Post-Operative Radiation Therapy Contouring Guidelines for Endometrial Carcinoma After TAH-BSO

Risk Stratification Framework

The American College of Radiology recommends that for post-operative radiation therapy contouring in endometrial carcinoma after TAH-BSO, the target volumes must be risk-stratified: intermediate-risk disease requires vaginal cuff plus 2-3 cm of proximal vagina for brachytherapy alone, while high-risk or stage II disease mandates a clinical target volume (CTV) encompassing the entire pelvic nodal regions, vaginal cuff, upper 3-4 cm of vagina, and parametrial tissues, with an upper border at L4-L5 or L5-S1 interspace 1
For low-risk disease, such as Stage IA, Grade 1-2 endometrioid histology with <50% myometrial invasion and no lymphovascular space invasion (LVSI), observation only is recommended with no radiation therapy required, as per the National Comprehensive Cancer Network guidelines 2, 1
The European Society for Medical Oncology recommends that for intermediate-risk disease, such as Stage IA-IB with Grade 2-3, or ≥50% myometrial invasion, LVSI negative, vaginal brachytherapy alone is warranted 2, 1

The American Society for Radiation Oncology recommends that for Stage IIB (cervical stromal invasion) or high-risk Stage I disease, the clinical target volume (CTV) should include common iliac, external iliac, internal iliac, obturator, and presacral lymph nodes, vaginal cuff, upper 3-4 cm of vagina, and parametrial tissues, with a superior border at L4-L5 or L5-S1 interspace 1
The International Commission on Radiation Units and Measurements recommends a margin of 7-10 mm to CTV for setup uncertainty and organ motion, with a dose prescription of 45-50.4 Gy in 1.8-2.0 Gy fractions 1

The American Association of Physicists in Medicine recommends that mandatory OARs to contour include bladder, rectum, sigmoid colon, small bowel, femoral heads, and bone marrow, with dose constraints of V40Gy <60% for rectum, V45Gy <50% for bladder, and V45Gy <200cc for small bowel 1, 2

The Society of Gynecologic Oncology recommends that non-endometrioid histologies (serous, clear cell, undifferentiated, carcinosarcoma) are considered high-risk regardless of stage, and require aggressive combined modality therapy 2

The PORTEC-1 and PORTEC-2 trials provide high-quality evidence that vaginal brachytherapy alone provides equivalent pelvic control to external beam RT for intermediate-risk disease with significantly less toxicity, with a strength of evidence rated as high 1
The PORTEC-3 trial demonstrated improved 5-year overall survival with chemoradiotherapy versus RT alone for high-risk endometrial cancer, with a strength of evidence rated as high 1