for endometrial cancer and to determine the contribution of micro-metastasis (MM) to the overall nodal metastasis rate.

We reviewed all patients who underwent SLN mapping forendometrial cancer. We used a cervical injection of blue dye in allcases. SLNs were examined by routine hematoxylin and eosin (H&E)and, if negative, by a standardized institutional pathology protocolthat included additional sections and immunohistochemistry (IHC) todetect MMs.Results: Between September 2005 and March 2010, 266 patients withendometrial cancer who underwent SLN mapping were analyzed. Thehistologic subtypes included: endometrioid, 220 (82%); serous, 22 (8%);carcinosarcoma, 18 (7%); and other types, six (2%). FIGO stagedistribution was: stage I, 207 (78%); stage II, five (2%); stage III, 50(19%), and stage IV, four (1%). SLN identification was possible in 223(84%) cases. Positive nodes were diagnosed in 33 of 266 (12%) patients.In eight of the 33 (24%), the metastasis was detected only by additionalsection or IHC of the SLN, and would have been missed otherwise. Thetotal number of SLNs removed was 801 (3.6 nodes/patient). The totalnumber of non-SLNs removedwas 2698 (10.1 nodes/patient). ExcludingSLNswithMMs, 24 of 801 (3%) SLNs and 30of 2698 (1%) non-SLNswerepositive for metastatic disease (P=0.00027).Conclusions: Metastatic cells from endometrial cancer are morelikely to be detected in the SLN than in the non-SLN. This findingstrongly supports the concept of lymphatic mapping in endometrialcancer to fine-tune the nodal dissection topography. By adding SLNmapping to our current surgical staging procedures, we can increasethe likelihood of detecting metastatic cancer cells in regional lymphnodes. An additional benefit of incorporating pathologic ultrastagingof SLNs is the detection of MMs, which may be the only evidence ofextrauterine spread in 3% (8/266) of cases.

doi:10.1016/j.ygyno.2010.12.045

39The role of lymphadenectomy in endometrial cancer: Wasthe ASTEC trial doomed by design and are we destined torepeat that mistake?R. NaumannCarolinas Medical Center, Charlotte, NC

Objective: This study examines the outcome of the ASTEC study withrespect to lymph node (LN) dissection and explores future trialdesigns that address LN dissection in endometrial cancer (EC).

Data from several trials were used to create a decisionanalysis model that predicts the risk of LN spread and the effectsof treatment on patients with EC. This decision model wasapplied to the population in the ASTEC trial as well as otherfuture trial designs that might be used to address the role of LNdissection in EC.Results: The model closely predicted the survival results of the ASTECtrial with and without LNs for the entire group, as well as the low-risk(LR) and intermediate-risk (IR) patients, with less than 4% differencebetween actual and predicted outcomes in all subgroups. The modelpredicts that there would be a survival difference of less than 2%between LNs and no LNs in the ASTEC trial, even if there was a 70%survival advantage associated with the removal of isolated positivepelvic LNs. This prediction is the same in both the LR and IRsubgroups. Sensitivity analyses reveal that these conclusions arerobust. Future trial designs comparing hysterectomy only, hyster-ectomy with radiation in IR, and hysterectomy with extended surgicalstaging with radiation reserved only for node-positive patients werealso tested. Predicted survival rates with these respective strategieswere 88, 90 and 93% in clinical stage I patients and 78, 82 and 89% inIR patients.

Conclusions: This decision analysis model confirms the futility of theASTEC trial design and has important implications for future trials ofsurgical staging in EC. If trials comparing hysterectomy only withextended surgical staging and selective radiation are conducted in allstage I patients, only a 5% difference in outcome will be seen even ifeffective treatment for positive LNs is given. If trials using this design arelimited to IR patients, a difference of greater than 10% in overall survivalis expected and would significantly reduce the sample size needed.

doi:10.1016/j.ygyno.2010.12.046

Closing Plenary Session VIIWednesday, March, 9, 2011, 7:35AM–11:25AMFloridian Ballrooms A-IModerators, Abstracts: 40-51: John Farley, MD, Uniformed ServicesUniversity of the Health Sciences, Bethesda, MD; Laura JeanHavrilesky MD, Duke University Medical Center, Durham, NC

40Phase II trial of cetuximab in the treatment of persistent orrecurrent squamous or nonsquamous cell carcinoma of thecervix: A Gynecologic Oncology Group studyA. Santin1, G. Patricia2, M. Sill3, D. McMeekin4, M. Leitao5, J. Brown6,G. Sutton7, L. Van Le8, C. Boardman9

1Yale University School of Medicine, New Haven, CT, 2Upstate CarolinaCCOP, Spartanburg, SC, 3Roswell Park Cancer Institute, Buffalo, NY,4University of Oklahoma, Oklahoma City, OK, 5Memorial Sloan–KetteringCancer Center, New York, NY, 6University of Texas M.D. Anderson CancerCenter, Houston, TX, 7St. Vincent Hospital, Indianapolis, IN, 8University ofNorth Carolina School of Medicine, Chapel Hill, NC, 9Medical College ofVirginia, Richmond, VA

Objective: Epidermal growth factor receptor (EGFR, HER1/erbB-1)has been identified as a target for cancer therapy in multiple humantumors. The Gynecologic Oncology Group (GOG) conducted a phase IItrial to assess the efficacy and tolerability of cetuximab, a human/murine chimeric monoclonal anti-EGFR1 antibody, in persistent orrecurrent carcinoma of the cervix.

Eligible patients had cervical cancer, measurable disease, andGOG performance status 2. Treatment consisted of cetuximab400 mg/m2 as an initial dose followed by 250 mg/m2 weeklyuntil disease progression or prohibitive toxicity. The primaryendpoints were progression-free survival (PFS) at six monthsand response. The study used a two-stage group sequentialdesign.Results: Thirty-eight patients were entered with three exclusions,leaving 35 evaluable for analysis. Thirty-one patients (88.6%) receivedprior radiation as well as either one (n=25, 71.4%) or two (n=10)prior cytotoxic regimens. Twenty-four patients (68.6%) had asquamous cell carcinoma. Grade 3 adverse events at least possiblyrelated to cetuximab included dermatologic (n=5), gastrointestinal(n=4), anemia (n=2), constitutional (n=3), infection (n=2),vascular (n=2), pain (n=2), and pulmonary, neurologic, vomitingand metabolic (n=1 each). No clinical responses were detected. Fivepatients (14.3%, two-sided 90% CI=5.8–30%) survived progressionfree for at least six months. The median PFS and overall survival timeswere 1.97 and 6.7 months, respectively. All patients with PFS at sixmonths harbored tumors with squamous cell histology.Conclusions: Cetuximab has limited activity in patients with recurrentcervical cancer in progression after palliative chemotherapy. Cetuximabseems to be well tolerated in this patient population and its activityseems to be limited to patients with squamous cell histology.

doi:10.1016/j.ygyno.2010.12.047

S18 ABSTRACTS / Gynecologic Oncology 120 (2011) S2–S133