The science of treating a patient with cancer has evolved tremendously over the years - and with ongoing research (and funding), it will continue to bring hope and health where darkness still persists. But an equally important aspect in the battle against The Scourge, as an adjunct to therapeutic advancements, are all of the premedication and preventive prescriptions provided to counteract side effects.
At least 50% (if not more) of the "drugs" that I take on a regular basis are prophylactic - proactively intended to bolster my body’s ability to deal with the incoming toxins (chemo, etc.) as well as minimize the known adverse effects (AEs) - major or minor - that come along with the benefits of any given therapy.
In my case, as with most other cancer patients, pre-meds that address anticipated issues serve to enhance the overall efficacy of the treatment through consistency and compliance. Each cocktail is custom crafted to address an individual patient's strain of cancer. Chemo is generally cumulative in its nature and therefore is most effective when the full course of medication is administered (often over a series of months), and allowed to "seed" in the body and take root to fight the disease. A break in that flow compromises the medical foundation being built and disrupts the consistency of the dosing pattern, or at worst eliminates that option entirely - if the AEs are just too much for the patient to manage.
Keep in mind that any cancer patient has the right to refuse treatment, so if they are overwhelmed by the volume or vehemence of annoying or debilitating side effects (this is sometimes referred to as "treatment fatigue"), that can cause an interruption (or in some extreme cases, a discontinuation) of the prescribed treatment regimen. Pre-meds seek to diminish the downside and allow the potions and the patients to work at optimum performance.
In the early days of battling cancer, they basically flooded the troublesome area with a tsunami of toxins hoping it would kill the bad cells and that the strong, healthy cells would grow back - leaving the patient cancer 'free' (cancer reduced). Today's Oncologists are armed with much more scientifically advanced, much more targeted, and much more effective options. Successful eradication is further augmented by a collection of tailored pre-meds that proactively support the body, the surrounding treatment area, and myriad related organs that can be adversely affected by the cancer or the chemo itself. In essence, a proactive rather than reactive approach to cancer therapy which enhances the chances of a positive outcome.
