Resection outcomes for primary and local recurrent retroperitoneal liposarcoma patients

Deciphering the roles of non-coding RNAs in liposarcoma development: Challenges and opportunities for translational therapeutic advances

Liposarcoma is one of the most prevalent forms of soft tissue sarcoma, and its prognosis is highly dependent on its molecular subtypes. Non-coding RNAs (ncRNAs) like microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) can bind various cellular targets to regulate carcinogenesis. By affecting the expressions and activities of their downstream targets post-transcriptionally, dysregulations of miRNAs can alter different oncogenic signalling pathways, mediating liposarcoma progression. On the contrary, lncRNAs can sponge miRNAs to spare their downstream targets from translational repression, indirectly affecting miRNA-regulated oncogenic activities. In the past 15 years, multiple fundamental and clinical research has shown that different ncRNAs play essential roles in modulating liposarcoma development. Yet, there is a lack of an effective review report that could summarize the findings from various studies. To narrow this literature gap, this review article aimed to compare the findings from different studies on the tumour-regulatory roles of ncRNAs in liposarcoma and to understand how ncRNAs control liposarcoma progression mechanistically. Additionally, the reported findings were critically reviewed to evaluate the translational potentials of various ncRNAs in clinical applications, including employing these ncRNAs as diagnostic and prognostic biomarkers or as therapeutic targets in the management of liposarcoma. Overall, over 15 ncRNAs were reported to play essential roles in modulating different cellular pathways, including apoptosis, WNT/β-catenin, TGF-β/SMAD4, EMT, interleukin, and YAP-associated pathways to influence liposarcoma development. 28 ncRNAs were reported to be upregulated in liposarcoma tissues or circulation, whereas 11 were downregulated, making them potential candidates as liposarcoma diagnostic biomarkers. Among these ncRNAs, measuring the tissues or circulating levels of miR-155 and miR-195 was reported to help detect liposarcoma, differentiate liposarcoma subtypes, and predict the survival and treatment response of liposarcoma patients. Overall, except for a few ncRNAs like miR-155 and miR-195, current evidence to support the use of discussed ncRNAs as biomarkers and therapeutic targets in managing liposarcoma is mainly based on a single-center study with relatively small sample sizes or cell-based studies. Hence, more large-scale multi-center studies should be conducted to further confirm the sensitivity, specificity, and safety of ncRNAs as biomarkers and therapeutic targets. Instead of furthering investigation to confirm the translational values of all the discussed ncRNAs, which can be time- and cost-consuming, it would be more practical to focus on a few ncRNAs, including miR-155 and miR-195, to evaluate if they are sensitive and safe to be used as liposarcoma biomarkers and therapeutic agents or targets.

Prognostic value of 18 F-FDG PET/CT in postoperative recurrence of retroperitoneal liposarcoma: a single-center retrospective study

OBJECTIVE

Recurrence is the leading cause of tumor-related death in retroperitoneal liposarcoma (RPLPS). Variant subtypes of RPLPS determine different recurrence 18 F]-fluoro-2-deoxy-D-glucose ( 18 F-FDG) PET/computed tomography (PET/CT). This study analyzed the characteristics of different histologic subtypes of 18 F-FDG PET/CT and their associations with recurrence and prognosis.

METHODS

Clinical-pathological information, 18 F-FDG PET/CT data, recurrence, and progression-free survivals (PFS) of 83 patients with RPLPS were collected. Maximum and peak standardized uptake values (SUV max and SUV peak , respectively) and mean CT value (CT mean ) of tumors were measured and correlated with histologic subtype. Receiver operating characteristics (ROC) curves were used to analyze the predictability for subtype and recurrence. Kaplan-Meier analysis examined SUV max and SUV peak as recurrence risk factors.

RESULTS

Studied patients with different types of liposarcomas. Dedifferentiated liposarcomas (DDLPS) had higher SUV max and SUV peak than well-differentiated (WDLPS) and myxoid/round cell (MLPS) types. WDLPS had lower CT mean values compared to MLPS and DDLPS. Using ROC curves, determined cut-off values for SUV max (5.1) to differentiate DDLPS, SUV peak (3.0) for WDLPS, and CT mean (12.3 Hu) for WDLPS. These cut-offs were found to be best for predicting recurrence. Kaplan-Meier analysis showed that histologic subtype, SUV max , and SUV peak were all linked to recurrence-free survival.

