Endometrial stromal sarcoma. Is there a place for radiotherapy?

Clinical, histological and therapeutical aspects in the management of uterine and extrauterine stromal sarcomas: Case reports

Endometrial stromal sarcoma (ESS) is a rare tumor, predominantly occurring as a primary tumor of the uterus. Rare cases of primary extrauterine ESS (EESS) have been reported. Low-grade ESS (LG-ESS) is more common than high-grade ESS (HG-ESS). We present five cases of ESS and one case of EESS. All cases received external radiotherapy (EBRT) at the Radiotherapy Department of the Emergency Clinical Hospital ‘Sfantul Apostol Andrei’ Galati, during 2004-2020. Five cases underwent EBRT in two-dimensional (2D) technique and only one patient received EBRT with three-dimensinal conformational radiotherapy (3DCRT) technique with a linear accelerator, Elekta Synergy. Five patients were referred to postoperative radiotherapy after hysterectomy. The median age of the patients was 57.4 years. One patient was referred to radiotherapy with palliative intent. EESS localized in the retroperitoneum, in the para-aortic region, was identified in one 64-year-old patient with a personal history of hysterectomy and bilateral salpingo-oophorectomy in 1997; EESS was complicated with vertebral extension at the L1-L2 level and spinal cord compression syndrome. ESS represents a rare diagnosis and a high- or low-grade tumor profile is distinguished by immunohistochemistry (IHC) tests. Up to 30% of patients have EESS at presentation. The treatment of ESS is multimodal, its management requiring a multidisciplinary team, and it is different according to the primary tumor location and tumor staging. The role of adjuvant radiotherapy remains controversial in high-grade EESS and due to the rarity of these cases there are limited data concerning the efficacy of adjuvant EBRT available from prospective randomized control clinical trials.

Adjuvant Radiotherapy Improved Survival in Stage I to II Low-Grade Endometrial Stromal Sarcoma: A Retrospective Study of 152 Cases

Objective

Low-grade endometrial stromal sarcoma (LG-ESS) is a rare gynecological tumor. Whether adjuvant radiotherapy benefits survival in patients with resected early-stage ESS remains controversial. This study was designed to explore the role of adjuvant radiotherapy in stage I to II LG-ESS.

Methods

We retrospectively reviewed patients with stage I to II LG-ESS in our center from Jan. 1998 to Feb. 2018. All patients underwent a total hysterectomy and postoperative radiotherapy was administrated based on clinical and pathological characteristics.

Results

A total of 152 patients with stage I to II resected LG-ESS were included. Forty patients received adjuvant radiotherapy (RT group) while 112 patients did not receive adjuvant radiotherapy (no RT group). The baseline characteristics of the two groups were comparable, except that the proportion of stage II patients in the RT group was higher than that in the no RT group (32.5% vs. 11.6%, in RT vs. no RT groups, respectively; p = 0.003). For both patient groups, median overall survival was not reached. The median disease-free survival (DFS) was 144 months. Radiotherapy was associated with significantly improved DFS (92 months vs. not reached in RT vs. no RT groups, respectively; p = 0.008) and pelvic failure-free survival (PFFS) (92 months vs. not reached in RT vs. no RT groups, respectively; p=0.004). Subgroup analysis revealed that RT benefited survival most among patients with stage IB to IIB disease. Adjuvant radiotherapy significantly reduced the pelvic recurrence rate (10.0%, 4/40 vs. 28.6%, 32/112, p = 0.018). No radiotherapy-induced grade 4 to 5 toxicity was observed.

Conclusion

For patients with stage I to II LG-ESS, adjuvant radiotherapy showed significant improvement in DFS and PFFS with tolerable adverse effects, especially in patients with stage IB to IIB disease.

A nomogram for predicting overall survival in patients with low-grade endometrial stromal sarcoma: A population-based analysis

Background

Low‐grade endometrial stromal sarcoma (LG‐ESS) is a rare tumor that lacks a prognostic prediction model. Our study aimed to develop a nomogram to predict overall survival of LG‐ESS patients.

Methods

A total of 1172 patients confirmed to have LG‐ESS between 1988 and 2015 were selected from the Surveillance, Epidemiology and End Results (SEER) database. They were further divided into a training cohort and a validation cohort. The Akaike information criterion was used to select variables for the nomogram. The discrimination and calibration of the nomogram were evaluated using concordance index (C‐index), area under time‐dependent receiver operating characteristic curve (time‐dependent AUC), and calibration plots. The net benefits of the nomogram at different threshold probabilities were quantified and compared with those of the International Federation of Gynecology and Obstetrics (FIGO) criteria‐based tumor staging using decision curve analysis (DCA). Net reclassification index (NRI) and integrated discrimination improvement (IDI) were also used to compare the nomogram's clinical utility with that of the FIGO criteria‐based tumor staging. The risk stratifications of the nomogram and the FIGO criteria‐based tumor staging were compared.

