The Case for Lung Cancer Screening
JULIA ROTOW: I’m Dr. Julia Rotow. I’m a thoracic medical oncologist at the Dana-Farber Cancer Institute in Boston, Massachusetts. So EGFR-mutated lung cancer is a subset of lung cancer diagnoses that’s most likely to affect younger individuals and individuals with a minimal or absent history of tobacco use.
And this occurs in approximately 15% to 20% of lung cancer in this country. Overseas, for example, in Asian countries, that rate can be as high as 50% to 60%. So it’s an important subset of lung cancer to identify a diagnosis.
JULIA ROTOW: So there are many risk factors for lung cancer. And it is correct that a history of tobacco use or current tobacco use is indeed a risk and does elevate the chances of lung cancer. That’s why lung cancer screening is so critical, particularly for those with this history.
But that’s not the only risk for lung cancer. And in fact, lung cancer can also strike those you might not expect, so those, for example, without history of tobacco use, younger patients. And this is really where the data for EGFR mutations becomes critical.
We know that for young people or people who never smoked with a diagnosis of lung cancer, their chance of having what’s called a driver mutation– mutation in their cancer that has caused this cancer to form– can be quite high. Over 50%– maybe even more than 75%– might have one. And these can be treated with targeted therapy pills in many circumstances.
EGFR is the most common of these driver mutations. And as I said before, it’s most common in young people, young women, and in those of Asian descent.
JULIA ROTOW: Current lung cancer screening guidelines, and here I’ll cite the US Preventive Services Task Force guidelines recommend lung cancer screening for those at high risk as defined by cumulative years of tobacco use and age. So the current guidelines, which released in 2021, recommend screening for those 50 and older, technically 50 to age 80 with at least a 20 pack-year history of tobacco use. And that means either one pack of cigarettes per day for 20 years, two packs per day for 10 years, and so on.
And that’s considered to be high risk, and they recommend an annual low-dose screening CT scan. We know that by doing this screening, we can reduce the risk of death from lung cancer by catching lung cancer early when it’s more treatable. This improves survival.
Unfortunately, in this country, uptake of lung cancer screening has been very low. And in many studies, only 15% to 30% of people who are eligible for lung cancer screening actually have this done. And that’s a real missed chance to catch lung cancers at an early stage particularly with all these different advances we’re seeing improving outcomes for early stage lung cancer.
JULIA ROTOW: The first step is to speak with your primary care doctor. It’s a great opportunity to have a conversation about whether lung cancer screening might be helpful for you as an individual. And our physicians really enjoy speaking with their patients about this to help reduce their risk, just as you might talk about colonoscopies, or mammograms, or prostate cancer screening.
Now, our current lung cancer screening guidelines don’t catch everyone who might be high risk, and there are some abstracts and presentations at ASCO this year that are getting to that point. For example, we know there are racial and ethnic disparities in both access to lung cancer screening and eligibility for screening based on current guidelines. And there are ongoing efforts to try to offer more risk-adaptive scores or risk-adaptive strategies to try to understand a lung cancer risk.
I’d like to highlight a lung cancer screening study being presented at this year’s ASCO being led by Dr. Elaine Xu at NYU. And this study looks at instituting lung cancer screening with three annual CT chest scans in young Asian women who never smoked. So starting at age 40, even younger than our standard guidelines, and in people who never smoked or very minimally smoked– again, an unusual population for our wider national guidelines.
And this speaks to the high risk of lung cancer mortality and Asian-Americans. It’s the leading cause of cancer death for this population. They have a higher rate of these actionable driver mutations, like EGFR in their cancers.
And at this ASCO, Dr. Xu will be presenting in an upcoming session some preliminary results from the first 200 patients who enrolled on the study. And here they found a 1.5% rate of lung cancer in this young, non-smoking patient population. And all of the lung cancers they identified were EGFR mutated and were able to go on to receive adjuvant EGFR-targeted therapy. So it speaks to the importance of not just thinking about our traditional high risk patient population, who should absolutely get 100% screening if we could achieve it, but also these other less-common patient populations who can still benefit from potential screening strategies.
JULIA ROTOW: EGFR is a protein that sits within tumor cells. It’s called the epidermal growth factor. And when active, it tells cells to grow and divide. In lung cancer cells, that can be made abnormally active by having a mutation which causes it to turn on when it should not. And this, we know, helps to drive lung cancer formation and growth and survival. And this is by targeting EGFR with EGFR inhibitors, which can shut down that protein and stop that survival signal, can improve outcomes for patients with this subtype of lung cancer.
So for people diagnosed with an early stage lung cancer, so a lung cancer that might be able to be removed surgically with intent to cure, there are a number of different treatments that can be offered before or after surgery to try to reduce the risk of relapse and improve survival.
These include what’s called neoadjuvant therapy, So presurgical therapy, usually chemotherapy or immunotherapy, for example, immune stimulating drugs; or adjutant therapy. And that’s post-operative therapy, so therapy after recovery from surgery that is similarly meant to reduce risk of relapse in the future.
