Now, Later of Never: Multicenter Randomized Controlled Trial Call—Is Surgery Necessary after Atypical Breast Core Biopsy Results in Mammographic Screening Settings?

Table 1

Primary outcome, breast cancer specific mortality.

Death of breast cancer	Comparison (current surgical management)	Intervention arm (conservative management)
Event
No event
	Control event rate (CER) =	Experimental event rate (EER) =

Relative risk (RR): EER/CER (95% CI).
Absolute risk reduction (ARR, risk difference): EER − CER (95% CI).
Number needed to treat: 1/ARR.