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Lung Cancer Screening

By Harry James McCarty III, M.D., radiation oncologist at Alliance Cancer Care

November is Lung Cancer Awareness Month – and to recognize that, this month’s first blog is on lung cancer screening.  Most people know that we can use mammograms (X-rays of the breasts) to screen for breast cancer.  Many people, however, do not know that we can use low-dose chest CT scans to do the same for lung cancer.  The chest CT scan does not require an IV or contrast and is just like getting chest X-rays.  The goal of the screening is to detect lung cancer at earlier stages.  According to the American Cancer Society, the 5-year cancer survival for early and/or localized lung cancer is around 65%.  If the cancer has already spread to nodes, 5-year survival drops to about 35%.  If the cancer has spread to other places (distant metastasis), 5-year survival drops down to less than 10%.  Therefore, there is a huge advantage to early detection.

There have been seven randomized, controlled clinical trials that have evaluated whether or not lung cancer screening can save lives.  These studies have shown that screening at-risk patients can reduce lung cancer deaths to about 75-85% of what we see if there is no screening.  We will save one life for about every 300 chest CT screenings we do.  The U.S. Preventive Services Task Force (USPSTF) has been recommending low-dose CT screenings since 2013.  In fact, they were so impressed by how many lives are saved by screening, that in 2021 they relaxed the guideline recommendations to allow even more patients to be screened.  (They lowered the age from 55 to 50, and lowered the pack-years** from 30 to 20.)

Someone is considered at higher risk for lung cancer and eligible for low-dose CT scans for screening if:

  • They are aged 50 to 80
  • Have smoked for at least 20 pack years**

** Pack-years are obtained by multiplying the average number of packs a person has smoked per day by the number of years they have smoked.  So one pack a day for 20 years gets you 20 pack years – but so does two packs a day for 10 years, or half a pack a day for 40 years.

If someone is eligible and is screened with a CT scan, there are several possible outcomes.  The CT scan can show no nodules or nodules that are small or relatively stable over time.  In that case, the risk of cancer is likely less than 1%, and these people do not have to do anything other than get another low-dose CT scan the next year.  This is similar to a woman getting annual mammograms – although if a person has favorable CT scans over time and gets more than 15 years out from when they were smoking, they can eventually stop getting screening chest CTs.  90% of folks who are screened are found to be in this lowest-risk category.  If the CT scan shows a nodule that is a little bit bigger (e.g., a 6-8m solid nodule – a bit larger than a pencil eraser), then the risk of that nodule being cancer is 1-2%, and the recommendation is to repeat the CT scan in 6 months to make sure nothing is growing.  If the nodule is 8-15 mm (something like a pea or a small peanut), then the risk of cancer is 5-15%, and the recommendation is for a PET scan or a repeat CT scan in 3 months.  If the nodule is bigger than 15mm (for example, dime-sized or larger), then the chance of cancer could be greater than 15%.  This happens in about 2% of people getting screening chest CTs.  This is the situation in which we are more likely to consider a lung biopsy to learn more about what we are dealing with.

If you or a loved one are eligible for low-dose CT screening for lung cancer, November is a great month to get that done!  And of course, screening is not the only way to prevent a lung cancer death.  For people who smoke, it is NEVER too late to quit smoking.  Quitting smoking is probably the most important thing someone can do to decrease his or her risk of dying of lung cancer.  Other things include avoiding secondhand smoke or other tobacco products, avoiding radon exposure, and eating a healthy diet (like fresh fruits and vegetables).

At Alliance Cancer Care, we do not want to just treat cancers, we want to prevent as many cancers as possible, or catch them as early as possible if they cannot be prevented.