Radioguided occult lesion localisation (roll) as a diagnostic and therapeutic procedure: clinical review at a single tertiary hospital in South Africa

Abstract

Introduction: Due to the increase in screening programmes and the advancement of technology and high resolution imaging, the detection frequency of impalpable occult breast lesions worldwide has increased. Occult breast lesions account for 25 - 35% of breast cancer. The early detection and management of early stage breast cancer lesions has a significant effect on the treatment outcomes for the patient. It is thus important that these lesions are accurately identified and localised to enable a successful histologic diagnosis. This has led to the use and modification of various localisation methods to overcome the challenge of diagnosing and managing these non-palpable lesions. Where a fine needle aspiration biopsy (FNAB) or large core needle biopsy (LCNB) fails to provide a definitive diagnosis, a surgical excision may be necessary. Accurate pre-operative localisation facilitates complete excision with minimal tissue damage. Various pre-operative localisation methods have been used to assist the surgeon to obtain an adequate resection. The wire-guided localisation (WGL) technique is the most widely used and is still the preferred method for preoperative localization of impalpable breast lesions. Despite its widespread use, WGL does have many reported drawbacks such as patient discomfort, technical difficulty, and risk of complications. The radioguided occult lesion localisation (ROLL) is an alternative technique using a radioactive tracer injected into or close to the lesion under radiographic guidance. The surgical removal of the lesion is then aided by a hand-held gamma probe. The ROLL procedure has been shown to provide a simple, accurate and effective method of occult lesion localisation. The ROLL method has been reported to be technically easier, quicker and more accurate when compared to the WGL. An added advantage is it that in the case of histologically proven impalpable breast cancers, a sentinel lymph node biopsy can be done simultaneously (sentinel node with occult lesion localisation or SNOLL) to detect axillary metastases. In 2003 the ROLL procedure was implemented at this institution. The aim of this study was to evaluate the ROLL procedure, assess the accuracy and efficacy of the ROLL technique for diagnostic and therapeutic excisions at our institution. Materials and methods: A retrospective analysis was done using data on 190 patients who underwent a ROLL procedure for diagnostic or therapeutic excision of occult breast lesions at Groote Schuur Hospital, Cape Town during the period January 2003 to December 2016. All data was collected from patient files, nuclear medicine reports, radiological reports, surgical notes and histology reports. Data was collected on patient and tumour characteristics, localisation procedures, surgical and diagnostic outcomes. Primary outcomes measured were successful localisation rates, volume of tissue removed, complete tumour resection rates (i.e. negative margins), number of re-operations performed and the proportion of SLN detection.

The Pearson’s Chi Squared test was used to test for significance between variables. The level of significance was set at α = 0.05. The ROLL procedure was done after radiographic and percutaneous histology results. Depending on results, the procedure was done either as diagnostic or therapeutic intent (SNOLL) for highly suspicious lesions. 99mTc tin colloid or 99mTc hepatate (5-22 MBq) was injected intratumourally for the ROLL procedures whereas a single intratumoural injection of 99mTc nanocolloid (71-113MBq) was injected for the SNOLL procedures. Both same day and day before injection methods were used. Results: Correct radiopharmaceutical placement was achieved in 177/190 (93.2%) lesions. In 9 (4.7%) cases, the excised lesion was not representative of the pathology, with 6 of them being repeated. Of those repeated, 3 were found to be malignant and the other 3 were benign. Where the intent of surgery was therapeutic, 37/37 (100%) of lesions were correctly excised on the first attempt. Histology examination of the excised specimens found 115/190 (61%) to be malignant. Of these, 37/115 (32.2%) had involved margins. Complete excision margins was achieved in 50/70 (71.4%) cases of invasive cancer based on tumour free margins and in 11/45 (24.4%) of DCIS lesions based on excision margins >2mm. Where lymphoscintigraphy was performed, the Sentinel node (SN) was successfully identified in 30/37 (81.1%) of cases. Conclusions: ROLL is an effective tool in pre-operative localisation of occult lesions for surgical biopsy, especially in cases where percutaneous needle biopsy results are found to be indeterminate or inconclusive. The single intra-tumoural injection with 99mTc nanocolloid combined with lymphoscintigraphy is a reliable method of localising the SN. The procedure was able to obtain tumour free margins in 78/115 (68%) of malignant lesions, however special consideration should be given when suspected DCIS is involved as tumour margins are more likely to be involved due to the nature of the pathology.