Neoadjuvant radiotherapy for myxoid liposarcomas: Oncologic outcomes and histopathologic correlations

Significance of radiation therapy in the myxoid round-cell liposarcoma treatment regimen

BACKGROUND AND PURPOSE

Because myxoid liposarcomas are more radiosensitive than other soft tissue sarcomas, there have been several reports of 50 Gy preoperative radiation therapy combined with surgery, but the wound complication rate is reportedly high. We have performed preoperative irradiation at a reduced dose of 40 Gy and definitive radiation therapy for unresectable cases. This study aimed to report the tumor reduction rate and oncological results with a reduced dose of preoperative irradiation and the outcome of definitive irradiation for unresectable cases.

MATERIALS AND METHODS

Forty-one patients with myxoid liposarcoma treated in our institution between 2002 and 2021 were included. We examined the tumor volume shrinkage rate with preoperative radiation, compared complications and oncological outcomes between preoperative radiation and surgery-only cases, and investigated the prognosis and tumor shrinkage of definitive radiation cases.

RESULTS

The total dose irradiated was 40 Gy except in two cases. The mean tumor volume reduction rate was 52.0%. A decreased dose of preoperative radiation did not worsen clinical outcomes with fewer complications. The total dose of definitive radiation was approximately 60 Gy. The mean tumor volume reduction rate was 55.0%. The tumor shrinkage maintenance rate was 100% in a median follow-up period of 50.5 months.

CONCLUSION

Preoperative radiation therapy for myxoid liposarcoma near vital organs is a good approach because even with a reduced dose of 40 Gy, significant tumor reduction and excellent results were achieved. Definitive radiation therapy is the recommended treatment for older patients with serious comorbidities or inoperable patients.

Enormous myxoid/round cell liposarcoma: A case report

Myxoid/round cell liposarcomas (MRCLPS) are a rare soft tissue sarcoma. We report the largest sarcoma in our institutional history. We discuss the patient's surgical management and treatment of the tumor and challenges given its dimensions. Several complications arose following primary resection that were managed by a multidisciplinary team. Although MRCLPS can vary in size, large MRCLPS must be treated cautiously given the potential for complications. Additionally, multidisciplinary treatment of MRCLPS is essential in diagnosing and treating these complex cases.

Myxoid liposarcoma: MRI features with histological correlation

BACKGROUND AND AIMS

Myxoid liposarcoma is classified in the group of sarcomas with adipose differentiation, which is the second most common group of sarcomas. However, myxoid liposarcoma is not a homogeneous entity, because the behavior and clinical course of these tumours can vary widely. This study aimed to describe the magnetic resonance imaging (MRI) features of myxoid liposarcomas and to determine whether the MRI features are associated with the histologic grade and can differentiate between low-grade and high-grade tumours and thus help in clinical decision making.

MATERIAL AND METHODS

We studied 36 patients with myxoid liposarcomas treated at our centre between 2010 and 2018. We analysed clinical variables (age, sex, and tumour site) and MRI features (size, depth, borders, fatty component, myxoid component, non-fatty/non-myxoid component, apparent diffusion coefficient (ADC), and type of enhancement after the administration of intravenous contrast material). We correlated the MRI features with the histologic grade and the percentage of round cells.

RESULTS

In our series, patients with myxoid liposarcomas were mainly young adults (median age, 43 years). There were no differences between sexes; 97.2% were located in the lower limbs, 86.1% were deep, and 77.8% had well-defined borders. Of the 23 myxoid liposarcomas that contained no fat, 16 (69.6%) were high grade (p = 0.01). All the tumors with a myxoid component of less than 25% were high grade (p = 0.01); 83.3% of those with a non-fatty/non-myxoid component greater than 50% were high grade (p = 0.03) and 61.5% had more than 5% round cells (p = 0.01). Diffusion sequences were obtained in 14 of the 36 patients; ADC values were high (median, 2 × 10-3 mm2/s), although there were no significant associations between low-grade and high-grade tumours. Contrast-enhanced images were available for 30 (83.3%) patients; 83.3% of the tumours with heterogeneous enhancement were high grade (p = 0.01).

