Background: Sunitinib is a standard first-line option for metastatic renal cell carcinoma (mRCC). Body composition is a prognostic factor in cancer patients and patients with loss of skeletal muscle mass and fat-free mass (FFM) are prone to dose-limiting toxicity (DLT) during targeted drug therapy. We investigated whether body composition by computed tomography predicted DLT from sunitinib in mRCC.
Methods: Patients with clear cell mRCC receiving sunitinib (50 mg) were included. Skeletal muscle cross-sectional area at L3 was measured by computed tomography. Sarcopenia was defined using published cutoffs. Toxicity was assessed after 4 cycles of the drug.
Results: Fifty-five patients (43 male), mean age 64 years were included. Overall, 33% (N=18) of all patients were sarcopenic and of these 12.7% (N=7) were sarcopenic and overweight or obese. DLT occurred in <6 months in 53% of patients (44% male vs. 83% female) and those who experienced DLT were older (68 vs. 60 y), had a lower skeletal muscle index (51.7 vs. 59.4 cm2/m2), a lower FFM (51.4 vs. 57.7 kg), and received a higher drug dose in mg/kg FFM (0.9 vs. 0.8). Patients with the lowest compared with the highest measurements of skeletal muscle mass experienced more DLT, respectively, 92% versus 57% and experienced on average 5 toxicities versus 2.
Conclusions: Sarcopenia is prevalent in patients with mRCC, is an occult condition in patients with normal/high body mass index, and is a significant predictor of DLT in patients receiving sunitinib. Our results highlight the potential use of baseline body composition to predict toxicity.
*Department of Food & Nutritional Sciences
∥School of Mathematical Science, University College Cork
†Department of Medical Oncology, Mercy & Cork University Hospitals
§Department of Radiology, Mercy University Hospital, Cork
‡Department Medical Oncology, Adelaide & Meath Hospital incorporating National Children’s Hospital, Tallaght, Ireland
This project was supported by an Investigator Initiated Research Educational grant from Pfizer Healthcare Ireland. Pfizer did not have any role in the study design, data collection, analysis, interpretation, or writing of the paper.
The authors declare no conflicts of interest.
Reprints: Aoife M. Ryan, PhD, RD, Lecturer in Nutritional Sciences, School of Food & Nutritional Sciences, University College Cork, College Road, Cork, Ireland. E-mail: firstname.lastname@example.org.