Rolling out radioguided occult lesion localisation for breast tumours

There is a disconnection between the high-resolution displays in the medical imaging department and what the clinician can detect at the bedside. One example is the flood of impalpable tumours which can account for more than half of those detected by breast cancer screening programs: how to guide the surgeon to where the lesion is? One solution is the subject of the article by Landman et al. in this issue of the journal. There is more than one solution for guiding surgical excision of impalpable breast lesions. Intra-operative ultrasound would appear to be a ready fix – the surgeon merely brings the imaging suite into the operating suite. However, this necessitates extra planning and cost because it commits extra personnel and equipment. A more convenient solution is to inject a marker within or in the vicinity of the lesion. One kind of marker is a coloured dye such as methylene blue or carbon particles in suspension. Its disadvantages are that the surgeon still starts the dissection unsighted and there is a limited time before the dye disperses in the case of methylene blue. Another kind of marker is a needle wire. These wires have a distal anchor which is positioned within or near to the lesion of interest. The method provides easier localisation, decreases the operative time and enables excision of a small volume of tissue. It does have difficulties such as migration, kinking and fracture of the wire post insertion. Also up to 20–50% of wired guided excisions in published series are incomplete by virtue of contaminated margins. Nevertheless, this has become the preferred option in most centres and regarded as the gold standard procedure. A third alternative marker is a radioactive source. This arose from the experience breast surgeons gained in utilising radiocolloid lymphoscintigraphy and the intraoperative gamma probe to localise the sentinel lymph nodes. With his proficiency in the use of the gamma probe to localise nodes, one surgeon issued a challenge to his nuclear physician colleague to make the impalpable breast lesions a similar target. Thus, the technique of radiocolloid localisation was born. Radioguided occult lesion localisation (ROLL) is a simple but effective method of guiding the excision of clinically occult breast lesions with a minimum of adjacent normal tissue. Either mammography or ultrasound is used to guide injection of a small volume of radiolabelled colloid into the centre of the lesion. In the operating theatre, this focus of radioactivity is detected by a handheld pencil gamma probe which converts the intensity of the gamma emission to a sound and visual scale. The surgeon can use this to guide the skin incision at a point directly over and closest to the lesion. As the dissection proceeds, the probe can be used as often as desired by the operator for guidance towards the lesion and to centre it within the excised specimen. Finally, the probe can confirm complete excision by detecting low residual radioactivity in the cavity. The gamma radiation dose to the patient and the operators is very low and well within safe nuclear regulatory limits. This method has been rolled out in many centres using wire localisation as a control. In most studies to date, ROLL compares favourably against wire localisation. The interventional radiologists have reported that ROLL is easier than inserting a needle wire. The surgeons have reported that it is easier to use the gamma probe to guide the dissection and centralise the lesion: resulting in shorter operating times, smaller excision volumes, higher rates of tumour-free margins and lower rates of re-operation. The patients have reported less discomfort with ROLL than wire localisation, and a better cosmetic result. A systematic review that summarised 27 studies and a meta-analysis that accepted only four of these studies, set out with the main objective of testing the rate of contaminated or inadequate margins when biopsy was guided by ROLL versus wire localisation. Both concluded that ROLL did result in lower positive margin rates and fewer repeat