With intravesical therapy, the doctor puts
the drug directly into the bladder (through a catheter) rather than
giving it by mouth or injecting it into a vein. This may be either
immunotherapy, which causes the body’s own immune system to attack the
cancer cells, or chemotherapy.
Medicines given this way mainly affect the
cells lining the bladder, with little to no effect on cells elsewhere.
This means that any cancer cells outside of the bladder lining,
including those that have grown deeply into the bladder wall, are not
treated. Drugs put into the bladder also can’t reach cancer cells in the
kidneys, ureters, and urethra, or those that have spread to other
For this reason, intravesical therapy is used only for non-invasive (stage 0) or minimally invasive (stage I) bladder cancers.