|C. Bluemel, A. Schnelzer, A. Ehlerding, A. Okur, K. Scheidhauer, M. Kiechle, M. Schwaiger
Evaluation of freehand SPECT in sentinel lymph node biopsy of breast cancer
Proceedings of the Annual Congress of the European Association of Nuclear Medicine (EANM), Birmingham, UK, October 2011 (bib)
Evaluation of performance of sentinel lymph node biopsy in breast cancer patients using freehand (fh) SPECT
Up to date, 44 breast cancer patients (38-84 y) undergoing SLN biopsy were recruited (1 bilateral case) and scanned intraoperatively using fhSPECT (declipseSPECT, SurgicEye?, Munich, Germany). The amount of SLNs detected with fhSPECT before incision was counted and compared with the planar scintigraphy (PS) acquired the day before. After post-excision control of axillary region using gamma probe (GP), fhSPECT image was used to verify absence of radioactivity. Additionally hot spots were confirmed with GP. If clinically indicated, additional SLNs were also resected.
Preoperatively, 64 SLNs were mapped on conventional PS (95 MBq, SD 18 MBq). Pre-incision GP managed to map nodes in 41 of 45 axillary regions (sensitivity 91%), while fhSPECT had a sensitivity of 93% (42/45). Compared to PS, fhSPECT mapped all but 11 SLNs (sensitivity 88%) in the identical position, as well as 3 further nodes. In total 124 SLNs were resected and confirmed to be radioactive, whereof metastatic involvement was found in 9 patients. Post-excision fhSPECT detected in 29 % of the armpits 1 further SLN despite negative measurement with GP. In 7 patients (16%) 7 additional SLNs were resected. However, the protocol used did not allow determining if the additionally resected nodes changed the pathological nodal status. In the remaining 6 patients harvesting of these nodes was discarded as SLNs with higher uptake had been removed already. Pre-incision scans took approx. 2.6 min and post-excision ones 2.2 min; thus the mean surgical procedure was extended about 5 min.
Preliminary experience indicates that intraoperative imaging with fhSPECT for lymphatic mapping in breast cancer enables more intuitive and more sensitive detection of SLNs than the use of GP with minimal alteration of the surgical workflow. Post-excision fhSPECT showed additional SLNs and motivated additional harvest in 16 % of the patients. Despite these data, no change in therapy could be proven. But the high number of additional SLNs motivates to setup a further prospective study to clarify the impact of fhSPECT on pathological status, therapy or prognosis. Furthermore for quality assurance the system can document digitally the absence of residual SLNs at the end of surgery. Controlled studies could perhaps also clarify the role of lymphatic uptake on selecting nodes for surgical resection.
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