Visceral metastases describe a situation where cancer that originated in one location, called the primary site, has spread to the internal organs. These organs are located within the body’s major cavities, such as the chest or abdomen. When cancer cells form a new tumor in an organ, it is not a new type of cancer. Instead, it is the original cancer growing in a new place; for example, breast cancer that spreads to the lung is called metastatic breast cancer, not lung cancer. This distinction is important because the metastatic tumor shares the features of the primary cancer.
The Process of Metastasis to Visceral Organs
The process begins when individual cancer cells break away from the original tumor. These cells must first invade the surrounding tissues and then gain access to the body’s transportation networks: the bloodstream or the lymphatic system. The lymphatic system is a network of vessels that carries immune cells and fluid throughout the body.
Once inside a blood or lymph vessel, the circulating tumor cells travel throughout the body. This journey is perilous, and most of these cells do not survive. However, some cells manage to stop in the small blood vessels of a distant organ, exit the vessel, and invade the new tissue. If the conditions in this new environment are suitable, the cell can begin to multiply and form a new tumor, known as a metastasis.
Common Locations and Associated Symptoms
While cancer can spread to almost any organ, certain visceral sites are more common, including the liver, lungs, and brain. The specific symptoms a person might experience depend on which organ is affected and the size of the new tumors. When metastases form in the liver, they can cause symptoms such as abdominal pain, particularly in the upper right side, unexplained weight loss, and jaundice, which is a yellowing of the skin and eyes.
Metastases in the lungs can interfere with breathing, leading to a persistent cough, shortness of breath, or coughing up blood. If cancer spreads to the brain, it can cause neurological symptoms. These may include headaches, seizures, dizziness, or changes in personality or behavior. The peritoneum, the thin tissue lining the abdominal wall and covering most of the abdominal organs, can also be a site of metastasis, which may cause abdominal swelling and bloating.
Diagnostic Methods for Visceral Metastases
Identifying visceral metastases requires imaging technologies and laboratory tests. Doctors use advanced imaging to locate and assess tumors, such as computed tomography (CT) scans that create detailed cross-sectional images of organs. Magnetic resonance imaging (MRI) uses magnetic fields for high-resolution pictures, useful for the liver and brain. Positron emission tomography (PET) scans can detect cancer cells throughout the body using a radioactive tracer.
While imaging provides strong evidence, a biopsy is often performed to confirm a diagnosis. During a biopsy, a small sample of tissue is removed from the suspected metastatic tumor and examined under a microscope by a pathologist. This examination confirms that the tumor is a metastasis from the original cancer, which is important for determining the best course of treatment.
Therapeutic Approaches
Treatment for visceral metastases is complex and involves systemic therapies designed to reach cancer cells throughout the body. Common options include:
- Chemotherapy, which uses drugs to kill rapidly dividing cells.
- Targeted therapy, which uses drugs that attack specific molecules involved in cancer growth.
- Immunotherapy, which helps the body’s own immune system recognize and fight cancer cells.
- Hormone therapy, which may be used when the cancer’s growth is fueled by hormones.
In addition to systemic treatments, localized therapies may be used to target specific tumors. Radiation therapy uses high-energy rays to destroy cancer cells in a particular area and can be effective for palliating symptoms. A specialized form, stereotactic radiation, delivers a highly focused dose of radiation to the tumor, minimizing damage to surrounding healthy tissue. Surgery to remove a limited number of metastases or other procedures like ablation may also be considered.
Impact on Prognosis and Treatment Goals
The presence of visceral metastases is a significant factor in a cancer prognosis. This stage of disease, often classified as Stage IV, indicates that the cancer has spread extensively. Because the cancer is in multiple locations, it is considered advanced, and a cure is often not possible. The prognosis can vary depending on the primary cancer type and the specific organs involved.
The primary goals of treatment often shift from curative intent to palliative care. The focus becomes managing the cancer as a chronic condition, with the aim of slowing its progression and controlling symptoms. This approach prioritizes maintaining the best possible quality of life. Treatment decisions are made to balance the potential benefits of a therapy against its side effects, ensuring the patient’s comfort and well-being.