Renal cell carcinoma, often abbreviated as RCC, is the most prevalent form of kidney cancer diagnosed in adults. This cancer originates within the tiny tubes of the kidneys, which are responsible for filtering waste from the blood. RCC is often discovered incidentally during imaging tests for other medical reasons, as it may not cause symptoms in its early stages. The approach to treating RCC has changed, moving beyond generalized therapies to highly specific drugs designed to interact with the cancer in precise ways. This has led to improved outcomes for many individuals.
Targeted Therapy Drugs
Targeted therapy treats renal cell carcinoma by interfering with specific molecules that fuel cancer growth. These drugs are not like traditional chemotherapy; instead of attacking all rapidly dividing cells, they focus on pathways that are particularly active in kidney cancer cells. This approach allows for a more focused attack on the tumor while limiting damage to healthy tissues.
A primary group of these drugs is known as vascular endothelial growth factor (VEGF) inhibitors. Tumors require a dedicated blood supply to grow and spread, a process called angiogenesis. VEGF is a protein that signals the body to form new blood vessels. By blocking the action of VEGF, these inhibitor drugs effectively cut off the tumor’s nutrient and oxygen supply, which can slow its growth or even cause it to shrink.
Drugs in this category include:
- Sunitinib
- Pazopanib
- Axitinib
- Cabozantinib
Another class of targeted drugs is the mTOR inhibitors. The mTOR protein is part of a pathway that regulates cell growth, division, and survival. In some kidney cancers, this pathway becomes overactive, promoting uncontrolled cell proliferation. mTOR inhibitors, such as temsirolimus and everolimus, block this specific protein, disrupting the signals that tell cancer cells to multiply.
Immunotherapy Drugs
Immunotherapy harnesses the body’s own immune system to identify and eliminate cancer cells. The immune system is naturally equipped to fight off invaders like bacteria and viruses, but cancer cells often develop ways to hide from it. Immunotherapy for RCC primarily involves immune checkpoint inhibitors, which are designed to overcome the cancer’s evasive tactics. These treatments are a foundational element of care for many patients with advanced RCC.
The immune system has natural “checkpoints” in place to prevent it from becoming overactive and attacking the body’s healthy tissues. These checkpoints are proteins on the surface of immune cells, such as T-cells, that act as brakes. Some cancer cells exploit these mechanisms by displaying proteins that engage these checkpoints, effectively telling the immune system to stand down. This allows the tumor to grow unchallenged.
Checkpoint inhibitors work by blocking these specific proteins, essentially “releasing the brakes” on the immune system. The two main checkpoint pathways targeted in RCC are PD-1/PD-L1 and CTLA-4. Drugs like nivolumab and pembrolizumab are PD-1 inhibitors, while ipilimumab is a CTLA-4 inhibitor. By blocking these interactions, the drugs allow T-cells to recognize and attack the cancer cells.
Combination Treatment Approaches
To enhance treatment effectiveness, oncologists often combine different types of drugs. The rationale is that attacking cancer from multiple angles can produce a more powerful response than a single agent. By disrupting different growth pathways and stimulating an immune response, these combinations can overcome treatment resistance. This has become a standard of care for many with advanced RCC.
One common approach pairs two immunotherapy drugs, such as a PD-1 inhibitor like nivolumab with a CTLA-4 inhibitor like ipilimumab. This dual approach releases two different brakes on the immune system, creating a more robust anti-cancer attack. This combination is often used for patients with intermediate- or poor-risk disease.
Another strategy combines an immunotherapy drug with a targeted therapy drug. For instance, a PD-1 inhibitor may be paired with a VEGF inhibitor like axitinib. This combination fights the cancer on two fronts: the targeted drug cuts off the tumor’s blood supply, while the immunotherapy unleashes the immune system to attack cancer cells directly.
Managing Common Side Effects
Targeted therapies and immunotherapies can cause side effects that differ based on how the drugs work. Managing these effects is a collaborative process between the patient and their healthcare team. Open communication about new or worsening symptoms is necessary for timely adjustments to the treatment plan, like supportive medications or dose modifications.
Targeted therapy drugs are associated with side effects that arise because the drugs can affect healthy cells using similar molecular pathways. These include:
- Fatigue
- Diarrhea
- High blood pressure
- Hand-foot syndrome, which causes redness, swelling, and pain on the palms and soles
Immunotherapy side effects are known as immune-related adverse events. Because these drugs amplify the immune system, they can cause it to attack healthy organs, leading to inflammation. Promptly reporting these symptoms is important, as early intervention can prevent them from becoming severe. This can manifest as:
- Skin rashes
- Colitis (inflammation of the colon causing diarrhea)
- Pneumonitis (inflammation of the lungs)
- Thyroid problems
How Treatment Plans Are Personalized
The selection of a treatment for renal cell carcinoma is a highly individualized process. Oncologists consider several factors to create a personalized plan that is appropriate for both the specific characteristics of the cancer and the patient’s overall health.
A primary consideration is the patient’s risk group, classified as favorable, intermediate, or poor risk. This classification helps predict the cancer’s behavior and informs which drug combinations are likely to be most effective. The histological subtype of the RCC is also a factor; for example, clear cell RCC, the most common subtype, may respond differently to certain drugs than non-clear cell subtypes.
The patient’s treatment history and overall health are also weighed. Prior therapies and the cancer’s response influence subsequent choices. A person’s general health, including other medical conditions, can affect their ability to tolerate certain drugs and their potential side effects.