Results

Seven variables were selected to establish the nomogram for LG‐ESS. The C‐index (0.814 for the training cohort and 0.837 for the validation cohort) and the time‐dependent AUC (> 0.7) indicated satisfactory discriminative ability of the nomogram. The calibration plots showed favorable consistency between the prediction of the nomogram and actual observations in both the training and validation cohorts. The NRI values (training cohort: 0.271 for 5‐year and 0.433 for 10‐year OS prediction; validation cohort: 0.310 for 5‐year and 0.383 for 10‐year OS prediction) and IDI (training cohort: 0.146 for 5‐year and 0.185 for 10‐year OS prediction; validation cohort: 0.177 for 5‐year and 0.191 for 10‐year OS prediction) indicated that the established nomogram performed significantly better than the FIGO criteria‐based tumor staging alone (P < 0.05). Furthermore, DCA showed that the nomogram was clinically useful and had better discriminative ability to recognize patients at high risk than the FIGO criteria‐based tumor staging.

Conclusions

A prognostic nomogram was developed and validated to assist clinicians in evaluating prognosis of LG‐ESS patients.

Tyrosine kinase receptor status in endometrial stromal sarcoma: an immunohistochemical and genetic-molecular analysis

Endometrial stromal sarcomas (ESS) are rare uterine malignant mesenchymal neoplasms, which are currently treated by surgery, as effective adjuvant therapies have not yet been established. Tyrosine kinase inhibitors have rarely been applied in ESS therapy, with few reports describing imatinib responsivity. The aim of this study was to analyze the status of different tyrosine kinase receptors in an ESS series, in order to evaluate their potential role as molecular targets. Immunohistochemistry was performed for EGFR, c-KIT, PDGFR-α, PDGFR-β, and ABL on 28 ESS. EGFR, PDGFR-α, and PDGFR-β gene expression was investigated by real-time polymerase chain reaction (qRT-PCR) on selected cases. "Hot-spot" mutations were screened for on EGFR, c-KIT, PDGFR-α, and PDGFR-β genes, by sequencing. All analysis was executed from formalin-fixed, paraffin-embedded specimens. Immunohistochemical overexpression of 2 or more tyrosine kinase receptors was observed in 18 of 28 tumors (64%), whereas only 5 tumors were consistently negative. Gene expression profiles were concordant with immunohistochemical overexpression in only 1 tumor, which displayed both high mRNA levels and specific immunoreactivity for PDGFR-α, and PDGFR-β. No activating mutations were found on the tumors included in the study. This study confirms that TKRs expression is frequently observed in ESS. Considering that the responsiveness to tyrosine kinase inhibitors is known to be related to the presence of specific activating mutations or gene over-expression, which are not detectable in ESS, TKRs immunohistochemical over-expression alone should not be considered as a reliable marker for targeted therapies in ESS. Specific post-translational abnormalities, responsible for activation of TKRs, should be further investigated.

Endometrial stromal tumors: immunohistochemical and molecular analysis of potential targets of tyrosine kinase inhibitors

BACKGROUND

The systemic treatment of malignant endometrial stromal tumors (EST) is not well established. A few reports describe objective responses to imatinib, which suggest a novel therapeutic strategy for these tumors. Due to these facts, we aimed to perform a retrospective analysis of possible molecular targets of tyrosine kinase inhibitors (TKI) in EST: KIT, PDGFRA and EGFR.

METHODS

52 endometrial stromal sarcomas and 13 undifferentiated endometrial sarcomas were examined and reviewed. Mutational analysis were performed for exons 9, 11, 13, and 17 of the KIT gene, exons 12 and 18 of the PDGFRA gene and exons 18, 19, 20 and 21 of the EGFR gene. The incidence and distribution of the KIT, PDGFRA, and EGFR expression were examined by immunohistochemistry, and EGFR amplification was assessed by fluorescence in situ hybridization.

RESULTS

No mutations in KIT, PDGFRA and EGFR genes were detected. Overexpression of KIT, PDGFRA, EGFR, was detected in 2 (3%), 23 (35.4%), 7 (10.8%) cases respectively, whereas amplification of EGFR gene was not found.

CONCLUSIONS

Absence of significant expression, amplification and activating mutations on these tyrosine kinase receptors suggest that it is unlikely that EST can benefit from therapies such as TKI on the systemic setting.