A phase II trial of temozolomide as a 6-week, continuous, oral schedule in patients with advanced soft tissue sarcoma

Phase II Study of Olaparib and Temozolomide for Advanced Uterine Leiomyosarcoma (NCI Protocol 10250)

PURPOSE

Uterine leiomyosarcoma (uLMS) is an aggressive subtype of soft-tissue sarcoma with frequent metastatic relapse after curative surgery. Chemotherapy provides limited benefit for advanced disease. Multiomics profiling studies have identified homologous recombination deficiency in uLMS. In preclinical studies where olaparib and temozolomide provided modest activity, the combination was highly effective for inhibiting uLMS tumor growth.

PATIENTS AND METHODS

NCI Protocol 10250 is a single-arm, open-label, multicenter, phase II study evaluating olaparib and temozolomide in advanced uLMS. Patients with progression on ≥1 prior line received temozolomide 75 mg/m2 orally once daily with olaparib 200 mg orally twice a day both on days 1-7 in 21-day cycles. The primary end point was the best objective response rate (ORR) within 6 months. A one-stage binomial design was used. If ≥5 of 22 responded, the treatment would be considered promising (93% power; α = .06). All patients underwent paired biopsies that were evaluated with whole-exome sequencing (WES)/RNAseq and a RAD51 foci formation assay.

RESULTS

Twenty-two patients were evaluable. The median age was 55 years, and 59% had received three or more prior lines. Best ORR within 6 months was 23% (5 of 22). The overall ORR was 27% (6 of 22). The median progression-free survival (mPFS) was 6.9 months (95% CI, 5.4 months to not estimable). Hematologic toxicity was common (grade 3/4 neutropenia: 75%; thrombocytopenia: 32%) but manageable with dose modification. Five of 16 (31%) of tumors contained a deleterious homologous recombination gene alteration by WES, and 9 of 18 (50%) were homologous recombination-deficient by the RAD51 assay. In an exploratory analysis, mPFS was prolonged for patients with homologous recombination-deficient versus homologous recombination-proficient tumors (11.2 v 5.4 months, P = .05) by RAD51.

CONCLUSION

Olaparib and temozolomide met the prespecified primary end point and provided meaningful clinical benefit in patients with advanced, pretreated uLMS.

Soft Tissue Sarcoma, Version 2.2022, NCCN Clinical Practice Guidelines in Oncology

Soft tissue sarcomas (STS) are rare malignancies of mesenchymal cell origin that display a heterogenous mix of clinical and pathologic characteristics. STS can develop from fat, muscle, nerves, blood vessels, and other connective tissues. The evaluation and treatment of patients with STS requires a multidisciplinary team with demonstrated expertise in the management of these tumors. The complete NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Soft Tissue Sarcoma provide recommendations for the diagnosis, evaluation, and treatment of extremity/superficial trunk/head and neck STS, as well as retroperitoneal/intra-abdominal STS, desmoid tumors, and rhabdomyosarcoma. This portion of the NCCN Guidelines discusses general principles for the diagnosis and treatment of retroperitoneal/intra-abdominal STS, outlines treatment recommendations, and reviews the evidence to support the guidelines recommendations.

Anti-cancer activity of the combination of cabozantinib and temozolomide in uterine sarcoma

PURPOSE

To evaluate the anti-cancer effects of cabozantinib, temozolomide, and their combination in uterine sarcoma cell lines and mouse xenograft models.

EXPERIMENTAL DESIGN

Human uterine sarcoma cell lines (SK-LMS-1, SK-UT-1, MES-SA, and SKN) were used to evaluate the anti-cancer activity of cabozantinib, temozolomide, and their combination. The optimal dose of each drug was determined by MTT assay. Cell proliferation and apoptosis were assessed 48 hours and 72 hours after the drug treatments. The tumor weights were measured in an SK-LMS-1 xenograft mouse model and a patient-derived xenograft (PDX) model of leiomyosarcoma treated with cabozantinib, temozolomide, or both.

RESULTS

Given individually, cabozantinib and temozolomide each significantly decreased the growth and viability of cells. This inhibitory effect was more pronounced when cabozantinib (0.50 µM) and temozolomide (0.25 mM or 0.50 mM) were co-administered (p-value < 0.05). The combination of the drugs also significantly increased apoptosis in all cells. Moreover, this effect was consistently observed in patient-derived leiomyosarcoma cells. In vivo studies with SK-LMS-1 cell xenografts and the PDX model with leiomyosarcoma demonstrated that combined treatment with cabozantinib (5 mg/kg/day, per os administration) and temozolomide (5 mg/kg/day, per os administration) synergistically decreased tumor growth (both p-values < 0.05).

CONCLUSION

The addition of cabozantinib to temozolomide offers synergistic anti-cancer effects in uterine sarcoma cell lines and xenograft mouse models, including PDX. These results warrant further investigation in a clinical trial.

Efficacy and Safety of Epirubicin Combined with Temozolomide for Treatment of Advanced Leiomyosarcoma

BACKGROUND

Leiomyosarcoma (LMS) accounts for 24% of all soft tissue sarcomas (STSs) and this STS subtype has high metastatic potential. Previous studies indicated the best median progression-free survival (mPFS) time was 9.2 months and the best overall response rate (ORR) was 30.9%. We evaluated the efficacy and safety of epirubicin combined with temozolomide (EPI-TMZ) for treatment of advanced LMS.

METHODS

This was a retrospective review of the records of patients with advanced LMS at the National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College. All patients initiated EPI-TMZ treatment between January 2018 and December 2020.

RESULTS

We examined 15 patients who received EPI-TMZ for LMS. This was a first-line treatment in 6 patients, a second- or third-line treatment in 7 patients, and a fourth-line treatment in 2 patients. At the time of data cutoff (April 25, 2021), the median PFS was 10 months, 1 patient had clinical complete response (cCR), 7 had partial response (PR), and 7 had stable disease (SD). The overall response rate (ORR) was 53.3% (8/15) and the disease control rate (DCR) was 100.0% (15/15). The most common treatment-related adverse effects were leukopenia, neutropenia, thrombocytopenia, anemia, nausea, vomiting, fatigue, and oral mucositis. One patient had severe adverse effect (febrile neutropenia), but there were no treatment-related deaths.

CONCLUSION

EPI-TMZ is potentially effective for treatment of advanced LMS, and the adverse effects appear tolerable. EPI-TMZ provided better outcomes than reported in previous studies of other treatments for advanced LMS.

