Renal cell carcinoma (RCC) is a common type of kidney cancer that originates in the lining of the kidney tubules, which are tiny tubes responsible for filtering waste from the blood to produce urine. When RCC is described as “metastatic,” it means that cancer cells have spread from the kidney to distant parts of the body, forming new tumors. This advanced stage of cancer is also referred to as Stage IV RCC.
Understanding Metastatic Renal Cell Carcinoma
Renal cell carcinoma typically begins as a tumor in one kidney, though it can sometimes develop in both. Metastasis can occur in a few ways: cancer cells may invade the tissue immediately surrounding the kidney tumor, enter the lymphatic system, or travel through the bloodstream to reach other organs. Approximately one-third of individuals diagnosed with RCC already have metastatic disease at the time of their diagnosis.
The most frequent sites for RCC to metastasize include the lungs (70-71% of cases), lymph nodes (45-49%), and bones (32-36%). Other common sites for spread include the liver (18-21%), adrenal glands (9-10%), and brain (8-9%). Signs and symptoms of metastatic RCC can vary depending on where the cancer has spread. Common general symptoms include unexplained weight loss, persistent fatigue, and a low-grade fever.
Symptoms vary based on the affected organ. If the cancer has spread to the lungs, individuals may experience shortness of breath, a persistent cough, or chest discomfort. When bones are involved, symptoms can include localized pain and an increased risk of fractures. Metastasis to the brain can lead to headaches, seizures, confusion, or changes in personality or behavior.
Diagnosing Metastatic Renal Cell Carcinoma
Diagnosing metastatic renal cell carcinoma involves a combination of imaging techniques and tissue analysis. Imaging tests, such as computed tomography (CT) scans, magnetic resonance imaging (MRI), and sometimes positron emission tomography (PET) scans, are used to locate the primary tumor in the kidney and identify any areas where the cancer may have spread. CT scans, particularly multiphasic contrast-enhanced ones, are often the initial imaging choice for diagnosis and staging, providing detailed information about the tumor and potential lymph node involvement. MRI is also used, especially if there is suspicion of venous involvement or if a patient cannot receive CT contrast.
A biopsy, taking a tissue sample from a suspected tumor, is often performed for a definitive diagnosis and to classify the specific type of RCC. While biopsies of the primary kidney tumor are not always performed due to potential risks or if imaging is conclusive, they are often used for metastatic lesions to confirm the diagnosis. Blood tests also play a role in assessing a patient’s overall health and kidney function. These tests can reveal abnormalities such as anemia, elevated white blood cell counts, or changes in liver enzymes and calcium levels, which can be indicators of cancer or its spread.
Treatment Approaches for Metastatic Renal Cell Carcinoma
Treatment for metastatic renal cell carcinoma has advanced, with systemic therapies being a primary approach. Targeted therapies, such as tyrosine kinase inhibitors (TKIs), work by blocking specific proteins involved in cancer cell growth and the formation of new blood vessels. Examples of TKIs used in RCC include sunitinib, pazopanib, cabozantinib, and axitinib. These medications are taken orally and are continued as long as they are effective in controlling the tumor.
Immunotherapies, specifically immune checkpoint inhibitors, are another advancement in treatment. These drugs, such as nivolumab and pembrolizumab, work by “unmasking” cancer cells, enabling the immune system to recognize and attack them. Checkpoint inhibitors block proteins like PD-1 or CTLA-4, which cancer cells use to evade the immune system. These therapies are given intravenously and have demonstrated improved survival rates in many patients with metastatic RCC.
In addition to systemic treatments, local therapies may also be used. Surgery, such as cytoreductive nephrectomy, involves removing the primary kidney tumor even when metastases are present. While once a standard approach, recent studies have led to a more selective use of immediate cytoreductive nephrectomy, often deferring it until after a period of systemic therapy or reserving it for symptom relief. Surgery to remove individual metastatic lesions (metastasectomy) may also be considered.
Radiation therapy is primarily used for symptom management, such as alleviating pain from bone metastases or addressing brain lesions. Clinical trials are ongoing, exploring new treatments and combinations, offering additional options for some patients.
Living with Metastatic Renal Cell Carcinoma
Living with metastatic renal cell carcinoma presents ongoing challenges, but treatment advancements have improved the outlook for many individuals. The median survival for patients with metastatic RCC has improved due to targeted therapies and immunotherapies. This marks a significant improvement compared to previous decades.
Supportive care is an important aspect of managing the condition, alleviating symptoms and managing treatment side effects. This involves addressing issues like pain, fatigue, and digestive problems. A multidisciplinary medical team, including oncologists, urologists, radiologists, and palliative care specialists, develops a treatment plan. This team ensures all aspects of a patient’s care are addressed.