Meta-analysis of sentinel lymph node biopsy in breast cancer using the magnetic technique.

BACKGROUND: The standard for sentinel lymph node biopsy (SLNB), the dual technique (radiolabelled tracer and blue dye), has several drawbacks. A novel magnetic technique without these drawbacks has been evaluated in a number of clinical trials. It uses a magnetic tracer and a handheld magnetometer to identify and excise sentinel lymph nodes. A systematic review and meta-analysis was performed to assess the performance and utility of the magnetic in comparison to the standard technique. METHODS: MEDLINE, PubMed, Embase and the Cochrane online literature databases were used to identify all original articles evaluating the magnetic technique for SLNB published up to April 2016. Studies were included if they were prospectively conducted clinical trials comparing the magnetic with the standard technique for SLNB in patients with breast cancer. RESULTS: Seven studies were included. The magnetic technique was non-inferior to the standard technique (z = 3·87, P < 0·001), at a 2 per cent non-inferiority margin. The mean identification rates for the standard and magnetic techniques were 96·8 (range 94·2-99·0) and 97·1 (94·4-98·0) per cent respectively (risk difference (RD) 0·00, 95 per cent c.i. -0·01 to 0·01; P = 0·690). The total lymph node retrieval was significantly higher with the magnetic compared with the standard technique: 2113 (1·9 per patient) versus 2000 (1·8 per patient) (RD 0·05, 0·03 to 0·06; P = 0·003). False-negative rates were 10·9 (range 6-22) per cent for the standard technique and 8·4 (2-22) per cent for the magnetic technique (RD 0·03, 0·00 to 0·06; P = 0·551). The mean discordance rate was 3·9 (range 1·7-6·9) per cent. CONCLUSION: The magnetic technique for SLNB is non-inferior to the standard technique, with a high identification rate but with a significantly higher lymph node retrieval rate.

Magnetic sentinel node and occult lesion localization in breast cancer (MagSNOLL Trial).

BACKGROUND: Non-palpable breast cancers require localization-guided surgery and axillary staging using sentinel lymph node biopsy (SLNB). This study investigated the novel technique of magnetic-guided lesion localization and concurrent SLNB, which avoids the need for wire-guided localization and radioisotopes. METHODS: An ultrasound-guided intratumoral injection of magnetic tracer (0·5 ml) was performed in a protocol-driven predefined minimum of ten patients with palpable breast cancer to assess the ability of the magnetic tracer safely to localize the tumour at the site of injection and concurrently drain to the lymphatics. Once successful lesion localization had been confirmed (peak magnetometer count retained at the centre of the tumour), the technique was undertaken in a further 20 patients with non-palpable breast cancers awaiting wide local excision and SLNB. All patients underwent SLNB with both the magnetic and standard dual (radioisotope and Patent Blue V dye) techniques. RESULTS: Thirty-two patients were recruited, of whom 12 (1 with bilateral disease) presented with palpable and 20 with non-palpable breast cancer. Peak magnetometer counts were retained at the tumour centre in all palpable (13) and non-palpable (20) breast cancers. Re-excisions for involved margins were necessary in two patients with non-palpable breast cancers. The sentinel lymph node identification rates were 28 of 33 procedures for the magnetic technique alone, 32 of 33 for the magnetic technique combined with blue dye, and 32 of 33 for the standard dual technique. CONCLUSION: Magnetic lesion localization is feasible, with intratumoral magnetic tracer injection combined with a periareolar injection of blue dye for subsequent SNLB.

Intraoperative radiotherapy in early breast cancer.

BACKGROUND: Intraoperative radiotherapy (IORT) constitutes a paradigm shift from the conventional 3-5 weeks of whole-breast external beam radiotherapy (EBRT). IORT enables delivery of radiation at the time of excision of the breast tumour, targeting the area at highest risk of recurrence, while minimizing excessive radiation exposure to healthy breast tissue. The rationale for IORT is based on the observation that over 90 per cent of local recurrences after breast-conserving surgery occur at or near the original operation site. METHODS: This article reviews trials of IORT delivered with different techniques and devices. RESULTS: IORT is a very attractive option for delivering radiotherapy, reducing the traditional fractionated treatment to a single fraction administered at the time of surgery. IORT has been shown to be associated with reduced toxicity and has several potential benefits over EBRT. Only two randomized clinical trials have been published to date. The TARGIT-A and ELIOT trials have demonstrated that IORT is associated with a low rate of local recurrence, although higher than that after EBRT (TARGIT-A: 3·3 versus 1·3 per cent respectively, P = 0·042; ELIOT: 4·4 versus 0·4 per cent, P < 0·001). However, the local recurrence rate for IORT fell within the predefined 2·5 per cent non-inferiority margin in TARGIT-A, and the 7·5 per cent equivalence margin in ELIOT. CONCLUSION: Longer follow-up data from existing trials, optimization of patient criteria and cost-effectiveness analyses are needed. Based on the current evidence, IORT can be offered as an alternative to EBRT to selected patients within agreed protocols, and outcomes should be monitored within national registries.