Establishment of Patient-Derived Succinate Dehydrogenase-Deficient Gastrointestinal Stromal Tumor Models for Predicting Therapeutic Response

PURPOSE

Gastrointestinal stromal tumor (GIST) is the most common sarcoma of the gastrointestinal tract, with mutant succinate dehydrogenase (SDH) subunits (A-D) comprising less than 7.5% (i.e., 150-200/year) of new cases annually in the United States. Contrary to GISTs harboring KIT or PDGFRA mutations, SDH-mutant GISTs affect adolescents/young adults, often metastasize, and are frequently resistant to tyrosine kinase inhibitors (TKI). Lack of human models for any SDH-mutant tumors, including GIST, has limited molecular characterization and drug discovery.

EXPERIMENTAL DESIGN

We describe methods for establishing novel patient-derived SDH-mutant (mSDH) GIST models and interrogated the efficacy of temozolomide on these tumor models in vitro and in clinical trials of patients with mSDH GIST.

RESULTS

Molecular and metabolic characterization of our patient-derived mSDH GIST models revealed that these models recapitulate the transcriptional and metabolic hallmarks of parent tumors and SDH deficiency. We further demonstrate that temozolomide elicits DNA damage and apoptosis in our mSDH GIST models. Translating our in vitro discovery to the clinic, a cohort of patients with SDH-mutant GIST treated with temozolomide (n = 5) demonstrated a 40% objective response rate and 100% disease control rate, suggesting that temozolomide represents a promising therapy for this subset of GIST.

CONCLUSIONS

We report the first methods to establish patient-derived mSDH tumor models, which can be readily employed for understanding patient-specific tumor biology and treatment strategies. We also demonstrate that temozolomide is effective in patients with mSDH GIST who are refractory to existing chemotherapeutic drugs (namely, TKIs) in clinic for GISTs, bringing a promising treatment option for these patients to clinic.

Targeted therapy in SDH-deficient GIST

The medical management of advanced gastrointestinal stromal tumors (GIST) has improved with the development of tyrosine kinase inhibitors (TKIs) targeting KIT and PDGFRA mutations. However, approximately 5-10% of GIST lack KIT and PDGFRA mutations, and about a half are deficient in succinate dehydrogenase (SDH) that promotes carcinogenesis by the cytoplasmic accumulation of succinate. This rare group of GIST primarily occurs in the younger patients than other subtypes, and is frequently associated with hereditary syndromes. The role of TKIs in patients with SDH-deficient GIST is controversial, with conflicting results; thus, there is an urgent need to uncover the disease mechanisms, treatment patterns, and responses to systemic therapy among these patients. Here, based on an extensive literature search, we have provided a rigorous overview of the current evidence on the medical treatment of SDH-deficient GIST.

Oral metronomic chemotherapy is a cost effective alternative to pazopanib in advanced soft tissue sarcoma

INTRODUCTION

Soft tissue sarcoma(STS) is a rare and heterogeneous group of disorders with dismal outcomes in metastatic setting. Pazopanib and oral metronomic chemotherapy (OMT) have been evaluated as therapeutic options in this cohort.

MATERIALS AND METHODS

We conducted a retrospective, single center study evaluating 45 patients with unresectable and/or metastatic STS, who received pazopanib or oral metronomic regimen as per instituitonal protocol between January 2013 and December 2019. An informal cost minimisation analysis was conducted for both OMT and pazopanib arms, considering equivalent outcomes for both (PFS and OS).

RESULTS

Median PFS in OMT and Pazopanib groups was 4.13 months and 3.53 months,respectively (HR1.31, 95% CI:0.68-2.51, p = 0.41) Only one patient in the OMT group achieved an objective response (partial response) and no objective response was noted in the pazopanib group. The incidence of grade III/IVtoxicities was higher with pazopanib than with OMT (p = 0.08). There were no toxicity related deaths noted in either arm.

CONCLUSIONS

Our study demonstrates that OMT have a similar progression free survival (PFS) and overall survival (OS) in metastatic STS. This study raises the possibility that OMT might be an equally efficacious and less toxic alternative to pazopanib, without compromising survival outcome especially in LMIC.

Metastatic Myxofibrosarcoma with Durable Response to Temozolomide Followed by Atezolizumab: A Case Report

Myxofibrosarcoma (MFS) is a well-recognized histotype of soft tissue sarcomas that generally presents with localized disease. Herein, we describe the case of a patient with metastatic MFS who experienced durable response to sixth-line therapy with temozolomide. Upon further progression, his tumor was notable for a high tumor mutational burden, and he was subsequently treated with seventh-line immunotherapy, atezolizumab, achieving a second durable response. This case highlights the role of immunotherapy after administration of alkylating agents. Review of the literature indicates that recurrent tumors treated with alkylating agents often experience hypermutation as a means of developing resistance and that checkpoint inhibitors are subsequently effective in these tumors. KEY POINTS: To the authors' knowledge, this is the first report of a patient with myxofibrosarcoma with high tumor mutational burden after administration of temozolomide monotherapy. Hypermutation may be a resistance mechanism for patients with soft tissue sarcoma who develop resistance to alkylating agents. Checkpoint inhibition may be effective therapy in patients with soft tissue sarcoma with high tumor mutational burden as a consequence of alternate systemic therapy resistance.

Eribulin Regresses a Doxorubicin-resistant Dedifferentiated Liposarcoma in a Patient-derived Orthotopic Xenograft Mouse Model

BACKGROUND/AIM

Dedifferentiated liposarcoma (DDLPS) is recalcitrant type of sarcoma. DDLPS has a low survival rate with high recurrence and metastasis. In the present study, we evaluated the efficacy of several drugs against doxorubicin-resistant DDLPS in a patient-derived orthotopic xenograft (PDOX) model for precision oncology. To establish the PDOX model, a tumor from a patient who had recurrent high-grade DDLPS from the retroperitoneum was previously grown orthotopically in the retroperitoneum of nude mice.

MATERIALS AND METHODS

We randomized DDLPS PDOX models into 8 treatment groups when tumor volume became approximately 100 mm³: control, no treatment; G2, doxorubicin (DOX); G3, pazopanib (PAZ); G4, gemcitabine (GEM) combined with docetaxel (DOC); G5, trabectedin (YON); G6, temozolomide (TEM); G7, palbociclib (PAL); G8, eribulin (ERB). Tumor length and width were measured both at the beginning and at the end of treatment.

RESULTS

At the end of treatment (day 14), all treatments significantly inhibited DDLPS PDOX tumor growth compared to the untreated control, except DOX. ERB was significantly more effective and regressed tumor volume compared to other treatments on day 14 after initiation of treatment. No significant differences were found in the relative body weight on day 14 compared to day 0 in any group.

CONCLUSION

The clinical potential of ERB against DDLPS is herein presented in a PDOX model.

Multi-omics analysis of copy number variations of RNA regulatory genes in soft tissue sarcoma

AIMS

RNA regulatory genes were closely associated with tumorigenesis and prognosis in multiple tumors. Copy number variation (CNV) is a frequent characteristic in soft tissue sarcomas (STS). However, little is known regarding their possible roles in STS.

