Sarcopenia and BMI predict sunitinib treatment toxicity risk
medwireNews: Patients with metastatic renal cell carcinoma (mRCC) who have sarcopenia and a low body mass index (BMI) appear to be at increased risk for sunitinib-induced early dose-limiting toxicities (DLTs), study findings suggest.
The study results showed that sarcopenic patients with a BMI below 25 kg/m2 experienced more DLTs (50 vs 19.5%) than other patients. This difference was largely attributed to higher rates of acute vascular toxicities (20 vs 0%) and more cumulative grade 2 or 3 toxicities (four per patient; 20 vs 0%) and cumulative grade 3 toxicities (at least two per patient; 30 vs 7%).
"Our findings have potentially direct bedside implications, as evaluating sarcopenia on CT [computed tomography] scan and BMI calculation are feasible in daily practice," say Olivier Mir (University Paris Descartes, France) and colleagues.
"This would enable closer follow-up of patients at risk and, therefore, avoid severe toxicities by early dose adjustments or therapeutic interventions when needed."
The researchers retrospectively reviewed 61 patients with mRCC treated with sunitinib, of whom 52.5% were sarcopenic and 32.8% had both sarcopenia and a BMI below 25 kg/m2.
In all, 29.5% of the patients experienced a DLT, which was defined as any toxicity leading to dose reduction or treatment discontinuation. For all but two of the participants, there were multiple toxic effects of grade 2 and/or 3.
The researchers note in the British Journal of Cancer that the sum of several toxicities, which individually were not dose limiting, led to permanent termination of sunitinib in six (30%) patients with sarcopenia and a low BMI, compared with just one (2.4%) patient in the other group.
Overall, patients with sarcopenia and a low BMI were four times more likely to experience DLTs than other patients.
"Remarkably, the excessive toxicity observed in patients with sarcopenia and BMI <25 kg m-2 did not translate into a significantly poorer PFS [progression-free survival] or poorer OS [overall survival]," Mir and team write.
They suggest that this could be due to up to 40% of patients with sarcopenia and low BMI who experienced a DLT resuming sunitinib within a median of 33 weeks, or because of efficient second-line treatment in five of the seven patients for whom sunitinib was permanently withdrawn.
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By Lucy Piper, Senior medwireNews Reporter