Summary of findings 3. Outcome of follow‐up testing using a CEA threshold of 5 µg/L.

Month when CEA measured	per 1000 patients tested at a threshold of 5 µg/L					False alarm rate
	Estimated recurrences¹	Referrals for raised CEA	Cases of recurrence detected	Cases of recurrence missed	False alarms (cases investigated when cancer not present)
Follow‐up years 1 and 2: 3‐monthly CEA testing
3	19	131	13	6	118	90%
6	19	131	13	6	118	90%
9	39	143	28	11	115	80%
12	39	143	28	11	115	80%
15	37	142	26	11	116	82%
18	37	142	26	11	116	82%
21	31	138	22	9	116	84%
24	31	138	22	9	116	84%
Follow‐up years 3, 4 and 5: 6‐ monthly CEA testing
30	46	147	33	13	114	78%
36	36	142	26	10	116	82%
42	27	136	19	8	117	86%
48	25	135	18	7	117	87%
54	17	130	12	5	118	91%
60	14	128	10	4	118	92%

¹Estimates are based on data reported by Sargent 2007. Three‐monthly data were unavailable, and so constant rates were assumed during each six‐month period for the first two years. Estimates are rounded.