PORTEC-4a: Molecular Profile-based Versus Standard Adjuvant Radiotherapy in Endometrial Cancer

Randomised Phase III Trial of Molecular Profile-based Versus Standard Recommendations for Adjuvant Radiotherapy for Women With Early Stage Endometrial Cancer: PORTEC-4a Trial

This is prospective, multicenter, randomised phase III trial among women with endometrial cancer with high-intermediate risk features to investigate the role of an integrated clinicopathological and molecular risk profile to determine if participants should receive no adjuvant therapy, vaginal brachytherapy or external beam radiotherapy based on a favourable, intermediate or unfavourable profile as compared to standard adjuvant vaginal brachytherapy.

Adjuvant therapy for women with endometrial cancer has increasingly been tailored to prognostic factors to prevent overtreatment and select those women for adjuvant treatment who will have a clinically relevant reduction of the risk of relapse by the adjuvant treatment. Risk profiles have traditionally been based on clinicopathological factors such as age, stage, grade, LVSI and depth of invasion. Newer, both molecular-genetic (the cancer genome atlas subgroups) or immunohistochemistry-based (L1-CAM) risk factors have become available which are strongly related to outcomes and risk of cancer spread. In a comprehensive analysis of the PORTEC-1 and-2 biobank an integrated clinicopathological and molecular risk profile was determined which separated the current high-intermediate risk group of endometrial cancer in 3 separate groups (favourable, intermediate or unfavourable) with clearly separated outcomes, which is now prospectively tested in the clinic to determine adjuvant treatment. This is the first randomised trial using the molecular risk factors to assign adjuvant treatment for women with stage I-II high-intermediate risk endometrial cancer.

Inclusion Criteria:

• Histologically confirmed endometrioid type endometrial carcinoma, International Federation of Gynecology and Obstetrics (FIGO) 2009 stage I, with one of the following combinations of stage, grade, age, and lymph-vascular space invasion (LVSI):

  1. Stage IA, grade 3 (any age, with or without LVSI)
  2. Stage IB, grade 1 or 2 and age >60 years
  3. Stage IB, grade 1-2 with documented LVSI
  4. Stage IB, grade 3 without LVSI
  5. Stage II (microscopic), grade 1

• World Health Organization (WHO)-performance status 0-2

• Written informed consent

Exclusion Criteria:

• Any other stage and type of endometrial carcinoma
• Histological types serous carcinoma or clear cell carcinoma (at least 10% if mixed type), or undifferentiated or neuroendocrine carcinoma
• Uterine sarcoma (including carcinosarcoma)
• Previous malignancy (except for non-melanomatous skin cancer) < 5 yrs
• Previous pelvic radiotherapy
• Expected interval between the operation and start of radiotherapy exceeding 8 weeks