Toremifene, rather than tamoxifen, might be a better option for the adjuvant endocrine therapy in CYP2D6*10T/T genotype breast cancer patients in China. Issue 10 (19th September 2018)

• Record Type: Journal Article
• Authors: Lan, Bo; Ma, Fei; Chen, Shanshan; Wang, Wenna; Li, Qiao; Fan, Ying; Luo, Yang; Cai, Ruigang; Wang, Jiayu; Yuan, Peng; Zhang, Pin; Li, Qing; Xu, Binghe
• Is Part Of: International journal of cancer. Volume 143:Issue 10(2018)
• Page Start: 2499
• Page End: 2504
• Publication Date: 2018-09-19
• Subjects: breast cancer -- TAM -- TOR -- CYP2D6 -- SNP; Cancer -- Periodicals; Cancer -- Prevention -- Periodicals; 616.994
• DOI: 10.1002/ijc.31639
• Languages: English
• ISSNs: 0020-7136

Abstract

Abstract : Toremifene (TOR) is a valid and safe alternative to tamoxifen (TAM) for adjuvant endocrine therapy in breast cancer patients with a metabolic pathway that differs from that of TAM. TOR might have a therapeutic advantage in certain subgroups of patients, such as Chinese women with the CYP2D6 *10 (c.100C > T) T/T genotype, who would get less benefit when receiving adjuvant TAM treatment. A total of 230 breast cancer patients who received adjuvant TAM ( n = 115) or TOR ( n = 115) at the National Cancer Center were analyzed. The CYP2D6 *10 genotype was not significantly associated with DFS in patients who received TOR ( p = 0.737). Patients treated with TOR had a higher 5‐year disease‐free survival (DFS) rate than those treated with TAM (89.6% vs. 80.9%, p = 0.009). TOR treatment remained an independent prognostic marker of DFS in multivariate analysis compared with TAM (hazard ratio = 0.51; p = 0.014). For all of the 50 CYP2D6 *10 T/T genotype patients, TOR treatment group had a significantly higher 5‐year DFS rate than TAM group (90.9% vs. 67.9%, p = 0.031). For the remaining 170 CYP2D6 *10 C/C or C/T genotype patients, there was no significant difference between the 5‐year DFS rates of the TOR and TAM groups (89.2% vs. 85.1%, p = 0.188). The advantage of adjuvant TOR over TAM in Chinese breast cancer patients might be caused by the significant benefit obtained by the CYP2D6 *10 T/T patients, who accounted for one‐fifth of the overall population. TOR might be a good option for adjuvant endocrine therapy in this subgroup of patients in China. Abstract : What's new? The CYP2D6*10 T/T genotype is associated with worse clinical outcomes in Chinese breast cancer patients receiving adjuvant TAM treatment, due to reduced metabolizing ability. Whether TOR—a chlorinated TAM derivative—could provide a therapeutic advantage remains unclear. This study suggests that TOR achieves better clinical outcomes than TAM in Chinese breast cancer patients overall. Because CYP2D6*10 is the most common polymorphism in Asian populations, the finding may be explained by the significant benefit observed in CYP2D6*10 T/T patients. TOR might thus be a good option for adjuvant endocrine therapy in China, and in the CYP2D6*10 T/T patient subgroup, in particular.