People don't get vaccines because they literally can kill you. Go google the US governments vaccine court payouts for DEATHS from vaccines.
Anything you do in life has a chance of killing you. And certainly anything you inject into your body, has the potential to kill you.
So there is a risk in all these things.
Problem is, there is a risk in not doing these things as well.
There is a chance that not having a tumor removed, the tumor will go away on its own. This happens very often.
There is also a chance that if you remove the tumor, that you will die on the operating table, or have seriously life changing complications.
It is entirely possible that you could die from surgery to remove the tumor, when you would not have died from the tumor.
The question is, what is the risk assessment? Which is the bigger danger? Obviously with most people, the larger danger is letting the tumor stay there. The chance that it just evaporates on it's own, are real... but very small.
Equally the chances you'll die in operation, are real... but small.
The most likely result is that you don't remove it and die, or that you do remove it, and live.
The vast majority of Vaccines are the same. Specifically the real bad illnesses, Polio and Smallpox, the vaccination has an extremely high effective rate, and extremely low risk factor.
Is it possible some may die? Sure. But without vaccination, thousands died every year. One or two deaths in millions of vaccinations, is a very good number relative to at one point 5,000 deaths from Polio in 1952 I think.
One is far better than the other.
About the only vaccine that I'm not a big fan of, is the Flu vaccine. And the reason is that there are a dozen different flu viruses, and the vaccine only deals with 2 or 3 strains. Which means that the only time the vaccine is effective, is when you happen to be exposed to the exact same strain, that your vaccine was against. Otherwise, it has virtually no benefit.