In patients with DCIS: is it sufficient to histologically examine only those tissue specimens that contain microcalcifications?

The purpose was to investigate in patients with histologically proven DCIS to what extent there is agreement between radiographically proven microcalcifications of specimens obtained by vacuum-assisted biopsy and the histologic diagnosis of microcalcifications and DCIS, and second, to assess the accuracy of biopsy in relation to the number of specimens obtained in patients with high-grade and low-grade DCIS. Four hundred twenty specimens from 35 patients who were diagnosed with DCIS were examined radiographically and histologically for the presence of microcalcifications. The results were analyzed using the McNemar-test. In addition, the average numbers of biopsy specimens necessary for diagnosing low-grade DCIS and high-grade DCIS were compared using the t-test. Specimen radiography had a PPV of 0.50 and a NPV of 0.85 for the demonstration of DCIS. Differences in localization between radiographically proven microcalcifications and DCIS were statistically significant (p<0.01). The difference between the mean numbers of specimens required per patient for correctly diagnosing high-grade or low-grade DCIS was statistically significant (p<0.01). Specimen radiography is very limited in identifying those specimens that are crucial for diagnosing DCIS. The rate of underestimation is expected to be higher for low-grade than for high-grade DCIS. The findings suggest that all samples obtained by vacuum-assisted breast biopsy should be histologically examined.