I have looked at this question from the standpoint of natural solutions. Two major natural solutions systems are widely acknowledged. They are Ayurveda and TCM. My comments are based on these two systems.
TCM (Traditional Chinese Medicine) believes that ailment conditions are to be treated with appropriate food to a specific meridian and its associated organs. The emphasis is on recommending the right food. This helps restore an imbalance in the body. Imbalances are the cause of disease. Restoring these helps in disease prevention.
TCM diet is varied with the type of cancer. Diet recommendations are tailored for an individual, something like the Ayurveda concept of personalized diet. Diet and exercise are prescribed to prevent cancer than to aid the healing process.
Ayurveda insists that dietary planning is aligned with nature and prevailing environmental conditions. Diet needs to be in tune with an individual’s personality (Prakriti), Vikriti (adverse personality traits), dosha, and body type.
Ayurveda and TCM emphasize the ability of the body to self-heal. There is emerging scientific evidence to support this thinking. It is now understood that the neural systems constantly undergo a cycle of death and renewal. Neurons die, and new neural connections are created. Kandel, the neuropsychiatrist who was awarded the Nobel Prize in 1990, found that if we do not use neural connections, they bring to shrink and die. These further point to our ability to reshape our brains. If this is so, relaxation and mind–body techniques will be valuable supports to prevention and healing in alternate medicine therapies.
In Ayurveda, TCM, and even in Tibetan Medicine, cancer is attributed to malefic and toxic effects generated from the environment and improper lifestyle. Detoxifying the body to get rid of these effects is one of the key treatment modes in all these ancient medicine systems. However, the scientific support to detoxification recommendations is tenuous.
Acupuncture, yoga, tai chi, and meditation, on the other hand, have been studied and scientific evidence in support of benefits in prevention and assistance in healing is quite strong.
Additional reading link to my books on natural solutions is https://amzn.to/3dovSuY. You will find these concepts and healing strategies explained in detail.