MAIN METHODS

RNA sequence profiles and CNV data of 255 STS patients were downloaded from the Cancer Genome Atlas (TCGA). The correlation analysis involved CNVs of RNA regulatory genes, patient survival, immune infiltration, and DNA methylation. Drug sensitivity (IC50) was analyzed and validated by MTT assays in STS cell lines.

KEY FINDINGS

CNV events were frequently observed in all kinds (m6A, m5C, ac4C, m1A, m3C, m6Am, m7G, and Ψ) of RNA regulatory genes. Diploid copy number (CN) of METTL4 was associated with better overall survival (OS) in STS and the subtypes (leiomyosarcoma, LMS; dedifferentiated liposarcoma, DDLPS). In STS and LMS, diploid CN of METTL4 was significantly associated with higher infiltration fraction of resting mast cells. In STS and DDLPS, diploid CN of METTL4 possessed lower methylation level in CpG site of cg12105018, which represented better OS. Besides, sensitive drugs for STS cell lines were analyzed according to lower IC50 for the loss CN of METTL4. Temozolomide and Olaparib were identified. Further validation by MTT assays demonstrated that GCT was the most sensitive cell line to both Temozolomide and Olaparib.

SIGNIFICANCE

CNV of METTL4 could be a prognostic biomarker for STS by potentially influencing mast cell infiltration and DNA methylation. Besides, STS with loss CN of METTL4 would be sensitive to Temozolomide and Olaparib.

Abnormal MGMT Promoter Methylation in Gastrointestinal Stromal Tumors: Genetic Susceptibility and Association with Clinical Outcome

Purpose

KIT/PDGFRA wild-type (WT) gastrointestinal stromal tumors (GISTs) represent a heterogeneous subgroup of GISTs that lack KIT or PDGFRA mutations and possess distinct genetic alterations and primary resistance to imatinib. Succinate dehydrogenase (SDH)-deficient GISTs comprise the largest subpopulation of WT GISTs that are characterized by loss-of-function of SDH. O6-methylguanine-DNA methyltransferase (MGMT) is a specific DNA repair enzyme that has been identified as a predictor of positive treatment response to alkylating agents in a variety of cancers. The aim of this study was to evaluate the expression of MGMT and the prevalence of MGMT promoter methylation in GISTs and to determine the association between MGMT promoter methylation and clinicopathological characteristics and clinical outcomes.

Patients and Methods

A heterogeneous cohort of 137 primary GISTs that confirmed by immunohistochemistry and KIT/PDGFRA mutation analysis were retrospectively selected and analyzed for MGMT expression and MGMT promoter methylation using immunohistochemical staining and methylation-specific PCR (MSP). A concordance analysis between MGMT promoter methylation and clinicopathological characteristics and prognosis was also performed.

Results

A total of 44.5% (65/137) of GIST patients displayed loss of MGMT protein expression, and 10.9% (15/137) of these patients exhibited MGMT promoter methylation. However, no significant correlation was observed between the loss of MGMT protein expression and MGMT promoter methylation. WT GISTs possessing an epithelioid or mixed phenotype, particularly those that were SDH-deficient, displayed a markedly higher prevalence of MGMT promoter methylation compared to that in KIT/PDGFRA mutated GISTs. Moreover, MGMT promoter methylation was identified as a potential independent prognostic factor for OS and DFS in patients with GIST.

Conclusion

MGMT promoter methylation is particularly frequent in SDH-deficient GISTs and in WT GISTs possessing an epithelioid/mixed phenotype, and knowledge of this methylation status may offer a novel potential therapeutic option for WT GISTs.

Current management of succinate dehydrogenase-deficient gastrointestinal stromal tumors

Gastrointestinal stromal tumors (GISTs) are increasingly recognized as having diverse biology. With the development of tyrosine kinase inhibitors molecularly matched to oncogenic KIT and PDGFRA mutations, GISTs have become a quintessential model for precision oncology. However, about 5-10% of GIST lack these driver mutations and are deficient in succinate dehydrogenase (SDH), an enzyme that converts succinate to fumarate. SDH deficiency leads to accumulation of succinate, an oncometabolite that promotes tumorigenesis. SDH-deficient GISTs are clinically unique in that they generally affect younger patients and are associated with GIST-paraganglioma hereditary syndrome, also known as Carney-Stratakis Syndrome. SDH-deficient GISTs are generally resistant to tyrosine-kinase inhibitors, the standard treatment for advanced or metastatic GIST. Thus, surgical resection is the mainstay of treatment for localized disease, but recurrence is common. Clinical trials are currently underway investigating systemic agents for treatment of advanced SDH-deficient GIST. However, further studies are warranted to improve our understanding of SDH-deficient GIST disease biology, natural history, surgical approaches, and novel therapeutics.

Succinate Dehydrogenase-Deficient Gastrointestinal Stromal Tumors: Small Steps Toward Personalized Medicine?

Various molecular triggers define heterogeneous subsets of gastrointestinal stromal tumors (GISTs), differing in clinical behavior and drug sensitivity. KIT/PDGFRA-wild-type GISTs, including those succinate dehydrogenase (SDH)-deficient, are overall unresponsive to the tyrosine kinase inhibitors commonly used, fostering the development of specific alternative therapeutic strategies. Epigenetic inactivation of O⁶-methylguanine-DNA methyltransferase (MGMT) through promoter methylation leads to effectiveness of alkylating agents in several human cancers. SDH-deficient GISTs typically feature widespread DNA methylation. However, the actual occurrence of MGMT methylation in these tumors, potentially predisposing them to respond to alkylating drugs, has not been investigated so far. Here we discuss the recent findings concerning the occurrence of MGMT methylation in different GIST subgroups, including SDH-deficient ones, as a premise for a possible reappraisal of alkylating agents specifically targeting these small, otherwise overall chemorefractory, GIST subgroups.

Soft tissue leiomyosarcoma-diagnostics, management, and prognosis: Data of the registry cancer of the center of Tunisia

Background:

Soft tissue leiomyosarcomas are rare, accounting for almost 5%–10% of all soft tissue sarcomas; they account for almost 1% of all sarcomas. They are aggressive tumors where location, size, and management require a multidisciplinary approach. Since there are few series published, we here analyze epidemiological pattern, clinical and pathologic features of soft tissue leiomyosarcomas.

Methods:

We conducted a retrospective study of 29 consecutive cases of histologically proven soft tissue leiomyosarcoma extracted from the database of the Cancer Registry of the Center of Tunisia and the Department of Pathology of Farhat Hached University Hospital of Sousse of Tunisia, during a 10-year period (from January 1996 to December 2005). Epidemiologic details, clinico-pathological features, and treatment modalities were assessed with focus on patients’ 5-year overall survival, tumor relapse, and metastases.

