Treatment outcomes in poor metabolizers of cytochrome P450 2A6 with concurrent chemoradiotherapy in locally advanced head- and neck-squamous cell carcinoma.

Posttreatment expression levels of CYP2A6 were found to be a better predictor for tumor response to the treatment than the pretreatment expression levels. Almost all the patients having higher RQ folds had CR and those having lower RQ folds had either no response or progressive disease on follow-up visits.