Detection of sentinel lymph nodes after hysteroscopic peritumoral injection of Tc-99m-Nanocolloid in grade 1 endometrial carcinoma

Objectives In early stage endometrial carcinoma laparoscopic tumor resection and sentinel lymph node (SLN) exstirpation instead of classic lymphadenectomy offers the opportunity for less invasive surgery. This study analyzes the use of a dual-time-point approach with hysteroscopic peritumoral injection and scintigraphy on the day before intraoperative SLN-detection by gamma probe.

Methods A total number of 132 patients with histologically proven pT1(a-c) stage corpus carcinoma were treated by laparoscopic hysterectomy, adnexectomy and lymph node exstirpation. A matched subgroup of 62 pts. received 300-350 MBq Tc-99m-Nanocolloid via hysteroscopic peritumoral injection followed by SPECT-CT of the abdominal and pelvic region 3-5 h p.i.. Patient characteristics, tumor-specific data, SLN-detection as well as peri- and postoperative events were recorded.

Results Scintigraphic detection of SLNs was possible in 77% of our pts. (48/62). Failure to detect SLNs was due to poor injection depot (n= 2), parainjection accompanied by peritoneal radioactivity (n= 4), increased drain via venous vessels (n=2) or lacking drain from the injection area (n= 6). Of note, the rate of detection failure decreased with increasing experience of the applicating physician. As could be expected in a low-risk cohort, lymph node metastasis was rare in our pts. (2/62 pts. with SLN-scintigraphy vs. 2/70 pts. without). Paraaortal lymph node exstirpation in addition to pelvic resection was performed more often in pts. with SLN-imaging (39% vs. 19%). Nevertheless, the duration of surgery, blood loss and the rate of postoperative events did not increase.

Conclusions Hysteroscopy with peritumoral Nanocolloid injection allows for detection of SLNs in most pts. with early stage endometrial cancer. Resection of frequently found paraaortal SLNs does not increase peri- or postoperative morbidity. Thus staging according to TNM and adequate treatment in case of lymph node involvement is possible in laparoscopic surgery