Sentinel Lymph Node Detection Using SPECT and Gamma Probe in Low-Risk Endometrial Cancer: Efficacy and Factors Associated With Detection Failure

Introduction: This study examined factors that affected sentinel lymph node (SLN) identification of patients with endometrial cancer having a preoperative estimation of low recurrent risk. Methods: This study included 97 patients with endometrial cancer who attempted to identify SLN using a uterine cervical injection of technetium-99 m phytate under laparoscopic or robotic-assisted surgery at our institute. A preoperative single photon emission computed tomography (SPECT) and intraoperative gamma probe were used to detect hot nodes. Multiple clinical factors, including age, body mass index (BMI), and so on, were investigated for their association with SLN mapping failure. Results: Among 97 cases, SPECT failed to detect SLN unilaterally in 38 cases (39%) and on both sides in 9 cases (9%). Meanwhile, the gamma probe failed to detect SLN unilaterally in 23 cases (24%) and on both sides in 3 cases (3%). While only age was significantly associated with SLN detection failure using the SPECT detection system, both age and BMI were significantly associated with SLN detection failure using the gamma probe detection system. When limiting to the preoperative SLN detection failure cohort of 47 cases, there was a strong association between intraoperative SLN detection failure and BMI, but not age. Conclusion: The SLN biopsy system was effectively applied to patients with endometrial cancer who underwent minimally invasive surgery (MIS). Attempts to improve SLN identification in older patients and those with obesity are warranted to obtain maximum benefits of MIS for low- or medium-risk cases.