Axitinib and kidney cancer treatment: Balancing tumor shrinkage with body composition.

Axitinib and Weight Loss: What Does It Mean for Kidney Cancer Treatment?

Samir D’Costa in Health & Wellness July 2025 • 4 min read.

"Unpacking the link between a targeted therapy, body composition, and outcomes in non-metastatic renal cell carcinoma"

Targeted therapies like axitinib have revolutionized cancer treatment, but their effects extend beyond just tumor cells. Researchers are increasingly interested in how these drugs impact a patient's overall body composition, including muscle mass and fat distribution. Understanding these changes is crucial for optimizing treatment strategies and improving patient outcomes.

A recent study delved into the effects of neoadjuvant axitinib—axitinib given before surgery—on anthropometric parameters (measurements of the human body) in patients with locally advanced non-metastatic renal cell carcinoma (RCC). This research offers valuable insights into how axitinib affects body composition in this specific patient population.

This article breaks down the key findings of this study, explaining the connection between axitinib, weight loss, sarcopenia (loss of muscle mass), and treatment response in non-metastatic RCC. We'll explore why these factors are important and what they could mean for future treatment decisions.

Axitinib's Impact on Body Composition: More Than Just Weight Loss

Axitinib and kidney cancer treatment: Balancing tumor shrinkage with body composition.

Axitinib, a tyrosine kinase inhibitor (TKI), is used to block the growth of new blood vessels that feed tumors. While effective in shrinking tumors, TKIs can also interfere with muscle-building pathways, leading to a loss of lean muscle mass. The study revealed that weight loss associated with axitinib was primarily due to a reduction in skeletal muscle and subcutaneous fat, with little change in visceral fat.

This selective weight loss pattern has been observed in other cancers, such as hepatocellular carcinoma, where visceral fat is inversely correlated with treatment response. It highlights the complexity of how targeted therapies affect the body and emphasizes the need to look beyond simple weight measurements.

Weight Loss Specificity: Weight loss from axitinib treatment primarily affects skeletal muscle and subcutaneous fat.
Muscle Mass Matters: Loss of muscle mass (sarcopenia) can influence treatment outcomes and overall survival.
Visceral Fat's Role: The amount of visceral fat might be connected to how well patients respond to TKI therapy, echoing findings in liver cancer studies.

The study found that a median weight loss of 4.5 kg was observed in patients treated with axitinib for 12 weeks, with 19 out of 23 patients experiencing some weight loss. This highlights that weight loss is commonly reported in metastatic renal cell carcinoma (mRCC) patients treated with targeted therapies. It remains unclear whether weight loss in mRCC patients is principally caused by systemic treatments or the metastatic tumors themselves, which may produce high levels of cytokines and cachexia.

Pretreatment Sarcopenia: A Potential Predictor?

Interestingly, the study found a direct correlation between pretreatment sarcopenia and the radiologic extent of tumor shrinkage during axitinib treatment. This suggests that patients who already have lower muscle mass before starting axitinib might experience greater tumor shrinkage.

While previous research has linked pretreatment sarcopenia to poorer RCC survival and increased toxicities from targeted therapies, this study highlights a potential positive association with tumor shrinkage. However, the researchers emphasize that these results need further confirmation.

If validated, pretreatment sarcopenia could become an important factor in selecting patients who might benefit most from pre-surgical systemic treatment. Further research is needed to fully understand the implications of these findings and to develop strategies to manage weight loss and sarcopenia in patients receiving axitinib.

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Everything You Need To Know

How does axitinib specifically lead to weight loss in kidney cancer patients?

Axitinib, classified as a tyrosine kinase inhibitor (TKI), primarily works by impeding the formation of new blood vessels that nourish tumors. However, its influence extends to the body's muscle-building pathways, which may lead to a reduction in lean muscle mass. The observed weight loss from axitinib is mainly attributed to a decrease in skeletal muscle and subcutaneous fat, while visceral fat remains relatively unaffected. This specificity is a key aspect of how axitinib impacts body composition during kidney cancer treatment.

Does having low muscle mass before starting axitinib impact tumor shrinkage?

The study indicated that pretreatment sarcopenia, or having lower muscle mass before starting axitinib, correlates with greater tumor shrinkage during treatment. This suggests that a patient's initial body composition, specifically muscle mass, could predict their response to axitinib. It highlights the importance of assessing pretreatment muscle mass as a potential predictive marker for treatment outcomes.

Why is the weight loss associated with axitinib treatment a significant factor?

Weight loss during axitinib treatment is significant because it's associated with changes in body composition, particularly a reduction in muscle mass (sarcopenia) and subcutaneous fat. Sarcopenia can influence treatment outcomes and overall survival. Monitoring these changes is important because it may impact the patient's strength, functional status, and tolerance to treatment. This understanding allows for potential interventions, such as nutritional support or exercise programs, to mitigate muscle loss and optimize treatment response.

What role does visceral fat play in how kidney cancer patients respond to axitinib?

Visceral fat's role is intriguing, as the study suggests a potential connection between the amount of visceral fat and the response to TKI therapy, similar to findings in liver cancer studies. Visceral fat is inversely correlated with treatment response. While the precise mechanisms are not fully understood, this implies that body composition, including the distribution of fat, can influence the effectiveness of axitinib treatment. Further research is needed to fully elucidate this relationship and its implications for treatment strategies.

In what specific group of kidney cancer patients was the impact of axitinib on weight loss studied?

The study focused on patients with non-metastatic renal cell carcinoma (RCC) undergoing neoadjuvant axitinib treatment. This specific context is important because the effects of axitinib on body composition may differ in patients with metastatic RCC (mRCC), where weight loss could also be influenced by systemic effects of the disease or the presence of cytokines and cachexia induced by the tumors themselves. The findings provide specific insights into how axitinib affects body composition in the neoadjuvant setting for non-metastatic RCC, which might not be directly transferable to other stages or types of kidney cancer.