Metastatic cancer is the term used when cancer cells from an original, or primary, tumor spread to other parts of the body. This advanced stage of cancer, often referred to as stage IV, signifies that the disease is no longer localized. The name of the metastatic cancer reflects its origin; for instance, breast cancer that has spread to the lungs is called metastatic breast cancer, not lung cancer. This distinction is important because the cancer cells in the new location are identical to those of the primary tumor, which guides treatment decisions.
The Process of Cancer Metastasis
Metastasis is a multi-step process that begins with local invasion, where cancer cells from the primary tumor grow into nearby healthy tissues. The cells then enter the bloodstream or lymphatic system through a process called intravasation. These systems act as highways, allowing cancer cells to travel to distant parts of the body.
Once in circulation, these circulating tumor cells must survive a damaging journey. A surviving cell must exit the vessel in a process called extravasation and establish itself in a new location. To grow into a secondary tumor, the cell must multiply and stimulate the growth of new blood vessels to supply it with nutrients, a process called angiogenesis.
Symptoms and Diagnosis of Metastatic Cancer
The symptoms of metastatic cancer can be general or specific to the area of spread, and sometimes there are no symptoms. General signs may include unexplained weight loss, significant fatigue, or pain that does not go away. Specific symptoms point to the location of the secondary tumors; for example, cancer that has spread to the bones can cause pain or fractures, while metastases in the lungs may lead to shortness of breath.
If cancer spreads to the liver, a person might experience jaundice, which is a yellowing of the skin and eyes, or abdominal swelling. Headaches, seizures, or dizziness can be signs of brain metastases. To diagnose metastatic cancer, doctors use a variety of tests. Imaging techniques like CT scans, MRIs, PET scans, and bone scans are used to locate tumors throughout the body. A biopsy, which involves taking a small tissue sample from the suspected site, is performed to confirm the presence of cancer cells, and blood tests for tumor markers can also provide information.
Treatment Strategies for Metastatic Cancer
The approach to treating metastatic cancer shifts from curative intent to controlling the disease and managing symptoms to improve quality of life. Treatments are systemic, meaning they work throughout the entire body. Systemic therapies include chemotherapy, which uses drugs to kill cancer cells, and hormone therapy, which is effective for cancers sensitive to hormones, such as certain breast and prostate cancers.
In addition to systemic treatments, local therapies may be used to manage specific tumors that are causing problems.
- Targeted therapy uses drugs to attack specific molecules involved in cancer growth.
- Immunotherapy harnesses the body’s own immune system to fight the cancer.
- Radiation therapy can be directed at a metastatic tumor to relieve pain or other symptoms.
- Surgery might be an option in certain situations to remove a limited number of metastases.
Palliative care is a part of the treatment plan, focusing on relieving symptoms and providing support to patients and their families.
Prognosis and Living with Metastatic Cancer
The prognosis for metastatic cancer depends on several factors, including the type of primary cancer, where it has spread, and the extent of the disease. A person’s overall health and how the cancer responds to treatment also influence the outlook. While a cure is not possible for most metastatic cancers, advancements in treatment are helping people live longer with a better quality of life. Some types, like metastatic testicular cancer, can have high cure rates.
Living with metastatic cancer means managing it as a chronic illness with ongoing treatments and monitoring. Support systems, including social workers, therapists, and support groups, can help individuals and their families cope with the emotional and practical challenges. Focusing on achievable goals and open communication with the healthcare team helps manage life with the disease. Clinical trials may also offer access to new treatments.