What is kidney cancer (renal carcinoma)
Kidney cancer is the third most common genitourinary cancer and accounts for approximately 3% of neoplasms in adults. Among these cases, the most common type is clear cell renal cell carcinoma, which accounts for 85% of diagnosed tumors. In children, the most common kidney cancer is Wilms’ tumor (7% of cases).
Renal cell carcinoma most commonly affects people aged 50 to 70 years and is twice as common in men as in women.
Approximately 54% of currently diagnosed kidney tumors are localized only in the kidney, 20% are locally advanced (involving regional lymph nodes near the kidney), and 25% have already spread and present metastases, especially in the lungs, liver, and bones.
The incidence of kidney cancer appears to be increasing. One reason may be the expanded and more frequent use of imaging tests, such as computed tomography, in medical practice.
Kidney cancer symptoms
It is estimated that 6% to 10% of patients with kidney cancer experience flank pain (pain in the side of the lower back), described as a dull ache in the region, without an apparent cause. Blood in the urine (hematuria), which can appear pink, bright red, or cola-colored, and a palpable abdominal mass are also symptoms of kidney cancer.
Other signs and symptoms include:
- Fatigue;
- Loss of appetite;
- Unexplained weight loss;
- Persistent fever not caused by an infection; and
- Anemia.
Experiencing one or more of the symptoms above does not necessarily mean you have kidney carcinoma. They are also commonly seen in other benign conditions, such as kidney stones or urinary tract infections.
Diagnosis of kidney cancer
Kidney cancer is often discovered accidentally, during a routine exam or for another reason. The good news is that in many of these cases, it is still in the early stages, located exclusively in the kidney, and has a higher chance of being cured.
The diagnosis of kidney carcinoma is generally made through ultrasound and computed tomography (CT) scans of the abdomen, which are also very useful in staging (determining the size of the tumor and if there are metastases) and planning treatment. The stages of kidney cancer are indicated by Roman numerals from I to IV (with I being the simplest, restricted to the kidney, and IV being the most complex, with metastases).
Other approaches include chest x-rays to check for lung involvement. Magnetic resonance imaging (MRI) is rarely used for these tumors, reserved only for very specific situations.
Kidney biopsy, when requested, is used to differentiate between malignant and benign lesions, with benign ones not requiring treatment. Blood and urine tests may also be part of the diagnostic process.
Treatment for bladder cancer
Surgery is the initial treatment of choice for most kidney 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 cancer; and
- Partial nephrectomy: removal of only the tumor located in the kidney. It is more commonly used for smaller tumors that have not metastasized.
In certain cases, kidney cancer can also be eliminated through non-surgical approaches. Here are the main ones:
- Cryoablation: treatment that freezes cancer cells. A special needle, guided by ultrasound, is inserted through the skin to reach the kidney tumor. A cold 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 into the cancer cells, causing them to be overheated and, consequently, eliminated.
In the case of advanced kidney cancer or cancer that has recurred even after treatment, there are some treatments aimed at controlling the disease. Some examples include surgery to remove as much of the cancer as possible, targeted therapies, and immunotherapy. Overall, kidney carcinoma does not respond well to chemotherapy and radiation therapy.
Prevention of kidney cancer
The main factors that can increase the risk of developing kidney cancer are:
- Advanced age;
- Smoking;
- Obesity;
- High blood pressure (“hypertension”);
- Treatment for kidney failure (people who have been on hemodialysis for a long time have a higher risk of kidney cancer); and
- Having certain hereditary syndromes, such as von Hippel-Lindau disease, Birt-Hogg-Dube syndrome, tuberous sclerosis complex, hereditary papillary renal carcinoma, and familial kidney cancer.
Some of these risk factors are modifiable and avoidable. For example: it is possible to not smoke, adopt healthy lifestyle habits, and follow a balanced diet, as well as maintain good control of blood pressure. So, get moving! Engage in physical activities and keep an eye on your diet and behaviors.
