Effect of local therapy on locoregional recurrence in postmenopausal women with breast cancer in the Tamoxifen Exemestane Adjuvant Multinational (TEAM) trial.

Background And Purpose: The TEAM trial investigated the efficacy and safety of adjuvant endocrine therapy consisting of either exemestane or the sequence of tamoxifen followed by exemestane in postmenopausal hormone-sensitive breast cancer. The present analyses explored the association between locoregional therapy and recurrence (LRR) in this population.

Material And Methods: Between 2001 and 2006, 9779 patients were randomized. Local treatment was breast conserving surgery plus radiotherapy (BCS+RT), mastectomy without radiotherapy (MST-only), or mastectomy plus radiotherapy (MST+RT). Patients with unknown data on surgery, radiotherapy, tumor or nodal stage (n=199), and patients treated by lumpectomy without radiotherapy (n=349) were excluded.

Results: After a median follow-up of 5.2 years, 270 LRRs occurred (2.9%) among 9231 patients. The 5-years actuarial incidence of LRR was 4.2% (95% CI 3.3-4.9%) for MST-only, 3.4% (95% CI 2.4-4.2%) for MST+RT and 1.9% (95% CI 1.5-2.3%) for BCS+RT. After adjustment for prognostic factors, the hazard ratio (HR, reference BCS+RT) for LRR remained significantly higher for MST-only (HR 1.53; 95% CI 1.10-2.11), not for MST+RT (HR 0.78; 95% CI 0.50-1.22).

Conclusion: This explorative analysis showed a higher LRR risk after MST-only than after BCS+RT, even after adjustment for prognostic factors. As this effect was not seen for MST+RT versus BCS+RT, it might be explained by the beneficial effects of radiation treatment.