To throw another reference into the discussion, section 1.8 of McKinnell et al.'s The Biological Basis of Cancer spends a few pages on this. Summary: cancers can cause organ failure, but because the body has "an enormous reserve of normal tissue plus a built-in mechanism to regenerate more" organ failure is not usually the proximate cause of (edit: non-leukaemia) cancer death; the most common cause of death is instead cachexia (wasting) and hence infection.
This thread is for asking any questions that might seem obvious, tangential, silly or what-have-you. Don't be shy, everyone has holes in their knowledge, though the fewer and the smaller we can make them, the better.
Please be respectful of other people's admitting ignorance and don't mock them for it, as they're doing a noble thing.
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