Effect of low-dose tamoxifen after surgical excision of ductal intraepithelial neoplasia: results of a large retrospective monoinstitutional cohort study
Menée sur une cohorte de 983 patientes présentant une néoplasie mammaire intra-épithéliale de type canalaire et ayant subi une résection chirurgicale (durée médiane de suivi : 7 ans), cette étude évalue, en fonction du statut ménopausique des patientes et des niveaux d'expression tumorale du récepteur des oestrogènes et du récepteur de la progestérone, l'effet d'une faible dose de tamoxifène sur le risque de récidive et le risque de cancer de l'endomètre
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.Patients and 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.
Annals of Oncology 2013