Mammographic prediction of close or involved deep margin involvement following breast surgery


Year:

Session type:

David Hwang1,2, Lyndsae Wheen1,2, Russell Davies1,2
1Royal Devon and Exeter Hospital, Exeter, UK, 2University of Exeter, Exeter, UK

Background

Involved or close surgical margin involvement after attempted excision of malignant breast lumps is an independent poor prognostic indicator of loco-regional recurrence and survival.

Predicting involved or close surgical margins would be a useful tool and may prompt the increased use of neo-adjuvant therapies such as chemotherapy or hormonal treatment to minimise this adverse occurrence.

Method

A retrospective mammogram and histopathology review for all patients treated on the breast cancer unit at the Royal Devon and Exeter hospital was performed for all patients with confirmed malignancy operated on following diagnostic biopsy in 2008.

A consultant radiologist with an interest in breast cancer (R.D.) recorded the measurable distance from the posterior visible limit of the tumour and the perpendicular (shortest) distance to the pectoralis muscle on the mammographic oblique view (P-P distance).

The posterior margin was re-measured on all available histological tissue which was the shortest microscopic distance between the most posterior aspect of the tumour and the pectoralis muscle or deep aspect of the resected tissue.

Results

Three hundred and ninety-five women were identified from the Exeter Breast Cancer database. 364 (92%) patients' pathology specimens and 328 (83%) oblique mammograms were available for review. The tumour was not detectable on 48 (12%) mammograms and overlapped pectoralis major muscle in 19 (5%). 280 (71%) of the invasive tumours were infiltrating ductal in origin and 39 (10%) were lobular in origin. 52 (13%) were DCIS and 5 (1%) were LCIS.

Pearson's correlation coefficient was measured at 0.254 (p< 0.01) for all cases, for ductal was 0.274 (p<0.01) and lobular 0.393 (p<0.026).

Conclusion

There is significant correlation between the measurable radiological distance between the posterior extent of the tumour and the pectoralis muscle present on oblique mammograms and the deep surgical margin.