Presentation Authors: Hiroki Ishihara*, Toshio Takagi, Tsunenori Kondo, Hironori Fukuda, Kazuhiko Yoshida, Junpei Iizuka, Hirohito Kobayashi, Masayoshi Okumi, Hideki Ishida, Kazunari Tanabe, Tokyo, Japan
Introduction: Sarcopenia is a state of degenerative skeletal muscle wasting induced by cancer cachexia. To evaluate the prognostic impact of change in skeletal muscle mass (SMM) during first-line sunitinib therapy on oncological outcomes in metastatic renal cell carcinoma (mRCC).
Methods: Sixty-nine patients were evaluated retrospectively. The skeletal muscle index (SMI) was calculated based on computed tomography images obtained before the initiation (pretreatment SMI) and after two cycles of sunitinib treatment (posttreatment SMI). The change in SMM was evaluated based on the value of Î´SMI which was calculated as [(posttreatment SMI-pretreatment SMI)/ pretreatment SMI] Ã— 100. We divided the patients as follows: Î´SMI < 0 (SMM decrease) and Î´SMI â‰¥ 0 (SMM maintenance). Oncological outcomes were compared between the groups.
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 Î´SMI < 0 than in those with Î´SMI â‰¥ 0 (median PFS: 9.53 vs. 28.4 months, p < 0.0001; OS: 19.8 vs. 52.6 months, p = 0.0001). The Î´SMI was an independent 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 Î´SMI < 0 than in those with Î´SMI â‰¥ 0 (23.7% vs. 51.6%, p = 0.0164).
Conclusions: Decreased SMM during first-line sunitinib therapy can be a useful marker of outcome prediction for mRCC.