Lesion size is a major determinant of the mammographic features of ductal carcinoma in situ: findings from the Sloane project
Received 14 November 2008; received in revised form 28 April 2009; accepted 8 May 2009.
Aim
To assess the radiological features of calcific ductal carcinoma in situ (DCIS) in a large, multicentre dataset according to grade and size, and to investigate the possibility that DCIS has different mammographic features when small.
Materials and methods
The dataset consisted of all Sloane Project DCIS cases where calcification was present mammographically and histological grade and size were available. The radiology data form classifies calcific DCIS as casting/linear, granular/irregular, or punctate. The pathology dataset includes cytonuclear grade and microscopic tumour size. Correlations were sought between the radiological findings and DCIS grade and size. The significance of differences was assessed using the chi-square test and chi-square test for trend.
Results
One thousand, seven hundred and eighty-three cases were included in the study. Of these, 1128, 485, and 170 had high, intermediate, and low-grade DCIS, respectively. Casting calcification was more frequently seen the higher the grade of DCIS, occurring in 58% of high grade, 38% of intermediate grade, and 26% of low-grade cases, respectively (p<0.001). Casting calcification was also increasingly common with increasing lesion size, irrespective of the histological grade (p<0.001). Thus casting calcifications in small (<10mm) high-grade DCIS lesions were seen with a similar frequency (50%) to those in moderate-sized (21–30mm) intermediate-grade lesions (48%), and to those in large (>30mm) low-grade lesions (46%).
Conclusion
Lesion size has a strong influence on the radiological features of calcific DCIS; small, high-grade lesions often show no casting calcifications, whereas casting calcifications are seen in nearly half of large, low-grade lesions. As small clusters of punctate or granular calcifications may represent high-grade DCIS, an aggressive clinical approach to the diagnosis of such lesions is recommended as the adequate treatment of high-grade DCIS will prevent the occurrence of potentially life-threatening high-grade invasive disease.
aNinewells Hospital and Medical School, Mailbox 4, Dundee DD1 9SY, Scotland UK
bWest Midlands Cancer Intelligence Unit, Birmingham UK
eKings College London, Guys and St Thomas' Hospitals, London, UK
Guarantor and correspondent: Centre for Oncology and Molecular Medicine, Ninewells Hospital and Medical School, mailbox 4, Dundee DD1 9SY, Scotland UK. Tel :+44 (0) 1382 632196; fax:+44 (0) 1382 496363.
ABSTRACT