I Had A Partial Right Nephrectomy Done 2 Yrs Ago.

I had a partial right nephrectomy done 2 yrs ago. I am having intermittent swelling of the right foot and ankle area. Its uncomfortable when this swelling occurs but I was not on my feet a lot or sitting in one spot hanging them down. I just am curious what could the cause be. I had renal cell carcinoma and it was removed entirely with enough kidney to leave it functioning still. .... Thank you, Amanda