Poster Viewing Abstracts S423
Volume 87 Number 2S Supplement 2013 Purpose/Objective(s): Traditionally, when treating gynecologic malignancies with pelvic radiation therapy, a four-field box technique is used, planned with 3-dimensional conformal radiation therapy (3DCRT). This approach provides a robust margin on the pelvic structures at risk, but also includes a large volume of normal pelvic anatomy. Recently, there has been strong interest in using intensity modulated radiation therapy (IMRT) for these patients. RTOG 0418, as well as multiple single institution trials, have shown the feasibility of an IMRT approach. Currently, RTOG 1203 randomizes to the 3DCRT approach versus IMRT. Given the greater conformality of IMRT to the target, there is some concern about vaginal movement between fractions. The RTOG has recommended using an internal target volume approach that requires the prescription dose to be delivered to an area greater than that encompassed by the structure itself. Jhingran et al (2012) have reported vaginal displacement of 0.59 cm laterally, 1.46 cm anteriorly/posteriorly, and 1.2 cm superiorly/inferiorly. Here, we report on the feasibility of using a rectal balloon (RB) to minimize vaginal displacement. Materials/Methods: We reviewed our records to locate patients who had been treated with IMRT with the use of a RB for gynecologic malignancies where a component of the vagina was included in the target. We then selected the patients whose treatment setup had been verified with onboard kilovoltage Cone Beam CT (CBCT). These patients were set up to tattoo, and then registration with CBCT was performed. An auto match was then achieved, with review by a physician before shifts were applied. The magnitude of the shifts applied was extracted from the electronic patient information management system. Results: We located six patients who met the criteria. A total of 105 separate CBCT sets were reviewed. We noted an average displacement of 0.16 cm in the superior/inferior direction (87% decrease from previously reported). An average displacement of 0.25 cm was seen in the lateral direction (42% decrease). An average displacement of 0.42 cm was seen in the anterior/posterior direction (71% decrease). Conclusions: We have shown that with the use of a RB we have achieved a much smaller displacement of the vaginal target than has been reported. This suggests an ability to eliminate the need for a vaginal ITV, and allow smaller PTV margins. Further study is necessary to validate these findings. Author Disclosure: I. Deutsch: None. J. Wright: None. S. Lewin: None. T. Herzog: None. T. Wang: None. D. Gidea-Addeo: None. S. Cheng: None. E. Connolly: None. S. Isaacson: None. K. Chao: None.
2574 Early-Stage Papillary Serous or Clear Cell Carcinoma Confined to or Involving Endometrial Polyp: Outcomes With and Without Adjuvant Chemotherapy or Radiation Therapy C.N. Chang-Halpenny and J.M. Hwang-Graziano; Kaiser Permanente Medical Center, Los Angeles, CA Purpose/Objective(s): Uterine papillary serous (UPSC) and clear cell carcinoma (CC) of the endometrium are known to carry a poorer prognosis and there is no clear standard of treatment for early stage disease. Our study investigated outcomes from stage IA UPSC/CCS arising from or associated with a polyp. Materials/Methods: From 2000 to 2011, we identified 202 cases of stage IA UPSC, CC or mixed endometrial cancer. Of these, 37 cases had stage IA disease involving a polyp. Results: Median age was 65. Of the 37 cases identified, 74% were UPSC, 18% of mixed histology and 8% CC. Of these, 22 patients had tumor confined only to a polyp with no MMI or surface spread (59%). Polyp with UPSC/CC was found on biopsy, with no residual disease on TAH BSO for 6 of these patients. Fifteen patients (41%) had either superficial surface involvement, MMI or both. It is not clear whether tumor arose from or only involved polyps in those cases. Of note, 26% of patients had history of breast cancer, with at least 7/10 patients given hormone therapy. The majority of patients did not receive adjuvant treatment (81%). Two patients received adjuvant chemotherapy alone (carboplatin/paclitaxel), one received radiation (RT) alone (via vaginal brachytherapy [VB]), and five had chemotherapy and RT (with pelvic RT with or without VB). Patients
