Lung cancer screening opens to more Americans — should Canada follow? What to know about the disease

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While lung cancer death rates drop across Canada and the United States, the American Cancer Society (ACS) is expanding its screening guidelines for the disease.

At the start of November, which is Lung Cancer Awareness Month, the ACS announced people within a greater age range would be able to get lung cancer screenings, marking its first update in a decade.

The new guidelines recommend annual lung cancer screenings for Americans between ages 50 and 80 who currently smoke or formerly smoked and have a 20 pack-year history. A pack-year is defined as smoking an average of one pack of cigarettes per day for one year.

The previous guidelines were set in 2013, and prompted people between 55 to 74 years old get a screening if they they smoked or quit smoking less than 15 years ago and had a 30 pack-year smoking history. The Canadian Task Force on Preventive Health Care implemented that same guideline in 2016.

Calgary-based family physician Dr. Raj Bhardwaj told CBC News that Canada will likely follow these updated guidelines at some point, but it's a "big review process."

A report released last week by the Canadian Cancer Society indicated lung cancer deaths have dropped by 4.3 per cent per year since 2014 for men, and 4.1 per cent per year since 2016 for women in the country. For both men and women, it has declined by 3.8 per cent annually since 2015.

While it's the fastest decline in lung cancer mortality reported to date in Canada, thoracic oncologist Dr. Adrian Sacher said there's more to the message.

"It's important to keep in mind that this is more of a sign that we can change the outcomes from lung cancer with research and treatment," the Princess Margaret Cancer Centre scientist told Yahoo Canada earlier this month. "I wouldn't take it as a sign this is a 'mission accomplished' moment by any measure."

Lung cancer remains the leading cancer for Canadians among all cancer types, and it's expected to affect around 31,000 Canadians in 2023 alone. Read on to learn more about lung cancer, its causes and key warning signs.

What is lung cancer?

Cancer is a disease in which cells in the body grow out of control.

According to the Canadian Cancer Society, "lung cancer starts in the cells of the lung," and when it starts in lung cells, "it is called primary lung cancer."

Lung cancers are usually grouped into two main types called small cell and non-small cell.

Non–small cell lung cancer usually starts in glandular cells on the outer part of the lung, and small cell lung cancer usually starts in cells that line the bronchi in the centre of the lungs. Non–small cell is more common.

While lung cancer might not be as common as skin or breast cancer for example, it's the mortality rate that's concerning, according to a Yahoo Canada interview with Dr. Susanna Yee-Shan Cheng last November.

"Lung cancer is actually the number one cause of cancer death," says the Sunnybrook Health Sciences Centre medical oncologist. "It is common but it's actually the mortality that's the biggest issue. Stage by stage lung cancer is prognostically worse than most cancers."

What causes lung cancer?

Cheng says smoking is "the number one cause" of lung cancer. As per Lung Cancer Canada, the majority of lung cancer cases — about 85 per cent — are directly related to smoking tobacco, particularly cigarettes.

Smoking increases lung cancer risk by:

• Causing genetic changes in the cells of the lungs

• Damaging the lungs' normal cleaning process by which they get rid of foreign and harmful particles

• Lodging cancer-causing particles in the mucus and developing into cancer tumours

But Cheng reveals there's a "growing number of patients who are non-smokers."

"We're now seeing patients who've never smoked or never had second-hand smoke exposure developing lung cancer, which is interesting because usually smoking is a key cause," shares Cheng. "There's a number of patients who are never smokers and might not have a reason to get lung cancer, so that's the concerning part."

Cheng says "we don't know why" non-smokers develop lung cancer, so more research needs to be done. However, her best guess is that it's "related to certain hormones."

What are the signs and symptoms of lung cancer?

In its early stages, lung cancer might not cause any signs or symptoms. As the tumour grows and causes changes in the body, it usually results in coughing and shortness of breath.

However, if you have any of the below signs and symptoms that are linked to lung cancer, it's important you see a doctor or medical professional as soon as possible:

• A cough that gets worse or doesn't go away

• Shortness of breath

• Chest pain that you can always feel, and that gets worse with deep breathing or coughing

• Blood in mucus coughed up from the lungs

• Wheezing

• Weight loss

• Fatigue

• Hoarseness or other changes to your voice

• Difficulty swallowing

• Swollen lymph nodes in the neck or above the collarbone

• Headache

Cheng notes that she usually sees "cough, infection or pneumonia" as precursors to lung cancer.

However, she reveals "COVID put a stint in it."

"Nowadays when someone has has COVID they they can be coughing for weeks and weeks," she says. "Some cannot really tell what the symptoms are for sometimes, which can make it hard to diagnose at first."

She adds that cough, shortness of breath (especially when moving), unexplained weight loss, loss of appetite, chest pain, and hoarse voice are other possible warning signs of lung cancer.

"In smokers they may always have a chronic cough but in non-smokers they may never have a cough or develop it over time. Which can delay a lung cancer diagnosis," adds Cheng.

How is lung cancer diagnosed and treated?

Lung cancer is usually diagnosed after a visit to your family doctor, who will ask you about your health history, symptoms, and perform a physical exam. You may also take a blood test, or get an X-ray, MRI or CT scan.

If lung cancer is diagnosed, other tests are done to find out how far it has spread through the lungs, lymph nodes, and the rest of the body. This process is called staging.

Screening for lung cancer is another important step that can help detect the condition early. With lung cancer, early detection is vital. The sooner the disease is diagnosed, the greater chances of survival.

"It’s unfortunate that there isn’t really screening for people who aren’t smokers yet, but hopefully soon," says Cheng.

When it comes to treatment, Cheng believes it's going in a positive direction.

"In the last 20 years things have transformed significantly. We used to only have chemotherapy, but now it's based on their pathology and their genetic mutations, which predicts what kind of treatment they get, such as immunotherapy and targeted drugs," Cheng explains.

How can I prevent or reduce the risk of lung cancer?

Unfortunately, not all lung cancers can be prevented. However, there are things you can do to help prevent developing the condition, such as changing the risk factors that you can control.

Cheng says that the first thing you can do is to avoid smoking.

"Really, don’t smoke, and try not to be around a loved one who smokes because second-hand smoke risk is also very real," she says.

Cheng adds that there aren't many risk factors related to diet or alcohol, but keep an eye on "occupational exposure."

"Watch occupational exposure like Ephesus. You could also check for radon in your house, but other than that there isn’t really much you could do," she explains.

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