Stage 4 bladder cancer is a metastatic, or widespread, form of cancer. In this type of cancer, the abnormal cell growth that characterizes all cancers forms a tumor that originates in the transitional cells lining the bladder itself. At stage 4, cells from the tumor have spread from the bladder to other parts of the body.
Typically, the progression of cancer is divided into stages measured by the overall growth and spread of the disease. Stage 4 is the final stage of bladder cancer. In this stage, the abnormal cells infiltrate distant sites of the body, such as other organs and lymph nodes, causing tumors elsewhere in the body. Stage 4 cancers are generally considered systemic, meaning that they are no longer confined to a localized area and now effect the body as a whole.
The most likely sites for the spread of stage 4 bladder cancer are, in no particular order, the lymph nodes surrounding the bladder; the rectum; the prostate; the vagina; the uterus; or the ureters. In some cases, cancers can spread to less typical areas or areas farther away from the bladder. The abnormal cells travel using the lymphatic system, which is a critical part of the immune system with outposts all over the body. Less commonly, then, stage 4 bladder cancer can attach the lymph nodes in the pelvis, the lungs, the liver, or the bones.
Once the disease spreads, it strives to create tumors other areas of the body. This dramatically reduces the probability of forcing the cancer into remission, and also reduces the number of available treatment options. The combination of progression in the disease and regression in the available options for dealing with stage 4 bladder cancer results in a low survival rate for those affected with the condition.
Stage 4 bladder cancer cannot be effectively treated with targeted therapies such as the removal of the bladder, chemotherapy, or immunotherapy. Once the disease has made its way into multiple areas of the body, the only treatment approach is one that affects the patient as a whole. One example of this is widespread chemotherapy, which can be a difficult treatment protocol for patients to tolerate.
Even if a diffuse plan of treatment is practical, stage 4 bladder cancer is widely considered terminal. If the cancer has only spread to the surrounding lymph nodes, between 10 and 15 percent of people will survive for more than five years. If the cancer has spread to the liver, bones, or lungs, the average survival time is between 12 and 18 months. Concrete survival rates are challenging to assess, because each case is unique. Better outcomes are also possible for individuals receiving care at locations where clinical trials are being conducted.