因此，不久前公布的对其有效性的质疑令人震惊 — — 同样令人震惊的还有去年2月发表的加拿大国家乳腺筛查研究25年随访记录。
That is why recent doubts about its effectiveness – intensified by the publication in February of the 25-year follow-up to the Canadian National Breast Screening Study – have come as such a shock.