GOG 173 Study

Lymphatic Mapping and Sentinel Lymph Node Biopsy in Women With Squamous Cell Carcinoma of the Vulva: A Gynecologic Oncology Group Study
Disease site


Publication month/year

July 2012

Study question

Is it safe to do sentinel lymph node biopsy as a replacement for inguinal femoral lymphadenectomy in selected women with vulvar cancer.

Type of study

prospective multi-institution validation trial

Interventions compared

Sentinel lymph node biopsy vs inguinal femoral

Experimental arm (Intervention)

Sentinel Lymph Node Biopsy (SLN)

Control arm

Inguino-femoral Lymphadenectomy

Primary outcome

Negative predictive value of a sentinel groin lymph node

Inclusion criteria
  • Tumour at least 2 cm and no more than 6 cm. Depth at least 1 mm.
  • Tumour confined to vulva.
  • Good performance status and able to undergo surgery.
Exclusion criteria

Women who had:

  • Prior groin irradiation
  • Prior groin dissection
  • Multifocal disease
  • Recurrent vulvar cancer
  • Grossly inflamed tumor were excluded.
Randomised (n)
SLN identified
With lymph node metastasis
Identified by immunohistochemistry
23% of TP cases
  • 515 patients accrued. 452 had SLN mapping.
  • 320 had bilateral SLN and 132 had unilateral SLN.
  • Analysis available for 418 patients.
  • Metastasis detected in 132/418 = 31.6%.
  • Of the 132 node-positive women, 11 had false-negative findings on SLN (8.3%; 90% CI, 4.7% – 13.4%).
  • The sensitivity was 91.7%, and the false negative predictive value was 3.7%.
  • For women with tumors smaller than 4 cm, the false-negative predictive value was 2.0%, and for women with tumors 4 to 6 cm, the false-negative predictive value was 7.4%. 
  • Sentinel lymph node biopsy is a reasonable alternative  to inguinal femoral lymphadenectomy in selected women with squamous cell carcinoma of the vulva.
  • Women with primary tumours smaller than 4 cm who can be counselled preoperatively that if the SLN is negative, they have a less than 3% risk of a groin relapse due to a false-negative SLN.
Study limitations
  • The study took longer to complete than anticipated (1999-2009).
  • The false-negative rate might have been lower if surgeon skill verification had been required
  • The rate of performance of immunohistochemical analysis was much lower than required by the protocol.
  • Preoperative imaging was not required.
  • The management of women with positive findings on SLN was not addressed in this study.


Reviewer name