Reductions in recurrence in women with early breast cancer entering clinical trials between 1990 and 2009: a pooled analysis of 155 746 women in 151 trials.

Analyses of tumour characteristics by year of diagnosis showed a significant trend towards lower risk tumours in more recent years, driven by a highly significant trend towards lower nodal status (p<0·0001 for both oestrogen receptor-positive and oestrogen receptor-negative groups; table 1 ; appendix p 35 ).

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