- Title
- Adjuvant letrozole versus tamoxifen according to centrally-assessed ERBB2 status for postmenopausal women with endocrine-responsive early breast cancer: supplementary results from the BIG 1-98 randomised trial
- Creator
- Rasmussen, Birgitte B.; Regan, Meredith M.; Braye, Stephen; Altermatt, Hans J.; Gelber, Richard D.; Castiglione-Gertsch, Monica; Goldhirsch, Aron; Gusterson, Barry A.; Thürlimann, Beat; Coates, Alan S.; Viale, Giuseppe; Lykkesfeldt, Anne E.; Dell'Orto, Patrizia; Del Curto, Barbara; Henriksen, Katrine L.; Mastropasqua, Mauro G.; Price, Karen N.; Méry, Eliane E.; Lacroix-Triki, Magali
- Relation
- Lancet Oncology Vol. 9, Issue 1, p. 23-28
- Publisher Link
- http://dx.doi.org/10.1016/S1470-2045(07)70386-8
- Publisher
- Elsevier
- Resource Type
- journal article
- Date
- 2008
- Description
- Background: The Breast International Group (BIG) 1-98 trial (a randomised double-blind phase III trial) has shown that letrozole significantly improves disease-free survival (DFS) compared with tamoxifen in postmenopausal women with endocrine-responsive early breast cancer. Our aim was to establish whether the benefit of letrozole versus tamoxifen differs according to the ERBB2 status of tumours. Methods: The BIG 1-98 trial consists of four treatment groups that compare 5 years of monotherapy with letrozole or tamoxifen, and sequential administration of one drug for 2 years followed by the other drug for 3 years. Our study includes data from the 4922 patients randomly assigned to the two monotherapy treatment groups (letrozole or tamoxifen for 5 years; 51 months median follow-up [range <1 to 90 months]). A central assessment of oestrogen receptor (ER), progesterone receptor (PgR) and ERBB2 status using paraffi n-embedded primary tumour material was possible for 3650 (74%) patients. ER, PgR, and ERBB2 expression were measured by immunohistochemistry (IHC) and ERBB2-positivity was confirmed by fluorescence in-situ hybridisation (FISH). Positive staining in at least 1% of cells was considered to show presence of ER or PgR expression. Tumours were deemed ERBB2-positive if amplified by FISH, or, for the few tumours with unassessable or unavailable FISH results, if they were IHC 3+. Hazard ratios (HR) estimated by Cox modelling were used to compare letrozole with tamoxifen for DFS, which was the primary endpoint, and to assess treatment-by-covariate interactions. The BIG 1-98 trial is registered on the clinical trials site of the US National Cancer Institute website http://www.clinicaltrials.gov/ct/show/NCT00004205. Findings: By central assessment 7% (257 of 3650) of tumours were classified as ERBB2-positive. In 3533 patients with tumours confirmed to express ER, DFS was poorer in patients with ERBB2-positive tumours (n=239) than in those with ERBB2-negative tumours (n=3294; HR 2·09 [95% CI 1·59–2·76]; p<0·0001). There was no statistical evidence of heterogeneity in the treatment effect according to ERBB2 status of the tumour (p=0·60 for interaction), thus, letrozole improves DFS compared with tamoxifen regardless of ERBB2 status. The observed HRs were 0·62 (95% CI 0·37–1·03) for ERBB2-positive tumours and 0·72 (0·59–0·87) for ERBB2-negative tumours. Interpretation: A benefit of letrozole over tamoxifen was noted, irrespective of ERBB2 status of the tumour, and, therefore, ERBB2 status does not seem to be a selection criterion for treatment with letrozole versus tamoxifen in postmenopausal women with endocrine-responsive early breast cancer.
- Subject
- hormone receptor status; HER-2; progesterone receptors; estrogen receptors
- Identifier
- http://hdl.handle.net/1959.13/41443
- Identifier
- uon:4800
- Identifier
- ISSN:1470-2045
- Language
- eng
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