My dad had esophageal cancer and until he was diagnosed with stage 4 with multiple metastases he didn't really have symptoms. He'd had a lower appetite and lost

My dad had esophageal cancer and until he was diagnosed with stage 4 with multiple metastases he didn't really have symptoms. He'd had a lower appetite and lost weight in the months leading up to his diagnosis, but thought that was just lifestyle and diet changes finally clicking. Esophageal cancer with multiple metastases is usually fatal at about four months after diagnosis (my dad died at 3.5 months after diagnosis). But you don't go from no cancer to dead in 4 months, the cancer is there for years. This research is finding signals from blood tests that correlate to cancer long before it has visible effects. The trigger event you're theorizing is just cancer at a lower level