 RATIONALE: Interferon alfa may interfere with the growth of tumor cells. Interleukin-2 may stimulate a persons white blood cells to kill tumor cells. Drugs used in chemotherapy use different ways to stop tumor cells from dividing so they stop growing or die. Combining interferon alfa and interleukin-2 with fluorouracil may kill any remaining tumor cells following surgery. It is not yet known whether combining interferon alfa and interleukin-2 with fluorouracil is more effective than observation after surgery for kidney cancer. 