Why is it not posible to inject medicine into cancer cells to disrupt only their growth and posibly kill them instead of exposing all body to chemo?

Lack of access: Tumor cells are microscopic and not accessible for direct injection as these cells are scattered all over the body. If the tumor cell has a specific marker that can be targeted, then it is some times feasible as in the case of the new CAR T treatment. Wish you good health! - Have a diet rich in fresh vegetables, fruits, whole grains, milk and milk products, nuts, beans, legumes, lentils and small amounts of lean meats. Avoid saturated fats. Drink enough water daily, so that your urine is mostly colorless. Exercise at least 150 minutes/week and increase the intensity of exercise gradually. Do not use tobacco, alcohol, weed or street drugs in any form. Practice safe sex, if you have sex.

Size/location: Think of a cancer cell as a ant moving along the dirt or in a giant mound (a local tumor). The needles we have would be the relative size of a bus.We cannot find the ant or inject medicines with a needle the size of a bus. There are therapies that try to concentrate the treatment on the mound (surgery, gamma knife) but chemo is needed to reach the ant on the ground. New immune therapies are local