An interesting and exceedingly relevant area in cancer treatment is evolution. An interesting conceptualization of the disease I learned in the past year and a half is looking at it as a population, some of which live and die in an environment (your body). Natural selection is constantly occuring in neoplastic (tumor) populations, because daughter cells that respond and proliferate more after being subjected to selection by internal defenses and treatments will have higher fitness, or reproductive success.
I'm learning about research that has to do with Epigenetics and cancer, in which heritable changes in how genes are expressed (how strongly or weakly, say), occur without actual modification of DNA. This includes everything from DNA methylation to histone modification. This is big, because drugs designed to counteract pro-cancer epigenetic mechanisms could have a huge effect on how certain cancers progress and develop. They are not a bullseye cure for cancer, but as adjuvant therapy it could be vital in the future.
If you want I can post some literature on it as well. Relatively complicated..