CONCLUSIONS

The use of SUV and CT features on 18 F-FDG PET/CT imaging may increase confidence in subtype diagnosis. Patients with SUV max  > 5.1 or SUV peak  > 3.0 suggest a poor prognosis.

GLI1 Coamplification in Well-Differentiated/Dedifferentiated Liposarcomas: Clinicopathologic and Molecular Analysis of 92 Cases

GLI1(12q13.3) amplification is identified in a subset of mesenchymal neoplasms with a distinct nested round cell/epithelioid phenotype. MDM2 and CDK4 genes are situated along the oncogenic 12q13-15 segment, amplification of which defines well-differentiated liposarcoma (WDLPS)/dedifferentiated liposarcoma (DDLPS). The 12q amplicon can occasionally include GLI1, a gene in close proximity to CDK4. We hereby describe the first cohort of GLI1/MDM2/CDK4 coamplified WD/DDLPS. The departmental database was queried retrospectively for all cases of WD/DDLPS having undergone next-generation (MSK-IMPACT) sequencing with confirmed MDM2, CDK4, and GLI1 coamplification. Clinicopathologic data was obtained from a review of the medical chart and available histologic material. Four hundred eighty-six WD/DDLPS cases underwent DNA sequencing, 92 (19%) of which harbored amplification of the GLI1 locus in addition to that of MDM2 and CDK4. These included primary tumors (n = 60), local recurrences (n = 29), and metastases (n = 3). Primary tumors were most frequently retroperitoneal (47/60, 78%), mediastinal (4/60, 7%), and paratesticular (3/60, 5%). Average age was 63 years, with a male:female ratio of 3:2. The cohort was comprised of DDLPS (86/92 [93%], 6 of which were WDLPS with early dedifferentiation) and WDLPS without any longitudinal evidence of dedifferentiation (6/92, 7%). One-fifth (13/86, 17%) of DDLPS cases showed no evidence of a well-differentiated component in any of the primary, recurrent, or metastatic specimens. Dedifferentiated areas mostly showed high-grade undifferentiated pleomorphic sarcoma-like (26/86,30%) and high-grade myxofibrosarcoma-like (13/86,16%) morphologies. A disproportionately increased incidence of meningothelial whorls with/without osseous metaplasia was observed as the predominant pattern in 16/86 (19%) cases, and GLI1-altered morphology as described was identified in a total of 10/86 (12%) tumors. JUN (1p32.1), also implicated in the pathogenesis of WD/DDLPS, was coamplified with all 3 of MDM2, CDK4, and GLI1 in 7/91 (8%) cases. Additional loci along chromosomal arms 1p and 6q, including TNFAIP3, LATS1, and ESR1, were also amplified in a subset of cases. In this large-scale cohort of GLI1 coamplified WD/DDLPS, we elucidate uniquely recurrent features including meningothelial whorl-like and GLI-altered morphology in dedifferentiated areas. Assessment of tumor location (retroperitoneal or mediastinal), identification of a well-differentiated liposarcoma component, and coamplification of other spatially discrete genomic segments (1p and 6q) might aid in distinction from tumors with true driver GLI1 alterations.

Identification of predictors for short-term recurrence: comprehensive analysis of 296 retroperitoneal liposarcoma cases

BACKGROUND

The short-term (≤ 1 year) recurrence (STR) is the primary determinant impacting both the life quality and survival duration in patients who have undergone surgical resection for retroperitoneal liposarcoma (RPLS), a condition with intricate and ambiguous pathogenesis. The purpose of this study was to analyze the risk factors associated with STR in cases of RPLS and primary retroperitoneal liposarcoma (PRPLS).

METHODS

For this retrospective observational study, a total of 296 RPLS cases were selected as research subjects, who experienced tumor recurrence during the follow-up period. The Local recurrence-free survival (LRFS) rates were estimated using the Kaplan-Meier method and subsequently compared between groups utilizing the log-rank test. The subsequent analyses involved univariate and multivariate logistic regression to identify predictors of STR in RPLS cases. Additionally, a logistic regression model was constructed for PRPLS.