Results:

Soft tissue leiomyosarcoma accounted for 17.5% of all soft tissue sarcomas diagnosed at our pathology department. Most of patients were of advanced age (median: 52 years), with extremes ranging from 12 and 87 years. There was a slight male predominance (sex-ratio = 1.07). Tumors were located mostly in the lower limbs (45%). Deep sites as retroperitoneum was found only in two cases. Tumor size was more than 5 cm in 83% of cases (average size = 9.4 cm). Five cases had metastasis on initial staging. For 24 patients, the disease was locally limited at the moment of diagnosis. Palliative chemotherapy was indicated for four patients and surgery was performed for 20 patients. Local recurrence occurred in 11 patients (55% of operated patients) and metastasis in 6 patients. Overall, 5-year survival was about 24%.

Conclusion:

Our study results highlight the scarcity of soft tissue leiomyosarcoma. Unfortunately, unusual tumor sites, disease’s advanced stages, and intralesional resection made the prognosis poorer than in other series. Clinical course of soft tissue leiomyosarcoma was highly marked by local recurrence and metastasis.

Preferential MGMT methylation could predispose a subset of KIT/PDGFRA-WT GISTs, including SDH-deficient ones, to respond to alkylating agents

BACKGROUND

Succinate dehydrogenase (SDH)-deficient gastrointestinal stromal tumors (GISTs) constitute a small KIT/PDGFRA-WT GIST subgroup featuring DNA methylation which, although pervasive, appears nevertheless not randomly distributed. Although often indolent, these tumors are mostly chemorefractory in aggressive cases. Promoter methylation-induced O⁶-methylguanine DNA methyltransferase (MGMT) inactivation improves the efficacy of alkylating agents in gliomas, colorectal cancer and diffuse large B cell lymphoma. MGMT methylation has been found in some GISTs, without determining SDH status. Thirty-six GISTs were enrolled in past sarcoma trials testing alkylating agents, with negative results. Nevertheless, a possible effect on MGMT-methylated GISTs could have escaped detection, since tested GISTs were neither selected by genotype nor investigated for SDH; MGMT was studied in two cases only, revealing baseline activity; these trials were performed prior to the adoption of Choi criteria, the most sensitive for detecting GIST responses to therapy. Under these circumstances, we investigated whether MGMT methylation is preferentially found in SDH-deficient cases (identified by SDHB immunohistochemistry) by analyzing 48 pathogenetically heterogeneous GISTs by methylation-specific PCR, as a premise for possible investigations on the use of alkylating drugs in these tumors.

RESULTS

Nine GISTs of our series were SDH-deficient, revealing significantly enriched in MGMT-methylated cases (6/9-67%-, vs. 6/39-15%- of SDH-proficient GISTs; p = 0.004). The pathogenetically heterogeneous KIT/PDGFRA-WT GISTs were also significantly MGMT-methylated (11/24-46%-, vs. 1/24-4%- of KIT/PDGFRA-mutant cases, p = 0.002).

CONCLUSIONS

A subset of KIT/PDGFRA-WT GISTs, including their largest pathogenetically characterized subgroup (i.e., SDH-deficient ones), is preferentially MGMT-methylated. This finding could foster a reappraisal of alkylating agents for treating malignant cases occurring among these overall chemorefractory tumors.

A combination of irinotecan/cisplatinum and irinotecan/temozolomide or tumor-targeting Salmonella typhimurium A1-R arrest doxorubicin- and temozolomide-resistant myxofibrosarcoma in a PDOX mouse model

Myxofibrosarcoma (MFS) is the most common sarcomas in elderly patients and is either chemo-resistant or recurs with metastasis after chemotherapy. This recalcitrant cancer in need of improved treatment. We have established a patient-derived orthotopic xenograft (PDOX) of MFS. The MFS PDOX model was established in the biceps femoris of nude mice and randomized into 7 groups of 7 mice each: control; doxorubicin (DOX); pazopanib (PAZ); temozolomide (TEM); Irinotecan (IRN); IRN combined with TEM; IRN combined with cisplatinum (CDDP) and Salmonella typhimurium A1-R (S. typhimurium A1-R). Treatment was evaluated by relative tumor volume and relative body weight. The MFS PDOX models were DOX, PAZ, and TEM resistant. IRN combined with TEM and IRN combined with CDDP were most effective on the MFS PDOX. S. typhimurium A1-R arrested the MFS PDOX tumor. There was no significant body weight loss in any group. The present study suggests that the combination of IRN with either TEM or CDDP, and S. typhimurium have clinical potential for MFS.

Patterns of sensitivity to a panel of drugs are highly individualised for undifferentiated/unclassified soft tissue sarcoma (USTS) in patient-derived orthotopic xenograft (PDOX) nude-mouse models

Undifferentiated/unclassified soft tissue sarcoma (USTS) is a recalcitrant disease; therefore, precise individualised therapy is needed. Toward this goal, we previously established patient-derived orthotopic xenograft (PDOX) models of USTS in nude mice. Here, we determined the extent of uniqueness of drug response in a panel on USTS PDOX models from 5 different patients. We previously showed that 3 of the 5 patients were resistant to doxorubicin (DOX) despite DOX being first-line therapy. Two weeks after orthotopic tumour implantation, PDOX mouse models were randomised into five groups: untreated control, DOX, gem-citabine/docetaxel (GEM/DOC), pazopanib (PAZ), temozolomide (TEM). Three PDOX cases were completely resistant to DOX. TEM had high efficacy for 4 USTS PDOX models, including DOX-resistant cases. GEM/DOC and PAZ were effective in three USTS PDOX. One case was completely resistant to TEM. Two cases were completely resistant to PAZ. The results showed the drug sensitivity pattern for each USTS PDOX was highly individualised and that at least one effective drug could be found for each. The PDOX model could be effective in precise individualised drug sensitivity testing which is especially important for heterogeneous cancers such as USTS, and can give the patient a greater chance to be treated with an effective drug.

Temozolomide post pazopanib treatment failure in patients with advanced sarcoma: A case series

Background

Sarcomas are rare, heterogeneous tumors for which prognosis remains dismal in patients with advanced disease. Pazopanib, a vascular endothelial growth factor receptor inhibitor, has shown modest efficacy in patients with soft tissue sarcoma who fail cytotoxic chemotherapy. The cytotoxic agent temozolomide has also demonstrated activity in patients with advanced sarcoma.

Objective

We performed a retrospective case series to evaluate the feasibility of adding temozolomide to pazopanib in advanced sarcoma patients following single-agent pazopanib failure.

Patients and methods

Patients with recurrent, metastatic sarcomas who had progressed on single-agent pazopanib and continued on pazopanib with the addition of temozolomide were included in this retrospective analysis to examine the tolerability and responses associated with the treatment combination.

