which is a product of uranium.
- Radon is present in indoor and outdoor air.
- The risk for lung cancer increases with significant long-term exposure to radon, although no one knows the exact risk. An estimated 12% of lung cancer deaths are attributable to radon gas, or about 21,000 lung cancer-related deaths annually in the U.S. Radon gas is the second leading cause of lung cancer in the United States after cigarette smoking. As with asbestos exposure, smoking greatly increases the risk of lung cancer with radon exposure.
- Certain occupations where exposure to arsenic, chromium, nickel, aromatic hydrocarbons, and ethers occurs may increase the risk of lung cancer.
- A person who has had lung cancer is more likely to develop a second lung cancer than the average person is to develop a first lung cancer.
What Causes Asthma?
The exact cause of asthma is not known.
- What all people with asthma have in common is chronic airway inflammation and excessive airway sensitivity to various triggers.
- Research has focused on why some people develop asthma while others do not.
- Some people are born with the tendency to have asthma, while others are not. Scientists are trying to find the genes that cause this tendency.
- The environment you live in and the way you live partly determine whether you have asthma attacks.
An asthma attack is a reaction to a trigger. It is similar in many ways to an allergic reaction.
- An allergic reaction is a response by the body's immune system to an "invader."
- When the cells of the immune system sense an invader, they set off a series of reactions that help fight off the invader.
- It is this series of reactions that results in inflammation of the lining of the air passages. This can result in a modification of the cell types lining these airways. More glandular-type cells develop, which can cause the production of mucus. This mucus, along with irritation to muscle receptors in the airways, can cause bronchospasm. These responses cause the symptoms of an asthma attack.
- In asthma, the "invaders" are the triggers listed below. Triggers vary among individuals.
- Because asthma is a type of allergic reaction, it is sometimes called reactive airway disease.
Each person with asthma has his or her own unique set of triggers. Most triggers cause attacks in some people with asthma and not in others. Common triggers of asthma attacks include
- exposure to tobacco or wood smoke;
- breathing polluted air;
- inhaling other respiratory irritants such as perfumes or cleaning products;
- exposure to airway irritants at the workplace;
- breathing in allergy-causing substances (allergens) such as molds, dust, or animal dander;
- an upper respiratory infection, such as a cold, flu, sinusitis, or bronchitis;
- exposure to cold, dry weather;
- emotional excitement or stress;
- physical exertion or exercise;
- reflux of stomach acid known as gastroesophageal reflux disease, or GERD;
- sulfites, an additive to some foods and wine; and
- menstruation. (In some, not all, women, asthma symptoms are closely tied to the menstrual cycle.)
Risk factors for developing asthma include
What Is the Treatment for Lung Cancer?
Treatment decisions in lung cancer depend first on whether SCLC or NSCLC is present. Treatment also depends on tumor stage. In NSCLC, the performance status of the patient is a key determinant of the likelihood of benefit from treatment. Performance status compares the patient's functional status -- how well they are doing as compared to their pre-illness levels of day to day activity. Risk of side effects and complications increase and chance of benefit decreases with declining performance status. In SCLC, a rapid response to treatment occurs often enough to overcome this issue.
The most commonly used treatments today for lung cancer involve surgery, radiation therapy, chemotherapy, and targeted therapies.
In SCLC (small cell lung cancer), patients with limited disease at presentation (disease confined to one lung and its regional lymph nodes) are distinguished from those with extensive stage disease, which includes all cases not classified as limited. Limited stage disease, treated with radiation and chemotherapy (including prophylactic, or preventative, brain radiation therapy), will frequently have all evidence of disease disappear for a time and are said to enter remission. About 80% will relapse within 2 years, but as many as 10% to 15% may survive 5 or more years.
In extensive stage SCLC, response to chemotherapy and palliative radiation occurs less frequently, and survival beyond 2 years is rare. Median survival is about 13 months.
In NSCLC, non-small cell lung cancer, those patients deemed medically inoperable may be treated with curative intent with radiation therapy with 5-year survival in early stage disease from 10%-25%.
In advanced stage, inoperable stages IIIB and IV NSCLC, treatment remains non-curative, but palliative radiation therapy and chemotherapy can provide meaningful symptom improvement and prolongation of life as compared to only supportive care.
The use of targeted therapies in NSCLC has been of increasing importance especially in adenocarcinoma of the lung. Agents with lower levels of toxicity and efficacy at least as good as chemotherapy have been identified which can be utilized in patients whose cancer cells show mutations in specific genes. In addition, the use of agents targeted to other features of lung cancer, such as tumor factors to recruit blood vessels to support their growth, have been developed and have proven advantageous in the palliative treatment of NSCLC.
Side effects of radiation therapy vary with the area being treated, the dose being given, and the type of radiation technique and equipment being used.
Side effects of chemotherapy again vary with the drug being given, the dose being used, and the patient's unique sensitivity to the type of chemotherapy selected. There are a wide variety of both chemotherapies and targeted agents that may be tried in these cases.
Finally, preventive or adjuvant chemotherapy, has been utilized in operable stages of NSCLC in an attempt to eradicate microscopic, hidden deposits of lung cancer that may have escaped prior to surgery, and remain undetectable for now but will cause relapse later if not killed. While not of proven use in stage I NSCLC, it does appear to be of potential benefit in stages II and IIIA disease.
Surgery is the preferred treatment for patients with early stage NSCLC. Unfortunately, a majority of patients have advanced or metastatic disease and are not suitable candidates for surgery after completing their staging evaluation.
- People who have NSCLC that has not spread can tolerate surgery provided they have adequate lung function.
- A portion of a lobe, a full lobe, or an entire lung may be removed. The extent of removal depends on the size of the tumor, its location, and how far it has spread.
- Cure rates for small cancers at the edges of the lung are around 80%.
- Despite complete surgical removal, many patients with early stage cancer have a recurrence of the cancer and die from it either due to local recurrence, distant metastases, or both.
Surgery is not widely used in SCLC. Because SCLC spreads widely and rapidly through the body, removing it all by surgery usually is impossible.
An operation for lung cancer is major surgery. Many people experience pain, weakness, fatigue, and shortness of breath after surgery. Most have problems moving around, coughing, and breathing deeply. The recovery period can be several weeks or even months.
What Is the Treatment for Asthma?
Since asthma is a chronic disease, treatment goes on for a very long time. Some people have to stay on treatment for the rest of their lives. The best way to improve your condition and live your life on your terms is to learn all you can about your asthma and what you can do to make it better.
- Become a partner with your health care provider and his or her support staff. Use the resources they can offer -- information, education, and expertise -- to help yourself.
- Become aware of your asthma triggers and do what you can to avoid them.
- Follow the treatment recommendations of your health care provider. Understand your treatment. Know what each drug does and how it is used.
- See your health care provider as scheduled.
- Report any changes or worsening of your symptoms promptly.
- Report any side effects you are having with your medications.
These are the goals of treatment:
- prevent ongoing and bothersome symptoms;
- prevent asthma attacks;
- prevent attacks severe enough to require a visit to your provider or an emergency department or hospitalization;
- carry on with normal activities;
- maintain normal or near-normal lung function; and
- have as few side effects of medication as possible.
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Fanta, C. "Asthma." NEJM 360 (2009): 1002-1014.
Santacroce, Luigi. "Paraneoplastic Syndromes." Medscape.com. Jan. 12, 2021. <http://emedicine.medscape.com/article/280744-overview>.
United States. National Cancer Institute, U.S. National Institutes of Health. "What You Need to Know About Lung Cancer." July 2012. <http://www.cancer.gov/cancertopics/types/lung>.