prostate cancer can usually be left alone and never kill or impact the patient at all
I upvoted your comment because it is largely correct. Most cases of prostate cancer can be responded to by "watchful waiting" with no particular treatment. However, I will note for the record that the cause of death of my late father-in-law in Taiwan, who had good medical care under that country's single-payer national health insurance program, was metastasized prostate cancer. He had successful heart surgery and other treatments that prolonged his life into his eighties until the prostate cancer got him.
Prostate cancer is still one of the more common causes of cancer deaths amongst men, though. All the patients with prostate cancer that don't die just mean that screening is little use in helping the ones who will.
It all depends. Even cancers that originate in the same organ are different depending on exactly what part of the DNA got mangled. There are certainly aggressive forms of prostate cancer.