Results

Nine patients with a range of sarcoma subtypes were identified (55% female; median age, 48 years; median number of therapies prior to pazopanib, 3). All patients received combination therapy. One patient was recently started on therapy and was excluded from the analysis (n = 8 evaluable patients). Median PFS for single-agent pazopanib was 7.5 months (range 2–19). For the eight evaluable patients (63% female), best response at 4 months with pazopanib plus temozolomide was partial response (n = 1), stable disease (n = 3) and progressive disease (n = 4), with a median PFS of 3.5 months (range 0–15). Median PFS with combination treatment in patients with stable disease or response was 8 months (range 5–15). All four patients who achieved clinical benefit remain on therapy and are tolerating the combination therapy with expected but manageable side effects.

Conclusions

In heavily pretreated patients with advanced sarcoma, the addition of temozolomide to pazopanib was found to be tolerable. Future prospective trials are required to deduce whether temozolomide extends the clinical benefit of pazopanib.

Primary extraskeletal myxoid chondrosarcoma in cerebellum: A case report with literature review

RATIONALE

Extraskeletal myxoid chondrosarcoma (EMC) is a rare malignant neoplasm of which intracranial EMC is the rarest.

PATIENT CONCERNS

We present an unusual case report of a 41-year-old woman who was sent to the emergency department for a sudden headache and other symptoms related to increased intracranial pressure.

INTERVENTIONS

Emergent CT revealed an occupying lesion in the left cerebellum with surrounding edema. A complete surgical excision of the lesion through a transcortical approach was performed. After the operation, this patient received adjuvant radiotherapy and temozolomide treatment.

DIAGNOSES

Pathology diagnosis was an intracranial EMC.

OUTCOMES

The patient survives with no tumor recurrence as of the last follow-up. Progression-free survival exceeded 20 months.

LESSONS

We have reviewed the literature and here summarize the diagnosis and treatment options for intracranial EMC. Diagnosis and treatment options of this rare disease are discussed.

Managing sarcoma: where have we come from and where are we going?

Sarcomas are a heterogeneous group of neoplasms of mesenchymal origin. Approximately 80% arise from soft tissue and 20% originate from bone. To date more than 100 sarcoma subtypes have been identified and they vary in molecular characteristics, pathology, clinical presentation and response to treatment. While sarcomas represent <1% of adult cancers, they account for approximately 21% of paediatric malignancies and thus pose some of the greatest risks of mortality and morbidity in children and young adults. Metastases occur in one-third of all patients and approximately 10-20% of sarcomas recur locally. Surgery in combination with preoperative and postoperative therapies is the primary treatment for localized sarcoma tumours and is the most promising curative possibility. Metastasized sarcomas, on the other hand, are treated primarily with single-agent or combination chemotherapy, but this rarely leads to a complete and robust response and often becomes a palliative form of treatment. The heterogeneity of sarcomas results in variable responses to current generalized treatment strategies. In light of this and the lack of curative strategies for metastatic and unresectable sarcomas, there is a need for novel subtype-specific treatment strategies. With the more recent understanding of the molecular mechanisms underlying the pathogenesis of some of these tumours, the treatment of sarcoma subtypes with targeted therapies is a rapidly evolving field. This review discusses the current management of sarcomas as well as promising new therapies that are currently underway in clinical trials.

Uterine leiomyosarcoma: a review of recent advances in molecular biology, clinical management and outcome

Uterine leiomyosarcoma (LMS) are rare but aggressive tumours with poor clinical outcomes regardless of stage. Most tumours are identified by histopathology at time of surgery, and pre-operative diagnosis remains a clinical challenge. Management of early-stage LMS relies on surgical resection. Cytotoxic chemotherapy remains the mainstay of therapy for advanced-stage, recurrent or metastatic LMS, and includes single or combination doxorubicin-, ifosfamide- or gemcitabine-based regimens. Recent interest in genetic biomarkers led to developments of targeted therapies for LMS, although more research is needed to understand the molecular complexities underlying LMS to guide the development of novel treatment strategies.

TWEETABLE ABSTRACT

The diagnosis and treatment of uterine LMS is challenging. Novel biomarkers offer hope for future therapies.

Systemic Therapy for Advanced Soft Tissue Sarcoma

Soft tissue sarcomas are rare tumors that present with distant metastasis in up to 10% of patients. Survival has improved significantly because of advancements in histologic classification and improved management approaches. Older agents such as doxorubicin, ifosfamide, gemcitabine, and paclitaxel continue to demonstrate objective response rates from 18% to 25%. Newer agents such as trabectedin, eribulin, aldoxorubicin, and olaratumab have demonstrated improvements in progression-free survival, overall survival, or toxicity profiles. Future studies on treatment of advanced soft tissue sarcoma will continue to concentrate on reducing toxicity, personalization of therapy, and targeting novel pathways.

Survival of patients with metastatic leiomyosarcoma: the MD Anderson Clinical Center for targeted therapy experience

Advanced stage leiomyosarcoma (LMS) is incurable with current systemic antitumor therapies. Therefore, there is clinical interest in exploring novel therapeutic regimens to treat LMS. We reviewed the medical records of 75 consecutive patients with histologically confirmed metastatic LMS, who had been referred to the Clinical Center for Targeted Therapy at MD Anderson Cancer Center. To lay the foundation for potential phase I trials for the treatment of advanced LMS, we analyzed tumor response and survival outcome data. The frequent hotspot gene aberrations that we observed were the TP53 mutation (65%) and RB1 loss/mutation (45%) detected by Sequenom or next-generation sequencing. Among patients treated with gene aberration-related phase I trial therapy, the median progression-free survival was 5.8 months and the median overall survival was 15.9 months, significantly better than in patients without therapy (1.9 months, P = 0.001; and 8.7 months, P = 0.013, respectively). Independent risk factors that predicted shorter overall survival included hemoglobin <10 g/dL, body mass index <30 kg/m2 , serum albumin <3.5 g/dL, and neutrophil above upper limit of normal. The median survivals were 19.9, 7.6, and 0.9 months for patients with 0, 1 or 2, and ≥3 of the above risk factors, respectively (P < 0.001). A prognostic scoring system that included four independent risk factors might predict survival in patients with metastatic LMS who were treated in a phase I trial. Gene aberration-related therapies led to significantly better clinical benefits, supporting that further exploration with novel mechanism-driven therapeutic regimens is warranted.

