Lymphatic mapping and sentinel node biopsy in squamous cell carcinoma of the vulva: systematic review and meta-analysis of the literature.

OBJECTIVES: We reviewed the available literature on the accuracy of sentinel node (SN) mapping in the inguinal lymph node staging of vulvar squamous cell carcinoma (SCC).

METHODS: Medline and SCOPUS were searched by using "sentinel AND vulv*" as key words. Studies evaluating the accuracy of SN mapping in the inguinal lymph node staging of vulvar SCC were included if enough data could be extracted for calculation of detection rate and/or sensitivity. Only studies validated by inguinal lymph node dissection were included for sensitivity meta-analysis.

RESULTS: Forty-nine studies were included in the systematic review. Pooled patient and groin basis SN detection rates were 94.4% [92.4-95.9] and 84.6% [80.5-88], respectively. Pooled patient and groin basis sensitivity were 92% [90-95] and 92% [89-94], respectively (or 8% [5-10] and 8% [6-11] false negative rates). Pooled negative predictive values were 97% [96-98] and 98% [97-99] for patient and groin basis analyses respectively. SN detection rate and sensitivity were related to mapping method (blue dye, radiotracer, or both) and location of the tumor (midline vs. lateral tumors). Patients with palpable inguinal nodes had lower detection rate and sensitivity.

CONCLUSION: SN mapping is an accurate method for inguinal node staging in vulvar SCC. Combining radiotracer and blue dye methods and excluding patients with palpable inguinal nodes result in the highest detection rate and sensitivity. For midline tumors possible false negative results of SN mapping should be taken into account.