How does treatment shrink your malignant tumors?

Kills them: Cancer treatments target rapidly-growing cells, killing them faster than other cells. By killing the tumor cells, the tumor shrinks as the body attacks the dead tissue and destroys it.

By targeting growth: Tumors grow faster than normal cells. Chemotherapy and radiation work by interfering with the machinery that helps tumor cells divide. It's a little like weeds in your lawn. Weedkiller acts on rapidly-growing weeds, but usually doesn't harm the grass. Faster-growing tumors are often easier to kill with chemotherapy compared to slower-growing tumors.

Shrink tumor: Chemotherapy or radiation therapy can cause cell death. Cancer cells are more sensitive to these treatment than normal healthy cells. When cell die, the tumor size decrease.