Do all oncology centers follow the same protocol for leukemia?

No: Firstly there are multiple types of leukemia (acute, chronic, granulocytic, lymphocytic, hairy cell). There's a general consensus based on respected multi-insitutional centers on the latest successful regimens. But these are only guidelines. Each person is unique and rx may need to individualized. Also new studies r always being done, and study portocols will vary from one institution to another.

Usually: All oncologists follow proven guidelines (usually nccn or asco), so the treatment for any cancer should be pretty much the same in portland, oregon or portland, maine. Some centers may have experimental protocols available, but one must remember they haven't been proven to be better or as good, or they would be the nccn standard.