Sentinel detection in endometrial cancer: technique, experience and results for isthmocervical labelling and the use of SPECT/CT

Objective: We analyze the clinical feasibility of transcervical subepithelial injection into the isthmocervical region of the myometrium as new labeling technique for sentinel detection in endometrial carcinoma (EC). We compared sentinel lymph node (SLN) detection rate by single photon emission computed tomography with CT (SPECT/CT) with planar lymphoscintigraphy.

Methods: In all patients transcervical injection of 10 MBq Technetium-99 m-nanocolloid was performed into the isthmocervical myometrium without anaesthesia in a unicentric prospective study. After 40 (30 – 60) minutes, lymphoscintigraphy and SPECT/CT were performed. Patent blue was administered before surgery. The number and localisation of SLN detected in SPECT/CT and lymphoscintigraphy were recorded and compared to the SLN and non-SLN dissected intra-operatively.

Results: Between August 2008 and March 2012, 31 patients with EC were enrolled. The new transcervical injection of labelling substances led to high intra-operative (90.3%) detection rates, pelvic bilateral (57%), para-aortic (25%). SPECT/CT significantly identified more SLN than lymphoscintigraphy (mean 2.2 (1 – 8) to 1.3 (1 – 7)) in more patients (29/31 (93.5%) to 21/31 (68%), p < 0,05). If SLN were identified in one hemi-pelvis, the histological evaluation of the SLN correctly predicted lymph node (LN) metastases for this basin which led to sensitivity 100%, NPV 100% and false negative results 0%.

Conclusion: Transcervical SLN marking in combination with SPECT/CT is easily applicable and leads to high physiologic detection rates in pelvic and para-aortic lymphatic drainage areas. Non-affected SLN truly predicted a non-affected LN basin. Combining both methods SLN dissection and detection may be a safe and feasible staging technique for clinical routine in EC.