Objective: To evaluate the clinical feasibility of sentinel lymph node (SLN) technique and the role of single-photon emission computed tomography with CT (SPECT/CT) compared to lymphoscintigraphy for detection of SLN in vaginal cancer.
Methods: The study was performed in a prospective, unicentric setting. Patients with vaginal carcinoma were scheduled for surgery and SLN labeling by peritumoral injection of 10-MBq technetium Tc 99m nanocolloid and patent blue. After 30 minutes, lymphoscintigraphy and SPECT/CT were carried out. We evaluated the number of SLNs in lymphoscintigraphy, SPECT/CT, and intraoperative histology of SLN and non-SLN as well as the impact of these results to therapeutic approach.
Results: Between January 2009 and December 2012, the SLN technique was used for 7 of 11 patients treated due to vaginal cancer. Detection rate was 100% (7/7). Lymphoscintigraphy and SPECT/CT showed at least one SLN in each patient. Lymphoscintigraphy detected 2.6 SLNs (range, 2-4 SLNs) per patient compared to 4.3 SLNs (range, 2-8 SLNs) in SPECT/CT (P = 0.053). Sentinel lymph nodes were detected in all patients during surgery with a mean number of 4.3 (range, 1-5). Pelvic SLNs were detected in all 6 patients with infiltration of middle or proximal vaginal third (100%). If the distal vaginal third was additional (3/7 patients) or exclusively (1/7 patients) infiltrated, the inguinal SLN detection rate was 33% and 100%, respectively. All patients with nodal metastases had at least one SLN positive for tumor. There were no false negatives. In 2 (29%) of 7 patients, treatment approach was modified owing to affected SLN.
Conclusion: The SLN technique was favorably used in vaginal cancer in this series. It assists in identifying an inguinal and/or pelvic lymphatic drainage. When performed accurately (technetium Tc 99m nanocolloid, lymphoscintigraphy and/or SPECT/CT, blue dye), this technique predicts regional nodal status. This allows tumor stage-adjusted therapy. Single photon emission computed tomography/CT improves preoperative planning and facilitates detection, thus enhancing the clinical value of the SLN technique and improving the oncologic safety of surgery.