A randomized phase II trial of indole-3-carbinol in the treatment of vulvar intraepithelial neoplasia

Int J Gynecol Cancer. 2006 Mar-Apr;16(2):786-90. doi: 10.1111/j.1525-1438.2006.00386.x.


The aim of this study was to determine the potential therapeutic benefits of indole-3-carbinol (I3C) in the management of vulvar intraepithelial neoplasia (VIN). Women with histologically confirmed high-grade VIN were randomized to receive 200 and 400 mg/day of I3C. Symptomatology by visual analog scale and vulvoscopic appearance were assessed at recruitment, 6 weeks, 3 months, and 6 months. Tissue biopsy to determine histologic response was obtained at completion of the study period. Urine samples were obtained at each visit to determine 2-hydroxyestrone to 16-alpha-hydroxyestrone ratios. Data from 12 women were suitable for analysis. There was a significant improvement in symptomatology with the introduction of I3C (itch, P= 0.018; pain, P= 0.028). Lesion size and severity were also significantly reduced (size, P= 0.005; appearance, P= 0.046). In addition, there was a significant increase in 2-hydroxyestrone to 16-alpha-hydroxyestrone ratio following commencement of I3C, P= 0.05. However, tissue biopsy from the worst-affected vulval areas revealed no improvement in grade of VIN during the 6-month period, P= 0.317. There were no significant differences in results between those women taking 200 mg/day of I3C and those on 400 mg/day. This study has shown significant clinical improvement in symptomatology and vulvoscopic appearance of VIN with I3C therapy. Further clinical and scientific investigations are required to support these preliminary findings.

Publication types

  • Clinical Trial, Phase II
  • Comparative Study
  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Aged
  • Carcinoma in Situ / drug therapy*
  • Carcinoma in Situ / metabolism
  • Carcinoma, Squamous Cell / drug therapy*
  • Carcinoma, Squamous Cell / metabolism
  • Disease-Free Survival
  • Female
  • Humans
  • Hydroxyestrones / metabolism
  • Indoles / therapeutic use*
  • Middle Aged
  • Neoplasm Staging
  • Survival Rate
  • Treatment Outcome
  • Vulvar Neoplasms / drug therapy*
  • Vulvar Neoplasms / metabolism


  • Hydroxyestrones
  • Indoles
  • 16-hydroxyestrone
  • indole-3-carbinol
  • 2-hydroxyestrone