Please tell me, could a kidney cancer exist for 17 years?

Very, very unlikely: Kidney cancers almost always grow a lot faster, although it is theoretically possible that it could have existed as a tiny tumor for a number of years before enlarging. Kidney cancers can also develop in complex kidney cysts. So 17 year-old kidney x-rays or ultrasounds might demonstrate a cyst at present site of a tumor. Benign angiomyolipomas of kidney can turn into kidney cancer with time.