Vaping might be safer than cigarette smoking, but they carry their own health risks. A New Jersey man’s electronic cigarette habit likely contributed to his fast-spreading, fatal lung cancer, his doctors say.

Doctors at the AtlantiCare Regional Medical Center in Atlantic City detailed the tragic death this month in the American Journal of Case Reports. The 51-year-old former smoker and longtime vaper developed an aggressive lung cancer that killed him just months after diagnosis. Though a causative link isn’t confirmed, the authors say more studies are needed to figure out vaping’s cancer risk.

According to the report, the man visited a local hospital sometime in 2020 after he started to cough up blood. During the prior month, he had also been experiencing symptoms of weight loss, chest discomfort, and shortness of breath. Tests soon revealed that he had a form of non-small cell lung carcinoma, specifically determined to be squamous cell carcinoma. The cancer had already started to spread and break off into pieces that reached the heart, making surgery unfeasible. He was discharged and quickly placed on chemotherapy, but to no avail. The man’s health continued to rapidly deteriorate and he died three months after his diagnosis.

The man had a history of cigarette smoking, the equivalent of 10 pack-years (meaning he smoked roughly a pack a day for 10 years). But he told the doctors he quit in 2009 and switched exclusively to e-cigarettes for the next 11 years. He regularly received lung and heart check-ups, and his last chest X-ray two years earlier was normal, suggesting his cancer only recently emerged. Because of the aggressive and non-responsive nature of the cancer, his relatively young age (most cases are caught in people over 65) and the lack of recent cigarette use, the doctors suspect that vaping probably played a part in his death.

“While causality cannot be established, the case highlights a potential association between [vaping] and malignancy,” they wrote.

People have gotten seriously sick from vaping before, though usually under specific circumstances. In 2019, for instance, a mysterious lung disease that affected thousands of people in the U.S. was ultimately traced back to toxic additives primarily used in THC-containing vapes (while the initial outbreak did subside, these cases still appear occasionally). Other chemicals used to flavor vapes have also been tied to rare lung illnesses. But this appears to be one of the first case reports to explicitly link vaping and lung cancer. Other isolated reports have found a connection between vaping and mouth cancer. Some studies have also suggested that people who both vape and smoke (so-called dual users) have a higher risk of lung cancer than people who only smoke.

At the same time, the overall research to date doesn’t appear to show a significant added risk of lung cancer among people who only vape and have never smoked. And studies have also long found that vaping is less harmful in general than smoking. Given that this case is only one anecdote, the doctors aren’t pushing for formal changes to screening guidelines just yet. But they are calling for further studies to untangle the unique dangers that vaping may pose.