CONCLUSIONS

MRI can be useful for differentiating between high- and low-grade myxoid liposarcomas and can help in clinical decision making.

Histological response to radiotherapy is an early event in myxoid liposarcoma

Compared to other sarcomas, myxoid liposarcoma (MLS) is exceptionally sensitive to radiation therapy, but the underlying mechanism remains unknown. The objective was to assess the tissue-based changes in MLS during and after neoadjuvant radiotherapy in 26 patients of the DOREMY trial. Morphological assessment was performed on biopsies pre-treatment, after 8 fractions, 16 factions, and after surgical resection and included percentage of viable tumor cells, hyalinization, necrosis, and fatty maturation. Furthermore, immunohistochemistry was performed for apoptosis (cleaved caspase-3), anti-apoptosis (Bcl-2), activity of mTOR signaling (phospho-S6), hypoxia (CAIX), proliferation (Ki67), inflammation (CD45 and CD68), and microvessel density (CD34 Chalkley count). A pronounced reduction in vital tumor cells was observed early with a drop to 32.5% (median) tumor cells (IQR 10-93.8%) after 8 fractions. This decreased further to 10% (IQR 5-30%) after 16 fractions and 7.5% (IQR 5-15%) in the surgical specimen. All but one patient had an excellent response with < 50% remaining tumor cells. Inversely, treatment response was mainly observed as hyalinization and less often as fatty maturation. Additionally, a decrease of inflammatory cells was noticed especially during the first eight fractions. Microvessel density remained stable over time. Immunohistochemical markers for apoptosis, anti-apoptosis, activity of mTOR signaling, proliferation, and hypoxia did not show any marked changes within the remaining tumor cells during and after radiotherapy. As a modest dose of neoadjuvant radiotherapy induces profound tissue changes in MLS, mainly during the first 8 fractions, current findings might suggest that in a carefully selected patient population further deintensification of radiotherapy might be explored.

Prognosis of Liposarcoma Patients in Modern ERA: Single-Center Experience

Objective  Liposarcomas are relatively rare tumors. Prognostic and predictive factors and treatment options are limited. We herein presented our 10-year experience with liposarcomas. Materials and Methods  Adult patients with liposarcoma treated between 2005 and 2015 in our center were included. Demographic and clinicopathologic features of patients were retrieved from patient files. Statistical Analyses  Outcomes in terms of disease-free survival (DFS) and overall survival (OS) were assessed along with potential prognostic factors using Kaplan-Meier analyses. Results  A total of 88 patients were included. The median age was 52. Rates of well-differentiated (WDLS), dedifferentiated (DDLS), myxoid (MLS), and pleomorphic liposarcomas (PLS) were 42, 9.1, 37.5, and 4.5%, respectively. Only 10% of patients had high-grade tumors and 93% had localized disease. Ninety-six percent of patients ( n  = 84) underwent surgery. Adjuvant chemotherapy was delivered to 16 patients. The most common regimen was ifosfamide-doxorubicin. Recurrences were observed in 30 patients, 21 had local, and 9 had distant metastasis. Five-year DFS of patients with the localized disease was 68%. All patients with PLS had relapses and those had the highest distant relapse rates among all subtypes. Multivariate analysis showed T stage and grade were associated with DFS. Five-year OS of the entire population was 68%. Five-year OS was 79, 76, 50, and 0% in WDLS, MLS, DDLS, and PLS, respectively ( p  = 0.002). Conclusion  Management of liposarcomas is still challenging. Surgery is the mainstay of treatment. Novel effective therapies are needed, particularly in advanced disease settings.