High-grade undifferentiated pleomorphic sarcoma of the pelvis: A case report and review of literature

High-grade spindle cell sarcomas are rare undifferentiated pleomorphic cancers that present a treatment challenge to urological practices, especially when they present in the pelvis. We report a 46-year-old male patient who presented to our urology clinic with urinary retention after having a Foley catheter placed at an outlying facility. A voiding trial was attempted, but the patient failed this trial. This failure resulted in cystoscopy with bilateral retrograde pyelograms, which revealed a compressed bladder due to extrinsic compression. This finding had been evaluated with a computed tomography (CT) scan with and without intravenous contrast that showed a 14 cm pelvic mass with bladder displacement and compression. A fine needle aspiration was done at this outlying facility, prior to referral to our office, and it confirmed spindle cell pathology. The mass was surgically excised with the histology revealing a pelvic spindle cell sarcoma with positive surgical margins. Further, metastatic work-up with CT/positron emission tomography revealed bone and lung metastasis. The patient is currently undergoing chemotherapy and radiation. In this case study, we will review staging, management, differential diagnosis, chemotherapy, and radiation.

The role of adjuvant therapy in uterine leiomyosarcoma

Uterine leiomyosarcoma (uLMS) is a rare mesenchymal tumor of the gynecologic tract. Although diagnosed in only 1-3% of patients with uterine cancer, uLMS accounts for the majority of uterine cancer-related deaths. The standard of care for patients with uLMS includes total hysterectomy and bilateral salpingo-oophorectomy (BSO). There are no standard recommendations regarding adjuvant or palliative therapy. Many cytotoxic and targeted agents have been studied in clinical trials in an effort to identify an effective therapy that may alter the natural history of this disease. Unfortunately, as of now, there are no adjuvant therapy regimens that improve overall survival in this patient population. There is, therefore, an unmet need to identify a novel therapy that will improve the survival of women diagnosed with this aggressive disease. Here we summarize the existing literature on adjuvant therapy in uLMS, specifically highlighting advances made in the last 5 years.

Treatment of Adult Soft Tissue Sarcomas: An Overview

Sarcomas are uncommon malignancies accounting for about 1% of all adult malignancies. Sarcomas are a heterogeneous group of tumors which includes more than 100 different subtypes. Surgery is the mainstay therapy for localized disease. In selected patients the combination of surgery with radiotherapy achieves better local control and offers the best chance of cure. Systemic treatment including cytotoxic chemotherapy or targeted therapies remains the mainstay therapy for most patients with advanced disease. There are a wide variety of clinical situations, such that an individualized treatment plan must be defined by a multidisciplinary tumor board. Treatment decisions should take into consideration the histology, site of disease, stage, performance status, treatment goals, and the patient's wishes. The management of patients should be carried out in a center with expertise in the treatment of sarcomas for optimal outcome. This review will cover the different treatment modalities of adult soft tissue sarcomas.

Effect of temozolomide on the viability of musculoskeletal sarcoma cells

Musculoskeletal sarcomas (MSS) are a heterogeneous group of malignancies with relatively high mortality rates. The prognosis for patients with MSS is poor, with few drugs inducing measurable activity. Alkylating agents, namely ifosfamide and dacarbazine, which act nonspecifically on proliferating cells, are the typical therapy prescribed for advanced MSS. A novel alkylating agent, temozolomide (TMZ), has several advantages over existing alkylating agents. TMZ induces the formation of O⁶-methylguanine in DNA, thereby inducing mismatches during DNA replication and the subsequent activation of apoptotic pathways. However, due to conflicting data in the literature, the mechanism of TMZ action has remained elusive. Therefore, the present study aimed to evaluate apoptosis in MSS cells treated with TMZ, and to evaluate the correlation between TMZ action and survival pathways, including the phosphoinositide 3-kinase (PI3K)/Akt and extracellular signal-regulated kinase (ERK)1/2 mitogen activated protein kinase (MAPK) pathways. Cell proliferation was evaluated by performing an XTT (sodium 3'-[1-(phenylaminocarbonyl)-3,4-tetrazolium]-bis (4-methoxy-6-nitro) benzene sulfonic acid hydrate) assay. Apoptotic morphological changes, for example chromatin condensation, were evaluated by fluorescence confocal microscopy. The expression of the apoptosis-associated proteins caspase-3, poly adenosine diphosphate ribose polymerase (PARP), Akt and ERK1/2, was determined by western blotting. The results of the present study indicated that, in certain MSS cells, the IC₅₀ value was lower than that in TMZ-sensitive U-87 MG cells. Furthermore, TMZ treatment was associated with apoptotic morphological changes and the expression levels of pro-apoptotic cleaved caspase-3 and PARP were also increased in TMZ-treated MSS cells. In addition, the results indicated that PI3K/Akt and ERK1/2 MAPK were constitutively phosphorylated in MSS cells, and phosphorylation of PI3K/Akt was suppressed in certain cells, and maintained in other cells, by TMZ. These observations emphasized the plasticity of MSS cells, and suggested that this plasticity may contribute to the variance in cell sensitivity to TMZ and TMZ-resistance in MSS.

Gynecologic Cancer InterGroup (GCIG) consensus review: uterine and ovarian leiomyosarcomas

OBJECTIVES

The Gynecologic Cancer InterGroup aimed to provide an overview of uterine and ovarian leiomyosarcoma management.

METHODS

Published articles and author experience were used to draft management overview. The draft manuscript was circulated to international members of the Gynecologic Cancer InterGroup for review and comment, and appropriate revisions were made.

RESULTS

The approach to management of uterine and ovarian leiomyosarcoma management is reviewed.

CONCLUSIONS

Uterine and ovarian leiomyosarcomas are rare and aggressive cancers that require specialized expertise for optimal management.

A retrospective chart review of drug treatment patterns and clinical outcomes among patients with metastatic or recurrent soft tissue sarcoma refractory to one or more prior chemotherapy treatments

Background

Limited clinical data on real-world practice patterns are available for patients with metastatic/relapsed soft tissue sarcomas (STS). The primary objective of this study was to evaluate treatment patterns in patients with metastatic/relapsed STS following failure of prior chemotherapy by examining data collected from 2000 to 2011 from a major tertiary academic cancer center in the United States.

Methods

Medical records, including community-based referral records, from a tertiary cancer center for adult patients with metastatic/relapsed STS with confirmed disease progression who commenced second-line treatment between January 1, 2000 and February 4, 2011, and with at least 3 months of follow-up data following second-line treatment initiation, were retrospectively reviewed. Overall survival, time to progression, and clinician-reported tumor response were collected.

Results

A total of 99 patients (leiomyosarcoma, n = 48; synovial cell sarcoma, n = 7; liposarcoma, n = 5; or other histological subtypes, n = 39) received an average of four lines of treatment (maximum of 10). No consistent or dominant regimens were used in each treatment line beyond the second line. Median second-line treatment duration was 4.1 months (95% confidence interval, 3.0–5.0). Overall, 72 of 99 patients (73%) discontinued second-line treatment due to progressive disease. Median progression-free survival from initiation of second-line treatment varied across regimens from 2.0 to 6.6 months (overall median, 5.4 months).

