Percutaneous minimally invasive stereotactic primary radiotherapy for breast cancer.

Abstract

A 73-year old lady, admitted to our breast clinic, was found to have a lump in the left breast. She had recently been diagnosed with motor neurone disease and pseudobulbar palsy with a generally poor prognosis. Physical examination, mammography, and fine-needle-aspiration cytology (triple assessment) showed a 2·5 cm infiltrating duct-carcinoma. Since she was too frail for conventional surgery, the usual option would have been to treat her with tamoxifen. However, there is some evidence that local treatment is effective, in combination with tamoxifen, because it reduces breast cancer morbidity and deaths (risk reduction=0·62, 95% CI 0·41–0·94) and may improve survival. We recently received ethics approval to use a novel method of delivering interstitial radiotherapy while withholding tamoxifen (20 mg/day) for 1 month after treatment. Our patient was happy to undergo this single dose outpatient-based treatment. We assessed response objectively using contrast-enhanced MRI and core-cut biopsy before, and at various intervals after, treatment (figure 1). This novel approach uses a minimally invasive therapy which incorporates three converging technologies: (a) the Fisher Mammotest table for digital real-time tumour localisation, (b) the Mammotome vacuum biopsy system for large excision biopsy, and (c) the PRS400 (PeC Photoelectron Corporation) for localised portable radiotherapy. The patient lies prone on the Fisher stereotactic localisation table and the breast is suspended under the table between the image sensor and a small windowed compressing pad (figure 2). The Mammotome vacuum biopsy apparatus is targeted at the tumour through a tiny incision in the breast under local anaesthesia and a largevolume breast biopsy is taken. The PRS400 is a portable (1·8 kg) electron-beam soft X-ray source that provides a point source of low energy Xrays (50kV) at the tip of a 3·2 mm diameter tube that can be positioned in the breast through the tract created by the Mammotome needle. Positioning of the X-ray tube is carried out under realtime stereotactic control on a prone table under local anaesthetic. The typical prescribed physical dose is 20 Gy (biological equivalent dose=286 Gy for an / ratio of 1·5) at the surface of the tumour. At the centre, the physical dose is approximately 130 Gy. The dosimetry is similar to interstitial brachytherapy but does not have the disadvantage of radioisotope handling and is less complex to calculate. The treatment is delivered in about 12 minutes in a routine X-ray room on an outpatient basis. Using this technique, the area of

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Cite this paper

@article{Vaidya2002PercutaneousMI, title={Percutaneous minimally invasive stereotactic primary radiotherapy for breast cancer.}, author={Jayant Sharad Vaidya and Margaret A. Hall-Craggs and Michael J Baum and Jeffrey S. Tobias and Marie Falzon and Derek D'souza and Steve Morgan}, journal={The Lancet. Oncology}, year={2002}, volume={3 4}, pages={252-3} }