Primary High-Grade Myxoid Liposarcoma of the Extremities: Prognostic Factors and Metastatic Pattern

(1) Background: This retrospective study aimed to analyze the history and treatment outcomes of localized, high-grade MLS of the extremities. (2) Methods: We retrospectively reviewed 82 patients with primary high-grade MLS of the extremities. OS, LRFS, MFS, PRS, and DFS were analyzed. (3) Results: Five-year OS and LRS were 96% (95% CI: 86-98) and 94% (95% CI: 85-98), respectively. Statistical analysis indicated no risk factors for OS and LFRS. MFS was 77% (65-85) at 5-year follow-up. Size (p = 0.0337) was the only risk factor statistically significant for MFS (HR = 0.248, 95% CI: 0.07-0.84). Median PRS after distant metastasis was 34 months (range: 1-127 months). Five-year PRS was 79% (48-93). Overall, the 5-year DFS was 76% (65-85). (4) Conclusions: Patients with MLS were found to have a good prognosis. In high-grade deep-seated tumors, common risk factors for MLS do not correlate with survival. Tumor size appears to be the only predictor of long-term DSF and MSF.

Artificial intelligence significantly improves the diagnostic accuracy of deep myxoid soft tissue lesions in histology

Deep myxoid soft tissue lesions have posed a diagnostic challenge for pathologists due to significant histological overlap and regional heterogeneity, especially when dealing with small biopsies which have profoundly low accuracy. However, accurate diagnosis is important owing to difference in biological behaviors and response to adjuvant therapy, that will guide the extent of surgery and the need for neo-adjuvant therapy. Herein, we trained two convolutional neural network models based on a total of 149,130 images representing diagnoses of extra skeletal myxoid chondrosarcoma, intramuscular myxoma, low-grade fibromyxoid sarcoma, myxofibrosarcoma and myxoid liposarcoma. Both AI models outperformed all the pathologists, with a significant improvement of accuracy up to 97% compared to average pathologists of 69.7% (p < 0.00001), corresponding to 90% reduction in error rate. The area under curve of the best AI model was on average 0.9976. It could assist pathologists in clinical practice for accurate diagnosis of deep soft tissue myxoid lesions, and guide clinicians for precise and optimal treatment for patients.

Preoperative Radiation for Soft Tissue Sarcomas: How Much Is Needed?

OPINION STATEMENT

Preoperative radiation therapy is an important component of curative treatment for extremity and superficial trunk soft tissue sarcomas. It has traditionally been delivered to a dose of 50 Gy in 2 Gy fractions over 5 weeks. With significant advances in the multidisciplinary approach to soft tissue sarcomas, preoperative radiation therapy may be omitted for certain cases, delivered over a shortened period of time (1-3 weeks), deintensified for myxoid liposarcomas, or combined with systemic therapy to improve the therapeutic ratio. This article reviews the innovative preoperative radiation therapy strategies currently used to treat extremity and superficial trunk soft tissue sarcomas.

Magnetic resonance imaging of trunk and extremity myxoid liposarcoma: diagnosis, staging, and response to treatment

Myxoid liposarcoma (MLS) accounts for approximately 30% of all liposarcomas. The majority are intermediate-grade tumours, but the presence of >5% round cell component renders it a high-grade sarcoma with subsequent poorer outcome. MLS most commonly arises in the lower extremities, has a predilection for extra-pulmonary sites of metastatic disease, and is recognized to be radiosensitive. The purpose of the current article is to review the role of MRI in the management of MLS, including the characteristic features of the primary tumour, features which help to identify a round cell component and thus determine prognosis, the role of whole-body MRI for evaluation of extra-pulmonary metastatic disease, and the utility of MRI for assessing treatment response. The MRI differential diagnosis of MLS is also considered.

Management of myxoid liposarcoma of the extremity

Myxoid liposarcoma (MLPS) is the second most common type of LPS after the well differentiated LPS. MLPS is primarily localized to the extremities. The incidence of LPS is ~2 per million worldwide. MLPS accounts for ~30% of all LPS cases. MLPS is usually encountered in adults, but can also occur in younger individuals more than other types of LPS. MLPS can be divided into low- and high-grade subtypes, which present with differences in patient prognosis and outcome. Methods of tumor management include surgery, radiotherapy and chemotherapy; however, there is no unified treatment based on tumor characteristics alone. The present manuscript reviews the surgical management, radiotherapeutic and chemotherapeutic approaches reported in the literature for different types of MLPS in the extremities, as well as the post-treatment outcomes. In addition, the present review provides an evidence-based management plan for MLPS in the form of an organogram based on specific tumor and patient parameters.

