By Heather Millar
As a cancer patient, it feels intuitively right that early screening and early detection of cancer means a better chance of survival. I’m pretty sure that I won in the mammography sweepstakes: My aggressive breast cancer was found when it was still Stage I. On the other hand, my father didn’t have early screening and his lung cancer wasn’t detected until it had already metastasized. He died a year later.
But the thing about science is that hunches and gut feeling are not enough. You have to prove that your intuition is right: In the past year, several studies have come out questioning whether early screening for cancers such as lung, breast and prostate really save lives, or if they just mean that more people suffer through risky and often toxic cancer treatments.
The debate over this issue rages on, but a new study came out just before Christmas that further questions whether expensive, population-wide cancer screening is as useful as we feel it should be.
Researchers at University of Texas Southwestern Medical Center started out asking two key questions: Without screening, why and how do patients with lung cancer get diagnosed with the disease in the first place? And what proportion of these cases might have been detected if they had had access to screening?
The study follows the 2010 National Lung Screening Trial (NLST). The NLST already showed that lung cancer deaths might be cut if there was widespread screening of certain groups: people aged 55 to 74 years, and people with a smoking history (at least 30 years of a one-pack-a-day habit).
The UT researchers reviewed the records of patients who were diagnosed with Stage 1 or Stage 2 non-small cell lung cancer over a recent 10-year period. They found that the proportion of cases identified by CT scan (without preceding chest X-ray) increased almost 50 percent during this period. This supports the “early screening is better” hunch.
But at the same time, the proportion of patients who underwent initial chest imaging to evaluate symptoms—those who sought medical help because something didn’t feel right—declined more than 30 percent. My dad went to the doctor because his shoulder hurt, and they found lung cancer. In the UT study group, fewer people got diagnosed in this way.
And only half of the early-stage lung cancer cases met the age (55-74) and smoking habit (pack-a-day, 30 years) criteria set out by the NLST. So widespread screening a la NLST may cut lung cancer deaths, but the UT study suggests it misses half of early stage cancers.
When it comes to screening, there are no easy answers. As Science Daily put it, “Whether radiographic screening for lung cancer should be extended to a broader population is not yet known.”
I’m sure we’ll be talking about the pros and cons of screening for years to come. If you have, or have had, lung cancer, how was it detected?