Correlation or causation? Smoking, lung cancer and pancreas cancer

Cigarette

Most people know that smoking tobacco is detrimental to our health. It’s a tough habit to quit, and quitting can be hard to talk about. 

November is lung cancer and pancreatic cancer awareness month. Here we address association versus cause, what happens to these organs when a person smokes and the impact of quitting.

As we break it down, keep in mind: 

  • Smoking is a key risk factor in the development of many cancers
  • Smoking can block a person’s ability to fight cancer once they have it
  • There are over 7,000 chemicals in tobacco smoke, many of which are carcinogenic and harmful
  • Tobacco smoke causes damage to cell tissue and can change a cell’s DNA
  • Tobacco smoke can weaken the body’s immune system, which can lead to the uncontrolled, ongoing growth of cancer tumors

Smoking and lung cancer

There is no doubt that smoking causes lung cancer and is responsible for 90% of all lung cancers. As the number one cancer killer in the United States, more people die from lung cancer every year than from colon, breast and prostate cancers combined.

What happens in the lungs when a person smokes?

When people smoke, they inhale harmful chemicals that cause cell damage inside the lungs. Repeated damage causes the body’s immune system to try to kill the damaged cells and repair the lungs with new, healthy cells. When the damage and repair cycle continues, eventually, the body makes a mistake by creating new cells with the markers that can lead to cancerous growth.

The challenge: Lung cancer doesn’t make itself known until late in the disease 

When lung cancer grows, it takes a long time before the diseased tissue causes any apparent symptoms. “By the time we see symptoms, lung cancer is hard to treat,” says Keenan Taylor, MD, Nebraska Medicine interventional pulmonologist. “Since screening is the only way to catch lung cancer in its early stages, it’s essential for smokers to get screened regularly.” 

If symptoms appear, they may include:

  • Persistent cough, with or without blood
  • Shortness of breath
  • Unintentional weight loss

Only about 10% to 15% of patients eligible for lung cancer screening are getting screened  

Lung cancer screening is a vital tool to save lives but is underutilized by those who need it. When lung cancer is diagnosed in stage one, the cure rate can be as high as 70% to 80%. Screening is a low-risk tool for preventing lung cancer or catching it early and is as simple as a quick, low-dose CT scan. 

Annual screening is recommended for:

  • People ages 50 to 80 years who currently smoke or have quit within the past 15 years
  • People with at least a 20-pack-years smoking history (this is the number of packs of cigarettes per day multiplied by the number of years smoked). For example, someone who smoked two packs a day for 10 years has 20-pack-years of smoking, as does a person who smoked one pack a day for 20 years

Although the risk of lung cancer is much lower for those who have never smoked, people with a family history of lung cancer or who have lived with a smoker for a long time should talk to their doctor about getting screened.

If a person quits smoking, does it reduce the risk of lung cancer?

Yes, research shows that quitting undoubtedly decreases lung cancer risk.

  • After quitting, at five years, cancer risk is greatly reduced
  • 15 years after quitting, there is an 80% to 90% risk reduction of developing lung cancer
  • Adults who quit smoking increase their life expectancy by 6 to 10 years, depending on the age they quit  

“It’s never too late to quit smoking,” says Dr. Taylor. “Even those who stop after age 80 can increase their life expectancy. The benefits of quitting are not only to reduce the risk of lung cancer but also to significantly reduce the risk of a cardiovascular event due to coronary heart disease and the risk of developing other types of cancer.”

Smoking and pancreatic cancer

Pancreatic cancer is currently the third leading cause of cancer-related death in the U.S. after lung and colon cancers. It is expected to be the second leading cause by 2030. People who smoke are two to three times more likely to develop pancreatic cancer than those who do not smoke. About 25% of pancreas cancers are thought to be caused by smoking.
 
“Smokers not only develop pancreatic cancer more frequently than nonsmokers, but they also tend to develop the disease much sooner, in some scenarios up to 20 years earlier than non-smokers,” says Christina Hoy, DNP, FNP-BC, clinical program director at the Nebraska Medicine Pancreatic Diseases Specialty Clinic.

How the pancreas functions, and if a person can live without one

Playing a vital role in the digestive system, the pancreas produces enzymes that help turn food into fuel for the body. It also helps control blood sugar by releasing essential hormones to maintain a healthy sugar level in the blood. 

Although a person can live without a pancreas, it is not a risk worth taking. Without a pancreas, the body no longer produces insulin or the digestive enzymes necessary to digest food. As a result, medical care, diet and lifestyle changes, and daily medication is needed. Blood sugar levels need to be monitored regularly with insulin administration as needed. 

How smoking impacts the pancreas and increases pancreatic cancer risk

“Pancreatic cancer happens when normal cells in the pancreas develop the ability to grow uncontrollably, eventually growing into a mass or tumor,” says Dr. Hoy. “Evidence has shown that cigarette smoke can cause inflammation and scarring within the pancreas. These changes work together with other factors allowing cells to actually avoid cell death while rapidly increasing in number.”

If a person quits smoking, does it reduce the risk of pancreatic cancer?

Yes, quitting gradually reduces the risk of pancreatic cancer. So much so that after 15 to 20 years, a previous smoker’s risk is the same as that of someone who has never smoked.

Remember that you achieve other health benefits as soon as you quit smoking

Consider these additional advantages:

  • Heart rate and blood pressure begin to decrease within 20 minutes
  • The level of carbon monoxide in your blood reduces after 12 hours 
  • Lung function increases as soon as two weeks 
  • Coughing and shortness of breath begin to improve as soon as one month
  • The risk of heart attack decreases by half within one year
  • The risk of coronary heart disease is halved by year one and falls to about the same as someone who has never smoked by 15 years 

Quitting still makes a difference, even if a person has been diagnosed with cancer

If you’ve been diagnosed with cancer, quitting can help:

  • Lower the risk of getting another form of cancer
  • Lower the risk of surgical complications, making surgery safer
  • Help achieve a quicker and better recovery after treatment
  • Make radiation treatment more effective by maintaining an adequate oxygen level in the blood
  • Make chemotherapy drugs more effective

If you need help to quit smoking, there are resources that can help you succeed. The smoking cessation team stands ready to help you quit smoking through support, counseling and medication. The Lung Cancer Screening Program not only screens but also helps address the psychological and physical addiction to smoking.

Schedule an appointment to discuss the best ways to help you quit smoking, or if high risk, schedule a lung cancer screening. Call 800.922.0000 to get started.