Different approaches to advanced soft tissue sarcomas depending on treatment line, goal of therapy and histological subtype

A morphological mimic: An NTRK3-rearranged spindle cell neoplasm presenting as a groin mass

Neurotrophic receptor tyrosine kinase (NTRK)-rearranged spindle cell neoplasms are a recently described group of soft tissue tumors. They commonly present as a painless mass on the extremities of children and young adults. They are characterized microscopically by a heterogeneous spectrum of infiltrative spindle cell proliferations, which can morphologically mimic several other spindle cell neoplasms. Their identification is vital, as they may be amenable to treatment with tyrosine kinase-targeted therapy. This case report describes a rare NTRK3-rearranged spindle cell neoplasm in the groin of a 29-year-old female and provides further clinical and morphological features of this entity.

Early phase trials in soft-tissue sarcomas: clinical benefit of inclusion in early lines of treatment, molecular screening, and histology-driven trials

BACKGROUND

The prognosis of patients with advanced soft-tissue sarcomas (STS) remains dismal, and systemic therapeutic options are limited. Early phase trials are becoming increasingly safe and effective. This study aimed to identify the prognostic factors for progression-free survival (PFS).

PATIENTS AND METHODS

This retrospective analysis included all STS patients participating in early phase trials at Gustave Roussy and Léon Bérard between 1 January 2012 and 31 December 2020.

RESULTS

Overall, 199 patients accounted for 214 inclusions in advanced STS. The most frequent histotypes were well-differentiated/dedifferentiated liposarcomas (n = 55), leiomyosarcomas (n = 53), synovial sarcomas (n = 22), undifferentiated pleomorphic sarcomas (n = 15), angiosarcomas (n = 12), and myxoid liposarcomas (n = 10). The median PFS was 2.8 months (95% confidence interval 2.7-4.1 months). The median PFS in the first, second, and later lines was 8.3, 5.4, and 2.6 months, respectively (P = 0.00015). The median PFS was 2.8 months in case of molecular screening, 4.1 months in case of histology-driven screening, and 1.6 months (P = 0.00014) in the absence of either screening modalities. In univariate analysis, histotype (P = 0.026), complex genomics (P = 0.008), number of prior lines (P < 0.001), prior anthracyclines (P < 0.001), number of metastatic sites (P = 0.003), liver metastasis (P < 0.001), lung metastasis (P < 0.001), absence of molecular or histology-driven screening (P < 0.001), first-in-human trials (P < 0.001), dose-escalation cohorts (P = 0.011), and Royal Marsden Hospital (RMH) score >1 (P < 0.001) were significantly associated with shorter PFS. In multivariate analysis, independent prognostic factors for shorter PFS were myxoid liposarcoma (P = 0.031), ≥2 prior lines of treatment (P = 0.033), liver metastasis (P = 0.007), and RMH score >2 (P = 0.006). Factors associated with improved PFS were leiomyosarcomas (P = 0.010), molecular screening (P = 0.025), and histology-driven screening (P = 0.010). The median overall survival rates were 36.3, 12.6, and 9.2 months in the first, second, and later lines, respectively (P = 0.0067). The grade 3-4 toxicity rate was 36%.

CONCLUSIONS

Early phase trials provide an active therapeutic option for STS, even in first-line settings. Molecular screening and histology-driven trials further improve the clinical benefit.

Case Report: Adult NTRK-Rearranged Spindle Cell Neoplasm: Early Tumor Shrinkage in a Case With Bone and Visceral Metastases Treated With Targeted Therapy

Background

NTRK (neurotrophic tyrosine receptor kinase)-rearranged spindle cell neoplasms are a new group of tumors included in the new 5^th edition of the World Health Organization (WHO) classification of soft Tissue and Bone Sarcomas. These tumors are characterized by NTRK gene fusions and show a wide spectrum of histologies and clinical behavior. Several targeted therapies have recently been approved for tumors harboring NTRK fusions, including STS.

Case Presentation

A 26-year-old male with advanced, pretreated NTRK rearranged spindle cell neoplasm and liver, lung and bone metastases was treated with larotrectinib on a continuous 28-day schedule, at a dose of 100 mg twice daily. An ¹⁸FDG-PET/CT scan performed after 7 days of treatment showed tumor shrinkage in both visceral and bone lesions. There was no drug-related toxicity. Subsequent evaluations confirmed continued tumor regression in disease sites. The patient is well and continues treatment.

Conclusion

The clinical and radiological response of our patient with an uncommon TPM4 (exon 7)-NTRK1 (exon 12) gene fusion tumor treated with a first-generation TRK inhibitor could contribute to a better understanding of the biology of this new STS entity and help to improve patient management.

A DNA damage repair gene-associated signature predicts responses of patients with advanced soft-tissue sarcoma to treatment with trabectedin

Predictive biomarkers of trabectedin represent an unmet need in advanced soft‐tissue sarcomas (STS). DNA damage repair (DDR) genes, involved in homologous recombination or nucleotide excision repair, had been previously described as biomarkers of trabectedin resistance or sensitivity, respectively. The majority of these studies only focused on specific factors (ERCC1, ERCC5, and BRCA1) and did not evaluate several other DDR‐related genes that could have a relevant role for trabectedin efficacy. In this retrospective translational study, 118 genes involved in DDR were evaluated to determine, by transcriptomics, a predictive gene signature of trabectedin efficacy. A six‐gene predictive signature of trabectedin efficacy was built in a series of 139 tumor samples from patients with advanced STS. Patients in the high‐risk gene signature group showed a significantly worse progression‐free survival compared with patients in the low‐risk group (2.1 vs 6.0 months, respectively). Differential gene expression analysis defined new potential predictive biomarkers of trabectedin sensitivity (PARP3 and CCNH) or resistance (DNAJB11 and PARP1). Our study identified a new gene signature that significantly predicts patients with higher probability to respond to treatment with trabectedin. Targeting some genes of this signature emerges as a potential strategy to enhance trabectedin efficacy.

Grossing and reporting of a soft tissue tumor specimen in surgical pathology: Rationale, current evidence, and recommendations

Soft tissue tumors, including sarcomas are complex and diagnostically challenging tumors. This is as a result of their heterogeneity and overlapping clinicopathological, immunohistochemical and also molecular features, the latter to some extent. More than 80 types of sarcoma have been described. Current management, which is best offered at centers with active multidisciplinary care, is based on balancing oncologic and functional outcomes in such cases. This has transcended into the types of specimens received for grossing these rather uncommon tumors. Over the years, diagnostic specimens have reduced in their sizes from, open biopsies to core needle biopsies. These specimens need to be adequately and judiciously triaged for ancillary techniques, such as molecular testing. Conservative surgeries have led to resected specimens for marginal assessment. Lately, post neoadjuvant (chemotherapy or radiation therapy)-treated resection specimens of soft tissue sarcomas are being submitted for surgical pathology reporting. This article focuses on the grossing of soft tissue tumors, including sarcomas, in terms of types of specimens, grossing techniques including rationale, tissue triage, reporting, and recommendations from the surgical pathologists actively engaged in reporting musculoskeletal tumors, based on current evidence.