Studies have generally shown a slight advantage to getting chemotherapy before undergoing surgery. When these studies are combined, we are able to see about a 5% improvement in overall survival at five years.
One important point to make about preoperative chemotherapy is that it delays surgery by several weeks while the patient receives treatment. Not all patients will be helped by chemotherapy, and some patients will suffer from side effects.
There is a chance that the cancer could spread outside of the bladder while undergoing treatment. These patients might then have missed their window of opportunity to be cured by surgery because the chemotherapy treatments took several weeks to complete.
It is not yet clear whether the benefits of the chemotherapy outweigh this potential risk. It is usually beneficial to discuss the risks and benefits of your case with a qualified oncologist prior to undergoing surgery.