Research is very clear:
Exercise increases both survival times and your odds of beating cancer. Taking 45 to 60 minutes light to moderate exercise at least three days a week should be a crucial part of your activity to increase your personal odds of beating cancer.

In the USA the American Cancer Society conducted a seven-year research study on stage three cancer patients, all of whom had had chemotherapy and surgery. Those who adhered most closely to guidelines on diet and exercise had 31% less cancer recurrence, and 42% less deaths across the following years.

Name a drug that can do that!