Metastasis or tumor cell dissemination occurs via the hematogenous and lymphatic systems. For many carcinomas, the dissemination of tumor cells via lymphatic drainage of the tumor is the most common metastatic route.
During the metastatic cascade, changes in cell-cell and cell-matrix adhesion are of paramount importance. The metastatic cascade can be broadly separated into three main processes: invasion, intravasation and extravasation.
There are three primary ways tumors can spread to distant organs: Through the circulatory (blood) system (hematogenous) Through the lymphatic system. Through the body wall into the abdominal and chest cavities (transcoelomic).
Often, the first stop is the lymph nodes. And, as it advances, metastases can occur in distant parts of the body, some of the most common ones being the bones, lungs, liver, and brain.
Metastatic cancer is a cancer that has spread from the part of the body where it started (the primary site) to other parts of the body. When cancer cells break away from a tumor, they can travel to other parts of the body through the bloodstream or the lymph system.
In metastasis, cancer cells break away from where they first formed, travel through the blood or lymph system, and form new tumors in other parts of the body. Cancer can spread to almost anywhere in the body. But it commonly moves into your bones, liver, or lungs.
The skin, ovaries and spleen are less common sites of metastasis.
Metastasis occurs when cancer spreads beyond its original site to a distant part of the body. During this process, the cancer cells may: Spread into tissue near the original cancer site. Invade the walls of nearby blood vessels or lymph nodes.
A patient with widespread metastasis or with metastasis to the lymph nodes has a life expectancy of less than six weeks. A patient with metastasis to the brain has a more variable life expectancy (one to 16 months) depending on the number and location of lesions and the specifics of treatment.
The five-year survival rate of metastatic cancer depends on the type of cancer you have. For example, the five-year survival rate for metastatic lung cancer is 7%. This means that 7% of people diagnosed with metastatic lung cancer are still alive five years later.
For example, a breast cancer that spreads to the liver is called metastatic breast cancer, not liver cancer. This is because the cancer started in the breast and the treatment used is for breast cancer.
Cancer metastasizes due to several factors, namely attack by the immune system, lack of oxygen and necessary nutrients, large amounts of lactic acid produced by glycolysis and increased cell death. Therefore, the majority of the presently available treatments for cancer also bear the potential to induce metastasis.
Most metastases, however, occur within 10 years after removal of the primary tumor.
Stage 4 cancer is sometimes referred to as metastatic cancer, because it often means the cancer has spread from its origin to distant parts of the body. This stage may be diagnosed years after the initial cancer diagnosis and/or after the primary cancer has been treated or removed.
The 5-year survival rate tells you what percent of people live at least 5 years after the cancer is found. Percent means how many out of 100. The 5-year survival rate for women with metastatic breast cancer is 29%. The 5-year survival rate for men with metastatic breast cancer is 22%.
Some cancer research suggests that surgically removing metastatic tumors or killing them off with radiation may facilitate a better prognosis in patients with a limited number of identified tumors—say, five or fewer—a disease oncologists now describe as oligometastatic (oligo meaning “few” in Greek) cancer.
This is also called end-stage cancer or terminal cancer. (Sometimes terminal cancer is called metastatic cancer, but they aren't always the same thing.
Metastases that were once diagnostically confirmed disappear to a certain extent in computed tomography (CT) or magnetic resonance imaging (MRI). Such metastases were left untreated (10, 11). With a recurrence rate of up to 83% of untreated disappearing CRLMs (11), clinical effectiveness is a necessity.
If correct, metastases grow much faster than primary tumours. However, growth rates and proliferation indices of paired metastases and primary tumours are similar, with metastases growing up to twice as fast as primary tumours1.