Use of Tc99m-nanocolloid for sentinel nodes identification in cervical cancer

The initial draining lymph node for a primary tumor is referred to as the "sentinel" node. Firstly adopted in the management of patients with cutaneous melanoma and breast cancer, it is now widely tested in cervical cancer. In patients with cervical cancer, lymph node status is the most important prognostic factor for survival. In patients with cervical cancer FIGO stage I and II pelvic lymph node metastases are expected in 0-16 and 24.5-31% and para-aortic lymph node metastases are expected in 0-22 and 11-19% of patients. The removal of pelvic and para-aortic lymph nodes is essential for assessing the biology of the disease. Lymphoscintigraphy enables the visualisation of lymphatic drainage patterns from a great variety of tumour sites prior to surgery. Therefore, the current procedure is to perform the pre-operative mapping of sentinel nodes by static and/or dynamic lymphoscintigraphy, followed by in vivo identification using a gamma detection probe and selective surgical resection.

Between 2001-2003, 37 patients with cervical cancer FIGO stage I-IIa were seemed to be qualified to undergo lymphoscintigraphy. The day before surgery (99m)Tc-nanocolloid (100 MBq; 0.5-1.0 ml in volume) was applied in each quadrant of the cervix or around the tumor. The static scintigraphic scans were performed after 2 hours p.i. using a dual-head large-field-of-view Siemens gamma-camera equipped with high resolution collimators. SNs were identified intra-operatively using a handheld gamma detection probe (Navigator GPS-Tyco) and intra-operative lymphatic mapping with blue dye. After a resection of the SNs, a standard radical hysterectomy with pelvic and low para-aortic lymph node dissection was performed. Tumor characteristics were compared with sentinel node detection and with the histopathological and immunohistochemical results.

The scintigraphy showed a focal uptake in 35 of the 37 patients. In all women one or more sentinel lymph nodes were identified intra-operatively. Of them, 24 patients had those located bilaterally. Histologically positive SNs were found in 5 women (13.5%).

A combination pre-operatively administered radioactively labelled albumin with blue dye allows the successful detection of SN in patient with cervical cancer. This technique will result in a real advance in the less aggressive management of patients with early stage cervical cancer. Sentinel lymph node status may be representative of the pelvic lymph nodes status in cervical cancer and thus could provide important information for further treatment.