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Hot topics in radiology.

This issue of Advances in Breast Cancer addresses three diagnostic imaging areas where technical developments have seemingly pushed the boundaries of clinical expectations. Tsukagoshi and Allen review the current state of interventional breast biopsy systems. The doctrines of medical advancement do go round and come around. Fifteen years ago, the Advanced Breast Biopsy Instrumentation (ABBI) system introduced large-bore cannula biopsies to surgeons and radiologists [1]. High capital expenditure precluded affordable healthcare application and the system never became a widely used diagnostic biopsy tool, let alone a means for interventional non-surgical therapeutic excision. Since then, mammotome vacuum-assisted biopsy systems have evolved to obtain multiple cores in a piecemeal fashion from a constant target within the breast while the needle remains in the patient, allowing extensive biopsy specimens to reduce sampling error. The natural progression of this approach, predictably, was to use such devices as a means to excise target lesions in place of surgery for selected patients. This paved the way for intact large-bore needle excisions to re-emerge. The Intact[TM] Breast Lesion Excision System (BLES) utilises radiofrequency cauterisation to remove the lesion and is reviewed by the authors in this issue of Advances in Breast Cancer.

Whilst excision biopsy by needles would seem an attractive alternative to surgery, when applied to benign disease, a significant question that arises is why such lesions might need to be removed in the first place. A common reason for excision is on the basis of size. The larger the tumour, the longer the duration of the radiological intervention and one could argue that simple surgical excision fulfils all of the criteria, as a day case with complete excision nearly always guaranteed, and usually in a fraction of the time and with a good aesthetic scar. Another reason why seemingly benign lesions are sometimes excised is on the basis of atypia. However, abnormal histology that turns out to be DCIS requires complete excision and once again surgical excision fulfils this with a definitive measurable margin. Biopsy systems that sample adequately areas of atypia, such as LCIS or ADH, have an advantage by providing a larger amount of sampled tissue for analysis, thus avoiding surgical excision biopsy in suitable cases. In this regard, yet another tool is now available in the quest for minimally invasive diagnostic excision to the benefit of our patients.

MRI scanning in the breast has been used (and possibly overused) in the assessment of early breast cancer cases despite a relative lack of evidence base. O'Brien and Teh provide a comprehensive and practical view of the current status. The majority of studies that have driven the evolution of MRI in planning surgery are based on patient cohort series often from a single institution and with restricted numbers. The COMICE trial [2] in the UK attempted to address this in a structured manner and showed no additional benefit in utilising MRI to reduce re-excision rates after breast conservation surgery. The sample size was underpowered to detect any benefit in patient subsets and could not address a widely held uncertainty about its value in the pre-operative assessment of invasive lobular cancer.

Detection of apparent small volume multifocal disease away from the primary cancer in patients undergoing mastectomy is the sine qua non following the historic pathological studies of Holland et al. [3] and others that followed. Despite this, breast conservation surgery has become the gold-standard treatment for the majority of early breast cancer cases, with low local recurrence rates after effective multimodal therapy, and with proof of concept that has withstood the test of time. The historical data on which this evidence is founded are based on conventional imaging, and the arrival of MRI may see the emergence of new perceptions of healthcare that we should be cautious to adopt without long-term studies of outcome. A swing back to more liberal indications for mastectomy seems inappropriate and it is timely that a greater understanding and uptake of oncoplastic breast surgery may extend the role of breast conservation to keep up with developments in radiology. Whilst MRI may be a useful tool with high sensitivity for cancer, over-investigation in the work-up to surgery, including confirmation of apparently abnormal areas highlighted by MRI that ultimately turn out to be benign, is not an uncommon consequence. The availability of MRI-guided biopsies needs to become more widespread if we are to keep pace with the utilisation of MRI as a pre-operative diagnostic tool. There is value in MRI breast screening in high-risk groups such as gene carriers, and prior mantle radiotherapy has an established application, but the practicalities of service provision and resource should be assured.

Staging breast cancer for many years has varied in recommendation and uptake. With the hypothesis that breast cancer is systemic from the outset, multimodal therapy became indicated in wider patient subgroups and with this overall survival improved. Unmeasurable micrometastases were assumed for the majority of grade 3 tumours, especially in the presence of vascular invasion despite negative lymph nodes. Although lymph node micrometastases became measurable in the area of sentinel node biopsy, we disappointingly still have few answers as to the appropriate management. Grant and Sharma discuss the role of CT-PET in staging breast cancer. CT-PET scanning has the attractive advantage of combining functional uptake of fluorodeoxyglucose to anatomical studies, supposedly selective but the specificity of uptake remains relative, the limitations of which are nicely presented by the authors. CT-PET scans as a single investigation to fulfil staging requirements is an attractive option [4]. Criteria to offer systemic staging following early breast cancer diagnosis continue to be haphazard. Some oncologists will hold the view that early intervention in some scenarios of distant metastases may influence outcome. One of the most commonly cited is the place of intravenous bisphosphonate in bone metastases. Extended Herceptin use in patients who are HER-2 positive may yet be another such area to improve long-term outcome despite the presence of distant disease. The authors present a convincing case for CT-PET scans in distinguishing lytic from sclerotic bone metastases. If one were to perform efficient staging investigations in the current era, one would have to choose a test of high sensitivity and specificity. The definition of which patient groups should have staging investigations at all following an early breast cancer diagnosis may go some way towards rationalising ad hoc investigations but the evidence base for this remains sparse. If staging is indicated, should we replace the current low-technology investigations and where does clinical effectiveness stand against overall cost?

At a time when the NHS is undergoing crucial rationalisation of services, the pendulum of change may yet swing once again in each of these evolving areas.

References

[1.] Liberman L. Advanced Breast Biopsy Instrumentation (ABBI): analysis of published experience. AJR Am J Roentgenol, 1999, 172, 1413-1416.

[2.] Turnbull L, Brown S, Harvey I et al. Comparative effectiveness of MRI in breast cancer (COMICE) trial: a randomised controlled trial. Lancet, 2010, 375, 563-571.

[3.] Holland R, Veling SH, Mravunac M and Hendriks JH. Histologic multifocality of Tis, T1-2 breast carcinomas. Implications for clinical trials of breast-conserving surgery. Cancer, 1985, 56, 979-990.

[4.] Lavayssiere R, Cabee AE and Filmont JE. Positron Emission Tomography (PET) and breast cancer in clinical practice. Eur J Radiol, 2009, 69, 50-58.

Correspondence to: Gerald Gui

Breast Unit, Royal Marsden NHS Foundation Trust

Fulham Road, London SW3 6JJ, UK

email: gerald.gui@rmh.nhs.uk
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Title Annotation:Editorial
Author:Gui, Gerald
Publication:Advances in Breast Cancer
Date:Apr 1, 2010
Words:1227
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