Is it possible for someone to not know they have stage 4 cancer?

one of my female friends just found out recently that her father had stage 4 stomach cancer. and there claiming that the diagnosis was a surprise and that they weren't aware of this

but like seriously could there not have been signs before he became so ill? i know its common for some men to avoid the doctor even if there unwell but seriously

Is it possible for someone to not know they have stage 4 cancer?
Post Opinion