RESULTS

The 1-, 3-, and 5-year LRFS rates of the 296 RPLS cases were 51.7%, 16.9%, and 7.1%, respectively. In the univariate analysis, several factors were found to be associated with STR, including preoperative neutrophil/lymphocyte ratio (NLR), smoking history, surgical frequency, combined organ excision, operative time, intraoperative bleeding, transfer to the intensive care unit (ICU), multiple primary tumors, tumor shape and capsule characteristics, histological subtype, and presence of tumor necrosis. The elevated preoperative NLR, surgical frequency of ≥ 3 times, transfer to the ICU, presence of multiple primary tumors, and tumor necrosis were identified as independent risk factors for STR in surgically resected RPLS. Conversely, diabetes, intact tumor capsule, and well-differentiated histological subtype appeared to be independent protective factors. Analysis for PRPLS revealed that tumor capsule and tumor necrosis were independent predictors of STR.

CONCLUSIONS

The elevated preoperative NLR, surgical frequency of ≥ 3 times, transfer to the ICU, presence of multiple primary tumors, tumor necrosis, and tumor capsule were expected to serve as predictive factors of STR for surgical resected RPLS and PRPLS.

Immune characteristics of dedifferentiated retroperitoneal liposarcomas and the reliability of regional samples in evaluating their tumor immune microenvironments

BACKGROUND

Tumor immunotherapy is a new treatment breakthrough for retroperitoneal liposarcoma (RPLS), which is highly invasive and has few effective treatment options other than tumor resection. However, the heterogeneity of the tumor immune microenvironment (TIME) leads to missed clinical diagnosis and inappropriate treatment. Therefore, it is crucial to evaluate whether the TIME of a certain part of the tumor reliably represents the whole tumor, particularly for very large tumors, such as RPLS.

METHODS

We conducted a prospective study to evaluate the TIME in different regions of dedifferentiated RPLS (DDRPLS) by detecting the expressions of markers such as CD4+, CD8+, Foxp3+, CD20+, CD68+, LAMP3+, PD-1+ tumor-infiltrating lymphocytes (TILs), and PD-L1 in tumors and corresponding paratumor tissues via immunohistochemistry and RNA sequencing.

RESULTS

In DDRPLS, very few TILs were observed. Differentially expressed genes were significantly enriched in cell part and cell functions, as well as the metabolic pathway and PI3K-Akt signaling pathway. In addition, for most tumors (70-80%), the TIME was similar in different tumor regions.

CONCLUSIONS

For most tumors (70-80%), the TIME in any region of the tumor reliably represents the whole tumor. DDRPLS may regulate cell functions by modulating the metabolic and PI3K-Akt signaling pathways to promote its malignant behavior.

Correlation Analysis Between Demographic, Surgical, and Pathological Characteristics with Local Recurrence-Free Survival for Surgical Resected Retroperitoneal Liposarcoma

BACKGROUND

As the leading cause of mortality for retroperitoneal liposarcoma (RPLS) cases, postoperative recurrence has complicated and unclear risk factors. This study was conducted to explore the correlations between demographic, surgical, and pathological characteristics with local recurrence-free survival (LRFS) for surgical resected RPLS.

METHODS

RPLS cases that underwent radical operation were considered to be included in this analysis. LRFS rates were estimated based on the Kaplan-Meier method and were compared between groups by the log-rank test. Cox proportional hazard regression models were constructed to identified the predictors of LRFS. Subsequently, the independent predictors acquired from multivariate analyses were used to construct a nomogram.

RESULTS

348 RPLS cases who underwent radical operation were included. Of the 348 cases, 333 had tumor recurrence or with a follow-up period ≥5 years. Thus, 296 (88.9%) of the 333 cases had recurrent disease, and the median LRFS duration of 296 recurrence cases was 17.0 (95% confidence interval (CI) 13.2-20.8) months. Multivariate analysis identified the preoperative neutrophil/lymphocyte ratio (NLR), surgical frequency, operative time, tumor shape, histological subtype, and tumor necrosis as independent predictors of LRFS. Based on above independent predictors, a nomogram was constructed to predict the 1-, 3-, and 5-year LRFS of surgical resected RPLS.

CONCLUSION

Elevated preoperative NLR, ≥2nd time surgical frequency, extended operation time, irregular tumor shape, no well-differentiated histological subtype, and tumor necrosis could be used as predictors of LRFS for surgical resected RPLS.

