This ought to motivate you:
"Many studies have shown that being physically active has a tremendous impact on quality of life of cancer survivors. Now, studies have demonstrated that physical activity after cancer diagnosis is also associated with a lower risk of the cancer coming back and improved overall survival among multiple cancer survivor groups, including breast, colon, prostate, and ovarian cancer.
Among breast cancer survivors, a recent analysis showed that getting exercise after diagnosis was associated with a 34% lower risk of breast cancer deaths, a 41% lower risk of dying from all causes, and a 24% lower risk of breast cancer recurrence. Among colon cancer survivors, studies suggest exercise cuts deaths from colon cancer and all causes, and cuts the risk of the cancer coming back by up to 50%".