Can a sentinel node mapping algorithm detect all positive lymph nodes in cervical cancer?

The aims of this study were to determine the sensitivity and negative predictive value (NPV) of sentinel lymph node (SLN) detection in cervical cancer using a combination technique, and to test the SLN algorithm that was proposed by the Memorial Sloan Kettering Cancer Center (MSKCC).

The study included 57 FIGO stage IA2-IIA patients who were treated at the Erasto Gaertner Hospital, Curitiba, from 2008 to 2010. The patients underwent SLN mapping by technetium lymphoscintigraphy and patent blue dye injection. Following SLN detection, standard radical hysterectomy, including parametrectomy and systematic bilateral pelvic lymphadenectomy, was performed. The SLNs were examined by immunohistochemistry (IHC) when the hematoxylin and eosin results were negative.

The median age of patients was 42 years (range 24-71), the median SLN count was 2 (range 1-4), and the median total lymph node (LN) count was 19 (range 11-28). At least one SLN was detected in 48 (84.2 %) patients, while bilateral pelvic detection of SLNs was noted in 28 (58.3 %) cases-one case had bilateral pelvic SLNs and a para-aortic SLN, 19 (39.6 %) had unilateral pelvic LNs, and one (2.1 %) had an SLN in the para-aortic area. Metastatic LNs were found in 9 of 57 (15.8 %) patients. Eight of nine patients with LN metastasis had a positive SLN, yielding an overall sensitivity of 88.9 % and NPV of 97.5 %. Of the 75 sides that were mapped, the SLN detection method predicted LN involvement in 74 (98.6 %) hemi-pelvises. A total of ten hemi-pelvises had LN metastasis, nine of which involved the SLN, resulting in a sensitivity of 90 %, NPV of 98.5 %, and a false negative (FN) of 10 %. In two cases (4.2 %), the SLN was positive only after IHC.

Our SLN procedure is a safe and accurate technique that increases metastatic nodal detection rates by 4.2 % after IHC. The SLN method performed better when analyzing each side; however, one FN occurred, even after applying the MSKCC algorithm.