Survival analysis and treatment strategies for limb liposarcoma patients with metastasis at presentation

Limited data exist on patients with limb liposarcoma (LLS) with metastasis at presentation Moreover, the potential prognostic factors of this patient population are poorly documented because of its rarity. Therefore, we conducted this study to evaluate the clinicopathologic characteristics and prognostic factors for patients with metastatic LLS.All patients with LLS with metastasis at presentation from 1975 to 2016 were identified by using the Surveillance, Epidemiology, and End Results (SEER) database. The following clinical data were derived from this clinical database: age, sex, histologic grade, subtype, size of tumor, surgery, radiotherapy, chemotherapy, vital status, cause of death, and survival duration. The Kaplan-Meier method was performed to calculate median survival time and draw survivorship curves. Cox-proportional hazards regression model was used to reveal the statistical independence between various variables.The present study collected 184 cases from SEER database for survival analysis. Mean age was 57.8 years with 63.6% (n = 117) men. The 3-year overall survival (OS) and cancer-specific survival (CSS) rates of this population were 27.8% and 30.1%, respectively. Univariate analysis revealed that age, tumor grade, and surgery were significantly correlated with survival. Sex and tumor size did not reach significant predictor status of survival. Multivariate analysis revealed that age at diagnosis <60, low tumor grade, and local surgery were significantly correlated with improved OS and CSS.Patients with LLS with metastasis at diagnosis experienced quite poor prognosis. Currently, surgery for the primary tumor significantly prolonged the survival of those patients, whereas chemotherapy and radiotherapy need to be further confirmed.

Imaging response evaluation after neoadjuvant treatment in soft tissue sarcomas: Where do we stand?

Soft tissue sarcomas (STS) represent a broad family of rare tumours for which surgery with radiotherapy represents first-line treatment. Recently, neoadjuvant chemo-radiotherapy has been increasingly used in high-risk patients in an effort to reduce surgical morbidity and improve clinical outcomes. An adequate understanding of the efficacy of neoadjuvant therapies would optimise patient care, allowing a tailored approach. Although response evaluation criteria in solid tumours (RECIST) is the most common imaging method to assess tumour response, Choi criteria and functional and molecular imaging (DWI, DCE-MRI and ¹⁸F-FDG-PET) seem to outperform it in the discrimination between responders and non-responders. Moreover, the radiologic-pathology correlation of treatment-related changes remains poorly understood. In this review, we provide an overview of the imaging assessment of tumour response in STS undergoing neoadjuvant treatment, including conventional imaging (CT, MRI, PET) and advanced imaging analysis. Future directions will be presented to shed light on potential advances in pre-surgical imaging assessments that have clinical implications for sarcoma patients.

Myxoid liposarcoma: MRI features with histological correlation

BACKGROUND AND AIMS

Myxoid liposarcoma is classified in the group of sarcomas with adipose differentiation, which is the second most common group of sarcomas. However, myxoid liposarcoma is not a homogeneous entity, because the behavior and clinical course of these tumors can vary widely. This study aimed to describe the magnetic resonance imaging (MRI) features of myxoid liposarcomas and to determine whether the MRI features are associated with the histologic grade and can differentiate between low-grade and high-grade tumors and thus help in clinical decision making.

MATERIAL AND METHODS

We studied 36 patients with myxoid liposarcomas treated at our center between 2010 and 2018. We analyzed clinical variables (age, sex, and tumor site) and MRI features (size, depth, borders, fatty component, myxoid component, non-fatty / non-myxoid component, apparent diffusion coefficient (ADC), and type of enhancement after the administration of intravenous contrast material). We correlated the MRI features with the histologic grade and the percentage of round cells.