Predictive factors and a novel nomogram for recurrence of primary retroperitoneal liposarcoma: Comprehensive analysis of 128 cases

Since primary retroperitoneal liposarcoma (PRPLS) is rare in the clinic, related clinical studies are lacking. The present study was designed to investigate the predictive factors of short-term (≤1 year) recurrence (STR) and construct a novel nomogram of local recurrence-free survival (LRFS) for surgically resected PRPLS. A total of 128 PRPLS cases who underwent radical surgery were retrospectively analyzed. Based on the interval from the operation to tumor recurrence, the predictors of STR were screened using univariate and multivariate logistic regression analyses. Cox proportional hazard regression models were applied to identify the predictors of LRFS. Furthermore, the independent predictors acquired from multivariate analyses were used to construct a nomogram. Multivariate logistic regression analysis revealed that age ≥55 years [odds ratio (OR)=5.607, P=0.010], operative time ≥260 min (OR=9.716, P=0.005) and tumor necrosis (OR=3.781, P=0.037) were independent risk factors of STR for PRPLS. In the Cox regression analysis, clinical symptoms [hazard ratio (HR)=1.746, P=0.017], resection method (OR=0.370, P=0.021) and de-differentiated histological subtype (HR=1.975, P=0.048) were identified as independent predictors of LRFS. Subsequently, the independent predictors acquired from multivariate analyses were used to construct a nomogram for LRFS. Age, operative time, tumor necrosis, clinical symptoms, resection method and histological subtype were related to recurrence for surgically resected PRPLS and a novel nomogram was constructed based on the above predictors.

Sarcopenia is associated with worse surgical complications but not relapse-free survival and overall survival in patients with retroperitoneal liposarcoma

OBJECTIVE

This investigation aimed to explore the relationship between sarcopenia and severe postoperative complications, relapse-free survival (RFS), and overall survival (OS) in patients with retroperitoneal liposarcoma (RLPS).

MATERIAL AND METHODS

This retrospective study included 72 RLPS patients (47 men, 25 women; mean age, 57.49 years, SD 10.92) who had abdominal CT exams. Clinical information was recorded, including RLPS characteristics (histologic subtypes, grade, size), laboratory assessment (ALB, PALB, A/G, Hb, SCr), relapse-free survival, overall survival, and postoperative complications. The relationships between those variables and RFS and OS were analyzed using Cox proportional hazard models.

RESULTS

There were 8 severe postoperative complications (Clavien-Dindo grade > 2). The chi-square test showed sarcopenia was associated with severe postoperative complications (P = 0.011). In multivariate analysis, sarcopenia was not associated with relapse-free survival (P = 0.574) and overall survival (P = 0.578).

CONCLUSIONS

Sarcopenia predicts worse surgical complications but does not affect relapse-free survival and overall survival.

Development and Validation of a Prognostic Model to Predict the Prognosis of Patients With Retroperitoneal Liposarcoma: A Large International Population-Based Cohort Study

Background

Retroperitoneal liposarcomas (RPLs), sarcoma of mesenchymal origin, are the most common soft tissue sarcomas (STS) of the retroperitoneum. Given the rarity of RPLs, the prognostic values of clinicopathological features in the patients remain unclear. The nomogram can provide a visual interface to aid in calculating the predicted probability that a patient will achieve a particular clinical endpoint and communication with patients.

Methods

We included a total of 1,392 RPLs patients diagnosed between 2004 and 2015 from the Surveillance, Epidemiology, and End Results (SEER) database. For nomogram construction and validation, patients in the SEER database were divided randomly into the training cohort and internal validation cohort at a ratio of 7:3, while 65 patients with RPLs from our center between 2010 and 2016 served as the external validation cohort. The OS curves were drawn using the Kaplan-Meier method and assessed using the log-rank test. Moreover, Fine and Gray's competing-risk regression models were conducted to assess CSS. Univariate and multivariate analyses were performed to select the prognostic factors for survival time. We constructed a predictive nomogram based on the results of the multivariate analyses.