Conclusions

Wide variations in treatment were evident, with no single standard of care for patients with metastatic/relapsed STS. Most patients discontinued second-line treatment due to progressive disease, often receiving additional systemic therapy with other drugs. These data suggest a high unmet need for more efficacious treatment options and improved data collection to guide practice among patients with relapsed/refractory STS.

Uterine leiomyosarcoma with central nervous system metastases

Leiomyosarcoma (LMS) is a rare tumour and comprises 2–3% of all malignant uterus neoplasms [1]. Leiomyosarcoma is characterised by aggressive behaviour, high recurrence rates, and poor overall survival, despite multimodal treatment [3]. Surgery is the main treatment and consists of total abdominal hysterectomy. A randomised trial consisting of 224 patients diagnosed with uterine sarcomas stage I and II showed that adjuvant radiotherapy improves locoregional control. The role of adjuvant chemotherapy is still unclear [1]. Unfortunately, roughly 50% of patients with organ-confined disease will usually develop distant metastasis to lung, peritoneum, liver, pelvic, and para-aortic lymph nodes. Brain metastases are extremely rare [5].

Adjuvant therapy for high-risk soft tissue sarcoma in the adult

OPINION STATEMENT

Adult-type soft tissue sarcomas (STS) are curable in roughly one half of cases. Surgery is the treatment mainstay in patients with localized STS and should be performed in centers that have specific expertise with the disease. Radiation therapy complements surgery in several cases, improving the local control. The value of adjuvant chemotherapy is still debated. There is some evidence, however, backing the notion that adjuvant chemotherapy may add to the systemic control of the disease, and thereby overall survival, in the subgroup of patients with high-risk STS. These patients are those with a high-grade, large, and deep tumor. Unfortunately, benefit is apparent when merging all data generated by several trials performed throughout decades, but it was not confirmed by the largest trials, including one that was recently reported. A confounding factor for large clinical trials is that STS are a family of 50-plus different histological subtypes. It is difficult to perform studies that focus on each of them separately, and subgroup analyses suffer from many limitations. Indeed, some histological types are more sensitive to standard chemotherapy and other are less. Furthermore, some histologies are specifically sensitive to some agents that may be completely inactive in others. A prospective, randomized trial is underway to compare standard neoadjuvant chemotherapy in high-risk STS versus a neoadjuvant regimen that is tailored to different histologies. Some rare histological subtypes (alveolar soft part sarcoma, clear cell sarcoma, extraskeletal myxoid chondrosarcoma, solitary fibrous tumor) have shown promising sensitivity to molecular target agents in the metastatic setting, but the value of these therapies in the adjuvant one has not been studied yet. It is probable that in the future the biological background of the different soft tissue sarcoma subtypes will guide the selection of therapies as well as the setting to deliver them.

Ridaforolimus in advanced or metastatic soft tissue and bone sarcomas

Patient outcomes remain poor for advanced or metastatic soft tissue sarcomas (STS) and bone sarcomas despite a growing number of clinical trials involving single- and multi-agent chemotherapy. mTOR is an intracellular kinase that plays a central role in regulating cell growth, metabolism, survival and proliferation. mTOR inhibitors including temsirolimus, everolimus and ridaforolimus have demonstrated broad anticancer activity. Ridaforolimus is a non-prodrug analog of rapamycin (sirolimus) with conserved affinity for mTOR but improved solubility, stability and bioavailability when compared with sirolimus. Early clinical trials reveal a reproducible and predictable pharmacokinetic profile, a potent, rapid and prolonged target inhibition and an acceptable safety and tolerability profile. Phase II and III trials of ridaforolimus have produced promising clinical activity against advanced sarcomas and will be presented.

Correlation between overall survival and growth modulation index in pre-treated sarcoma patients: a study from the French Sarcoma Group

BACKGROUND

Growth modulation index (GMI), the ratio of two times to progression measured in patients receiving two successive treatments (GMI = TTP2/TTP1), has been proposed as a criterion of phase II clinical trials. Nevertheless, its use has been limited until now.

PATIENTS AND METHODS

We carried out a retrospective multicentre study in soft tissue sarcoma patients receiving a second-line treatment after doxorubicin-based regimens to evaluate the link between overall survival and GMI. Second-line treatments were classified as 'active' according to the EORTC-STBSG criteria (3-month progression-free rate >40% or 6-month PFR >14%). Comparisons used chi-squared and log-rank tests.

RESULTS

The population consisted in 106 men and 121 women, 110 patients (48%) received 'active drugs'. Median OS from the second-line start was 317 days. Sixty-nine patients experienced GMI >1.33 (30.4%). Treatments with 'active drug' were not associated with OS improvement: 490 versus 407 days (P = 0.524). Median OS was highly correlated with GMI: 324, 302 and 710 days with GMI <1, GMI = [1.00-1.33], and GMI >1.33, respectively (P < 0.0001). In logistic regression analysis, the sole predictive factor was the number of doxorubicin-based chemotherapy cycles.

CONCLUSION

GMI seems to be an interesting end point that provides additional information compared with classical criteria. GMI >1.33 is associated with significant OS improvement.

Phase I trial of sorafenib in combination with ifosfamide in patients with advanced sarcoma: a Spanish group for research on sarcomas (GEIS) study

BACKGROUND

This phase I trial assessed safety, pharmacokinetics (PK), dose limiting toxicity (DLT), maximum tolerated dose and recommended dose (RD) of the combination of sorafenib plus ifosfamide in patients with advanced sarcoma.

METHODS

Twelve sarcoma patients (9 soft-tissue, 3 bone sarcoma) were treated with sorafenib plus ifosfamide (starting doses 200 mg bid and 6 g/m(2) respectively). A 3 + 3 dose escalation design with cohorts of 3-6 patients was used. A study to assess the in vitro efficacy of the combination was also conducted.

RESULTS

Three DLTs were observed: fatigue grade 4 with sorafenib 400 mg bid plus ifosfamide 6 g/m(2) and encephalopathy and emesis grade 3 with sorafenib 400 mg bid plus ifosfamide 7.5 g/m(2). Other toxicities included diarrhea, hand-foot syndrome, mucositis, neutropenia, skin rash and thrombocytopenia. There were no relevant effects on PK of sorafenib but an increase in ifosfamide active metabolite 4-hydroxy-ifosfamide was observed. Eight patients achieved stable disease lasting more than 12 weeks. An additive effect was observed in vitro.

CONCLUSIONS

RD was sorafenib 400 mg bid plus ifosfamide 6 g/m(2), allowing administration of active doses of both agents. Limited preliminary antitumor activity was also observed. A phase II study is currently ongoing.

