Proportional incidence and radiological review of large (T2+) breast cancers as surrogate indicators of screening programme performance.
OBJECTIVE
Surrogate measures of screening performance [e.g. interval cancer (IC) proportional incidence] allow timely monitoring of sensitivity and quality. This study explored measures using large (T2+) breast cancers as potential indicators of screening performance.


METHODS
The proportional incidence of T2+ cancers (observed/expected cases) in a population-based screening programme (Trento, 2001-2009) was estimated. A parallel review of 'negative' preceding mammograms for screen-detected T2+ and for all ICs, using 'blinded' independent readings and case-mixes (54 T2+, 50 ICs, 170 controls) was also performed.


RESULTS
T2+ cancers were observed in 168 screening participants: 48 at first screen, 67 at repeat screening and 53 ICs. The T2+ estimated proportional incidence was 68% (observed/expected = 168/247), corresponding to an estimated 32% reduction in the rate of T2+ cancers in screening participants relative to that expected without screening. Majority review classified 27.8% (15/54) of T2+ and 28% (14/50) of ICs as screening error (P = 0.84), with variable recall rates amongst radiologists (8.8-15.2%).


CONCLUSIONS
T2+ review could be integrated as part of quality monitoring and potentially prove more feasible than IC review for some screening services.


CONCLUSIONS
• Interval breast cancers, assumed as screening failures, are monitored to estimate screening performance • Large (T2+) cancers at screening may also represent failed prior screening detection • Analysis of T2+ lesions may be more feasible than assessing interval cancers • Analysis of T2+ cancers is a potential further measure of screening performance.
UO Senologia Clinica e Screening Mammografico, Dipartimento di Radiodiagnostica, APSS, Trento, Italy. stefano.ciatto@gmail.com
S
S
Ciatto
D
D
Bernardi
M
M
Pellegrini
G
G
Borsato
P
P
Peterlongo
M A
MA
Gentilini
F
F
Caumo
A
A
Frigerio
N
N
Houssami
D000368:Aged; D015415:Biomarkers; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D005260:Female; D006801:Humans; D015994:Incidence; D007558:Italy / Q000453:epidemiology; D008327:Mammography / Q000706:statistics & numerical data*; D008403:Mass Screening / Q000706:statistics & numerical data*; D008875:Middle Aged; D017063:Outcome Assessment, Health Care / Q000706:statistics & numerical data*; D015397:Program Evaluation; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D015415:Biomarkers