Kidney cancer is a fairly uncommon cancer, and much less common than prostate cancer, bowel or breast cancer. Kidney tumours are usually found when a patient has a scan done for another reason, and are incidentally found during a CT scan or ultrasound of the abdominal organs. Only larger tumours may present with symptoms, and these are typically blood in the urine or pain over the kidney area, sometimes with weight loss or vague symptoms like feeling tired and sweats at night and loss of appetite.
Most kidney tumours are very slow growing (1-10mm growth in diameter per year) and very few have spread or "metastasized" at the time of diagnosis. There are several types of kidney cancer, the commonest (+/- 85%) being "clear cell" carcinoma. The larger the size of the tumour at diagnosis, the more aggressive it is likely to be and the higher the chance that it might have spread or may do so in the near future.
The cause of kidney cancers is generally not known, but a variety of factors including diet, obesity, smoking, family history, and overuse of certain pain medications are implicated in causing kidney cancer. The only curative treatment is surgical removal of the tumour and part of the adjacent kidney (partial nephrectomy) or removal of the whole kidney in large tumours.
Chemotherapy and radiotherapy generally have little efficacy in the treatment of primary tumours (i.e. tumours that haven't spread outside the kidney yet). These procedures are generally done with keyhole surgery nowadays, either with laparoscopic instruments or robot-assisted laparoscopic surgery. Recovery from this type of surgery is generally fairly rapid, with most patients only requiring on average a 3-day hospital stay after surgery.