Table 3.

Association of categorised DCIS detection frequencies at screening with subsequent invasive interval cancer incidence

	Average DCIS detection per 1000	Invasive interval cancers/total screened	Invasive interval cancers per 1000	RR (95% CI)
<1 per 1000	0·85	1236/392 982	3·15	1·0
1–<1·5 per 1000	1·27	6069/2 063 030	2·94	0·94 (0·88–0·99)
1·5–<2·0 per 1000	1·72	4844/1 686 588	2·87	0·91 (0·86–0·97)
≥2 per 1000	2·25	3065/1 101 058	2·78	0·89 (0·83–0·95)

DCIS=ductal carcinoma in situ. RR=relative risk.