Combined radioguided occult lesion and sentinel node localization for breast cancer

The incidence of non-palpable breast lesions requiring intraoperative localization has greatly increased, particularly because of the widespread use of mammographic screening. These lesions have previously been localized preoperatively using hook-wire or carbon track techniques. In the era of increasing acceptance of sentinel node biopsy (SNB) a separate procedure would be required for sentinel node localization (SNL). The present study describes an experience with ultrasound guided radionucleotide occult lesion localization (ROLL) as a reliable alternative that enables SNL synchronously.

Twenty-two patients with proven breast malignancy on core biopsy were enrolled in the present study. Preoperatively, technetium-99m was injected around the lesion under radiological guidance. A gamma-probe was then used to locate the lesion and guide its surgical removal. Complete excision was then confirmed immediately by verifying minimal residual radioactivity in the cavity wall tissue. Appropriate SNB then proceeded.

The primary breast lesion was identified in all cases except in one, where the radiotracer was injected into the wrong site, giving a miss rate of 1/22 (4.5%). The average size of the tumour was 13 mm (range 6-22 mm) and the closest margins ranged from 0 (1 patient) to 22 mm (mean 7 mm). Two patients had inadequate margins and required further excision giving a re-excision rate of 2/21 (9.5%). SNB specimens included a median of 3.7 nodes/patient.

Radionucleotide occult lesion localization/SNL is a simple, accurate and reliable method of combining localization of impalpable breast lesions with the localization required for SNB. The miss and re-excision rates compare favourably with the needle-wire systems and carbon tracking techniques. There are significant resource efficiency and time advantages.