Help me to understand treatments for stage 4 vaginal cancer.

Staging of Vaginal Cancer
Once cancer of the vagina has been diagnosed, more tests will be done to find out if the cancer has spread from the vagina to other parts of the body. This process is called staging. In order to plan the treatment, the provider/physician, often the oncologist, needs to know the stage of the disease. Oncologists have established the following stages for each step of progression:

Stage 0 or carcinoma in situ
Stage 0 cancer of the vagina is a very early cancer. The cancer is found inside the vagina only and is in only a few layers of cells.

Stage I
Cancer is found in the vagina, but has not spread outside of it.

Stage II
Cancer has spread to the tissues just outside the vagina, but has not gone to the bones of the pelvis.

Stage III
Cancer has spread to the bones of the pelvis. Cancer cells may also have spread to other organs and the lymph nodes in the pelvis. (Lymph nodes are small bean-shaped structures that are found throughout the body. They produce and store cells that fight infection.)

Stage IV
Stage IV is divided into stage IVA and stage IVB:

Stage IVA: Cancer may have spread to lymph nodes in the pelvis or groin and has spread to one or both of the following areas: The lining of the bladder or rectum. Beyond the pelvis.
Stage IVB: Cancer has spread to parts of the body that are not near the vagina, such as the lungs. Cancer may also have spread to the lymph nodes.

For more information:
- Vaginal Cancer Staging (PDQ®)
- ASCO Patient Information Cancer.Net
- Cancer Treatment Centers of America Vaginal Cancer Staging