Cancer screenings exist to try to detect the disease in its earlier stages, and ultimately to save lives. But screenings for lung cancer—the leading cause of cancer deaths worldwide—are narrow, and that’s causing missed diagnoses in many people, especially women and those who have never smoked.

That’s the main takeaway from a new JAMA Network Open study that suggests most lung cancer cases are missed due to these guidelines. Current guidelines from the U.S. Preventive Services Task Force (USPSTF) suggests annual lung cancer screenings for adults between the ages of 50 and 80 with a 20 pack-year smoking history and who currently smoke or who have quit within the past 15 years. That’s leaving out a lot of vulnerable people.

Why do these guidelines matter? They influence insurance coverage, and paying out of pocket for screening if you don’t fall under the recommended criteria isn’t cheap. Plus, many people won’t get screened for something if it’s not recommended.

“Lung cancer has the worst record for screening detection of all the cancers,” David Carbone, MD, PhD, oncologist and chair of lung cancer research at The Ohio State University Comprehensive Cancer Center, tells SELF. “At least part of that is all the restrictions we have on lung cancer screening.”

Here’s what the study found, plus what oncologists recommend doing to stay on top of your lung health.

What did the study find?

For the study, researchers analyzed data from nearly 1,000 patients treated for lung cancer at Northwestern Medicine. After looking at their health data, the researchers found that just 35% of those lung cancer patients would have qualified for screening based on USPSTF criteria. Two-thirds of those patients were disproportionately women and people who have never smoked.

Based on the findings, the researchers recommend expanding the screening to focus on people between the ages of 40 to 85. This would detect 94% of lung cancers and prevent more than 26,000 extra deaths each year, according to their estimates. The researchers also found that this would be cost-effective, with minimal risks from radiation exposure or biopsies outweighing the potential to save lives. “Age-based screening could improve detection and cost-effectiveness while reducing disparities,” the researchers wrote.

Detecting early signs of lung cancer can be hard.

Doctors agree that the current lung cancer screening guidelines aren’t great. “It does seem that expanding the age range for screening would help,” George Chaux, MD, a pulmonologist and medical director of Interventional Pulmonary at Providence Saint John’s Health Center in Santa Monica, CA, tells SELF.