A cancerous tumor is a tumor which is considered malignant, meaning that it has the potential to spread to neighboring organs, cutting off the supply of nutrients to these areas and eventually causing severe symptoms. Cancerous tumors require medical intervention to prevent the cancer from spreading, and ideally to excise the cancer altogether, so that the patient will return to normal health. Treating a cancerous tumor can involve a team of people, including a cancer specialist or oncologist and a surgeon.

Tumors are masses caused by uncontrolled cell growth. They are also called neoplasms. Tumors occur when cells start to duplicate with no checks in place, causing a proliferation of cells. Normally, the body carefully regulates cell production, ensuring that cells are duplicated as needed, but not allowed to grow uncontrollably. When a cell becomes mutated, however, it duplicates itself rapidly, cloning copies of the damaged cell and creating a neoplasm.

Neoplasms can sometimes be identified with palpation, and in other instances, they are diagnosed after a patient develops symptoms caused by the tumors. Depending on the location of a tumor, it can cause neurological symptoms, organ damage, hormone imbalances, and other problems. Tumors are diagnosed by using medical imaging to identify the site, and following up with a biopsy of the cells which includes a determination of whether or not the tumor is malignant.

If a neoplasm is malignant, it is classified as a cancerous tumor. A cancerous tumor is a cause for concern because it will continue to grow rapidly, and it will freely spread to neighboring organs. If it is left untreated, it may also spread to remote regions of the body. Cancerous tumors cut off the blood supply to organs, interfere with the production of hormones, and cause tissue death. Therefore, when a cancerous tumor is discovered, a treatment plan must be developed to address it.

Ideally, a cancerous tumor is removed in a surgical procedure, and the patient is given medication which is designed to prevent the recurrence of the tumor. In some cases, a tumor may be in an inoperable location, in which case drugs may be used to try and shrink the tumor so that it cannot grow any larger. Because cancer has a tendency to recur, even if the tumor is successfully killed or removed, the patient will require a lifetime of medical appointments to check for recurrence so that the cancer can be caught early if it does arise again.