What Is the Difference between Benign Tumors and Malignant Tumors?

Benign tumors and malignant tumors differ in how they grow, in the risk they pose to people, and in the treatments they require. All tumors represent the growth of abnormal cells. Benign types stay local and cannot spread to other areas, while malignant ones can distribute cancer cells to other parts of the body. Generally, malignant growths represent a much higher health hazard, due to their ability to spread. When possible, benign tumors should be treated with surgical removal, but malignant growths require more extensive treatment, often including surgery, chemotherapy, radiation or a combination of these.

Undoubtedly the most important differentiation between benign tumors and malignant tumors is metastasis. This is the ability for cancerous cells from one place to move and invade a different place. As they move, these cells corrupt and convert the body’s normal cells into cancer cells. Metastasis only occurs with malignant tumors. Benign growths can get large, but they can’t invade other structures of the body and make them cancerous.

Malignant tumors are inherently more dangerous due their tendency to harm all other structures of the body. They could spread toxic cells to organs, to bone, or even to the bloodstream. As these tumors metastasize, other body tissues are changed and corrupted. Cancer staging is usually based on the extent of this spread, and the disease has a poorer outlook when a malignancy is accompanied by cancer cell invasion of organs or other major body systems.

It’s not accurate to conclude that benign tumors and malignant tumors can be classified as safe and dangerous, respectively. Benign growths can still be medically serious because they can press on various parts of the body and create discomfort or dysfunction. A non-cancerous brain tumor might make it impossible for the brain to function correctly, and large growths around the heart, in the uterus or in the gastrointestinal tract all pose risk. Whenever possible, they should be removed.

There is usually a substantial difference in how benign tumors and malignant tumors are treated. Surgical removal of a whole benign growth usually means it won’t come back. If the tumor is only partially removed, it may regrow in the same location.

With malignant tumors, surgery alone isn’t enough, and regrowth is very likely unless more steps are taken. Physicians may use chemotherapy, radiation or both along with surgery to try to kill the cancer completely. How well this works tends to depend on the aggressiveness of the tumor type and the stage at which the cancer is discovered.