Gynecological Cancer

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TU_20_3520 - Vaginal Brachytherapy and External Beam Radiation therapy in Operable Stage II Endometrial Cancer: A National Cancer Database Study

Tuesday, October 23
2:45 PM - 4:15 PM
Location: Innovation Hub, Exhibit Hall 3

Vaginal Brachytherapy and External Beam Radiation therapy in Operable Stage II Endometrial Cancer: A National Cancer Database Study
S. N. Seyedin1, M. Marquardt2, C. M. Callaghan2, S. Mott3, J. M. Caster4, and W. Sun2; 1Department of Radiation Oncology, University of Iowa Hospitals & Clinics, Iowa City, IA, 2Department of Radiation Oncology, University of Iowa Hospitals and Clinics, Iowa City, IA, 3Holden Comprehensive Cancer Center, University of Iowa Hospitals and Clinics, Iowa City, IA, 4University of Iowa Hospitals and Clinics, Iowa City, IA

Purpose/Objective(s): We investigated the effect of radiotherapy modality for Federation of Gynecology and Obstetrics (FIGO) stage II endometrial cancer after hysterectomy using the National Cancer Database (NCDB).

Materials/Methods: Between 2004 and 2013, FIGO Stage II endometrial cancer patients who received a total, modified radical or extended hysterectomy were selected from the NCDB. Patients with positive margins were excluded. Adenocarcinoma, clear cell, and papillary serous histological subtypes were allowed. Differences in outcomes between patients who received external beam radiation (EBRT), vaginal brachytherapy (VBT), or both (EBRT+VBT) were investigated. Lymph node number removed and receipt of chemotherapy were also examined. The primary endpoint of this study was overall survival (OS).

Results: 4497 patients were eligible for analysis with a median follow-up of 47.8 months and median age of 62. Adenocarcinomas comprised 88.4% of the population, and 66.0% received radiation, with 16.8% receiving chemotherapy. Univariate analysis revealed race, Charlson-Deyo Score (performance status), grade, lymphovascular invasion (LVSI), receipt of radiation, lymph node number removed (<10 vs ≥10), and age to each be significant for OS (p<0.01). On multivariable analysis (MVA) of all patients, African-American (vs Caucasian) race, not receiving radiation, Charlson-Deyo Score 2, grade 2-3 cancer (vs grade 1), <10 lymph nodes resected, and older age were associated (p < 0.01) with worse OS. Of patients who received radiation, VBT was associated with a significantly improved OS (p=0.03) when compared to EBRT (HR 1.38, 95% CI 1.10-1.73) or EBRT+VBT (HR 1.25, 95% CI 1.02-1.54). On MVA of those who received radiation, no differences in OS were observed between VBT (HR 1.00), EBRT (HR 1.11, 95% CI 0.86-1.41), or EBRT+VBT (HR 1.08, 95% CI 0.86-1.36), and chemotherapy was not associated with improved OS (HR 0.82, 95% CI 0.63-1.07, p = 0.14). When evaluating individual patient cohorts separated by grade and radiation therapy modality, there existed no difference in 5 year OS between groups (p=0.74). On stratification by presence of LVSI and radiation modality, there was no difference in 5 year OS when comparing each individual group (p=0.4).

Conclusion: This study suggests that adjuvant radiation plays a key role in the management of operable Stage II endometrial cancer regardless of modality. VBT alone may be sufficient with stage II endometrial cancer regardless of grade or LVSI. Prospective data is required to further investigate and validate these results. Table. 5-year Overall Survival (95% CI) of Stage II Endometrial Cancer by Grade and Radiation Modality
Radiation Modality
Grade VBT EBRT EBRT+VBT
1 91.6% (87.0-94.7%) 88.9% (82.2-93.2%) 91.0% (86.2-94.2%)
2 85.1% (80.4-88.7%) 84.6% (79.0-88.8%) 84.6% (80.7-87.8%)
3 73.7% (67.0-79.3%) 65.6% (58.5-71.8%) 65.1% (59.0-70.5%)

Author Disclosure: S.N. Seyedin: None. C.M. Callaghan: None. S. Mott: None. J.M. Caster: None. W. Sun: None.

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