[1] Univ N Carolina, Sch Med, Chapel Hill, NC 27515 USA
[2] Univ N Carolina, Div Gynecol Oncol, Chapel Hill, NC 27515 USA
[3] Duke Univ, Med Ctr, Durham, NC USA
[4] Univ N Carolina, Lineberger Comprehens Canc Ctr, Biostat & Data Management, Chapel Hill, NC 27515 USA
[5] Univ N Carolina, Dept Obstet & Gynecol, Chapel Hill, NC 27515 USA