Interesting Article on SRX, page-13

Sirtex must have more prospects than ur average biopharma because of the linkage of its spheres to the liver. The liver is very critical to survival. If SRX can get it right either as a primary or survival treatment, SRX will become very important. Dose sales could follow an exponential trajectory IMHO but pls DYOR.

SRX's treatment is not easily substitutable due to the nature of the liver according to some of the research. In lay terms, the argument runs something like this (I may have made it too simple but try to not over-complicate it):

The liver, as an organ of the body, is regarded as a major regenerator. If cancer is found in a different or other regenerative organ, the liver is likely or in some cases bound to be affected as the liver supports every other organ in the body and is vital for survival.

In short, if you can beat the cancer taking hold of the liver and moving onto other organs, you can significantly increase survival and/ or longevity rates.
Re relationship to SRX, all IMHO but pls DYOR.