hemp oil has very different qualities than flax seed oil. There's really no substitute for flax seed oil in healing. Plenty of cases of cancer etc., have responded to flax seed, I don't know of any cases where the healer used hemp.
In addition to the oil, you should also eat cereals with powdered flax seeds, as the seeds have lignans that the oil does not. But mostly it is the linoleic, linolenic, Omega 3 and 5 fatty acids that have been known to help "dissolve" cancers.
If you can't find organic, go for the regular, but don't eat as much.