Effectiveness of early detection on breast cancer mortality reduction in Catalonia (Spain)

BMC Cancer

Table 2 Estimated effect of early detection of breast cancer (BC), in the 40-80 year age interval, with different BC survival scenarios.

	Scenario A		Scenario B		Scenario C
Interval of exams	Annual	Biennial	Annual	Biennial	Annual	Biennial
	MR (%)
40-74	29.8	22.9	32.5	25.1	44.0	33.8
50-69	25.3	19.6	27.6	21.3	36.7	27.6
	YLG per woman screened
40-74	0.222	0.165	0.203	0.151	0.208	0.154
50-69	0.176	0.132	0.161	0.120	0.162	0.119
	YLG per breast cancer detected
40-74	1.874	1.387	1.711	1.272	1.753	1.300
50-69	1.485	1.109	1.353	1.010	1.367	1.003

Relative BC mortality reduction (MR) and years of life gained (YLG). Catalonia, cohorts born in 1955-59.
A: Survival probability density functions (pdfs): Catalonia 1980-1989 (pre-dissemination of mammography screening).
B: Resulting survival pdfs after applying a hazard ratio of 0.75 to the 1980-1989 hazard rates, in order to take into account the effect of adjuvant treatments.
C: Survival pdfs: Catalonia 1990-2001 (survival functions have not been corrected by the lead time bias that originates from earlier detection). This scenario produces an overestimation of the effect of early detection.

ISSN: 1471-2407