With regards to people I know or have read about who live with cancer, most of their symptoms are results of chemotherapy, surgical interventions, etc., which have the goal of eradicating the cancer. Assuming the cancer went untreated,* what kinds of symptoms would the cancer itself lead to, and by what mechanism would it cause death (in most cases)?
Please excuse my ignorance. I know that every cancer is different, and even different cases of a single type of cancer can present differently; so there may be many different answers to this question, but I'm not sure if they eventually lead to the same thing.
*I'm asking purely out of curiosity – I'm not "opposed" to chemotherapy or anything like that.