EP115/#640 Are all stage IA p53abn endometrial cancers the same? Seeking clarity in the management of stage IA p53abn and/or non-endometrioid endometrial cancers without myometrial invasion. (4th December 2022)

• Record Type: Journal Article
• Authors: Jamieson, Amy; Leung, Samuel; Thompson, Emily; Lum, Amy; Grube, Marcel; Kwon, Janice; Gilks, Blake; Kommoss, Stefan; Mcalpine, Jessica
• Is Part Of: International journal of gynecological cancer. Volume 32(2022)Supplement 3
• Page Start: A94
• Page End: A94
• Publication Date: 2022-12-04
• Subjects: Generative organs, Female -- Cancer -- Periodicals; 616.99465
• DOI: 10.1136/ijgc-2022-igcs.206
• Languages: English
• ISSNs: 1048-891X

Abstract

Abstract : Objectives: Optimal management of stage IA p53abn and/or high-grade non-endometrioid endometrial cancer(EC) without myometrial invasion is unclear, classified as intermediate risk in new 2020 ESGO-ESTRO-ESP guidelines. Current practice varies from surgery alone to adjuvant vault brachytherapy (VB)±chemotherapy. Our aim was to assess the risk of disease recurrence within three subcategories of stage IA ECs without myoinvasion compared to IA with myoinvasion(<50%). Methods: Stage IA p53abn and high-grade non-endometrioid ECs of other molecular subtypes were identified from a retrospective EC cohort (2005–2016). Cases were segregated into IA with no myoinvasion, including i) tumor restricted to a polyp, ii) tumor confined to the endometrium, and iii) no residual tumor, vs. stage IA with myoinvasion(<50%), with treatment and outcomes assessed. Results: 169 stage IA p53abn and 49 stage IA non-endometrioid ECs of other molecular subtypes were identified (7 POLEmut, 24 MMRd and 18 NSMP). Table 1 shows the subcategories, adjuvant treatment, and disease recurrences. 12 patients(15%) with stage IA no myoinvasion recurred; 1 had received chemotherapy, 3 VB, 1 EBRT, 7 no adjuvant therapy. 35 patients with disease confined to the endometrium had received no adjuvant therapy with 6 (17.1%) recurrences (2 additional recurrences with VB). Stage IA patients not receiving chemotherapy had a ~17% recurrence rate, whether with myoinvasion (17.1%) or without (16.7%). Conclusions: Rates of recurrence were the same in patients with stage IA p53abn and/or non-endometrioid EC regardless of myoinvasion. Optimal treatment for the diverse spectrum of stage IA p53abn disease remains a challenge but these recurrence rates should prompt consideration of adjuvant therapy.