Abstract 810P
Background
Nearly half of uterine leiomyosarcomas (uLMS) express estrogen (ER) or progesterone (PR) receptors. Currently, few data accessed the concordance of hormonal receptor (HR) status in primary uLMS and metastasis. This study compares the expression of HR in primary and metastatic uLMS, as well as within different metastases of the same patient, addressing its prognostic value.
Methods
A retrospective cohort study (1980-2019) of all uLMS patients with recurrent/metastatic disease confirmed by histology (median follow-up 148.5 mo). Clinical files and histological slides were reviewed. ER/PR immunoexpression was assessed in primary and metastases samples, using a binary classification (+/-) and a semi-quantitative score by visual estimation (% positive tumor cells).
Results
Twenty-eight patients were included (near 30% of all uLMS patients treated). The most frequent site of the first relapse was the lung (n=18; 64.3%), and the median time to recurrence was 25.8 mo (95% CI 14.3-37.3). Most primary tumors were HR-positive (ER: n=20, 87.0%; PR: n=16, 69.6%), with a variable proportion of expression [median=30-40% (min-max: 0- 99%)]. Most had concordant binary HR expression with first recurrence/metastasis (n=15, 65.2%), while 8 had discordant results: 7 lost HR expression, 1 changed from negative to positive. Five that lost HR expression in metastasis had an HR expression score less than 40% in the primary tumor. Three showed discordant expression between metastases of the same patient. Treatment on relapse included surgical excision of metastasis (n=9, 32.1%), radiotherapy (n=5; 17.9%) and/or systemic therapy (n=21, 75.0%). HR loss in metastases (but not in primary tumors) tended to associate with worse progression-free survival, particularly PR (HR: 0.42, p=0.106). After metastatic disease onset, the median overall survival (OS) was 24.7 mo (95% CI 21.6-27.8). OS did not vary with HR expression.
Conclusions
Our study shows that HR expression discordance between primary and metastasis was present in 1/3 of uLMS. HR heterogeneity within same patient metastases was also observed. Metastasis HR expression seems to influence prognosis, warranting further confirmation in larger series and consideration in clinical trials design.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.