It all depends on the type of chemo.
BCG is "Immunotherapy", not chemotherapy. It is a TB vaccine used to stimulate an immune response which has been shown to be highly effective in killing cancer cells in the bladder. This is a done by a urologist (although some urologists are also classified as urological oncologists).
Mitomycin is a "chemotherapy" drug but in the case of bladder cancer, it is instilled through a catheter directly into the bladder. This is also done by a urologist.
The direct instillation into the bladder gets the immunotherapy or chemotherapy agents directly in contact with the cancer cells.
What we typically think of as "chemotherapy" is when they are injecting drugs into the circulatory system which then gets the drug into the entire body. This is done by an oncologist. Remember that some urologists are also oncologists but usually the ones at major bladder cancer centers (e.g. Memorial Sloan, MD Anderson).
With breast cancer and many other cancers the chemotherapy has to go throughout the body.
With bladder cancer, if it can be caught and dealt with prior to getting outside of the bladder then systemic chemotherapy isn't needed. NCCN has recently updated their guidelines though to recommend some chemotherapy prior to removal of the bladder for T2 (muscle invasive) and above because of a reduction in recurrence.
Does that answer your question?
Mike
Age 54
10/31/06 dx CIS (TisG3) non-invasive (at 47)
9/19/08 TURB/TUIP dx Invasive T2G3
10/8/08 RC neobladder(at 49)
2/15/13 T4G3N3M1 distant metastases(at 53)
9/2013 finished chemo -cancer free again
1/2014 ct scan results....distant mets
2/2014 ct result...spread to liver, kidneys, and lymph...