Of course there are (science lessons from chemo), and from one angle if chemo does save lives, it gets that credit.
Right now, like many parts of what we call medicine, chemotherapy doesn’t take into account enough about the bacterial biome makeup of each individual and its effect on the immune system (or, actually, its existence as a large part of the immune system), and oncologists practically ignore the desperate nutritional needs of the cancer patient. They are to this day told to eat whatever sounds good, whatever they can get down. Cancer thrives on sugar. They should eat ketogenic diets of natural clean foods only.