What if a person has a large tumor, or a large number of tumors?  

Depends. It depends on what kind of tumor he has - benign or malignant, their location, presence of other symptoms, its cell make up etc. Without more detailed information, it is impossible to talk about diagnosis, treatment and prognosis.
I've seen this? On the site for months. Not sure what you are asking. A large tumor in what organ? Size alone does not preclude removal. Many tumors in one place? Happens in breast cancer, but may indicate metastasis if found in lung or brain. Re-submit. I hope this helps.