title: Effect of low-dose tamoxifen after surgical excision of ductal intraepithelial neoplasia: results of a large retrospective monoinstitutional cohort study.
abstract: BACKGROUND
  Postsurgical treatment of ductal intraepithelial neoplasia (DIN) with standard doses of tamoxifen has not reached a consensus yet. Given positive results of low-dose tamoxifen on breast cancer biomarkers modulation, we analyzed a large cohort of DIN patients treated with low-dose tamoxifen or no treatment as per institutional guidelines.
  
  
  METHODS
  All consecutive women operated on at the European Institute of Oncology for estrogen receptor (ER)-positive DIN (474 treated with low-dose tamoxifen and 509 untreated patients) were followed up for a median of 7 years.
  
  
  RESULTS
  Compared with untreated patients, a significant 30% reduction in breast cancer risk was observed on low-dose tamoxifen with an adjusted hazard ratio (HR) = 0.70 [95% confidence interval (CI) 0.51-0.94], with a greater benefit in postmenopausal (HR = 0.57; 95% CI 0.34-0.94) than in premenopausal women (HR = 0.79; 95% CI 0.54-1.17). Treated patients with ER and progesterone receptor (PgR) >50% DIN had a lower incidence of breast events than untreated ones (HR = 0.61; 95% CI 0.40-0.94), whereas no protective effect has been observed in patients with ER or PgR <50% DIN. Drug discontinuation resulted in a doubled risk of recurrence in premenopausal women only (HR = 1.95; 95% CI 0.98-3.89). No excess of endometrial cancer occurred.
  
  
  CONCLUSIONS
  Low-dose tamoxifen is a promising and safe strategy for highly endocrine responsive DIN. Treatment adherence is crucial in premenopausal women. A definitive trial is ongoing.
authors.affiliation: Divisions of Cancer Prevention and Genetics.
authors.forename: A
authors.initials: A
authors.lastname: Guerrieri-Gonzaga
authors.affiliation: Divisions of Cancer Prevention and Genetics.
authors.forename: M
authors.initials: M
authors.lastname: Lazzeroni
authors.affiliation: Epidemiology and Biostatistics.
authors.forename: E
authors.initials: E
authors.lastname: Botteri
authors.affiliation: Divisions of Cancer Prevention and Genetics.
authors.forename: D
authors.initials: D
authors.lastname: Serrano
authors.affiliation: Epidemiology and Biostatistics.
authors.forename: N
authors.initials: N
authors.lastname: Rotmensz
authors.affiliation: Divisions of Cancer Prevention and Genetics.
authors.forename: M-C
authors.initials: MC
authors.lastname: Varricchio
authors.affiliation: Divisions of Cancer Prevention and Genetics.
authors.forename: M
authors.initials: M
authors.lastname: Cazzaniga
authors.affiliation: Divisions of Cancer Prevention and Genetics.
authors.forename: G
authors.initials: G
authors.lastname: Bollani
authors.affiliation: Divisions of Cancer Prevention and Genetics.
authors.forename: S
authors.initials: S
authors.lastname: Mora
authors.affiliation: Divisions of Cancer Prevention and Genetics.
authors.forename: C
authors.initials: C
authors.lastname: Montefrancesco
authors.affiliation: Pathology and Lab Medicine; University of Milan, School of Medicine, Milan.
authors.forename: G
authors.initials: G
authors.lastname: Pruneri
authors.affiliation: Pathology and Lab Medicine; University of Milan, School of Medicine, Milan.
authors.forename: G
authors.initials: G
authors.lastname: Viale
authors.affiliation: Breast Surgery.
authors.forename: M
authors.initials: M
authors.lastname: Intra
authors.affiliation: Breast Surgery.
authors.forename: V
authors.initials: V
authors.lastname: Galimberti
authors.affiliation: Department of Medicine, European Institute of Oncology, Milan.
authors.forename: A
authors.initials: A
authors.lastname: Goldhirsch
authors.affiliation: Epidemiology and Biostatistics; Department of Statistics, University of Milan-Bicocca, Milan.
authors.forename: V
authors.initials: V
authors.lastname: Bagnardi
authors.affiliation: Divisions of Cancer Prevention and Genetics.
authors.forename: B
authors.initials: B
authors.lastname: Bonanni
authors.affiliation: Divisions of Cancer Prevention and Genetics; Division of Medical Oncology, Ospedali Galliera, Genoa, Italy. Electronic address: andrea.decensi@galliera.it.
authors.forename: A
authors.initials: A
authors.lastname: DeCensi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018931:Antineoplastic Agents, Hormonal / Q000008:administration & dosage*; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000473:pathology / Q000601:surgery; D002278:Carcinoma in Situ / Q000188:drug therapy* / Q000473:pathology / Q000601:surgery; D018270:Carcinoma, Ductal, Breast / Q000188:drug therapy* / Q000473:pathology / Q000601:surgery; D017024:Chemotherapy, Adjuvant; D002986:Clinical Trials as Topic; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D015412:Mastectomy, Segmental; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000517:prevention & control; D012189:Retrospective Studies; D013629:Tamoxifen / Q000008:administration & dosage*; D016896:Treatment Outcome
chemical_list: D018931:Antineoplastic Agents, Hormonal; D013629:Tamoxifen
keywords: DCIS; DIN; breast cancer; compliance; low-dose tamoxifen