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Poster Discussion session - Breast cancer, early stage

4225 - The HOBOE-2 multicenter randomized phase 3 trial in premenopausal patients with hormone-receptor positive early breast cancer comparing Triptorelin plus either Tamoxifen or Letrozole or Letrozole + Zoledronic acid.


20 Oct 2018


Poster Discussion session - Breast cancer, early stage


Cytotoxic Therapy;  Clinical Research;  Cancer in Adolescents and Young Adults (AYA)

Tumour Site

Breast Cancer


Francesco Perrone


F. Perrone1, M. De Laurentiis2, S. de Placido3, M. Orditura4, S. Cinieri5, F. Riccardi6, A.S. Ribecco7, C. Putzu8, L. Del Mastro9, E. Rossi10, B. Daniele11, A.M. Mosconi12, F. Di Rella2, G. Landi2, F. Nuzzo2, C. Pacilio2, R. Lauria3, L. Arenare1, M.C. Piccirillo1, C. Gallo13

Author affiliations

  • 1 Clinical Trials Unit, Istituto Nazionale Tumori – I.R.C.C.S - Fondazione Pascale, 80131 - Napoli/IT
  • 2 Senology, Istituto Nazionale Tumori – I.R.C.C.S - Fondazione Pascale, 80131 - Napoli/IT
  • 3 Medical Oncology, AOU Policlinico Federico II, 80131 - Napoli/IT
  • 4 Dept Of Internal And Experimental Medicine, Università degli Studi della Campania Luigi Vanvitelli, 80131 - Napoli/IT
  • 5 Medical Oncology, Perrino Hospital, Brindisi/IT
  • 6 Oncologia Medica, Ospedale Cardarelli, 80131 - Napoli/IT
  • 7 Medical Oncology, Ospedale S. Giovanni di Dio, 50143 - Firenze/IT
  • 8 Oncologia Medica, Università di Sassari, 07100 - Sassari/IT
  • 9 Internal Medicine, IRCCS AOU San Martino - IST-Istituto Nazionale per la Ricerca sul Cancro, 16132 - Genova/IT
  • 10 Oncologia Medica, Azienda Ospedaliera S. Giuseppe Moscati, 83100 - Avellino/IT
  • 11 Oncology, Azienda Ospedaliera G. Rummo, 82100 - Benevento/IT
  • 12 Oncology-hematology Dpt, Azienda Ospedaliera di Perugia S. Maria della Misericordia, 6132 - Perugia/IT
  • 13 Medical Statistics, Università degli Studi della Campania Luigi Vanvitelli, 80131 - Napoli/IT


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Abstract 4225


Role of aromatase inhibitors and zoledronic acid as adjuvant treatment of premenopausal endocrine-responsive breast cancer patients is debated. Letrozole has never been tested in this clinical setting.


Following surgery and eventual neoadjuvant or adjuvant chemotherapy, premenopausal patients (last menses within 1 yr) were randomly assigned 1:1:1 to Triptorelin 3.75 mg every 4 weeks plus either Tamoxifen 20 mg/die (T), or Letrozole 2.5 mg/die (L) or Zoledronic acid 4mg iv every 6 months + Letrozole 2.5 mg/die (ZL), for 5 years. The primary end-point was disease-free survival (DFS) including locoregional or distant recurrence, second breast or non-breast invasive cancer and death without cancer as event. Analysis was based on intention-to-treatment. Pairwise comparisons (with Bonferroni-Holm correction) were allowed if overall test was statistically significant. The IDMC suggested final analysis be done after 5yrs median follow-up, independently of number of events.


From March 2004 to August 2015, 1065 patients were randomized (T: 354, L:356, ZL: 355) in 16 centres in Italy. Median age was 45; 68% had a pT1 tumor; 55% had negative nodes; 63% had received chemotherapy. After 65 months median follow-up, there were 58, 44, and 32 DFS events and 5 yrs DFS probability was 0.85, 0.93 and 0.93 in the T, L and ZL arms, respectively (P=0.008). Pairwise comparison was statistically significant for ZL vs T (HR 0.52, 95% CI 0.34-0.80, P=0.003) but not for L vs T (HR 0.72, 95% CI 0.48-1.07, P=0.06) and ZL vs L (HR 0.70, 95% CI 0.44-1.12, P=0.22). ZL was more effective than T in all subgroups, but for HER2-positive cases (interaction P=0.002). Twenty-six (7%) patients with T, 26 (7%) with L and 59 (17%) with ZL stopped assigned treatment before 5 yrs due to toxicity or refusal. Grade 3-4 side-effects were reported in 4%, 7% and 9% of patients with T, L and ZL, respectively; there were 4 cases of osteonecrosis of the jaw in the ZL arm.


HOBOE shows that, in premenopausal early breast cancer patients, the ZL+triptorelin combination is more effective than T+triptorelin in terms of DFS.

Clinical trial identification

clinicaltrials.gov: NCT00412022.

Editorial Acknowledgement

No editorial assistance

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