Nearly all cancers can metastasize (spread), but some types are notorious for it, including breast, lung, colorectal, prostate, melanoma, pancreatic, ovarian, and thyroid cancers, commonly spreading to the liver, lungs, bones, and brain. Metastasis occurs when cancer cells break from the primary tumor and travel via blood or lymphatics to form new tumors elsewhere, often affecting organs like the lungs, liver, bones, and brain.
Some of the most common sites of metastases are the:
Several other factors cause cancer to migrate, such as an attack on the immune system, lack of oxygen and nutrients in the tissue, lactic acid accumulation in the blood and cell death. Cancers that are most likely to metastasize include breast, colon, lung, ovarian, pancreatic, prostate and thyroid.
Metastatic cancer is diagnosed with imaging (CT scans, MRIs, and/or PET scans) to determine the extent of disease and with a biopsy of a tumor so that a pathologist can identify the specific type of cancer.
Benign metastasizing leiomyoma (BML) is a rare condition of uterine leiomyoma with pathologically benign findings but pulmonary metastasis. Fast-growing cystic BML is extremely rare. Many patients with BML have a medical history of myomectomy or hysterectomy.
Some of the more common symptoms include:
The main tests for metastases are:
There are three primary ways tumors can spread to distant organs:
The tumor cells may reinitiate growth to form metastases within a few weeks. Alternatively, tumor cells can survive and stay dormant for a long period before reinitiating growth and thus form clinically relevant metastases only months or years later.
How Does Cancer Metastasize? Cancer metastasizes when cells from the original tumor break apart and spread to other body parts. Causes of metastasis can be linked to an attack on cancer by the immune system or conditions where cancer struggles to survive—from a lack of oxygen or essential nutrients.
Specific types of benign tumors can turn into malignant tumors. These are monitored closely and may require surgical removal. For example, colon polyps (another name for an abnormal mass of cells) can become malignant and are therefore usually surgically removed.
Stage 4 means the cancer has spread from where it started to another body organ. For example to the liver or lung. This is also called secondary or metastatic cancer. Sometimes doctors use the letters A, B or C to further divide the number categories.
Whole-body MRI and PET-CT are now the most sensitive and specific methods for the detection of skeletal metastases. Whole-body MRI is becoming more widely available; it enables the most sensitive detection of bone-marrow metastases and extraosseous tumor extension.
The liver is the most common site of distant metastasis in solid tumors. Gastrointestinal cancers such as CRC, pancreatic cancer and tumors of the gallbladder, which are drained by the enterohepatic circulation, reach the liver first.
At a Glance. Breast, lung and bronchus, prostate, and colorectal cancers account for almost 50% of all new cancer cases in the United States. Lung and bronchus, colorectal, pancreatic, and breast cancers are responsible for nearly 50% of all deaths.
The most common sites of metastasis are bone, liver and lungs. Cancer is always identified in terms of where it first develops. For example, colon cancer that has spread to the lungs is still considered colon cancer.
The six least survivable cancers are aggressive and often diagnosed late. These include pancreatic, liver, esophageal, lung, stomach, and brain cancers. They grow fast and are hard to treat. Knowing what they have in common helps us find better ways to fight them.
The first step to metastasis is for a few hardy cells to escape the main tumor and enter the bloodstream. These are circulating tumor cells, or CTCs. The bloodstream is a dangerous highway — think of the Autobahn — and not every cancer cell can survive it.
Primary tumors are those located at the site where the tumor began to grow (i.e., where it originated). Metastatic (or Secondary) tumors are those that have spread to other parts of body from the original tumor site. Tumors are also classified based on their tendency to grow.
Physical exam and imaging can show that something abnormal is present, but a biopsy is the only sure way to know whether the problem is MBC. A biopsy is surgical removal of all or part of a suspected tumor/metastasis for examination under a microscope to check for cancer cells.
Doctors can't always tell if a tumor is cancerous just by looking. Some tumors might look suspicious, but a biopsy is needed for sure.
Which Type of Cancer Spreads Fastest? The fastest-moving cancers are pancreatic, brain, esophageal, liver, and melanoma. Pancreatic cancer is one of the most dangerous types of cancer because it's fast-moving, and there's no method of early detection.
Metastatic tumors, also known as secondary tumors, are cancerous growths that have generally spread from their original site to other parts of the body. When the cancer cells break away from the primary tumor, they may travel through the blood stream or lymphatic system.
It is theorized that metastasis always coincides with a primary cancer, and, as such, is a tumor that started from a cancer cell or cells in another part of the body. However, over 10% of patients presenting to oncology units will have metastases without a primary tumor found.