RESULTS

In our series, patients with myxoid liposarcomas were mainly young adults (median age, 43 years). There were no differences between sexes; 97.2% were located in the lower limbs, 86.1% were deep, and 77.8% had well-defined borders. Of the 23 myxoid liposarcomas that contained no fat, 16 (69.6%) were high grade (p=0.01). All the tumors with a myxoid component of less than 25% were high grade (p=0.01); 83.3% of those with a non-fatty / non-myxoid component greater than 50% were high grade (p=0.03) and 61.5% had more than 5% round cells (p=0.01). Diffusion sequences were obtained in 14 of the 36 patients; ADC values were high (median, 2 x 10-3 mm2/s), although there were no significant associations between low-grade and high-grade tumors. Contrast-enhanced images were available for 30 (83.3%) patients; 83.3% of the tumors with heterogeneous enhancement were high grade (p=0.01).

CONCLUSIONS

MRI can be useful for differentiating between high- and low-grade myxoid liposarcomas and can help in clinical decision making.

Dose Reduction of Preoperative Radiotherapy in Myxoid Liposarcoma: A Nonrandomized Controlled Trial

IMPORTANCE

Currently, preoperative radiotherapy for all soft-tissue sarcomas is identical at a 50-Gy dose level, which can be associated with morbidity, particularly wound complications. The observed clinical radiosensitivity of the myxoid liposarcoma subtype might offer the possibility to reduce morbidity.

OBJECTIVE

To assess whether a dose reduction of preoperative radiotherapy for myxoid liposarcoma would result in comparable oncological outcome with less morbidity.

DESIGN, SETTING, AND PARTICIPANTS

The Dose Reduction of Preoperative Radiotherapy in Myxoid Liposarcomas (DOREMY) trial is a prospective, single-group, phase 2 nonrandomized controlled trial being conducted in 9 tertiary sarcoma centers in Europe and the US. Participants include adults with nonmetastatic, biopsy-proven and translocation-confirmed myxoid liposarcoma of the extremity or trunk who were enrolled between November 24, 2010, and August 1, 2019. Data analyses, using both per-protocol and intention-to-treat approaches, were conducted from November 24, 2010, to January 31, 2020.

INTERVENTIONS

The experimental preoperative radiotherapy regimen consisted of 36 Gy in once-daily 2-Gy fractions, with subsequent definitive surgical resection after an interval of 4 or more weeks.

MAIN OUTCOMES AND MEASURES

As a short-term evaluable surrogate for local control, the primary end point was centrally reviewed pathologic treatment response. The experimental regimen was regarded as a success when 70% or more of the resection specimens showed extensive treatment response, defined as 50% or greater of the tumor volume containing treatment effects. Morbidity outcomes consisted of wound complications and late toxic effects.

RESULTS

Among the 79 eligible patients, 44 (56%) were men and the median (interquartile range) age was 45 (39-56) years. Two patients did not undergo surgical resection because of intercurrent metastatic disease. Extensive pathological treatment response was observed in 70 of 77 patients (91%; posterior mean, 90.4%; 95% highest probability density interval, 83.8%-96.4%). The local control rate was 100%. The rate of wound complication requiring intervention was 17%, and the rate of grade 2 or higher toxic effects was 14%.

CONCLUSIONS AND RELEVANCE

The findings of the DOREMY nonrandomized clinical trial suggest that deintensification of preoperative radiotherapy dose is effective and oncologically safe and is associated with less morbidity than historical controls, although differences in radiotherapy techniques and follow-up should be considered. A 36-Gy dose delivered in once-daily 2-Gy fractions is proposed as a dose-fractionation approach for myxoid liposarcoma, given that phase 3 trials are logistically impossible to execute in rare cancers.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02106312.

Prognostic Significance of Histological Subtype in Soft Tissue Sarcoma With Distant Metastasis

BACKGROUND/AIM

Few studies have examined the prognostic significance of histological subtypes in patients with soft tissue sarcoma (STS) and distant metastasis, and we evaluated the relationship between the histological subtypes and clinical outcomes.

PATIENTS AND METHODS

This retrospective study evaluated the histological subtypes of 105 patients with STS and distant metastasis. The STS histological subtypes were compared based on the clinical information.

