Conventional treatment of vulva cancer includes inguinal lymphadenectomy, undergoing with innumerous morbidities as excessive blood loss, infection of postoperative wound and lymphedema of lower limbs.
AIMS: To assess accuracy and feasibility of sentinel lymph node (SLN) mapping and biopsy in vulvar cancer, through radioguided surgery. To compare our results with those from literature data.
METHODS: From April 2000 to June 2004, a number of 16 patients with vulvar cancer, at stages I-IV (FIGO, 1988), were selected. In the patients who were scheduled to have the surgery on the following day, 2.0 mCi of 99mTc-Phytate were injected; in the patients having the surgery on the same day, 1.2 mCi of the radiotracer were injected. The total volume for each patient was 0.8 ml, distributed into 3 to 4 subepithelial points, around the lesion. Approximately 2h after 99mTc-Phytate injection, lymphoscintigraphy images of the pelvic region were obtained, from the anterior and lateral projections. Hyperconcentration sites of the material (SLN) were topographically marked on patient's skin. During surgery, a gamma-probe was used to identify SLN. All the patients were submitted to uni or bilateral inguinal lymphadenectomy, based on size, laterality of the lesion and on the migration pattern of lymphoscintigraphy. The surgical pieces were submitted to hematoxylin-eosin histo-pathological study. In some of the cases, Patent Blue was used in order to have lymph nodes identified; however, the ones regarded as SLN were those which showed radiotracer concentration (hot ones).
RESULTS: Migration of the radiotracer was observed in 100% of the patients. The number of 26 SLN was identified in the 16 patients analyzed (mean 1.62 lymph nodes / patient), from which 3 SLN showed to be positive in three different patients. Two patients had false-negative sentinel nodes, one at stage II and another at stage III. The negative predictive value was 84.61%. Migration of radiotracer and identification of at least one SLN in 100% of the patients are in accordance with literature data. A comparatively low negative predictive value in the present work might be due to the experience level of the team as well as by the fact that lymph nodes were only regarded as SLN those hot but not blue.
CONCLUSION: The SLN mapping and biopsy technique for vulvar cancer using radioguided surgery is feasible. It requires a experienced team and an adequate use of the Patent Blue. By validating SLN mapping and biopsy, surgical approaches may be less aggressive, preventing high morbidity of the radical lymphadenectomy.
