A six-year study conducted by Italian researchers indicates that mild knee arthritis may be the first sign of lung cancer, according to a report from Reuters.

During the study period, 6,654 patients were seen for various rheumatic disorders, including 296 with isolated knee arthritis. In five of the patients (1.7 percent), the arthritis appeared to be the first sign of lung cancer.

The five were all middle-aged men and each had a long history of heavy cigarette smoking.

Click here to read the Reuters story

Dr. Lecia Sequist, of Massachusetts General Hospital, told King 5 Seattle that this isn't the first time lung cancer and arthritis have been linked, but that doctors still don't understand the connection.