Lung Cancer Awareness Month is observed every November to draw attention to the malignant tumor, which is the leading cause of cancer deaths in the United States.

It is the third most common type of cancer in the U.S. Nearly 240,000 Americans will be diagnosed with lung cancer this year, according to the American Cancer Society.

"During National Lung Cancer Awareness Month, we honor the resilient people who have faced this diagnosis, the loved ones who rally to their side, and the medical professionals who do all they can to help patients survive and heal," a White House news release read.

This year's theme, "Education, Empowerment, and Eradication" aims to create public awareness about the importance of screening, early diagnosis and preventive measures. By investing in new, affordable ways for prevention, detection and treatment, officials aim to put an end to the deadly disease.

To promote greater awareness about lung cancer, Dr. Arjan Singh Flora, an interventional pulmonologist at Memphis VA Medical Center, Tennessee, explains some common misconceptions about the disease.

Myth #1: Lung cancer is a smoker's disease

Fact: Non-smokers can also get lung cancer.

While smoking is the number one risk factor for lung cancer, nonsmokers who are exposed to carcinogens such as radon, asbestos and vinyl chloride are also at high risk.

"Around 80-90% of lung cancers are associated with a history of cigarette smoking. The other 10-20%, however, can be related to a family history of lung cancer (for example, inherited mutations) or exposures to second-hand smoke, radon gas, occupational exposures to cancer-causing agents and indoor and outdoor air pollution," Dr. Flora said.

Myth #2: Once you smoke, there is no use quitting

Fact: It's never too late to quit, positive results are almost immediate.

Once a person stops smoking, the body shows immediate changes. Within just 20 minutes of quitting, both blood pressure and heart rate start to decrease, and within a few days, carbon monoxide levels return to normal. Lung function improves between two weeks and three months of quitting.

"While it is true that the risk of developing lung cancer after quitting smoking still exists, the added risk of developing lung cancer drops by half after 10-15 years of quitting. Even if a former smoker develops lung cancer, the prognosis is better compared to those who continue smoking," Dr. Flora said.

Apart from lung cancer, smokers who quit the habit also cut the risk of oral and laryngeal cancer by half in five to 10 years. After two decades of being smoke-free, their risk becomes equivalent to that of someone who never smoked. Furthermore, stopping smoking helps reduce all-cause mortality, by cutting the risk associated with heart attacks and strokes, Dr. Flora explained.

Myth #3: Lung cancer screening increases risk of cancer

Fact: For heavy smokers who are already at high risk, screening decreases the risk of death from lung cancer.

Screening using low-dose computerized tomography (LDCT) is the best way for early detection of lung cancer in people at high risk. Detecting lung cancer before it advances improves the chances of recovery.

"The amount of radiation from an LDCT scan is 1/5 (20%) of the amount from a standard chest CT, and about the same as the average person would receive in six months from natural background radiation living on Earth," Dr. Flora said.

However, since screening tests carry a certain amount of risk associated with radiation, they are typically reserved for people at high risk.

"As such, there is a valid concern from patients regarding radiation exposure leading to cancer. This is why we do not screen healthy, young, non-smokers. Those who are at high risk (aged 50-80 years, with a 20-pack-year smoking history, and are current smokers or quit within the past 15 years) are at a significantly higher risk of dying from lung cancer than they are from developing cancer as a result of radiation," Dr. Flora added.

Myth #4: If you don't have symptoms, you don't have lung cancer

Fact: By the time symptoms appear, lung cancer might have spread.

"Lung cancer is an insidious disease – you may have it and not even know it. There are no pain receptors in the lung, so a tumor can grow without causing pain or discomfort." Dr. Flora noted.

For high-risk individuals, the best way for lung cancer detection is to go for screening, as by the time symptoms appear, the cancer might have advanced. Many symptoms of lung cancer can also be mistaken as signs of less serious diseases.

"As such, if symptoms have developed, the cancer has possibly already spread – and thus we screen to catch lung cancer at its earliest stages," the doctor added.

Signs such as chronic cough, coughing up blood, wheezing and shortness of breath occur when the tumor has already advanced to the stage where it compresses the airways of the lungs. A patient may experience fatigue, weakness, unintentional weight loss and muscle wasting when the burden of the tumor is significant enough to consume more energy from the body than the calories taken in, Dr. Flora explained.