Laparoscopic identification of sentinel lymph nodes in early stage cervical cancer: prospective study using a combination of patent blue dye injection and technetium radiocolloid injection

OBJECTIVE: To determine the feasibility of intraoperative radioisotopic mapping using an endoscopic gamma probe associated with patent blue dye injection in patients with early stage cervical cancer. METHODS: Between April 2001 and March 2002 a total of 12 patients underwent laparoscopic bilateral pelvic lymphadenectomy (squamous carcinoma in 10 cases, all stage FIGO IB1, and adenocarcinoma in 2 cases, stages IA2 and IB1). Lymphoscintigraphies were performed on the day before surgery to visualize sentinel lymph nodes, 31 +/- 22.5 and 174 +/- 34 min after injection of 200 microCi of technetium 99m rhenium sulfur colloid. The marker was injected at the 3, 6, 9, and 12 o'clock positions. The day of surgery 2 ml of patent blue dye plus 2 ml of physiological serum was injected in the cervix, at the same locations as the radioactive isotope injection. RESULTS: A total of 35 sentinel lymph nodes were detected. Eight sentinel lymph nodes were only detected by color, 8 sentinel lymph nodes were only detected by the endoscopic gamma probe, and 19 sentinel lymph nodes were "hot and dyed." We found 3 metastatic lymph nodes. In one case, bilateral positive sentinel nodes were only detected by the endoscopic gamma probe. Permanent section identified one inframillimetric micrometastasis in a lymph node that was neither blue nor hot intraoperatively (sensitivity = 66%, specificity = 100%, positive predictive value = 100%, negative predictive value = 90%). CONCLUSION: The identification of the sentinel lymph node with blue dye and radioisotope using an endoscopic gamma probe is feasible and improves detection rate. False negatives still occur, but the proportion is low even at the beginning of the learning curve. Isotopic imaging identifies nodes in areas outside the pelvis not routinely sampled in early cervical cancer patients.