Cancer surgery can be used to prevent, diagnose, and remove cancer from the body. In cases where a cancerous tumor exists and the surgeon can’t remove it all, surgery will be utilized to remove as much of the tumor as is safe, but additional cancer treatments (i.e, chemotherapy, immunotherapy, and radiation) may be recommended to kill the remaining cancerous cells and tissues.

Here are the three primary ways surgery is used in cancer treatment:

Preventative cancer surgery
A surgical operation may be used as a preventative measure, for instance, to lower the risk of developing certain types of cancer (i.e., inherited breast cancer gene BRCA1 or BRCA2) by removing removes tissue that have a high risk of becoming cancerous. Certain inherited condition are considered to carry a higher risk of cancer development that warrants preventive surgery, or removal of an organ (i.e., the colon and rectum in instances where familial adenomatous polyposis exists) or a wide area of tissue (i.e., the breasts) to help lower your risk of developing that cancer to prevent cancer development in the patient’s future.

Surgery to diagnose cancer
In instances where your doctor suspects cancer may be present, he or she may opt to remove all or part of a tumor to diagnose for cancerous (malignant) or noncancerous (benign) tissues and cells. In addition to taking samples of tissue to test for cancer, medical professionals can also use surgery to diagnose a patient’s cancer stage or to see if cancer has spread to the lymph nodes. A doctor will also determine cancer staging via the size of the tumor and signs cancer has spread to other parts of the body (known as metastasized cancer).

Surgery for cancer treatment
If a patient’s cancer tumor is localized, doctors will often opt for surgery to eradicate cancerous cells and tissues before cancer spreads. However, in many instances, it’s not possible to remove all cancerous tissues and cells with surgery (i.e., if cancer is close to a vital organ). This means, in addition to cancer surgery to remove the majority of a tumor, the patient may undergo chemotherapy and/or radiation for full effectiveness.