title: A comparison of survival outcomes and side effects of toremifene or tamoxifen therapy in premenopausal estrogen and progesterone receptor positive breast cancer patients: a retrospective cohort study.
abstract: BACKGROUND
  In premenopausal women, endocrine adjuvant therapy for breast cancer primarily consists of tamoxifen alone or with ovarian suppressive strategies. Toremifene is a chlorinated derivative of tamoxifen, but with a superior risk-benefit profile. In this retrospective study, we sought to establish the role of toremifene as an endocrine therapy for premenopausal patients with estrogen and/or progesterone receptor positive breast cancer besides tamoxifen.
  
  
  METHODS
  Patients with early invasive breast cancer were selected from the breast tumor registries at the Sun Yat-Sen Memorial Hospital (China). Premenopausal patients with endocrine responsive breast cancer who underwent standard therapy and adjuvant therapy with toremifene or tamoxifen were considered eligible. Patients with breast sarcoma, carcinosarcoma, concurrent contralateral primary breast cancer, or with distant metastases at diagnosis, or those who had not undergone surgery and endocrine therapy were ineligible. Overall survival and recurrence-free survival were the primary outcomes measured. Toxicity data was also collected and compared between the two groups.
  
  
  RESULTS
  Of the 810 patients reviewed, 452 patients were analyzed in the study: 240 received tamoxifen and 212 received toremifene. The median and mean follow up times were 50.8 and 57.3 months, respectively. Toremifene and tamoxifen yielded similar overall survival values, with 5-year overall survival rates of 100% and 98.4%, respectively (p = 0.087). However, recurrence-free survival was significantly better in the toremifene group than in the tamoxifen group (p = 0.022). Multivariate analysis showed that recurrence-free survival improved independently with toremifene (HR = 0.385, 95% CI = 0.154-0.961; p = 0.041). Toxicity was similar in the two treatment groups with no women experiencing severe complications, other than hot flashes, which was more frequent in the toremifene patients (p = 0.049). No patients developed endometrial cancer.
  
  
  CONCLUSIONS
  Toremifene may be a valid and safe alternative to tamoxifen in premenopausal women with endocrine-responsive breast cancer.
authors.affiliation: Department of Breast Surgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China.
authors.forename: Ran
authors.initials: R
authors.lastname: Gu
authors.forename: Weijuan
authors.initials: W
authors.lastname: Jia
authors.forename: Yunjie
authors.initials: Y
authors.lastname: Zeng
authors.forename: Nanyan
authors.initials: N
authors.lastname: Rao
authors.forename: Yue
authors.initials: Y
authors.lastname: Hu
authors.forename: Shunrong
authors.initials: S
authors.lastname: Li
authors.forename: Jiannan
authors.initials: J
authors.lastname: Wu
authors.forename: Liang
authors.initials: L
authors.lastname: Jin
authors.forename: Lijuan
authors.initials: L
authors.lastname: Chen
authors.forename: Meijun
authors.initials: M
authors.lastname: Long
authors.forename: Kai
authors.initials: K
authors.lastname: Chen
authors.forename: Lili
authors.initials: L
authors.lastname: Chen
authors.forename: Qiaozhen
authors.initials: Q
authors.lastname: Xiao
authors.forename: Mei
authors.initials: M
authors.lastname: Wu
authors.forename: Erwei
authors.initials: E
authors.lastname: Song
authors.forename: Fengxi
authors.initials: F
authors.lastname: Su
mesh_terms: D000328:Adult; D018931:Antineoplastic Agents, Hormonal / Q000009:adverse effects / Q000627:therapeutic use*; D024221:Antineoplastic Protocols; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D015331:Cohort Studies; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008875:Middle Aged; D015999:Multivariate Analysis; D009364:Neoplasm Recurrence, Local / Q000473:pathology; D017697:Premenopause; D011960:Receptors, Estrogen / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism; D015203:Reproducibility of Results; D012189:Retrospective Studies; D013629:Tamoxifen / Q000009:adverse effects / Q000627:therapeutic use*; D017312:Toremifene / Q000009:adverse effects / Q000627:therapeutic use*
chemical_list: D018931:Antineoplastic Agents, Hormonal; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; D013629:Tamoxifen; D017312:Toremifene