Risks of conventional Therapies

For nearly half a century, systematic cancer treatment has been dominated by the use of maximum tolerated dose chemotherapy. While progress has been modest in terms of curing or significantly prolonging the lives of patients, it comes at a high price. Toxic side effects are frequently associated with MTD-based (Maximum Tolerated Dosage) chemotherapy and the improvement is often time minimal at best.

In addition, the long breaks between maximum dose treatment cycles can also allow cancer cells to recover and even develop resistance, ultimately resulting in treatment failure and cancer progression. Unless a cytotoxic therapy eradicates all cancer cells, its application to a tumor population produces natural selection forces that select for cells that are resistant to the therapy. In essence, repeatedly administering maximum tolerated chemotherapy produces a more resistant cancer that will eventually not respond to any chemotherapy (this is analogous to treating a bacterium with multiple antibiotics, until the bacterium becomes resistant to all antibiotics).

Other causes for chemotherapy failure include poor blood supply to the tumor (which inhibits chemotherapy delivery) and low tumor oxygen concentrations, which increases resistance to chemotherapy while it encourages the spread of tumors in search of a better blood supply. A fundamental principle of chemotherapy is to use drugs that are more toxic to rapidly dividing cells. However, since these drugs do not specifically target tumor cells, but rather interfere with cell division, they tend to do damage to the normal dividing cells of rapidly regenerating tissues, e.g. bone marrow, gut mucosa, and hair-follicle cells. Also, tumors are heterogeneous (meaning they consist of different types of cells); the outer rim consists of replicating cells, which are susceptible to being killed by chemotherapy, while the inner mass consist of cells in quiescent or non-dividing state. The cells on the outer rim of the tumor are the most readily targeted by cytotoxic therapies (due as much to their proximity to blood vessels as to their fast growth).

Because of this, integrative cancer physicians are turning away from the historical one-size-fits-all approach and are beginning to seek out personalized chemotherapy. It has become apparent to many physicians and researchers worldwide that cancer treatments, in order to be most effective, must be individualized.