Urothelial carcinoma (bladder cancer) affecting the ureter has traditionally been treated with complete kidney and ureter removal. A recent study indicates that in selected patients, removal of only the segment of ureter affected by cancer had similar overall survival rates. Applying this technique would help preserve kidney function and allow more options in later treatment (such as chemotherapy) if needed. Downsides are that more complex/consistent follow up would be needed as recurrence rates would be expected to be higher.
https://www.sciencedirect.com/science/article/abs/pii/S1078143920303719