metastatic
Meaning of metastatic: A tumor found in the liver may still be breast cancer, because spreading cells keep the identity of where they began.
Definition of metastatic
Metastatic describes cancer that has spread from the primary tumor where it began and formed new growths in other parts of the body. The cells in those deposits keep the features of the tissue they came from rather than the organ now hosting them. The word also covers anything relating to that spread, such as metastatic disease or a metastatic deposit.
How do cancer cells reach a distant organ?
Spread is not a single event. A cell has to loosen its grip on its neighbors, break through the wall of the structure holding it, survive the journey, settle somewhere new and persuade that site to feed it. Most cells that set out fail at one of those steps, which is why spread takes time even in an aggressive cancer. Three routes carry them, and the route taken shapes where the deposits turn up.
| Route | Where deposits tend to appear |
|---|---|
| Bloodstream | Lung, liver, bone and brain, following the path blood takes on leaving the organ |
| Lymph vessels | The nearest lymph nodes first, then further along the lymphatic system |
| Direct growth and seeding | Structures touching the tumor, or scattered across the lining of the abdomen or chest |
Why does a deposit in the liver still count as breast cancer?
Because the cells carry their origin with them. Under the microscope a breast cancer deposit in the liver looks like breast tissue gone wrong, not like liver, and it usually carries the same molecular markers the original tumor had. That is what separates a metastasis from a second, unrelated cancer that started on its own, and pathologists lean on those markers when a deposit is found and no primary tumor is obvious. The naming follows: it is called metastatic breast cancer, not liver cancer. So does the treatment, since the deposit generally answers to whatever the original tumor would have answered to.
What changes once a cancer is metastatic?
Staging changes first. Distant spread places a cancer in the highest stage whatever the size of the original tumor, and that single fact usually carries more weight than any measurement of the primary. The aim of treatment shifts too. A growth confined to one place can often be removed or irradiated where it sits, while disease scattered through the body calls for treatment that travels everywhere the cells might have reached. Local treatment does not vanish from the picture. A solitary deposit is sometimes removed, and radiation is used to ease pain or relieve pressure at one troublesome site. Metastatic disease is also not one situation. Some cancers spread widely and progress quickly, while others are held in check for long stretches and are managed much as a lasting condition would be.
Used in a sentence
Imaging revealed metastatic disease in the liver at the time of the patient's initial cancer diagnosis.
Good to know
A tumor can be malignant, meaning capable of invasion and spread, without yet being metastatic, since metastatic specifically describes cancer that has already established new tumors elsewhere in the body.
Word origin
Where “metastatic” comes from
Formed from Greek meta-, meaning beyond or change, and stasis, meaning a standing or placement, together describing a shift in position.