Table 5a.

Summary of Benefits and Harms-Comparison of Different Starting Ages Using Exemplar Model ¹

		Potential Benefits (vs. no screening)			Potential Harms²
Strategy	Average Screens/1000	% Mortality Reduction	Cancer Deaths Averted/1000	Life Years Gained per 1000	# False positives/1000	# of unnecessary biopsies/1000
Biennial
B 40–69	13865	16%³	6.1	120	1250	88
B 45–69	11771	17%	6.2	116	1050	74
B 50–69	8944	15%	5.4	99	780	55
B 55–69	6941	13%	4.9	80	590	41
B 60–69	4246	9%	3.4	52	340	24
Annual
A 40–69	27583	22%	8.3	164	2250	158
A 45–69	22623	22%	8.0	152	1800	126
A 50–69	17759	20%	7.3	132	1350	95
A 55–69	13003	16%	6.1	102	950	67
A 60–69	8406	12%	4.6	69	600	42

A= Annual

B= Biennial

Results are from Model S. Model S was chosen as an exemplar model to summarize the balance of benefits and harms associated with screening 1000 women under a particular screening strategy.

Over-diagnosis is another significant harm associated with screening. However, given the uncertainty in the knowledge base about DCIS and small invasive tumors, we felt that the absolute estimates are not reliable. In general, over-diagnosis increases with age across all age groups, but rises more sharply for women who are screened in their 70s and 80s.

Shaded strategies are dominated by other strategies; the strategy that dominates may not be on the table.