It has long been known that smoking cigarettes is a leading cause of lung cancer. But what might not be as obvious is that cigarette smoking can also lead to seemingly unrelated types of cancer, like urinary or pancreatic cancer.
A lung CT scan, or computerized tomography scan, is a vital tool used to detect lung cancer, but can also be useful in identifying non-lung cancers. In a new study, Brown researchers identified which abnormalities found in lung CT scans should be followed up with further testing and which should not be.
“If (the abnormalities are) not documented, physicians don’t really know which findings they should act on and which they should not,” Professor of Epidemiology and lead author Ilana Gareen said.
Typically, physicians follow up on most significant incidental findings — or abnormality — that they find, Gareen said. But following up on these findings with further testing, such as additional biopsies, may introduce additional risks, she explained.
Biopsies can come with more “serious” consequences, Gareen added. “For example, if you do a lung biopsy, you can have a lung collapse,” she said. “Doing a liver biopsy is a very painful and really invasive procedure.”
Gareen described the unnecessary follow-up testing that often occurs as a “cascade of care.”
“People kind of get on this roller coaster where they’re getting lots of procedures done, and it turns out to be nothing,” Gareen said. “We’re trying to minimize the number of people who get on that roller coaster.”
While early detection can be “very valuable” in “identifying a cancer and treating it in an earlier stage,” overdiagnosis comes with “unnecessary anxiety, extra testing or the detection of a cancer that never would have led to harm,” said co-author Amal Trivedi, professor of health services, policy and practice and of medicine.
Associate Professor of Medicine Adam Olszewski, who was not involved with the study, wrote in an email to The Herald that while doing more CT scans will always cause doctors to find more abnormalities, it is important to know which abnormalities are worth following up on.
“The question is whether these findings are leading to improvement in something meaningful, or just higher incidence of cancer diagnoses,” he added.
The study used data from the National Lung Screening Trial, a country-wide study that established a specific type of CT scan as a diagnostic tool for lung cancer. Gareen’s research analyzed 26,445 participants who had smoked the equivalent of one pack a day for 30 years and had also “smoked within the last 15 years,” Gareen said.
The NLST patients were followed over five to seven years and were studied to see “what happened to the people who had the incidental finding and what happened to those who didn’t,” Gareen said.
Ultimately, the researchers were able to identify abnormalities that were potentially indicative of cancer and those that were not, she said.
According to Olszewski, unnecessarily analyzing abnormalities can have “significant repercussions” for medical professionals such as radiologists who are “already burdened by the need to interpret any radiographic abnormality.”
“Finding and diagnosing cancer is an emotionally heavy issue for patients, who often discount the risks associated with diagnostic procedures,” Olszewski wrote.
Nishita Malhan is a senior staff writer covering science and research.
