Breast MRI Improves depiction of DCIS Components

A study by Kuhl et al published in Radiology found magnetic resonance imaging (MRI) of the breast improves depiction of ductal carcinoma in situ (DCIS) components of invasive breast cancers prior to surgery.

The authors performed a prospective two-center study of 593 patients with biopsy proven invasive breast cancer that underwent breast MRI in addition to conventional imaging. 

The outcomes showed surgical-pathologic evaluation demonstrated DCIS components in 139 (23%) women. MRI had significantly higher sensitivity in the diagnosis of DCIS components pre-operatively in (84%; 118 women out of 139) than that of conventional imaging, which detected (36%; 51 of the 139 women). More than 50 percent of DCIS components were detected with MRI alone. 

The researchers also found the sensitivity benefits of MR imaging over conventional imaging improved with increasing relative size, and with increasing nuclear grade of DCIS components. Positive margin rates were generally low and did not diverge significantly between the 139 women with DCIS components versus the 454 women who lacked them.

The authors concluded that breast MRI improves depiction of DCIS components of invasive breast cancers before surgery.

Breast MRI more accurate than mammography in diagnosing invasive cancer in high-risk women

A study by Sung et al published in Radiology found that breast MRI screening is more likely to detect invasive cancers than mammography in women at higher risk. 

The study was a retrospective review of 7,519 high-risk women due to family or personal history of breast cancer, high risk lesion, BRCA mutation status or radiation to the chest, who underwent MRI screening and mammography.

A total of 18 064 screening MR imaging examinations and 26 866 screening mammographic examinations were performed. Two hundred twenty-two cancers were diagnosed in 219 women, 167 (75%) at MR imaging, 43 (19%) at mammography, and 12 (5%) interval cancers. Median age at diagnosis was 52 years.  Cancers found at screening MR imaging were more likely to be invasive cancer 118 of 167 or 71%. Of the 43 cancers found at screening mammography, 38 (88%) manifested as calcifications and 28 (65%) were ductal carcinoma in situ. Interval cancers were associated with nodal involvement were of the triple-negative subtype.

In conclusion MRI of the breast was better than mammography in detecting invasive breast cancer in women at high risk for breast cancer.  Mammography had an advantage for the detection of calcifications and thus for ductal carcinoma in situ.

Diagnostic Disagreement among Pathologists Interpreting Breast Biopsies

Elmore et al in their article published in JAMA report their findings on diagnostic disagreement among 115 pathologists compared with a consensus panel.

The participating pathologists independently interpreted 240 cases, that included 23 cases of invasive breast cancer, 73 cases of ductal carcinoma in situ (DCIS), 72 cases with atypical hyperplasia (atypia), and 72 benign cases without atypia. Among the 3 consensus panel members, unanimous agreement of their independent diagnoses was 75%, and concordance with the consensus-derived reference diagnoses was 90.3%.

  

Compared with the consensus-derived reference diagnosis, the overall concordance rate of diagnostic interpretations of participating pathologists was 75.3%. Among invasive carcinoma cases 96% were concordant; among DCIS cases 84% were concordant, with 3% were over interpreted, and 13% were under interpreted; among atypia cases 48% were concordant, with 17% were over interpreted, and 35% were under interpreted; and among benign cases without atypia 87% were concordant. Disagreement with the reference diagnosis was statistically significantly higher among biopsies from women whose breasts were dense on prior mammograms.

In this study overall agreement between the individual pathologists’ interpretations and the expert consensus-derived reference diagnoses-was 75.3 percent, with the highest level of agreement 96 percent for invasive carcinoma and lower levels of agreement for DCIS 87 percent.  However, with atypical ductal hyperplasia the pathologists matched the experts only in 48 percent of the time.