Impact of breast density on radiological-pathological correlation in lobular breast cancer; is preoperative MRI a worthwhile exercise?

Congress:

ECR 2020

Poster Number:

C-07793

Type:

Scientific Exhibit

Keywords:

Performed at one institution, Observational, Retrospective, Cancer, Staging, MR, Breast

Authors:

S. D. Gawley¹, A. Nandakumar¹, Y. Masannat¹, E. Husain¹, T. Gagliardi²; ¹Aberdeen/UK, ²London/UK

DOI:

10.26044/ecr2020/C-07793

DOI-Link:

https://dx.doi.org/10.26044/ecr2020/C-07793

Fig. 1: BI-RADS breast density

Fig. 2: Additional ipsilateral malignant disease findings on MRI

Table 1: Additional malignancy in 4 category BI-RADS breast density

Table 2: Comparison between breast density and change in surgery, re-excision and...

Fig. 3: Area of occult tumour circled

Fig. 4: MRI, occult malignancy on mammogram

Fig. 5: Multiple areas of abnormal microcalcification

Fig. 6: MRI, large contrast enhancing mass in the left breast

Results

73 patients were identified, mean age was 59.9 years, age range 41-79 years.

41 patients (56.2%) were from screening, 31 patients (42.5%) were from the symptomatic service and 1 patient (1.4%) was on Family History Surveillance.

Breast density via BI-RADS 4th edition is shown in Figure 1.

26 patients (35.6%) had additional disease in either breast. 25 (34.2%) patients had additional disease in the ipsilateral malignant breast. In total 3 patients (4.1%) had contralateral malignancy, these patients had BI-RADS density of 2, 3 and 4, all were IDCs. Figure 2 documents additional ipsilateral malignant disease findings on MRI.

Of 52 patients who were BI-RADS 1 or 2, 17 (32.7%) had additional malignancy on MRI, of 21 patients who were BI-RADS 3 or 4, 9 (42.9%) had additional malignancy on MRI, p=0.582, chi-squared test. Table 1 shows additional malignancy in 4 category BI-RADS density groups.

16 patients (21.9%) had a change in surgical management following MRI. 11 of these patients had ipsilateral mastectomy, in 3 cases this was patient choice.

12 patients (16.4%) required further surgery to achieve clear margins. In all 4 patients who required a completion mastectomy there were residual foci of tumour.

The primary mastectomy rate was 30 patients (41.1%) and the final mastectomy rate was 34 patients (46.6%).

A comparison was performed between breast density and change in surgery, re-excision rate and mastectomy rate. Although there was a trend of more change in surgery and a higher mastectomy rate in the denser breast this was not statistically significant in either category, see Table 2.

25 patients (34.2%) had a second look ultrasound to assess additional findings identified on MRI. In 10 patients malignancy was identified and in 15 patients a benign lesion was found. In total 4 patients had an MRI guided biopsy and one patient had an MRI guided wire localisation.

In 5 cases multifocal disease was identified on MRI but the final pathology demonstrated either unifocal invasive malignancy or fewer malignant foci. In all these cases there was also in situ disease which may explain the MRI findings.

Figures 3 and 4 are from the same patient who was assessed for a right sided breast tumour and had an incidental finding of a malignant lesion in the left breast on MRI which was occult on mammogram.

Figures 5 and 6 are from the same patient who had dense breast tissue and suspicious microcalcification in the left breast. The MRI demonstrates a large mass which could not be delineated on the mammogram.