Leiomyosarcoma: One disease or distinct biologic entities based on site of origin?

Phase Ib Study of Unesbulin (PTC596) Plus Dacarbazine for the Treatment of Locally Recurrent, Unresectable or Metastatic, Relapsed or Refractory Leiomyosarcoma

PURPOSE

This multicenter, single-arm, open-label, phase Ib study was designed to determine the recommended phase II dose (RP2D) and to evaluate the safety and preliminary efficacy of unesbulin plus dacarbazine (DTIC) in patients with advanced leiomyosarcoma (LMS).

PATIENTS AND METHODS

Adult subjects with locally advanced, unresectable or metastatic, relapsed or refractory LMS were treated with escalating doses of unesbulin orally twice per week in combination with DTIC 1,000 mg/m2 intravenously (IV) once every 21 days. The time-to-event continual reassessment method was used to determine the RP2D on the basis of dose-limiting toxicities (DLTs) assessed during the first two 21-day treatment cycles. All explored doses of unesbulin (200 mg up to 400 mg) were in combination with DTIC. An expansion cohort was enrolled to evaluate the safety and efficacy of unesbulin at the RP2D.

RESULTS

Unesbulin 300 mg administered orally twice per week in combination with DTIC 1,000 mg/m2 IV once every 21 days was identified as the RP2D. On the basis of data from 27 subjects who were deemed DLT-evaluable, toxicity was higher in the unesbulin 400 mg group, with three of four subjects (75%) experiencing DLTs versus one of four subjects (25%) in the 200 mg group and three of 19 subjects (15.8%) in the 300 mg group. The most commonly reported DLTs and treatment-related grade 3 and 4 adverse events were thrombocytopenia and neutropenia. At the RP2D, seven subjects who were efficacy evaluable achieved partial response for an objective response rate of 24.1%.

CONCLUSION

Unesbulin 300 mg twice per week plus DTIC 1,000 mg/m2 once every 21 days was identified as the RP2D, demonstrating a favorable benefit-risk profile in a heavily pretreated population of adults with advanced LMS.

A novel nomogram and recursive partitioning analysis for predicting cancer-specific survival of patients with subcutaneous leiomyosarcoma

Accurately predicting prognosis subcutaneous leiomyosarcoma (LMS) is crucial for guiding treatment decisions in patients. The objective of this study was to develop prediction models for cancer-specific survival (CSS) in patients with subcutaneous LMS. The collected cases of diagnosed subcutaneous LMS were randomly divided into a training cohort and a validation cohort at a 6:4 ratio based on tumor location and histological code. The X-tile program was utilized to determine the optimal cutoff points for age index. Univariate and Cox multivariate regression analyses were conducted to identify independent risk factors for subcutaneous LMS patients. Nomograms were constructed to predict CSS, and their performance was assessed using C-index and calibration plots. Additionally, a decision tree model was established using recursive partitioning analysis to determine the total score for CSS prediction in subcutaneous LMS patients based on the nomogram model. A total of 1793 patients with subcutaneous LMS were found. X-tile software divides all patients into ≤ 61 years old, 61-82 years old, and ≥ 82 years old. The most important anatomical sites were the limbs (including the upper and lower limbs, 48.0%). Only 6.2% of patients received chemotherapy, while 44% had a history of radiotherapy and 92.9% underwent surgery. The independent risk factors for patients with subcutaneous LMS were age, summary stage, grade, and surgery. CSS was significantly decreased in patients with distant metastases, which showed the highest independent risk predictor (HR 4.325, 95% CI 3.010-6.214, p < 0.001). The nomogram prediction model of LMS was constructed based on four risk factors. The C-index for this model was 0.802 [95% CI 0.781-0.823] and 0.798 [95% CI 0.768-0.829]. The training cohort's 3-, 5-, and 10-year AUCs for CSS in patients with subcutaneous LMS were 0.833, 0.830, and 0.859, and the validation cohort's AUC for predicting CSS rate were 0.849, 0.830, and 0.803, respectively. Recursive segmentation analysis divided patients into 4 risk subgroups according to the total score in the nomogram, including low-risk group < 145, intermediate-low-risk group ≥ 145 < 176, intermediate-high-risk group ≥ 176 < 196, and high-risk group ≥ 196; The probability of the four risk subgroups is 9.1%, 34%, 49%, and 79% respectively. In this retrospective study, a novel nomogram or corresponding risk classification system for patients with subcutaneous LMS were developed, which may assist clinicians in identifying high-risk patients and in guiding the clinical decision.

