Table 2.

Mean life-years and costs for reference case and best alternative strategy from screening age until age 95 years

	Reference case*			Best alternative strategy†
	Not invited to screening	Invited to screening	Difference	Not invited to screening	Invited to screening	Difference
Life-years
Undiscounted	20·5451	20·5480	0·0029	16·4305	16·4353	0·0048
Discounted	13·9351	13·9367	0·0016	11·8599	11·8627	0·0028
Discounted, QA	10·4484	10·4495	0·0011	8·7257	8·7277	0·0020
Costs (£)
Undiscounted	90·33	126·23	35·90	84·53	134·93	50·40
Discounted	50·55	84·36	33·81	52·76	97·83	45·07
ICER (£ per life-year or QALY gained)
Discounted, life-years	..	..	21 620 (95% CI 8862–61 794)	..	..	16 016 (95% CI 6800–50 039)
Discounted, QA	..	..	30 170 (95% CI 12 238–87 002)	..	..	22 540 (95% CI 9522–70 638)

Selective sampling of individuals above the diagnosis threshold was used to calculate accurate incremental estimates whereas mean life-years and costs within groups were obtained from full population sampling. For consistency, estimates in the Invited group are therefore obtained by adding the incremental estimates to the estimates from the Not Invited group. QA=quality-adjusted. ICER=incremental cost-effectiveness ratio. QALY=quality-adjusted life-year.

^*Invitation to screening at age 65 years, diagnosis threshold 3·0 cm, intervention threshold 5·5 cm.

^†Invitation to screening at age 70 years, diagnosis threshold 2·5cm, intervention threshold 5·0cm.