The purpose of this trial is to address the question of the added value of adjuvant chemotherapy on survival in 70+ BC patients with ER+ disease, deemed "at risk of relapse" (pN+ or pN0 with a high prognostic classifier, namely GG by RT-PCR) and planned to receive as well adjuvant endocrine treatment. This benefit will be weighed with the competition exerted by comorbidities on mortality.