The worst I have seen... or should I say the fastest I have seen is a rare form of thyroid cancer. From the time lady felt something unusual till the day she died was only a few weeks.
Dr. Katie DDS
Mainly Pancreatic, because it's almost always caught in it's final stage when it has metastasized through out the body. It's usually only found early by accident. You could also argue that lung cancer is quite aggressive and can be one of the hardest cancers to survive. Metastatic melanoma is hard to beat as well due small metes through out the body, that multiply.
I would say late stage lung cancer. It kills the most people every year.
There isnâ€™t a most incurable. There are several that are not curable. It is a black and white thing either it is curable or it is not. Multiple myeloma, indolent lymphoma, glioblastoma multiforme are all examples of non-curable cancers.