Metronomic chemotherapy for cancer treatment: a decade of clinical studies

PURPOSE

Over the past few years, more and more new selective molecules directed against specific cellular targets have become available for cancer therapy, leading to impressive improvements. In this evolving scenario, a new way of delivering older cytotoxic drugs has also been developing. Many studies demonstrated that several cytotoxic drugs have antiangiogenic properties if administered frequently and at lower doses compared with standard schedules containing maximal tolerated doses (MTD). Such a new strategy, named metronomic chemotherapy, focuses on a different target: the slowly proliferating tumour endothelial cells. About 10 years ago, metronomic chemotherapy was firstly enunciated and hereafter many clinical experiences were published related to almost any cancer disease. This review analyses available studies dealing with metronomic chemotherapy and its combination with several targeted agents in solid tumours.

METHODS

A computerized literature search of MEDLINE was performed using the following search terms: metronomic OR "continuous low dose" AND chemotherapy AND cancer OR solid tumours.

RESULTS

Satisfactory results have been achieved in diverse tumour types, such as breast and prostate cancer or paediatric sarcomas. Moreover, many studies have reported that metronomic chemotherapy determined minimal toxicity compared to MTD chemotherapy. Overall, published series on metronomic schedules are very heterogeneous often reporting on retrospective data, while only very few studies were randomized trials. These limitations still prevent to draw definitive conclusions in diverse tumour types.

CONCLUSIONS

Large well-designed studies are eagerly awaited for confirming the promises of metronomic schedules and their combinations with targeted molecules.

Long lasting clinical response to chemotherapy for advanced uterine leiomyosarcoma: a case report

Introduction

Uterine leiomyosarcoma is one of the most frequent uterine sarcomas. In the metastatic setting it is sensitive to doxorubicin, ifosfamide, gemcitabine, docetaxel and a few other drugs, but time to progression is generally short. For this reason prognosis is often poor and there are few reports in the literature of long responders.

Case presentation

We report a case of a 40-year-old Caucasian woman with metastatic uterine leiomyosarcoma who began treatment six years before the presentation of this case report and for the following six years underwent ten lines of chemotherapy, achieving excellent results and a good quality of life. Among the treatments administered we observed a long response to temolozomide, an unconventional drug for this kind of disease.

Conclusion

Although there are few chemotherapeutic options for the management of metastatic uterine leiomyosarcoma, a small number of patients have an unexpected long lasting response to treatment. For this reason further research is needed to identify new therapeutic agents and the predictive factors for the achievement of response.

Pazopanib in the treatment of soft tissue sarcoma

Patients with advanced metastatic soft tissue sarcoma (STS) have a poor prognosis, and in the last two decades of the 20th century their overall survival has remained unchanged. Improved treatments are needed for these patients and for preventing metastases in earlier stages of disease. Numerous novel agents and new combination regimens are undergoing clinical testing in STS. Some of these agents show promising activity. Pazopanib is one such agent that has undergone Phase II and III evaluations in advanced STS. Pazopanib is a multi-tyrosine kinase inhibitor, blocking various signaling pathways, thereby preventing angiogenesis and metastasis, and inhibiting tumor cell growth and survival. In a Phase II study, pazopanib demonstrated activity in patients with advanced leiomyosarcomas, synovial sarcomas and other eligible STSs. This activity was confirmed in a Phase III trial, where pazopanib significantly extended the median progression-free survival versus placebo in a variety of STS subtypes.

O6-methylguanine-DNA methyltransferase (MGMT) promoter methylation is a rare event in soft tissue sarcoma

Background

Gene silencing of O6-methylguanine–DNA methyltransferase (MGMT) by promoter methylation improves the outcome of glioblastoma patients after combined therapy of alkylating chemotherapeutic agents and radiation. The purpose of this study was to assess the frequency of MGMT promoter methylation in soft tissue sarcoma to identify patients eligible for alkylating agent chemotherapy such as temozolomide.

Findings

Paraffin tumor blocks of 75 patients with representative STS subtypes were evaluated. The methylation status of the MGMT promoter was assessed by methylation-specific polymerase-chain-reaction analysis (PCR). Furthermore, immunohistochemistry was applied to verify expression of MGMT. MGMT gene silencing was assumed if MGMT promoter methylation was present and the fraction of tumor cells expressing MGMT was 20% or less. Methylation specific PCR detected methylated MGMT promoter in 10/75 cases. Immunohistochemical staining of nuclear MGMT was negative in 15/75 cases. 6/75 tumor samples showed MGMT promoter methylation and negative immunohistochemical nuclear staining of MGMT. In none of the tested STS subtypes we found a fraction of tumors with MGMT silencing exceeding 22%.

Conclusion

MGMT gene silencing is a rare event in soft tissue sarcoma and cannot be recommended as a selection criterion for the therapy of STS patients with alkylating agents such as temozolomide.

Multimodality therapy for metastatic sarcomas confined to the lung

Metastectomy or resection of sarcomas which have metastasized to the lung from other sites has a long and established history. At present, there are more than forty different drugs with activity in soft tissue sarcomas. A number of sarcomas demonstrate differential sensitivities to chemotherapy and targeted agents. Intimate knowledge of the biological behavior of each distinct type of sarcoma should predicate what treatment or protocol is most suitable. Certain patients might benefit from either neoadjuvant or adjuvant therapy following the resection of metastatic lesions. Much remains to be learned about the differential sensitivities of various sarcomas to different treatment regimens.

The promoter methylation and expression of the O6-methylguanine-DNA methyltransferase gene in uterine sarcoma and carcinosarcoma

O6-methylguanine-DNA methyltransferase (MGMT) gene promoter hypermethylation is observed in a number of solid tumors and is correlated with the silencing of MGMT expression. In glioblastoma patients treated with the alkylating agent temozolomide, MGMT gene methylation status was shown to have predictive value in terms of prolonged overall survival. Recently, temozolomide has demonstrated promising activity in the treatment of soft tissue sarcomas, including those of the uterus. The tissue specimens involving tumor samples and normal uterine fragments were obtained from nine patients with smooth muscle uterine sarcoma, 11 with stromal uterine sarcoma and 17 with mixed uterine tumors. MGMT gene promoter methylation was analyzed by combined bisulfite restriction analysis (COBRA) while its expression levels were assessed using the real-time reverse transcription polymerase chain reaction (qRT-PCR). MGMT promoter methylation was observed in 27% of all tumor samples analyzed. When stratified by the disease type, 55.5% (5/9) of smooth muscle sarcomas, 23.5% (4/17) of mixed uterine tumor tissues and 9% (1/11) of stromal sarcomas showed MGMT methylation. The MGMT promoter methylation was associated with lower levels of gene expression in tumors when compared with those with an unmethylated promoter (P=0.0232) or normal tissues (P=0.0141). To conclude, MGMT promoter methylation and downregulation of gene expression is observed in a fraction of carcinosarcomas and non-epithelial malignant tumors of corpus uteri. The assessment of MGMT promoter methylation status may potentially identify patients who would benefit from temozolomide treatment.