Will any holistic cancer therapies actually work?

Holistic = whole. "holistic therapy" means treating the whole person. It is not the same as substituting herbal or other nutritional supplements for allopathic medicine. The best cancer treatments address the needs of the entire person, and involve collaboration between multiple trained health professionals: medical oncologists, surgeons, radiation oncologists, nursing staff, psychiatrists/therapists, etc.
Not alone. I must warn you that if you choose a "natural / holistic / pop" remedy for cancer instead of an evidence-based surgical, radiation, and/or chemotherapeutic intervention, you will be horribly disappointed. Your personal physician is under a legal obligation to tell you the truth. An internet huckester posing as a "persecuted genius / humanitarian" is under no such obligation. It's your life.
Natural TX & CA. Standard treatments are put through a series of trials, phase 1 to 3, during which the tx is tested to see if it has any affect on any cancer, than does it have an effect on a certain type and finally does it do better than the standard tx. All of this can take 10 to 15 years or more to work through. Natural tx is just labeled as may work without the testing so there is no way to know.