Use of methylene blue dye for sentinel lymph node mapping in early-stage gynecological cancers-An option for low resource settings

Abstract

Context: Sentinel lymph node (SLN) mapping is a standard of care in gynecological cancers but with limited resources and equipment, intraoperative use of methylene blue for SLN mapping may be more useful. Aims: To authenticate the use of methylene blue dye for intraoperative SLN mapping in cases of early-stage gynecological cancers. Settings and Design: This pilot study was conducted in a tertiary care teaching hospital. Subjects and Methods: The cases included 14 cervical, 4 endometrial, 1 vulvar, and 1 synchronous cervical-vulvar cancer wherein 21 SLN mappings were done. Four ml of methylene blue was injected submucosally in the cervix in cervical and endometrial cancer. It was injected around the tumor in vulvar cancer. The pelvic lymphatic drainage area was examined in cervical and endometrial cancer while inguinofemoral area was examined in vulvar cancer for any blue LNs. Histopathological examination results were compared for the presence of metastasis in stained and unstained LNs. Statistical Analysis Used: The observations were presented as numbers and percentages. Results: The SLN mappings showed a detection rate of 76%. The mean number of LNs removed in each case was 10.3 with an average of 2.4 stained and 7.6 unstained LNs. SLN was most commonly found among right external iliac nodes. All stained and unstained nodes among the 16 SLN detections did not show any histological evidence of metastasis suggesting a negative predictive value of 100%. Conclusions: Methylene blue is an efficient, feasible, and safe dye for SLN mapping in early-stage gynecological cancer.