Sentinel lymph node detection using 99mTc combined with methylene blue cervical injection for endometrial cancer...

The aim of this study is to evaluate the effectiveness of a combined technique for sentinel lymph node (SLN) localization and surgical staging of endometrial carcinoma.

This is a single-center prospective observational study carried out from September 2011 to December 2013 including women with a diagnosis of endometrial cancer and scheduled for surgery. A regional lymph node mapping was obtained using SPECT-CT (cervical injection of Tc) the day before surgery. On the day of surgery, methylene blue was injected in the cervical tissue. The SLNs were identified intraoperatively guided both by a γ-probe and visual inspection of the blue dye. A pelvic and/or para-aortic lymphadenectomy was completed. A histological analysis was performed on all the removed lymph nodes. We calculated the detection rate for SLN and its negative predictive value (NPV) for malignancy.

Fifty patients underwent surgery. The SLN was isolated in 46 patients with detection rate of 92% (95% confidence interval, 80.77-97.78). The mean number of detected SLNs per patient was 1.54 (range, 1-5); the average number of non-SLNs removed was 17 (5-34) per patient. The most common SLN location was the external iliac lymph node chain, 33 (46.47%). Five SLNs (7.1%) were isolated in the para-aortic chain. Three SLN cases (5.9%) were positive for malignant cells; the totality of the remaining non-SLNs was negative. The NPV of the SLN was 100% (95% confidence interval, 89.79-99.79). Finally, pathologic findings were 42 endometrioid types (84%), 3 carcinosarcomas (6%), 4 clear cell (8%), and 1 serous papillary tumor (2%).

The SLN analysis may be useful to assess the presence or absence of lymph node metastases. Its high NPV may be used as criteria to avoid unnecessary lymphadenectomies in endometrial cancer patients.