Assessment of breast cancer opportunistic screening by clinical-pathological indicators: a population-based study.
BACKGROUND
Although some clinical-pathological features of breast cancers, such as the incidence of ductal cancer in situ (DCIS) and the diameter of invasive tumours, are sensitive indicators of early detection, comprehensive population-based studies of opportunistic screening are needed.


METHODS
Cases of DCIS or invasive breast cancer diagnosed in 1996-2007 were identified from the Ticino Cancer Registry (south of Switzerland). Time trends of age-adjusted incidence and mortality, as well as main clinical-pathological features, such as tumour diameter, AJCC stage and histological grade, were analysed.


RESULTS
A total of 3047 incident cases of female breast cancer were identified. The proportion of DCIS with respect to invasive cases increased from 5.8% in the period 1996-2001 to 6.4% in the period 2002-2007. The median tumour size of invasive cancers decreased from 20 mm in 1996-2001 to 18 mm in 2002-2007 (P<0.0001). An increase in well/moderately differentiated invasive tumours, from 67% in the period 1996-2001 to 73% in 2002-2007 (P<0.001), was detected and resulted in an Annual Percentage Change of incidence of 2.8 (95% confidence interval: 1.3; 4.3).


CONCLUSIONS
An opportunistic screening strategy can lead to an improvement of prognostic features at diagnosis, but these features are still less favourable than those achieved by organised screening programmes.
Bordoni
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A
Ticino Cancer Registry, Institute of Pathology, Via in Selva 24, Locarno CH-6600, Switzerland. andrea.bordoni@ti.ch
Probst-Hensch
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NM
Mazzucchelli
L
L
Spitale
A
A
D000368:Aged; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000453:epidemiology / Q000473:pathology*; D002278:Carcinoma in Situ / Q000175:diagnosis / Q000453:epidemiology / Q000473:pathology; D018270:Carcinoma, Ductal, Breast / Q000175:diagnosis / Q000453:epidemiology / Q000473:pathology; D055088:Early Detection of Cancer; D005260:Female; D006801:Humans; D015994:Incidence; D008403:Mass Screening / Q000379:methods; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D012042:Registries; D012307:Risk Factors; D013557:Switzerland / Q000453:epidemiology