Challenges in evaluation of screening for gastric cancer among men based on nonrandomized design

Figures & data

Figure 1. Design of the feasibility study on screening for gastric cancer in middle-aged men in two Finnish cities in 1994–1996 using a biomarker.

Table 1. Number and percentage of men, number of accumulated person years, and mean time per person in follow-up in 1994–2011 by screening status.

	Men		Person years
Screening status	Number	Percent	Number	Mean/person
Non-screened	4697	27.8	54,955	11.7
Screened	12,175	72.2	166,798	13.7
Total invited	16,872	100.0	221,023	13.1

Table 2. Standardized mortality ratios (SMR) and standardized incidence ratios (SIR) among the screened and non-screened men by the site of cancer 1994–2011.

		Screened (N = 12,175)				Non-screened (n = 4697)
Cancer site	Event	OBS	EXP	SMR or SIR	95%CI	OBS	EXP	SMR or SIR	95%CI
Stomach cancer	Deaths	31	58.1	0.53^a	0.36–0.75	24	18.7	1.28	0.82–1.90
	Cases	60	80.5	0.75	0.57–0.95	23	26.1	0.88	0.56–1.32
All cancers	Deaths	1 020	1 116.7	0.91	0.86–0.97	514	354.8	1.45	1.33–1.57
	Cases	3 088	2 747.6	1.12	1.08–1.16	976	881.4	1.11	1.04–1.17

^a p < 0.001.

Table 3. Potential years of life lost (PYLL values) per 1000 persons and mean PYLL values per death before age of 80 among the screened and non-screened men by site of cancer 1994–2011.

	Screened (n = 12,175)			Non-screened (n = 4697)
Cancer site	PYLL	95%CI	PYLL/death	PYLL	95%CI	PYLL/death
Gastric cancer	25.7	15.5–36.0	10.4	77.3	43.1–111.4	15.1
All cancers	875	815–935	11.0	1388	1259–1518	13.2

Table 4. Crude and corrected proportions (%) in reduction of mortality and of potential years of life lost (PYLL) among men attributable to SPGI screening.

	Attributable proportion (%)
Outcome indicator	Crude (E1)	Corrected (E2)
Mortality	59	23
PYLL	67	39