The impact of the introduction of irinotecan and oxaliplatin on the outcome of patients with advanced colorectal cancer.

none6The effectiveness of oxaliplatin and irinotecan in advanced colorectal cancer therapy has been shown by many randomized clinical trials. We developed a retrospective study on patients treated in the clinical practice. The main inclusion criteria were: diagnosis of unresectable colorectal adenocarcinoma and having undergone chemotherapy. Univariate and multivariate analyses were performed to identify the prognostic factors of survival. The study included 286 consecutive patients. Three factors were associated with worse survival: high CA19-9 levels (p=0.003), schedules without new regimens (p=0.031) and weight loss (p=0.070). The use of new regimens was associated with a significant improvement in median survival (15 to 10 months, p<0.001). Although the new regimens improved survival in clinical practice, the median gain is smaller than that reported in randomized trials. The palliative intent of these therapies should not be forgotten in order to improve quality of life rather than absolute survival.noneLelli G; Carandina I; Urbini B; Guarino S; Modonesi C; Pedriali M.Lelli, Giorgio; Carandina, Ilaria; Urbini, B; Guarino, S; Modonesi, Caterina; Pedriali, Massim

Predicting steady-state endoxifen plasma concentrations in breast cancer patients by CYP2D6 genotyping or phenotyping. Which approach is more reliable?

In previous studies, steady-state Z-endoxifen plasma concentrations (ENDOss) correlated with relapse-free survival in women on tamoxifen (TAM) treatment for breast cancer. ENDOss also correlated significantly with CYP2D6 genotype (activity score) and CYP2D6 phenotype (dextromethorphan test). Our aim was to ascertain which method for assessing CYP2D6 activity is more reliable in predicting ENDOss. The study concerned 203 Caucasian women on tamoxifen-adjuvant therapy (20mg q.d.). Before starting treatment, CYP2D6 was genotyped (and activity scores computed), and the urinary log(dextromethorphan/dextrorphan) ratio [log(DM/DX)] was calculated after 15mg of oral dextromethorphan. Plasma concentrations of TAM, N-desmethyl-tamoxifen (ND-TAM), Z-4OH-tamoxifen (4OH-TAM) and ENDO were assayed 1, 4, and 8months after first administering TAM. Multivariable regression analysis was used to identify the clinical and laboratory variables predicting log-transformed ENDOss (log-ENDOss). Genotype-derived CYP2D6 phenotypes (PM, IM, NM, EM) and log(DM/DX) correlated independently with log-ENDOss. Genotype-phenotype concordance was almost complete only for poor metabolizers, whereas it emerged that 34% of intermediate, normal, and ultrarapid metabolizers were classified differently based on log(DM/DX). Multivariable regression analysis selected log(DM/DX) as the best predictor, with patients' age, weak inhibitor use, and CYP2D6 phenotype decreasingly important: log-ENDOss=0.162-log(DM/DX)*0.170+age*0.0063 - weak inhibitor use*0.250+IM*0.105+(NM+UM)*0.210; (R2 =0.51). In conclusion, log(DM/DX) seems superior to genotype-derived CYP2D6 phenotype in predicting ENDOss