treated lacked or had incomplete nodal staging or had positive washings. None of the patients with tumor confined to polyp were treated. Toxicities were mild, with no grade 3-4 GI, GU or grade 4 hematologic toxicities. Median follow-up time was 40.4 months. At time of analysis, only 2 patients had progressed. There were no vaginal cuff recurrences. One untreated patient with 0.5 cm polyp confined UPSC, 20 lymph nodes dissected, and no MMI had pelvic sidewall mass recurrence 2.8 years after surgery. She was treated with salvage chemotherapy and RT and is now NED 1 month post-salvage. A second patient, who presented with mixed cytology (UPSC >50%) tumor, with surface spread beyond polyp, 3% MMI, atypical cytology, and pelvic (but no periaortic) dissection received adjuvant chemotherapy and VB, but developed carcinomatosis 6.5 months later. The patient died of disease 12.8 months after therapy. Overall survival for the group was 85%. Five patients died of other causes. Conclusions: To our knowledge, this is the largest series of limited UPSC/ CC arising from a polyp reported to date. Only 1/22 cases of UPSC/CC confined to polyp progressed and was salvaged, now NED with short-term follow-up thus far. Only 1/15 cases of UPSC/CC and polyp with surface or MMI progressed and died of disease. In general, patients with UPSC/CC disease limited to a polyp that have had surgical and nodal dissection appear to do well without adjuvant therapy. More data is needed to determine prognostic factors for treatment. Author Disclosure: C.N. Chang-Halpenny: None. J.M. Hwang-Graziano: None.
2575 WITHDRAWN
2576 Patterns of Relapse in Stage I-II Uterine Papillary Serous Carcinoma Treated With Adjuvant Intravaginal Radiation (IVRT) N.B. Desai, A.P. Kiess, M.A. Kollmeier, N.R. Abu-Rustum, V. Makker, R. Barakat, and K.M. Alektiar; Memorial Sloan-Kettering Cancer Center, New York, NY Purpose/Objective(s): IVRT is becoming the preferred form of adjuvant RT in early stage endometrial cancer. Whether such treatment is sufficient for high-risk histology, such as uterine papillary serous (UPS) remains debatable. The purpose of this study is to report a single institution experience using IVRT as the sole form of adjuvant RT in early stage UPS. Materials/Methods: From January 1996 to December 2010, 77 women with stage I-II UPSC underwent hysterectomy and bilateral salpingooophorectomy followed by IVRT. Sampling of pelvic nodes was performed in 67 (87%) patients (median #, 17), and sampling of para-aortic nodes was performed in 58 (75%) patients (median #, 6). The median IVRT dose was 21 Gy in 3 fractions. The median length of vagina treated was 7 cm (range, 4-7 cm). IVRT and adjuvant chemotherapy (carboplatin/ taxane-based) was given to 61 (79%) patients and IVRT alone to 16 (21%). The median follow-up time was 62 months. All noted confidence intervals (CI) are 95%. Results: Of the 77 patients, 11 (14%) relapsed. The sites of relapse were as follows: vaginal, 2 (3%); pelvic, 5 (6%); para-aortic, 5 (6%); peritoneal, 6 (8%); other distant sites, 8 (10%). In the group treated with IVRT alone, only 1 out of 16 developed recurrence (mediastinal). Conversely, the remaining 10/11 recurrences were all treated initially with adjuvant chemotherapy. Of the 11 total relapses, 4 were isolated (2 pelvic, 1 peritoneal, and 1 mediastinal). There were no isolated vaginal recurrences. Both pelvic recurrences were successfully salvaged with external beam radiation. The 5-year vaginal, pelvic, para-aortic, peritoneal, and distant recurrence rates were 2.7% (CI, 0-6.2%), 5.7% (CI, 0.5-10.9%), 5.3% (CI, 0.5-10.1%), and 7.9% (CI, 2.1-13.7%), respectively. The influence of age 60 years, deep myometrial invasion, lymphovascular invasion, cervical stromal invasion, pelvic LN sampling, and the use of chemotherapy were assessed in relation to risk for pelvic relapse. On univariate analysis, deep