Kidney cancer, (renal cell carcinoma, or RCC) is a malignancy arising in the small tubules of the kidney, and represents about 2% of all fatal cancers.
In the past RCC affected twice as many males as females, but this gap is narrowing now. RCC occurs mainly in the 50-60 years age group, and is rare under the age of 40. The recorded five-year survival rate has greatly improved to about 65%, largely due to early diagnosis and better surgical management.
There is no known absolute cause for the development of RCC, but many associations are well established:
- Exposure to toxins, e.g. asbestos, cadmium, petroleum by-products
- Analgesic abuse (overuse of pain-killers damages kidneys)
- Alcohol abuse
- Acquired cystic disease needing dialysis
- Hereditary papillary RCC, often involving both kidneys, occurs late in life, and tends not to spread to other organs
- Von Hippel-Lindau disease of brain capillaries has a high incidence of RCC
- Previous radiation therapy
Symptoms and diagnosis
RCC has few symptoms in the early stages, usually only becoming apparent when spread has already occurred. Even then, although symptoms may indicate a kidney problem, they are not diagnostic of RCC. These symptoms include:
- Dark urine, containing blood or blood breakdown products
- Enlargement of one testis
- Flank or back pain
- Abdominal swelling
- Unintentional weight loss
- Excess body hair in females (hirsutism)
- Fever, nights sweats, fatigue
- Distant spread (metastases), most often to lung, lymph glands, bone liver and brain, can cause symptoms related to those organs, e.g. bone fractures.
- Inferior vena cava involvement: the tumour spreads up the large vein towards the heart, and can cause leg swelling, abdominal fluid, abnormal liver function and pulmonary emboli.
Examination may reveal a mass in the region of the kidney, abdominal fluid and often a swollen testis or varicosity of the testis.
Blood tests include a full blood count, kidney and liver function tests, blood calcium, and analysis of the urine for blood and malignant cells.
Imaging tests for the kidney include abdominal ultrasound and/or MRI scans, or even renal angiograms. Chest X-rays and bone scans are performed to search for sites of spread.
The mainstay of treatment is surgical removal. At the time of diagnosis, 40% of RCCs are confined to the kidney, and up to 90% of cases can be cured in this way. In certain selected cases with only one site of spread, surgical cure can be obtained by removing the kidney and the secondary tumour.
If surgery is not possible, or a relapse occurs, immunotherapy is used, e.g. Interleukin and Interferon. New targeted treatments are being investigated .Currently available are the drugs Nexxavar and Sutent.
RCC itself does not respond well to radiation treatment, but it is used successfully to treat tumour symptoms from deposits in bone.
Small tumours still confined to the kidney, without any distant spread, treated with nephrectomy (removal of the kidney) or partial nephrectomy have the best prognosis of a 95% five-year survival rate. Spread to lymph glands reduces the survival rate to 16%; spread to distant organs reduces it to less than 10%.
Tumour recurrence after surgery is a poor sign: chemotherapy or radiotherapy here show poor results. Immunotherapy may be used, but a long-term remission is obtained in only 10-20% of these patients.
Reviewed Dr C Jacobs (Clinical Oncologist), 2008