Each cell in the human body is technically an individual. This cell,under the right circumstances, can be cloned into an organism. All the information that is required for an individual to exist and thrive is contained in that cell, actually, in almost every eukaryotic cell that has DNA. It is a question why that single cell decided to be part of an individual rather than living alone. There are many parameters that need to be fulfilled for any single cell to be part of an organism. In a certain way, we could say that the connections that a cell makes with an adjacent cell gives it a sense of meaning, a sense of connection, a sense of ownership, and a sense of being part of the collective. When any or many of the above parameters are not satisfied, a cell might decide to go its own way and leave the collective and that is a cancer cell. Stay as an individual or become a part of the collective. That is the deep question.
  The most important reason for a cell to maintain its Integrity is the availability of energy. The DNA plays a prominent role in ensuring that the right enzymes are encoded. If the energy is available for the cell to maintain its integrity or negative entropy, the cell lives. And when a cell senses that its own survival is in question, due to reduction in its energy or other resources, then it will try to leave the collective and will try to be, on its own, find food on its own and be like a bacteria and it's goal is survival and multiplication.
  All the possible reasons for cancer formation could be accounted for by a lack of energy or lack of resources be it mutation of DNA, radiation damage, a mutagen or other courses. There could be more than one reason for one or more cancers to exist or coexist in the body. It is important to identify the possible causes, the possible gaps through which energy is leaking, or is not converted properly or the extra formation of reactive oxygen species which could also lead to more DNA damage When this energy production mechanism is faulty, that could lead to an eukaryotic cell to become cancerous or become chronically sick.
  Genetic mutations and propensities play a major role and modern medicine gives prominence to these aspects in most of the currently used treatments. Please follow your mainstream doctor's orders. I can help you get a grip of the other aspects of cancers to strengthen your system.