Results

Through univariate and multivariate analyses, it is found that age, histological grade, classification, SEER stage, surgery constitute significant risk factors for OS, and age, classification, SEER stage, AJCC M stage, surgery, and tumor size constitute risk factors for CSS. We found that the nomogram provided a good assessment of OS and CSS at 1, 3, and 5 years in patients with RPLs (1-year OS: (training cohort: AUC = 0.755 (95% CI, 0.714, 0.796); internal validation cohort: AUC = 0.754 (95% CI, 0.681, 0.827); external validation cohort: AUC = 0.793 (95% CI, 0.651, 0.935)); 3-year OS: (training cohort: AUC = 0.782 (95% CI, 0.752, 0.811); internal validation cohort: AUC = 0.788 (95% CI, 0.736, 0.841); external validation cohort: AUC = 0.863 (95% CI, 0.773, 0.954)); 5-year OS: (training cohort: AUC = 0.780 (95% CI, 0.752, 0.808); internal validation cohort: AUC = 0.783 (95% CI, 0.732, 0.834); external validation cohort: AUC = 0.854 (95% CI, 0.762, 0.945)); 1-year CSS: (training cohort: AUC = 0.769 (95% CI, 0.717, 0.821); internal validation cohort: AUC = 0.753 (95% CI, 0.668, 0.838); external validation cohort: AUC = 0.799 (95% CI, 0.616, 0.981)); 3-year CSS: (training cohort: AUC = 0.777 (95% CI, 0.742, 0.811); internal validation cohort: AUC = 0.787 (95% CI, 0.726, 0.849); external validation cohort: AUC = 0.808 (95% CI, 0.673, 0.943)); 5-year CSS: (training cohort: AUC = 0.773 (95% CI, 0.741, 0.805); internal validation cohort: AUC = 0.768 (95% CI, 0.709, 0.827); external validation cohort: AUC = 0.829 (95% CI, 0.712, 0.945))). The calibration plots for the training, internal validation, and external validation cohorts at 1-, 3-, and 5-year OS and CSS indicated that the predicted survival rates closely correspond to the actual survival rates.

Conclusion

We constructed and externally validated an unprecedented nomogram prognostic model for patients with RPLs. The nomogram can be used as a potential, objective, and supplementary tool for clinicians to predict the prognosis of RPLs patients around the world.

Case Report: Retroperitoneal Sarcoma in Six Operations: Our Experience in Operative Management of Blood Vessels

Here we introduce a case of retroperitoneal liposarcoma, which is characterized by repeated recurrences after surgery, and has undergone a total of 6 operations. The diameter of the tumor was about 26 cm at the time of the patient's diagnosis. The imaging examination revealed that the surrounding organs and blood vessels were invaded, which brought great challenges to radical resection. The postoperative pathology of the patient’s first operation was dedifferentiated liposarcoma, and some areas showed myxofibrosarcoma differentiation. With the recurrence of sarcoma, myxofibrosarcoma dedifferentiated into rhabdomyosarcoma, and malignant fibrous histiocytoma appeared in some areas. How to treat this type of patient after recurrence? How to deal with blood vessels wrapped by sarcoma during surgery? The medical community has not yet reached the same conclusion. We describe the process of treating the patient and the experience of dealing with blood vessels during surgery.

Management of retroperitoneal sarcoma involving the iliac artery: Single-center surgical experience

BACKGROUND

Management of retroperitoneal sarcoma (RPS) involving the iliac artery is challenging and requires the concerted efforts of multidisciplinary team (MDT) members during surgical treatment.

AIM

To summarize the clinicopathologic features of RPS involving the iliac artery and our retroperitoneal soft tissue tumor MDT surgical experience.

METHODS

In this retrospective study, 15 patients with RPS involving the iliac artery who underwent surgery at our retroperitoneal soft tissue tumor center from July 2004 to June 2020 were analyzed. Statistical analyses were performed by Student’s t-test with SPSS 16.0.

RESULTS

Complete tumor resection (R0/R1) and iliac artery reconstruction were achieved in all 15 patients. All the operations were successful, with no serious complications or perioperative death. Resection with bilateral iliac artery reconstruction required a higher intraoperative blood transfusion volume than resection with unilateral iliac artery reconstruction. Recurrent cases were more likely to bleed and required a higher blood transfusion volume than primary cases. As of January 2021, 11 patients were alive, and 4 had died. Local recurrence occurred in two patients, one of whom developed liver metastasis.

CONCLUSION

Resection of RPS involving iliac vessels is feasible and effective when performed by MDT members. Iliac artery oncovascular resection and reconstruction are key to a successful operation. Adequate blood preparation is important for successful completion of surgery.