Kevin Keegan's tragic death yesterday, aged 75, came after a short battle with cancer – but he only discovered he had the disease after being involved in a car crash.The Liverpool and Newcastle United legend initially revealed he had been diagnosed in January with stomach cancer, a disease that affects 6,800 people in Britain each year and kills nearly 4,000.Typically, those with the disease will show symptoms such as persistent heartburn or acid reflux, difficulty swallowing, nausea, indigestion and feeling full after eating a small amount of food.Patients with suspected stomach cancer are typically referred for an upper endoscopy – also known as a gastroscopy – in which a tube fitted with a camera is passed down the throat into the stomach to check for signs of the disease. In Keegan's case, his cancer was detected after undergoing medical tests for stomach issues following a car accident.Some experts say people who have been involved in a crash are more likely to be diagnosed with cancer than people who have not.The potential reasons for this, however, are varied.One theory is that those who drive more often may have lifestyle factors associated with a higher cancer risk, including spending long periods sitting and being more likely to be overweight. Kevin Keegan's tragic death came after a short battle with stomach cancer