The association between BMI and BSA–temozolomide-induced myelosuppression toxicities: a correlative analysis of NRG oncology RTOG 0525

Background: Fearing increased myelotoxicity, many practitioners adjust the body surface area (BSA)-calculated doses in obese patients. Regarding temozolomide (TMZ), a prior study suggested men with a BSA >2 m(2) may experience increased toxicity; however, surprisingly, the inverse observation was noted in women, ie, BSA /=30. Results: There was no statistically significant correlation between gender and BSA and the occurrence of myotoxicities. For the standard arm, surprisingly the incidence of grade 3/4 myotoxicities in patients with a BMI /=30 (12% vs 1%, odds ratio [OR] 12.5, P < .001). There was no significant difference between obese and nonobese patients (BMI "cut-point" of 30) in the dose-dense arm (OR = 0.9, 95% confidence interval: 0.4-1.6). The grade hematological 3/4 toxicity rate was significantly higher in women vs men (14% vs 8%) P = .009 in spite of the lack of association between gender and BSA or BMI. Conclusion: TMZ dosing based on actual BSA is recommended with the caveat that woman are likely at higher toxicity risk.