Leiomyosarcoma in the extremities and trunk wall: systematic review and meta-analysis of the oncological outcomes

Background

Leiomyosarcomas are aggressive malignancies which can occur on the trunk and extremities whose pathogenesis is poorly understood. We aim to quantify the prognostic impact of various clinical and pathological markers on survival and recurrence of leiomyosarcomas.

Methods

We conducted a systematic review as per PRISMA protocol. Survival, local recurrence, and metastasis were the outcome measures. Data were extracted from the studies for the outcome variables; the resultant odds ratios (OR) and 95% confidence interval (CI) were used for the synthesis of a forest plot.

Results

Our search revealed thirteen studies comprising 1380 patients. Seven of these 13 publications were since 2012. Our analysis showed that tumor size larger than 5 cm adversely affected the outcome with an OR 3.39 (2.26–5.10, p < 0.01). Other factors which reduced the overall survival were positive margins of excision OR 2.12 (1.36–3.32, p < 0.01). A reduced risk of metastasis has strongly associated the use of radiotherapy with OR 10.84 (4.41–26.61, p < 0.01). Only a few studies analyzed the impact of factors on local recurrence.

Conclusions

Size larger than 5 cm and positive margins of excision are associated with poor overall survival. In comparison, the use of adjuvant radiotherapy was associated with a lower metastatic rate. There is a need for methodically high-quality studies with more uniform study design and reporting to evaluate the impact of various risk factors on local recurrence and metastases.

Level of evidence

Level 1 Prognostic

Comparison of clinical features and outcomes of patients with leiomyosarcoma of bone and soft tissue: a population-based cohort study

BACKGROUND

Leiomyosarcoma commonly occurs in soft tissue but rarely in the bone. Whether leiomyosarcoma of bone and soft tissue have similar clinical characteristics and outcomes remains unknown.

METHODS

This retrospective analysis was based on data from the Bone and Soft Tissue Tumor Registry in Japan. Patients with leiomyosarcoma of bone and soft tissue were enrolled. Overall survival and distant metastasis-free survival were estimated using the Kaplan-Meier method, and the Cox regression model was used to identify the prognostic factors.

RESULTS

A total of 888 patients (60 leiomyosarcoma of bone and 828 leiomyosarcoma of soft tissue) were included in the study. Clinical characteristics were similar between the two groups, except for younger age in leiomyosarcoma of bone than in leiomyosarcoma of soft tissue (median 56 years vs. 66 years, P < 0.0001). To evaluate the prognostic factors and efficacy of adjuvant chemotherapy, data of localized and locally curative cases were extracted (total 572: 33 leiomyosarcoma of bone and 539 leiomyosarcoma of soft tissue). The 5-year overall survival rates of leiomyosarcoma of bone and soft tissue patients were similar (63.8% vs. 75.2%, P = 0.43); the 5-year distant metastasis-free survival tended to be worse in leiomyosarcoma of bone than in leiomyosarcoma of soft tissue (37.4% vs. 57.9%, P = 0.28). Larger tumor size (≥5 cm) and older age (≥65 years) correlated with poor overall survival in leiomyosarcoma of soft tissue patients. Adjuvant chemotherapy tended to prolong the overall survival of both leiomyosarcoma of bone (P = 0.11) and leiomyosarcoma of soft tissue patients with tumor size >10 cm (P = 0.06).

