The association of skeletal muscle mass and cisplatin pharmacokinetics in head and neck cancer patients: The prospective PLATISMA study.

Abstract

6021 Background: Locally advanced head and neck squamous cell carcinoma (HNSCC) is commonly treated with cisplatin-based chemoradiotherapy (CRT). Cisplatin is associated with severe toxicity, which negatively affects survival. In recent years, a relationship between low skeletal muscle mass (SMM) and toxicity has been described. This increased toxicity may be related to an altered cisplatin distribution and binding in the fat-free body mass, of which SMM is the largest contributor. This study aims to investigate the association between cisplatin pharmacokinetics and SMM in HNSCC patients. Methods: We performed a prospective observational study in HNSCC patients treated with CRT with cisplatin. Patients received standard-of-care chemotherapy with three cycles of cisplatin, at a dose level of 100 mg/m2 per cycle. Quantitative data on body size descriptors including SMM, measured on computed tomography scans, and cisplatin pharmacokinetics (total and ultrafilterable plasma concentration) were collected, as well as data on toxicity. Results: 45 evaluable patients were included in the study. A large proportion of the study population had a low SMM (46.7%). The majority of patients (57.8%) experienced cisplatin dose limiting toxicities. Pharmacokinetic analysis showed a significant relationship between cisplatin pharmacokinetics and the body size descriptors SMM, weight, fat-free mass, and body surface area ( p< 0.005). In a simulation, patients with a low SMM were predicted to reach higher bound cisplatin concentrations. The higher concentration of bound cisplatin could be seen as a reflection of the smaller volume of distribution, and could thereby explain the increased toxicity in patients with a low SMM. Conclusions: We found an association between cisplatin pharmacokinetics and SMM. Patients with a low SMM were predicted to reach higher bound cisplatin concentrations, which could be an explanation for the increased toxicity in this patient group. Clinical trial information: Trial NL7469 (NTR7711).