Sentinel lymph node identification using hysteroscopy in patients with endometrial cancer

Endometrial carcinoma is the most frequent gynecologic malignancy. The incidence is 30 : 100,000 with an increasing tendency. The main therapeutic modality remains radical surgery. The purpose of the study is to evaluate the feasibility of sentinel lymph node (SLN) detection in endometrial cancer using hysteroscopic administration of radiocolloid and the combination of preoperative lymphoscintigraphy with intraoperative gamma-detection probe examination. From May 2006 to January 2009, 99mTc-labelled nanocolloid (100 MBq) was administered preoperatively in 21 patients with endometrial cancer. On the day of surgery, radiocolloid together with blue dye was injected via 20-gauge needle under the endometrium using hysteroscopy. Lymphoscintigraphy was performed in all patients after 60 minutes. Therapeutic surgery followed the tracer administration 2 hours later in extensity of abdominal hysterectomy, bilateral salpingo-oophorectomy, peritoneal wash, pelvic lymphadenectomy and in patients with positive high-risk prognostic factors of paraaortic lymphadenectomy. SLN was located by use of gamma-detecting probe intraoperatively. At least one SLN was detected in 17 of 21 (81%) patients included in the study. The mean number of detected SLNs was 2 (range 1-5). 8 of 17 (47%) patients had radioactive nodes only in the paraaortic area. Synchronic appearance of SLNs in the pelvic and paraaortic areas was detected in 1 of 17 (6%) cases. Overall, in 4 of 9 (44%) cases of sentinel lymph node localization in the paraaortic area the SLNs were detected at the level above the inferior mesenteric artery. The metastatic involvement of 3 sentinel lymph nodes was detected in one patient (3 lymph nodes with micrometastases). All the remaining lymph nodes not labelled as SLNs were histologically negative in this case. The sensitivity and specificity for SLN metastases detection was 100%. SLN detection in endometrial cancer appears to be a promising method with the potential to reduce unnecessary surgery radicality and to clarify staging. The utilization of hysteroscopic application of radiocolloid respects the anatomical consequences and natural lymphatic drainage of the endometrium. The combination of pre-operative lymphoscintigraphy and intra-operative detection using a handheld gamma probe can be beneficial.