Influence of injection technique on detection of sentinel lymph nodes by SPECT/CT in endometrial cancer

Objectives Scintigraphic mapping of sentinel lymph nodes (SLN) is increasingly performed in endometrial cancer although its routine clinical use is still under investigation. Previous studies have compared intraoperative detection rates after pericervical injection or hysteroscopic application without imaging^1,2. The aim of our study was to analyze preoperative SLN detection by SPECT/CT.

Methods We reviewed 139 consecutive patients with endometrial cancer who underwent surgery and SLN SPECT/CT at Tuebingen University Hospital between 2006 and 2013. 70 patients received hysteroscopic-peritumoral application (200-300 MBq Technetium-99m-nanocolloide) and 69 received pericervical injection at 3, 6, 9 and 12 o'clock positions. Each patient underwent SPECT/CT 3-5 h p.i. and total hysterectomy with lymphadenectomy the next day.

Results 324 SLN were detected by SPECT/CT (mean 3 per patient, range 0-9). The detection rate was significantly better with pericervical injection (84%) as compared to hysteroscopic injection (69%; Pearson's χ² test, p = 0.031), however hysteroscopic injection detected para-aortic SLN more frequently (43% vs. 32%, p = 0.18). In negative scans after hysteroscopic injection minor to failing injection depot was detectable in 7/22 patients (32%). With pericervical injection, this was only observed in 1/11 cases (9%). Often there was a strong uptake in the reticuloendothelial system of liver and spleen (12/22 vs. 6/11, 55%) and also in bone marrow (8/22 vs. 3/11, 27% vs. 36%).

Conclusions Pericervical injection leads to a significantly better scintigraphic detection of SLN while reducing invasiveness. Failure to detect SLNs is associated with major venous drainage.

Research Support 1. Int J Gynecol Cancer. 2009 Apr;19(3):391-4. doi: 10.1111/IGC.0b013e3181a1c0b1. Lymphatic mapping in endometrial cancer: comparison of hysteroscopic and subserosal injection and the distribution of sentinel lymph nodes. Robova H, Charvat M, Strnad P, Hrehorcak M, Taborska K, Skapa P, Rob L. 2. Gynecol Oncol. 2013 Nov;131(2):299-303. doi: 10.1016/j.ygyno.2013.08.018. Epub 2013 Aug 27. Tracer injection sites and combinations for sentinel lymph node detection in patients with endometrial cancer. Niikura H, Kaiho-Sakuma M, Tokunaga H, Toyoshima M, Utsunomiya H, Nagase S, Takano T, Watanabe M, Ito K, Yaegashi N.