A comparison of reading times in full-field digital mammography and digital breast tomosynthesis

Abstract

BI-RADS descriptors. To identify MRI characteristics of nonmass lesions which predict malignancy for invasive and non-invasive cancers. Methods: Retrospective analysis of 486 MRI-guided vacuum biopsies performed at Northwick Park Hospital between April 2006 and November 2011. Each lesion was categorised according to BI-RADS lexicon (ML vs. NML lesions) and time-enhancement curves, and given an overall score of MRI 1 to 5 according to overall level of suspicion for malignant disease where MRI 4 and 5 are considered suspicious or diagnostic for malignancy. Biopsy and surgical histology results obtained. Results: A total of 291 ML and 152 NML lesions, of which there were 150 cancers diagnosed. Positive predictive value of MRI characteristic for malignant mass lesions is 70%. Positive predictive value of MRI characteristic for nonmass lesions is 57%. Segmental enhancement is the most common MRI morphology found in 45% DCIS. No specific features predict for invasive disease in NML lesions. Time-enhancement curves were mainly type 2 (44.6%) and type 3 (52.7%) in malignant ML lesions and unhelpful in predicting malignancy in NML lesions (72% type 2 and 59% type 3 were benign). Conclusion: No specific BI-RADS feature predicts for invasive disease in NML lesions. Segmental enhancement is the most common MRI appearance for DCIS. Time-enhancement curves are unhelpful in predicting malignancy in NML lesions. O4 Use of MRI fusion second-look ultrasound in breast cancer: can MRI US fusion reduce the need for MRI-guided biopsy? SE McWilliams Guy's and St Thomas' NHS Foundation Trust, London, UK Breast Cancer Research 2012, 14(Suppl 1):O4 Introduction: Breast MRI is being increasingly used in breast cancer to look for extent of disease, in high-risk screening and in the dense breast. Frequently incidental lesions are detected on MRI that require second-look ultrasound or stereotactic biopsy. Incidental MRI-detected lesions may be occult on conventional imaging and require MRI-guided biopsy. We describe our experiences with US MRI fusion to try and reduce the need for MRI-guided biopsy. Methods: At our institution we have introduced an MRI breast biopsy service which is time consuming and expensive. We looked at 10 patients with MRI US fusion technology on our new Hitachi US MRI scanner to see whether lesions were easier to identify combining the MRI and US images, enabling US biopsy to be performed. Results: Ten patients with a known breast cancer had a further incidental lesion seen on MRI. The patients had an additional supine series on contrast MRI images in addition to the standard prone protocol. The supine images were loaded on the US machine and enabled confident detection of the lesion on US in nine out of 10 patients. Conclusion: Using MRI US fusion with one additional MRI series of supine images reduces the need for MRI-guided biopsy enabling US biopsy to be performed, which is cheaper, quicker and more patient acceptable. O5 Long-term survival of interval breast cancers in breast cancer screening in Wales Introduction: Breast Test Wales is part of the NHS Breast Cancer Screening Programme, and oversees the screening programme in Wales. It is successful in identifying asymptomatic cancers; however, interval cancers (IC) still occur between screenings. We aim to evaluate the overall long-term survival of IC and compare that with screen-detected cancers (SDC). Methods: Within BTW, SDC between 1998 and 2001 and IC occurring between 1998 and 2004 but screened between 1998 and 2001 were identified. IC were classified into true interval (TI), false negative (FN), occult (OCC) and unclassified (UCC). BTW receives notification of death of all women that underwent screening. The long-term survival rate was calculated from the date of initial screening and the date of death. Results: In the 3-year screening period, 199,082 women were screened. A total of 1,020 women had SDC and 692 further developed IC following screening. Of the 692 IC, 57.8% (391) were TI, 17.7% (120) were FN, 10% (68) were OCC and 14.5% were UCC. After at least 10 years of follow-up, the long-term survival rate (all-cause) for SDC was 81.6%, overall for IC was 72.4% (OR 1.67, P < 0.001), TI was 77.5% (OR 1.00, P = 0.99), FN was 55% (OR 2.36, P < 0.001), OCC was 54.4% (OR 3.17, P < 0.001) and UCC was 87.8% (OR 0.61, P = 0.19). Conclusion: Overall survival of IC is significantly different to SDC. However, SDC and TI were not statistically significantly different. FN and OCC had significantly worse long-term survival. Further research is required to identify the underlying cause of poor survival of FN and OCC. O6 Gamma probe and ultrasound-guided percutaneous localisation of the sentinel lymph node in breast cancer patients P Whelehan * , A Evans, S Vinnicombe, D Brown, D McLean University of Dundee, UK Breast Cancer Research 2012, 14(Suppl 1):O6 Introduction: A major reason for failure to diagnose axillary lymph node metastasis preoperatively in breast cancer patients is that needle biopsy may not target the sentinel node (SLN). We aimed to address this by testing the accuracy with which we could identify and target the sentinel lymph node percutaneously under combined radioisotope and ultrasound guidance. Methods: Ethical approval was obtained. In 48 patients scheduled for surgical sentinel lymph node biopsy (SLNB), following injection of radioisotope, one of three radiologists used a gamma probe in tandem with ultrasound guidance to identify a SLN prior to surgery and mark it with a localising wire. The patients then proceeded to surgical SLNB, guided by radioisotope and blue dye. The surgeon noted whether the wire had correctly marked a SLN. Results: The SLN was correctly localised in 75% of patients (36 of 48; 95% CI = 63 to 87%). A learning curve for the three operators was observed, with a rate of correct localisation in the first five procedures performed by each operator of 67% (10 of 15) rising to 79% in the subsequent 33 (26 of 33; 95% CI = 64 to 93%). Interoperator variations in accuracy were evident, with a success rate of 83% in the most experienced of the three. Conclusion: Percutaneous SLN localisation using combined radioisotope and ultrasound guidance is feasible. Use of this method to guide needle biopsy of the axilla could increase the preoperative diagnosis rate for axillary lymph node metastases in breast cancer patients.