[이데일리 이순용 기자] The kidney (kidney) is a reddish-brown kidney bean-shaped organ with a size of about 10 cm × 5 cm × 3 cm located in the retroperitoneum (behind the peritoneum covering the intestine) under both ribs, at the back of the abdominal organs. Its main function is to make urine. Making urine means filtering waste products from the blood and excreting unnecessary water. In addition, it functions to maintain homeostasis so that the concentration of substances essential for bodily functions such as sodium, potassium, calcium, and phosphorus can always be maintained in a constant state. The kidneys are also responsible for the endocrine function that secretes vitamin D, which makes bones strong, and hematopoietic hormone, which makes red blood cells.
Renal cancer is a malignant tumor of the kidney. Renal cancer is divided into renal pelvic cancer and renal cell carcinoma according to the location of occurrence. In general, kidney cancer refers to renal cell carcinoma that occurs in the parenchyma of the kidney (the part of the kidney that makes urine and consists of the medulla and cortex). Renal cell carcinoma accounts for about 85% of all renal tumors. The rest are benign tumors and sarcomas.
The number of new cases of renal cell carcinoma in Korea is about 5,000 annually, accounting for about 2% of all carcinomas. It is about 1/6 of the most common cancers such as stomach cancer, lung cancer, and liver cancer, which occur in about 30,000 people annually. Cancer is ranked 10th. It can occur in both men and women, but it is twice as common in men.
Kim Jeong-jun, a professor of urology at the Catholic University of Korea Incheon St. Mary’s Hospital, said, “Kidney cancer is difficult to detect without early screening because there are few symptoms, and if you visit a hospital after symptoms appear, it is often quite advanced.” “Early diagnosis through regular check-ups It is important to do this, but imaging tests such as abdominal ultrasound are not included in the current national mandatory examination items, so the diagnosis time is often missed,” he said.
Kidney cancer has a high cure rate if diagnosed early, but it is difficult to treat after symptoms appear, so it is called ‘cancer with the face of Janus’. In celebration of World Kidney Cancer Day on June 18, we learned about the prevention and treatment of kidney cancer.
◇If diagnosed after the onset of symptoms, 30-40% have already metastasized
The number of kidney cancer patients in Korea is steadily increasing. According to the Health Insurance Review and Assessment Service, the number of patients receiving treatment for kidney cancer last year stood at 36,340, a 30.3% increase from 27,888 in 2017. That is, about 100 people a day receive treatment for kidney cancer.
The cause of kidney cancer is not yet clear. However, several studies have pointed out that family history, smoking, diet, hypertension, obesity, and environment are risk factors. In particular, smoking is known to increase the incidence of cancer by as little as 30%, or as much as 2 times. In addition, there is a report that the risk of kidney cancer increases in patients on long-term hemodialysis, and the risk increases two to three times if there is a family history of renal cell cancer.
Professor Kim Jeong-joon said, “The subjective symptoms of kidney cancer only appear when the tumor grows to a certain extent, which causes the structure of the kidney to be deformed or to push the organs away. Because I am not a listener, it is difficult to expect a good prognosis if early screening fails.” He continued, “If you visit a hospital after symptoms appear and are discovered late, about 30-40% of patients can be considered to have already started metastasis.”
◇The principle of treatment is surgery… Early diagnosis through regular checkups is important
The treatment of kidney cancer depends on the progress of the cancer, the age of the patient, the general condition, and the presence or absence of other concomitant diseases. Treatment is, in principle, surgery. Previously, total resection, which involves extensive resection of the kidney and surrounding normal tissue, was the standard of care. If the tumor was small, only the tumor was removed while saving the surrounding kidney tissue. However, with advances in technology, standard care has also changed. According to the recent guidelines of the European Urology Association, it is recommended to perform partial resection as much as possible, even if the size is larger than 7 cm or the location is difficult.
Professor Kim Jung-jun said, “In most cases, kidney cancer is cured by surgery, so the quality and quantity of life after surgery are both important. Even if you do not progress to chronic kidney failure because the kidney on the opposite side has good function, you will be restricted in your daily life, such as eating and exercising, and your quality of life will decrease as well as your life expectancy. There are disadvantages compared to resection,” he explained, explaining the recent trend in which the importance of partial resection is being emphasized.
The surgical method may be robotic surgery, laparoscopic surgery, or open surgery. Although the recovery speed differs depending on the surgical method, in general, after 2 to 4 weeks of surgery to remove the tumor, daily life is possible. After that, regular follow-up is performed with imaging tests such as computed tomography (CT) or magnetic resonance imaging (MRI).
In most cases of stage 1 or 2, a complete cure is possible only with partial resection, and the 5-year survival rate is also 90-100%, which is high compared to other carcinomas. However, if there is distant metastasis to the lungs or bones, the prognosis is poor, with a 2-year survival rate of 50% and a 5-year survival rate of only about 20%.
Smoking cessation is very important to prevent kidney cancer. Diet management and weight control are also essential because the incidence rate greatly increases when obese or poor blood sugar control. Regular exercise can also help improve immunity.
In addition, for early diagnosis of kidney cancer, it is important to receive regular abdominal ultrasound examinations during health check-ups, and to receive regular examinations if you have kidney disease such as chronic kidney failure, diabetes, or obesity.
Professor Kim Jeong-jun said, “As kidney ultrasound has been included in the pay item since 2009, if you regularly visit the hospital for internal medical problems, it is advisable to consult with your attending physician on whether or not abdominal ultrasound is necessary. If the kidney tumor is small or faint, it is often missed, so it is recommended to perform periodic examinations every year or every other year,” he emphasized.