Bladder cancer involves the uncontrolled growth of abnormal cells within the bladder, forming a tumor. Metastasis occurs when these cells break away from the original tumor and travel to other parts of the body to form new tumors. The presence of metastasis indicates a more advanced stage of bladder cancer.
How Bladder Cancer Spreads
Bladder cancer cells can spread through several pathways, beginning with direct invasion of surrounding tissues. The cancer may grow into the bladder wall and extend into nearby fatty tissues and organs. This local spread can affect structures such as the ureters, urethra, or prostate.
Cancer cells can also enter the lymphatic system, a network of vessels and nodes. Once in the lymphatic system, these cells can travel to regional lymph nodes, particularly in the pelvis and abdomen. From there, they can spread to more distant lymph nodes throughout the body.
Another pathway for spread is through the bloodstream, a process called hematogenous metastasis. Cancer cells can break off from the primary tumor, enter small blood vessels, and circulate to distant parts of the body. These circulating cells can then exit the bloodstream at a new location, establish themselves, and begin to grow, forming new tumors.
Common Sites of Bladder Cancer Spread
Bladder cancer commonly spreads to regional lymph nodes in the pelvis and abdomen, which are frequent initial sites due to their proximity and role in lymphatic drainage. Swelling and pain around these nodes can sometimes occur.
Beyond the lymphatic system, common distant sites for bladder cancer to spread include the bones, lungs, and liver. Bone metastasis can lead to bone pain or increased risk of fractures. In the lungs, metastatic tumors may cause symptoms like a persistent cough, breathlessness, or recurrent chest infections.
When bladder cancer spreads to the liver, individuals might experience fatigue, loss of appetite, weight loss, or abdominal pain. It can also spread to the peritoneum or, rarely, to the brain.
Recognizing Metastatic Bladder Cancer
Recognizing metastatic bladder cancer involves observing new or worsening symptoms from areas where the cancer has spread. For instance, bone spread may cause pain or weakness. Lung spread can manifest as a persistent cough, shortness of breath, or coughing up blood. Liver involvement might lead to abdominal pain, swelling, jaundice, or significant weight loss.
General symptoms that can accompany metastatic bladder cancer include extreme fatigue, unexplained weight loss, and a general feeling of being unwell. Changes in urinary function, such as difficulty urinating or lower back pain on one side, can also be indicators, especially if the cancer has spread to nearby structures or caused kidney issues.
To diagnose metastatic bladder cancer, doctors employ various imaging tests. These can include CT scans, MRI scans, and PET scans, which help visualize the extent of cancer spread throughout the body. Bone scans are specifically used to detect if the cancer has spread to the bones. In some cases, a biopsy of the suspected metastatic tumor may be performed to confirm the presence of cancer cells and determine their origin, which helps ensure the new tumor is indeed from the bladder.
Managing Metastatic Bladder Cancer
Managing metastatic bladder cancer focuses on controlling the disease, alleviating symptoms, and improving the individual’s quality of life. Treatment strategies often involve systemic therapies, which work throughout the body to target cancer cells wherever they may be.
Chemotherapy is a common initial treatment for metastatic bladder cancer, often using combinations of drugs like gemcitabine with cisplatin. These drugs circulate through the bloodstream, aiming to destroy cancer cells or slow their growth. For individuals who cannot tolerate cisplatin due to kidney function or other reasons, carboplatin-based regimens may be an alternative.
Immunotherapy represents another important treatment approach. These therapies, such as immune checkpoint inhibitors like pembrolizumab, nivolumab, durvalumab, and avelumab, help the body’s immune system recognize and fight cancer cells. Immunotherapy can be used alone or as maintenance therapy after chemotherapy to sustain treatment benefits. Targeted therapies are also being explored, which focus on specific molecules involved in cancer growth.
Radiation therapy plays a role in managing symptoms, particularly pain from bone metastases or to control localized pelvic issues. While surgery is generally not a primary treatment for widespread metastatic disease, it might be considered in specific situations to alleviate symptoms, such as removing tumors from the bladder to manage bleeding or unblocking obstructed ureters. Supportive care is an integral part of management, addressing symptoms and treatment side effects to enhance daily comfort and overall well-being.