Effect of Changes in Skeletal Muscle Mass on Oncological Outcomes During First-Line Sunitinib Therapy for Metastatic Renal Cell Carcinoma.

BACKGROUND

Sarcopenia is a state of degenerative skeletal muscle wasting induced by cancer cachexia.

OBJECTIVE

To evaluate the prognostic impact of changes in skeletal muscle mass (SMM) during first-line sunitinib therapy on oncological outcomes in metastatic renal cell carcinoma (mRCC).

PATIENTS AND

METHODS

Sixty-nine patients were evaluated retrospectively. The skeletal muscle index (SMI) was calculated based on computed tomography images obtained before the initiation (pre-treatment SMI) and after two cycles of sunitinib treatment (post-treatment SMI). The change in SMM was evaluated based on the value of ΔSMI, which was calculated as [(posttreatment SMI - pretreatment SMI)/ pretreatment SMI] × 100. Oncological outcomes were compared between patients with ΔSMI <0 (SMM decrease) and ΔSMI ≥0 (SMM maintenance).

RESULTS

A decrease in SMM was observed in 38 patients (55.1%). Progression-free survival (PFS) and overall survival (OS) after sunitinib therapy initiation were significantly shorter in patients with ΔSMI <0 than in those with ΔSMI ≥0 (median PFS: 9.53 vs. 28.4 months, p < 0.0001; OS: 19.8 vs. 52.6 months, p = 0.0001). ΔSMI was an independent predictive factor for PFS (HR 3.25, 95% CI 1.74-6.29, p = 0.0002) and OS (HR 4.53, 95% CI 2.15-10.5, p < 0.0001). The objective response rate was significantly lower in patients with ΔSMI <0 than in those with ΔSMI ≥0 (23.7% vs. 51.6%, p = 0.0164).

CONCLUSION

Decreased SMM during first-line sunitinib therapy can be an effective marker of outcome prediction for mRCC.