Kidney cancer is often discovered in the late stages. Is drug treatment effective?

Author: Shi Hongzhe, deputy chief physician, Cancer Hospital, Chinese Academy of Medical Sciences

Reviewer: Li Changling, Chief Physician, Cancer Hospital, Chinese Academy of Medical Sciences

Kidney cancer has no obvious symptoms in its early stages and is difficult to detect. About one-fifth of kidney cancer patients are diagnosed in the late stages and have already metastasized.

Statistically, the most common late-stage metastasis of renal cancer is lung metastasis, followed by bone metastasis. Metastasis can also occur in organs such as the liver, pancreas, and brain.

The growth of metastatic lesions is uncontrolled and can grow indefinitely within the metastatic organ, eventually even causing compression symptoms.

For stage III renal cancer, although there is no metastasis, the tumor in the kidney can continue to grow. In clinical work, we can see huge renal tumors of 30-40 cm, which can cause compression symptoms such as back pain.

For stage IV renal cancer, metastasis has already occurred. If the metastatic lesions are in the lungs, there may be no symptoms in the early stages. However, when the tumor tissue grows to a certain extent and compresses the bronchus, coughing symptoms will occur. If it invades the pleura, pleural effusion will form, and a large amount of pleural effusion will cause difficulty breathing.

If the metastasis is in the skeletal system, the invasion of the periosteum will cause pain. Metastasis to the long bones of the limbs will also cause secondary fractures.

If the metastasis occurs in the brain, because the volume of the cranial cavity is unchanged, the growth of the tumor in the brain will cause intracranial hypertension, causing headaches, nausea, projectile vomiting and other symptoms of increased intracranial pressure. Once excessive intracranial pressure causes brain herniation, it will be life-threatening.

Figure 1 Original copyright image, no permission to reprint

Metastases to other organs may also cause compression symptoms, and the growth of liver metastases may cause pain in the liver area.

Targeted therapy is a landmark treatment advance for patients with metastatic renal cancer.

Before 2005, once renal cancer metastasized, treatment options were very limited. However, after the advent of targeted therapy in 2005, the treatment of metastatic renal cell carcinoma entered the era of targeted therapy. The overall efficacy of metastatic renal clear cell carcinoma can reach 70%.

There are three situations in which the treatment is considered effective: the tumor would have continued to grow, but after taking the targeted drug, the tumor stopped growing; the tumor shrank; the tumor disappeared. In other words, the treatment is considered effective if the condition is stable, partially eliminated, or completely eliminated.

Targeted therapy has been used for nearly 20 years at home and abroad, and its efficacy is very good. Moreover, unlike traditional chemotherapy, which requires intravenous administration, targeted therapy is an oral drug, which is very convenient to use and can be taken at home, without the need for hospitalization. Currently, targeted drugs used in metastatic renal cancer in China include sunitinib, axitinib, sorafenib, pazopanib, everolimus and other drugs.

Targeted drugs need to be taken for a long time because their therapeutic mechanism is to control or inhibit the formation of new blood vessels that supply tumor cells. Without blood supply from blood vessels, further growth of the tumor can be controlled, and even tumor necrosis may occur. If targeted drugs are discontinued, the tumor tissue will resume blood supply and continue to grow.

During long-term medication, we must pay attention to the side effects of targeted drugs, such as fatigue, indigestion, diarrhea, or hand-foot syndrome with swelling and pain in the hands and feet. These side effects can basically be tolerated after a period of targeted therapy.

Some targeted drugs have an impact on white blood cells and platelets, and some patients may experience elevated blood pressure after targeted treatment. If elevated blood pressure occurs, active treatment should be given for hypertension, and the target blood pressure after treatment should be controlled below 140/90 mmHg.

It is important to remind everyone that if you cannot tolerate the side effects of targeted drugs, you must go to the hospital to communicate with your doctor, undergo appropriate examinations, and then the doctor will decide whether to stop the medication or reduce the dosage.

After targeted therapy for advanced renal cancer, the current method of evaluating the efficacy is to measure the size of the tumor through imaging examinations such as CT or MRI.

For example, to measure the size of the primary lesion of renal cancer, enhanced CT or MRI is required; for example, to measure the size of the lung metastasis lesion, CT is required. In short, before targeted treatment, an objective imaging examination is performed to check the size of the primary lesion and metastatic lesion.

Then, during the targeted therapy, the test should be conducted every two or three months, and the effectiveness of the targeted therapy can be judged through comparison.

For example, if the lesion shrinks or disappears, the treatment is effective. If the lesion remains the same size and does not grow larger over two or three months, it also means that the treatment is effective.

Figure 2 Original copyright image, no permission to reprint

Of course, there is another situation where after taking the medicine, the tumor becomes necrotic internally, but its size does not change significantly. At this time, PET/CT must be performed to determine the true therapeutic effect.

PET/CT is a functional imaging. The bright lesions in the PET/CT film are active lesions. Although the lesions are still as big, the inside of the lesions has become darker, like a black hole, indicating that its activity has decreased, indicating that the targeted treatment is very effective.

After the examination, if there is no effect, you have to switch to other targeted drugs or other treatment methods. If it is effective, continue to take it. During the medication period, generally check once every three months to continuously evaluate the treatment effect. If other problems are found, adjust the treatment plan at any time.

For advanced renal cancer, targeted therapy and immunotherapy can be used in combination. Targeted therapy drugs can inhibit the formation of blood vessels in tumors and prevent the crazy growth of tumor cells; while immunotherapy activates the activity of cells with anti-tumor effects around tumors and in tumor tissues, and fights tumors by mobilizing the body's own immune cells. The combination of the two can exert a superimposed effect through different mechanisms.

In April 2024, the anti-PD-1 monoclonal antibody drug Teplizumab, which was independently developed in my country, was approved for the treatment of renal cancer. It can be combined with the targeted drug axitinib as a first-line treatment for patients with medium- and high-risk unresectable or metastatic renal cancer. This is also the first approved immune combined targeted therapy for renal cancer in my country.

Immunotherapy combined with targeted therapy is an effective treatment for medium- and high-risk metastatic renal cell carcinoma. It can be used for patients with extensive renal cell carcinoma metastasis or patients with poor response to targeted therapy. Therefore, the approval of immunotherapy combined with targeted therapy has given hope to many patients with advanced renal cell carcinoma.

Therefore, patients with advanced renal cancer should also maintain an optimistic attitude. With the continuous development of medical technology, more and more drugs will be gradually used in clinical practice, contributing to prolonging the life of patients with advanced renal cancer and improving their quality of life.