Abstract

Background: Lymph node status has a prognostic role in endometrial cancer patients and it determines the adjuvant therapy to be administered postoperatively. Complete lymphadenectomy carries the risk of serious complications. Sentinel Lymph Node mapping (SLN) may be a good option to reduce these complications. Cervical injection of methylene blue may be a suitable technique for SLN mapping, which can be applied in low-resource institutes.

Objective: Assessment of the detection rate, sensitivity and false negative rate of SLN mapping using cervical injection of methylene blue.

Methods: A total of 76 patients with early stage endometrial cancer were included. Methylene blue was injected into the cervix prior to surgery and open surgical approach was used. SLNs were detected by direct visualization of stained lymph nodes after opening of pelvic spaces. SLNs were excised and pelvic lymphadenectomy was performed. Para-aortic lymphadenectomy was performed when indicated and surgically feasible. Specimens were examined by H&E staining.

Results: The SLN detection rate was 47.4% and all detected SLNs were pelvic nodes. All patients with lymph node metastasis had metastatic disease in their SLNs. The technique had 100% sensitivity, 100% negative predictive value and a 0% false-negative rate. An inverse relationship between SLN detection and BMI was detected.

Conclusion: Cervical injection of methylene blue dye with an open approach to detect SLNs in patients with early stage endometrial cancer has a low detection rate. The most important factor associated with failed mapping is increased BMI. Further trials are needed to investigate the usefulness of this technique.

Keywords: Sentinel lymph node, lymphadenectomy, endometrial cancer, methylene blue, cervical injection, lymph node metastasis.

Graphical Abstract