786P - Exploring risk factors for recurrence in stage I uterine leiomyosarcomas: Is there a subgroup with a favorable prognosis?

Background

Despite standard surgical intervention stage I uterine leiomyosarcomas (uLMS) patients remain at considerable risk of recurrence. This has led to a growing trend in administering adjuvant chemotherapy (AC), despite the absence of robust prospective data. However, there may be a subset of patients with a more favorable prognosis, although they have not yet been clearly identified.

Methods

We studied 245 stage I uLMS patients from Daydream study, an international, multicenter observational, including surgically resected high-grade uterine sarcomas with or without AC from 2013 to 2018. Our objective was to identify recurrence risk factors (RF). We selected potential prognostic variables based on evidence and used multivariable logistic regression to calculate odds ratio (OR) for recurrence. Additionally, we assessed recurrence risk based on the number of RF present and AC use.

Results

We identified four recurrence-associated RF (p 5 cm (OR 2.1; 95%CI 1.09 - 4.1), > 20 mitoses per 10 HPF (OR 2.7; 95%CI 1.4 – 5.2), > 50% necrosis (OR 2.5; 95%CI 1.3 – 4.5), and substantial lymphovascular invasion (OR 2.1; 95%CI 1.1 – 5.2). The distribution of RF and their corresponding recurrence rates are outlined in the table. 29 patients had no RF, while 30 patients had all four, with recurrence rates of 10.3% and 83.3%, respectively. Each additional RF was associated to a relative increase in the risk of relapse of 138% (95%CI 81% - 213%). The proportions of women that received adjuvant chemotherapy (AC), were 7%, 28%, 49%, 51% and 87% in the groups of 0, 1, 2, 3 or 4 risk factors, respectively. Table: 786P

Distribution of the four recurrence-associated risk factors among stage I uLMS patients, with and without relapse

Conclusions

This analysis includes a representative sample of stage I uLMS patients, with a recurrence rate according to the evidence reported, around 50%. We identified a subgroup with a highly favorable prognosis, previously undefined. Despite the lack of evidence, more than 40% received AC. These findings highlight uLMS's heterogeneity and stress the need for personalized approaches.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

Clínica Universidad de Navarra.

Funding

Has not received any funding.

Disclosure

A. Gallego: Financial Interests, Personal, Invited Speaker: Roche, AstraZeneca, MSD, GSK, Clovis; Financial Interests, Personal, Advisory Board: GSK, MSD, Clovis, GSK; Other, Travel/accommodation/expenses: MSD, GSK, AstraZeneca. A. González-Martín: Financial Interests, Personal, Advisory Board: Amgen, AstraZeneca, Clovis, GSK, Genmab, Alkermes, Sutro, Roche, Sotio, PharmaMar, Oncoinvent, Novartis, Mersana, MSD, Macrogenics, Eisai, InmunoGen, Regeneron, HederaDx, Illumina, Tubulis; Financial Interests, Personal, Invited Speaker: GSK, AstraZeneca, Clovis, Roche, Novocure, MSD, Takeda, Zaylab; Financial Interests, Institutional, Coordinating PI, PI of ANITA trial: GSK, Roche; Financial Interests, Personal, Steering Committee Member, Member of ENGOT ov43-SC: MSD; Financial Interests, Institutional, Coordinating PI, ENGOT PI of EPIK-O trial: Novartis; Financial Interests, Institutional, Coordinating PI, ENGOT PI of AVB-500 phase III trial: Aravive. L. Chiva: Financial Interests, Personal, Invited Speaker: Astra Zeneca, Corza Medical; Financial Interests, Institutional, Invited Speaker: Roche, GSK. All other authors have declared no conflicts of interest.