World Cancer Day is observed annually on February 4. The Union for International Cancer Control (UICC) established the day in 2005 to raise awareness about cancer and support patients.
Cancer remains the leading cause of death among Koreans. For 40 consecutive years, it has ranked as the number one cause of death in South Korea. According to the 2021 National Cancer Registration Statistics, the most common cancers include thyroid, colorectal, lung, stomach, breast, and prostate cancers. However, since 2019, kidney cancer has steadily increased in cases and entered the top ten most common cancers.
Kidney cancer occurs more frequently in men than in women. In 2020, it was the eighth most common cancer among men and rose to seventh place in 2021.
Kidney cancer develops in the kidneys, located on either side of the spine below the diaphragm. It most commonly originates in the renal parenchyma as renal cell carcinoma, a malignant tumor.
While the exact causes of kidney cancer remain unclear, smoking, obesity, hypertension, and chronic kidney disease are known risk factors.
Kim Jung Kwon, a professor in the Department of Urology at Seoul National University Bundang Hospital, said that some patients wonder why they develop kidney cancer despite not smoking or drinking, exercising regularly, and having normal blood pressure. He explained that genetic mutations often play a larger role in kidney cancer than lifestyle factors, emphasizing that even those in good health should not be complacent.
Kidney cancer is often asymptomatic in its early stages, making early detection difficult. Like liver and pancreatic cancer, symptoms usually appear only after significant progression.
Kim said patients frequently ask whether proteinuria or kidney-related markers in health screenings indicate kidney cancer. While these markers may relate to other conditions, they are rarely specific to kidney cancer. He also noted that kidney cancer cannot be detected through blood or urine tests alone.
The main symptoms of kidney cancer include hematuria, flank pain, and a palpable abdominal mass. However, by the time these symptoms appear, the cancer is often in an advanced stage.
Jo Jung Min, a professor in the Department of Hematology and Oncology at Ewha Womans University Mokdong Hospital, said that only about 10-15% of patients exhibit all three symptoms. He advised individuals with a family history of kidney cancer or preexisting conditions such as chronic kidney disease or polycystic kidney disease to undergo regular screenings.
Fortunately, kidney cancer has a high survival rate when detected early.
Kim said that the survival rate for stage 1 kidney cancer patients after surgery is 100%, while stage 2 patients have a 97-98% survival rate. Even at stage 3, the survival rate remains above 90%. However, the recurrence rate for stage 3 cancer increases to 30%, approximately ten times higher than that of stage 1. Once the cancer reaches stage 4 and metastasizes to other organs, treatment becomes more complex, and the prognosis worsens.
Because kidney cancer often progresses silently, one-third of patients are diagnosed only after the cancer has already spread. Many doctors consider kidney cancer to be largely asymptomatic rather than associating it strictly with symptoms like hematuria, flank pain, or an abdominal mass.
Many cases are discovered incidentally during CT scans or ultrasounds for other medical reasons.
Kim emphasized the importance of abdominal ultrasounds, which are not yet included in standard screenings. He noted that these scans can help detect abnormalities in the kidneys and the liver, gallbladder, spleen, and pancreas.
He added that while stomach cancer screenings are recommended from age 40 and colon cancer screenings from age 50, no clear age-related guidelines exist for kidney cancer. Patients under 40 account for about 30% of kidney cancer cases, so he recommended an abdominal ultrasound every two years starting in one’s 40s, with earlier screenings for those with a family history.
Surgical removal of the tumor is the most effective treatment for operable kidney cancer. If surgery is not an option, the prognosis varies significantly depending on the risk category—low, intermediate, or high. Specialists determine the appropriate first-line treatment, including targeted therapies or immunotherapy. For high-stage cases, ongoing management and close monitoring, particularly in the first one to two years after surgery, are essential due to the high recurrence risk.
Robotic surgery has become a common approach for tumor removal, reducing postoperative complications. Complete kidney removal is rare; even if one kidney is removed, the other typically functions adequately.
However, patients with severely impaired kidney function or those who require the removal of both kidneys may need lifelong dialysis. Such cases are rare.
Kim stressed that even after successful kidney cancer surgery, the risk of developing another cancer remains. He advised patients to adopt healthy lifestyle habits like quitting smoking and maintaining a healthy weight. Studies indicate that kidney cancer survivors have a 1.5 times higher risk of developing secondary cancers, making proactive health management essential.