CONCLUSIONS

The clinical characteristics and outcomes of leiomyosarcoma of bone and soft tissue patients were similar. In localized cases, adjuvant chemotherapy may improve the survival of leiomyosarcoma of bone and soft tissue patients with large-size tumor.

Epigenetic signatures differentiate uterine and soft tissue leiomyosarcoma

Leiomyosarcomas (LMS) are diverse, rare, and aggressive mesenchymal soft tissue sarcomas. Epigenetic alterations influence multiple aspects of cancer, however epigenetic profiling of LMS has been limited. The goal of this study was to delineate the molecular landscape of LMS for subtype-specific differences (uterine LMS (ULMS) vs soft tissue LMS (STLMS)) based on integrated analysis of DNA methylation and gene expression to identify potential targets for therapeutic intervention and diagnosis. We identified differentially methylated and differentially expressed genes associated with ULMS and STLMS using DNA methylation and RNA-seq data from primary tumors. Two main clusters were identified through unsupervised hierarchical clustering: ULMS-enriched cluster and STLMS-enriched cluster. The integrated analysis demonstrated 34 genes associated with hypermethylation of the promoter CpG islands and downregulation of gene expression in ULMS or STLMS. In summary, these results indicate that differential DNA methylation and gene expression patterns are associated with ULMS and STLMS. Further studies are needed to delineate the contribution of epigenetic regulation to LMS subtype-specific gene expression and determine the roles of the differentially methylated and differentially expressed genes as potential therapeutic targets or biomarkers.

Leiomyosarcoma of the urinary bladder: A SEER database study and comparison to leiomyosarcomas of the uterus and extremities/trunk

No well-established staging system exists for bladder leiomyosarcoma (LMS), and the current staging system does not include tumor size, a thoroughly validated prognostic parameter for sarcomas. Uterine and extremity/trunk LMS are more common than those in the bladder and have well-established staging systems incorporating tumor size. We aim to improve the understanding of LMS of the urinary bladder by assessing cancer-specific survival (CSS) and comparing LMS at this unusual anatomic site to those arising at other sites using the Surveillance, Epidemiology, and End Results (SEER) database. The SEER database (1973-2013) was queried for bladder, uterus, and trunk/extremity LMS. Multivariable Cox proportional hazard regression was performed to identify predictors of CSS for each anatomic location and used to compare outcomes at different sites. We identified 165 bladder, 4987 uterus, and 2536 extremity/trunk LMS cases. Five-year CSS was 52% for uterus, 73% for bladder, and 82% for extremity/trunk LMS. For LMS at all sites, uterine location (HR = 2.14, P < 0.001) and increasing tumor size (HR = 1.05, P < 0.001) were significant predictors of worse CSS on multivariate analysis. For bladder LMS, increasing tumor size (HR = 1.18, P = 0.003) was an independent prognostic factor and the conventional staging cut-off threshold of 5 cm for sarcomas outside the head/neck showed statistical significance in stratifying patient risk of cancer-related death. Bladder LMS appears to have clinical behavior intermediate between those of the extremities/trunk and uterus. We suggest that the conventional sarcoma staging protocols based on tumor size be applied to LMS of the urinary bladder.

The Medical Device Applied to Uterine Fibroids Morcellation: Analysis of Critical Biological Issues and Drawbacks from A Medical-Legal Prospective

