When cancer spreads to another part of the body, it is called metastasis. A person with metastatic disease has cancer that has spread from the place where it began (the primary tumor) to other sites in the body, usually to organs such as the lungs, liver, bones, brain and abdomen. Cancer cells that have spread to a new location often look different from the cancer cells in the area where they originally formed. Because of this, doctors can tell the cells are metastatic by examining them under a microscope. Metastatic cells typically grow and reproduce more quickly than normal cells.
Many of the treatments that are now considered standard for metastatic cancer were first tested in clinical trials at MSK. These trials may test a new surgical procedure, a different kind of radiation treatment or a drug or combination of drugs. For example, several of the chemotherapies used to treat metastatic breast cancer were first developed at MSK.
In addition to surgery, other forms of treatment for metastatic disease include chemotherapy, hormone therapy and targeted therapy. These are all medications that travel throughout the body to kill cancer cells, whether they are at the site of the primary tumor or in other parts of the body. For many types of cancer, doctors use a sequence of medications called “lines” to try to find the right combination that will work best for each patient.
Some cancers, especially sarcomas and some carcinomas, tend to spread through the bloodstream into the lungs and liver. These cancers are known as hematogenous metastasis. In contrast, squamous cell carcinoma of the skin typically spreads through the lymphatic system into other areas of the body.
If cancer cells spread to the lungs or liver, they can cause fluid to build up in those spaces, a condition known as malignant pleural effusion or malignant ascites. The lungs are the most common place for cancer to spread to from other organs in the body. If cancer spreads to bone, it can result in pain and other symptoms, such as weakness or a weakened immune system. In some cases, it can be difficult to identify bone metastases because they are often not painful.
Despite the fact that metastatic cancer is often terminal, it has become increasingly possible to improve survival with new therapies. These have included a new approach to metastatic cancer called “molecular profiling.” This involves testing samples of the primary tumor and the metastatic tissue to identify genes that are changed in both. Using this information, scientists can develop targeted treatments to attack the cancers at their source and stop them from spreading.
Metastatic cancer is hard for patients and their families to understand, but it’s important to keep asking questions at your doctor’s appointments. Make a list of the questions you have and bring it with you to your appointments. Your doctor shouldn’t get upset if you need to repeat the same question over again. You can also ask for a second opinion or talk with a cancer support group.
