Intraoperative sentinel lymph node (SLN) examination during breast cancer surgery guides the need for immediate axillary clearance. This may be difficult to implement when surgery is performed distant to the centres where pathological examination is undertaken. We aimed to implement and validate a telepathology service for the remote examination of breast SLN by frozen section (FS).

We tested an Internet-based remote microscopy system to report intraoperative FS in real time from two district hospitals without on-site anatomical pathology services.

FS was performed remotely on 52 patients. Seventeen out of 52 patients had metastases, of which there were six false-negative diagnoses comprising four of micrometastatic disease and two of isolated tumour cells (ITCs). There were no false-negative diagnoses for macrometastatic disease and no false-positive diagnoses. As a control, we audited our experience with 239 consecutive SLN FS examined by on-site pathologists. Sixty out of 239 patients had metastases, of which there were 24 false-negative diagnoses comprising 12 cases of ITC, 5 of micrometastases and 7 of macrometastases. The accuracy of remote FS was equivalent to that of in-house FS (88.2% versus 89.9%).

Remote FS for breast SLN is an accurate procedure,which is not inferior to FS performed on site.