Following the FDA safety communication of 2014 increasing attention has been to the treatment of uterine fibroids, due to the suspicion of a potential leiomyosarcoma (ULM). FDA banned the use of power morcellation in the US, since this technique is likely to spread malignant cells from an unsuspected ULM. We criticized the medical legal consequences of this banning among gynecologists and patients, focusing on the drawbacks of biology and surgery. The authors analyzed literature data on one side, on the incidence, diagnosis and treatment of leiomyoma and ULM, and the other side, on the power morcellations and related critical issues, trying to highlight their main controversial aspects and to outline the possible impact on patients and on medical responsibility. The alternative methods to power morcellation are more invasive surgical solutions (as mini laparotomy or culdotomy), which inevitably involve associated risks with the surgical procedure as such and always request the containing bags. Although the in-bag morcellation is a promising technique, currently the used devices are largely off-label. This highlights the surgical risk, in case of complications, of suffering for malpractice claims both for not having used a containment system, favoring the spread of the neoplasm, and for its off-label use. Since the diagnosis of ULM is by histology after surgery, the fear of legal consequences or medical malpractice for unknown ULM power morcellation, should be targeted to analyze, in terms of cost/benefit ratio, the surgical priority. It should focus on the prevention of the risk of having a rare and statistically limited ULM or on the surgical-related complications, often linked to a slowdown minimally invasive surgery, or on the use of the authorized in-bag morcellations.

Hepatic metastases from primary extremity leiomyosarcomas: Two case reports

INTRODUCTION

Leiomyosarcoma is a highly malignant soft tissue sarcoma. Most leiomyosarcomas of the extremities metastasize initially to the lungs, with few metastasizing to the liver. Also, it is difficult to diagnose metastases to other regions of the lung during follow-up.

CASE PRESENTATION

The first patient was a 51-year-old Japanese woman diagnosed with a leiomyosarcoma of the left distal femur. She underwent chemotherapy, followed by wide tumor excision and reconstruction using frozen autograft with total knee arthroplasty. Eleven months later, a focal lesion was observed in her right liver, despite the absence of lung metastases. Partial hepatic resection was performed, and the hepatic lesion was diagnosed a metastasis of leiomyosarcoma. Two years later, there has been no evidence of local recurrence. The second patient was a 60-year-old Japanese male diagnosed with a leiomyosarcoma of the left thigh. He underwent preoperative chemotherapy followed by wide excision. Three years later, a focal lesion was found in his medial liver, despite the absence of lung metastases. Partial hepatic resection was performed, and the hepatic lesion was diagnosed as a metastasis of leiomyosarcoma. At the latest follow-up, there has been no evidence of local recurrence.

CONCLUSIONS

The lung is the most common site of metastases from leiomyosarcomas of the extremeties, because these metastases are hematogenous. Both our patients presented with metastases of the liver, despite the absence of lung metastases. Hepatic metastasis is commonly found in computed tomography (CT) scan. Periodic CT scans of the chest and abdomen are necessary in following-up patients who undergo resection of primary leiomyosarcomas of the extremities.

Emerging Opportunities for Target Discovery in Rare Cancers

Rare cancers pose unique challenges to research due to their low incidence. Barriers include a scarcity of tissue and experimental models to enable basic research and insufficient patient accrual for clinical studies. Consequently, an understanding of the genetic and cellular features of many rare cancer types and their associated vulnerabilities has been lacking. However, new opportunities are emerging to facilitate discovery of therapeutic targets in rare cancers. Online platforms are allowing patients with rare cancers to organize on an unprecedented scale, tumor genome sequencing is now routinely performed in research and clinical settings, and the efficiency of patient-derived model generation has improved. New CRISPR/Cas9 and small-molecule libraries permit cancer dependency discovery in a rapid and systematic fashion. In parallel, large-scale studies of common cancers now provide reference datasets to help interpret rare cancer profiling data. Together, these advances motivate consideration of new research frameworks to accelerate rare cancer target discovery.

Molecular Targets and Emerging Therapeutic Options for Uterine Leiomyosarcoma

Uterine leiomyosarcoma (uLMS) is an aggressive malignancy characterized by its early metastasis, high rates of recurrence, and poor prognosis. Multiple obstacles complicate the clinical management of uLMS. These include the fact that most uLMS are typically identified only after a woman has undergone hysterectomy or myomectomy, the limited efficacy of adjuvant therapy for early stage disease, and the poor response of metastatic disease to current treatments. Here, we discuss recent insights into the molecular basis of uLMS and discuss emerging options for its clinical management. Particular attention is given to the biologic basis of these strategies with the goal of understanding the rationale motivating their use.