RESULTS

The Kaplan-Meier curves for overall survival revealed that myxoid liposarcoma had a significantly better prognosis compared to Malignant Peripheral Nerve Sheath Tumor (MPNST) (p=0.0221). In the multivariate logistic regression analyses, the independent predictors of a poor prognosis were: i) large size, ii) advanced stage, and iii) non-surgical treatment for metastasis (p<0.05). The presence or absence of lung metastasis was not significantly associated with prognosis (p=0.4452).

CONCLUSION

Myxoid liposarcoma had a better prognosis compared to MPNST in STS patients with distant metastasis. The surgical removal of distant metastatic lesions may improve the patient's prognosis.

Magnetic resonance imaging assessment of chemotherapy-related adipocytic maturation in myxoid/round cell liposarcomas: specificity and prognostic value

OBJECTIVE

To investigate the specificity, clinical implication and prognostic value of MRI adipocytic maturation (MAM) in myxoid/round cells liposarcomas (MRC-LPS) treated with neoadjuvant chemotherapy (NAC).

METHODS

Of the 89 patients diagnosed with MRC-LPS at our sarcoma reference center between 2008 and 2018, 28 were included as they were treated with NAC, surgery and radiotherapy. All patients underwent contrast-enhanced MRIs at baseline and late evaluation. A control cohort of 13 high-grade pleomorphic and dedifferentiated LPS with same inclusion criteria was used to evaluate the specificity of MAM in MRC-LPS. Two radiologists analyzed the occurrence of MAM, changes in the tumor architecture, shape and surrounding tissues during NAC. Pathological features of tumor samples were reviewed and correlated with MRI. Metastatic relapse-free survival was estimated with Kaplan-Meier curves and Cox models. Associations between prognostic T1-based delta-radiomics features and MAM were investigated with Student t-test.

RESULTS

MAM was more frequent in MRC-LPS (p = 0.045) and not specific of any type of chemotherapy (p = 0.7). Regarding MRC-LPS, 14 out of 28 patients (50%) demonstrated MAM. Eight patients showed metastatic relapses. MAM was not associated with metastatic relapse-free survival (p = 0.9). MAM correlated strongly with the percentage of histological adipocytic differentiation on surgical specimen (p < 0.001), which still expressed the tumor marker NY-ESO-1. None of the prognostic T1-based delta-radiomics features was associated with MAM.

CONCLUSION

MAM seems a neutral event during NAC.

ADVANCES IN KNOWLEDGE

MAM predominated in MRC-LPS and was not specific of a type of chemotherapy. Occurrence of MAM was not associated with better patients' metastasis free survival.

Prognostic factors of patients with extremity myxoid liposarcomas after surgery

Background

Extremity myxoid liposarcoma (MLS) is a rare soft tissue sarcoma in adults. We performed this study to define distinctive clinical features of extremity MLS by assessing prognostic factors.

Methods

Between 1973 and 2015, 1756 patients with extremity MLS who underwent surgical resection were retrieved from the Surveillance, Epidemiology, and End Results (SEER) database of the US National Cancer Institute. Both overall survival (OS) and cancer-specific survival (CSS) were assessed using the Kaplan–Meier method (to obtain OS and CSS curves) and a Cox proportional hazards regression model.

Results

Of the 1756 patients with extremity MLS, the mean and median patient age at diagnosis were 47 and 45 years, respectively. More than half (n = 1027, 58.5%) of the patients were male. In terms of location, 10.5% tumors were located in the upper limbs and 89.5% in lower limbs. All patients received local surgery, and about half of the patients (57.2%) received radiation treatment. The 5- and 10-year OS rates of the entire cohort were 86.4% and 75.9%, respectively. The 5- and 10-year CSS rates were 90.5% and 85.2%, respectively. On multivariate analysis, older age, male gender, high tumor grade, and tumor size > 10 cm were found to be independent risk factors of both decreased OS and CSS. Year of diagnosis ≥ year 2000 was significantly associated with an increased CSS. In addition, radiation treatment failed to become an independent risk factor for either OS or CSS.

Conclusion

We identified age, gender, tumor grade, year of diagnosis, and tumor size as independent prognostic factors for OS and CSS in patients with extremity MLS.