What is kidney cancer (renal carcinoma)
Kidney cancer is the third most common cancer of the genitourinary system and accounts for approximately 3% of neoplasms in adults. Among these cases, the most common type is clear cell renal cancer, which accounts for 85% of the diagnosed tumors. In children, the most common kidney cancer is Wilm’s tumor (7% of cases).
Renal carcinoma most commonly affects people between the ages of 50 and 70 and is twice as common in men than in women.
About 54% of kidney tumors diagnosed today are located in the kidney alone, 20% are locally advanced (affecting regional ganglia close to the kidney), and 25% have already spread and metastasized, especially to the lungs, liver, and bones.
The incidence of kidney cancer seems to be increasing. One reason may be the expanded and more frequent use in the medical practice of imaging tests, such as CT scans.
Symptoms and Signs of Kidney Cancer
It is estimated that 6% to 10% of patients with kidney cancer have pain in the flank (one side of the back), like a bump in the area, for no apparent reason. Blood in the urine (hematuria), which can be pink, bright red or in a “coca-cola” coloration, and a palpable abdominal mass are also symptoms of the disease.
Other signs and symptoms include:
- Unexplained weight loss
- Persistent fever that is not caused by an infection; and
If you have one or more of the above symptoms, it does not necessarily mean that you have renal cell carcinoma. They are also commonly seen in other benign diseases, such as in cases of kidney stones or urinary tract infections.
Diagnosis of kidney cancer
It is common for kidney carcinoma to be discovered by accident, when performing a routine test, or for another cause. The good news is that in many of these cases it is still in its early stages, located exclusively in the kidney, and has a better chance of cure.
The diagnosis of renal carcinoma is usually made by ultrasound and CT scan of the abdomen, which is also very useful in staging (where the size of the tumor is determined and if there are any metastases) and in treatment planning. The stages of renal cancer are indicated by Roman numerals from I to IV (I being for the simplest, restricted to the kidney, and IV for the most complex, with metastases).
Other approaches include chest radiography, which checks for lung involvement. MRI, on the other hand, is rarely used in these tumors, being reserved only for very specific situations.
The renal biopsy, when requested, serves to differentiate malignant lesions from benign ones, which would not require treatment. Laboratory tests of blood and urine can also be part of the diagnostic process.
Surgery is the initial treatment of choice for most renal carcinomas. The goal of surgery is to remove the cancer while preserving kidney function (keeping the organ active). The types of surgical procedures are:
- Nephrectomy: total removal of the kidney affected by the cancer; and
- Partial Nephrectomy: removal of only the tumor located in the kidney. It is most commonly used for smaller tumors that do not metastasize.
In certain cases, kidney cancer can also be eliminated through non-surgical approaches. Learn about the main ones:
- Cryoablation: treatment that freezes the cancer cells. A special needle, guided by ultrasound, is introduced through the skin until it reaches the kidney tumor. An iced gas is injected through this needle to freeze the tumor cells; and
- Radiofrequency ablation: In this procedure, a special probe is inserted through the skin, also guided by ultrasound. An electric current is released inside the cancer cells, causing them to be overheated and consequently eliminated.
In the case of advanced kidney cancer, or if the cancer has returned (recurred) even after treatment, there are some treatments that aim to control the disease. Some examples include surgery to remove as much of the cancer as possible, targeted therapies, and immunotherapy. In general, renal carcinoma does not respond well to chemotherapy and radiation treatments.
The main factors that can increase the risk of developing kidney cancer are:
- Advanced age;
- Tobacco smoking;
- Hypertension (“high blood pressure”);
- Treatment for kidney failure (people who have been on hemodialysis for a long time have a higher risk for kidney cancer); and
- Some inherited syndromes, such as von Hippel-Lindau disease, Birt-Hogg-Dube syndrome, tuberous sclerosis complex, hereditary renal papillary carcinoma, and familial renal cancer.
Some of these risk factors are modifiable and preventable. For example, it is possible not to smoke, to adopt healthy lifestyle habits, to follow a balanced diet, and to have good blood pressure control. So, get moving! Practice physical activities and keep an eye on your diet and behaviors.