Table 1.

Descriptive characteristics of individuals eligible for analysis

Characteristics	Age at diagnosis, ya
	60-64		65-69		70-74		75-79b		Total
	Cases	Controls	Cases	Controls	Cases	Controls	Cases	Controls	Cases	Controls
Total No.	4263	8477	4785	9504	4639	9179	949	1876	14636	29036
Stage at diagnosis, %
Stage A	15.9		14.2		14.2		12.4		14.6
Stage B	20.9		23.7		24.1		22.9		22.9
Stage C	27.5		25.0		23.4		23.2		25.1
Stage D	13.0		13.0		11.6		10.9		12.4
Missing stage, %
Suspected Duke Dc	7.1		9.7		13.0		16.3		7.3
Stage B or worse NOSd	7.0		7.1		7.2		9.7		10.4
Stage unknown	8.6		7.3		6.5		4.6		7.3
Gender, %
Male	58.9		56.8		56.2		51.3		56.9
Female	41.1		43.2		43.8		48.7		43.1
Screening exposure, %
Invited but not screenede	40.3	45.9	38.4	36.2	40.5	39.3	49.5	40.2	40.3	40.3
Screened	59.7	54.1	61.6	63.8	59.5	60.7	50.5	59.8	59.7	59.7
Time since last screen, %
<1 y	40.3	28.4	34.8	28.3	27.7	21.7	1.7	3.8	32.0	24.7
>1 y to 2 y	14.4	18.7	18.2	24.4	11.6	15.1	19.5	25.9	15.1	19.9
>2 y to 3 y	3.7	5.7	5.2	7.0	7.1	8.9	16.2	17.4	6.1	7.8
>3 y to 4 y	1.1	1.1	2.1	2.3	6.8	7.2	5.7	6.6	3.5	3.8
>4 y	0.2	0.5	1.3	1.9	6.3	7.8	7.4	6.1	3.0	3.6

^aNote that prior to excluding cases who were not invited for screening, 47.5% of all cancers were diagnosed at ages 60-69 years. A larger proportion of cases were excluded at ages 70-79 years because they had not been invited prior to diagnosis. B+ NOS = Duke B or worse not otherwise specified.

^bThree controls opted into screening.

^cAll individuals died within 1 year of diagnosis and hence are suspected to be Duke D.

^dSurvival and other tumor characteristics suggest stage B+ NOS.

^e Excludes those whose only test was within 7 days of diagnosis or who only had tests at  younger than 60 years.