Increased pathological complete response rate after a long-term neoadjuvant letrozole treatment in postmenopausal oestrogen and/or progesterone receptor-positive breast cancer.

Abstract

BACKGROUND:

The objective of this study was to determine the optimal scheduling of 2.5 mg daily letrozole in neoadjuvant breast cancer patients to obtain pathological complete response (pathCR) and assess Ki-67 expression as an early predictor of response.

PATIENTS AND METHODS:

This single institution study comprised 120 oestrogen receptor (ER)-positive postmenopausal women with primary breast cancer (clinical stage ≥ T2, N0-1), from three sequential cohorts (cohort A of 40, cohort B of 40 and cohort C of 40 patients, respectively) based on different duration of the neoadjuvant letrozole. Biological markers such as ER, progesterone receptor, HER2 and Ki-67 expression were tested at diagnosis and at definitive surgery.

RESULTS:

A total of 89 patients (75.4%) achieved an objective response with 44 (37.3%) clinical CRs and 45 (38.1%) partial responses. The clinical CRs were significantly observed in cohort C (23 out of 40 patients, 57.5%) and B (16 out of 38 patients, 42.1%) compared with cohort A (5 out of 40 patients, 12.5%) (P-value for trend <0.001). Letrozole induced a similar significant reduction in Ki-67 index after treatment in all cohorts. The pathCR rate was significantly more frequent in cohort C (7 out of 40 patients, 17.5%) than in cohort A (1 out of 40 patients, 2.5%) and B (2 out of 40 patients, 5.0%) (P-value for trend <0.04).

CONCLUSION:

One-year neoadjuvant letrozole therapy leads to a higher pathCR rate and may be the optimal length of drug exposure.

• Authors: G Allevi, C Strina, D Andreis, V Zanoni, L Bazzola, S Bonardi, C Foroni, M Milani, M R Cappelletti, F Gussago, S Aguggini, R Giardini, M Martinotti, S B Fox, A L Harris, A Bottini, A Berruti, D Generali
• Journal: British journal of cancer (Br J Cancer) Vol. 108 Issue 8 Pg. 1587-92 (Apr 30 2013) ISSN: 1532-1827 [Electronic] England
• PMID: 23579222 (Publication Type: Clinical Trial, Comparative Study, Journal Article)

Chemical References

• Antineoplastic Agents
• Aromatase Inhibitors
• Ki-67 Antigen
• Nitriles
• Receptors, Estrogen
• Receptors, Progesterone
• Triazoles
• Letrozole

Topics

• Aged
• Aged, 80 and over
• Antineoplastic Agents (administration & dosage, adverse effects)
• Aromatase Inhibitors (administration & dosage, adverse effects)
• Breast Neoplasms (drug therapy, metabolism, pathology, surgery)
• Chemotherapy, Adjuvant
• Cohort Studies
• Drug Administration Schedule
• Female
• Humans
• Ki-67 Antigen (biosynthesis, metabolism)
• Letrozole
• Neoadjuvant Therapy
• Nitriles (administration & dosage, adverse effects)
• Receptors, Estrogen (metabolism)
• Receptors, Progesterone (metabolism)
• Triazoles (administration & dosage, adverse effects)