Building the Evidence for Systemic Treatment in Desmoid Fibromatosis: Is a New Metronomic Regimen Another Layer in the Foundation?

@Thalcin explains how a metronomic regimen for desmoid tumors fits in the current treatment landscape.

Evaluation of Metronomic Therapy as a Low-Cost, Sustainable, Standard-of-Care Option in Desmoid Fibromatosis: Real-World Data From a Tertiary Care Center in India.

PURPOSE: Desmoid fibromatosis (DF) is a locally aggressive tumor with low mortality but significant morbidity. There is a lack of standard of care, and existing therapies are associated with significant barriers including access, cost, and toxicities. This study aimed to explore the efficacy and safety of the metronomic therapy (MT) in DF in a large, homogenous cohort from India. PATIENTS AND METHODS: This study involved histologically confirmed DF cases treated with MT comprising vinblastine (6 mg) and methotrexate (15 mg) both once a week, and tamoxifen (40 mg/m2) in two divided doses once daily between 2002 and 2018. RESULTS: There were 315 patients with a median age of 27 years; the commonest site was extremity (142 of 315; 45.0%). There were 159 (50.1%) male patients. Of the 123 (39.0%) prior treated patients, 119 had surgery. Of 315 patients, 263 (83.5%) received treatment at our institute (MT-151, 77-local treatment, 9-tyrosine kinase inhibitor, and 26 were observed). Among the MT cohort (n = 163, 61.2%), at a median follow-up of 36 (0.5-186) months, the 3-year progression-free and overall survival were 81.1% (95% CI, 74.3 to 88.4) and 99.2% (95% CI, 97.6 to 100), respectively. There were 35% partial responses. Ninety-two patients (56.4%) completed 1-year therapy, which was an independent prognosticator (P < .0001; hazard ratio, 0.177 [95% CI, 0.083 to 0.377]). MT was well tolerated. Predominant grade ≥3 toxicities were febrile neutropenia, 12 (7.4%) without any chemotoxicity-related death. The annual cost of MT was $130 US dollars. CONCLUSION: The novel, low-cost MT qualifies as one of the effective, less toxic, sustainable, standard-of-care options for the treatment of DF with global reach and merits wide recognition.

Superficial fibromas with CTNNB1 mutation.

Superficial fibromas are a group of mesenchymal spindle cell lesions with pathomorphological heterogeneity and diverse molecular backgrounds. In part, they may be indicators of an underlying syndrome. Among the best-known entities of superficial fibromas is Gardner fibroma, a plaque-like benign tumor, which is associated with APC germline mutations and occurs in patients with familial adenomatosis polyposis (Gardner syndrome). Affected patients also have an increased risk to develop desmoid fibromatosis (DTF), a locally aggressive neoplasm of the deep soft tissue highly prone to local recurrences. Although a minority of DTFs occur in the syndromic context and harbor APC germline mutations, most frequently their underlying molecular aberration is a sporadic mutation in Exon 3 of the CTNNB1 gene. Up to date, a non-syndromic equivalent to Gardner fibroma carrying a CTNNB1 mutation has not been defined. Here, we present two cases of (sub-)cutaneous tumors with a hypocellular and collagen-rich Gardner fibroma-like appearance and pathogenic, somatic CTNNB1 mutations. We aim to differentiate these tumors from other fibromas according to their histological appearance, immunohistochemical staining profile and underlying somatic CTNNB1 mutations. Furthermore, we distinguish them from locally aggressive desmoid fibromatosis regarding their biological behavior, prognosis and indicated therapeutic strategies. Consequently, we call them CTNNB1-mutated superficial fibromas as a sporadic counterpart lesion to syndromic Gardner fibromas.

[Posterior Mediastinal Desmoid Tumor Suspected to be a Neurogenic Tumor Before Surgery:Report of a Case].

A man in his 50s who presented an abnormal shadow on chest X-ray was diagnosed with posterior mediastinal tumor that had grown compared to the previous chest X-ray. Computed tomography showed a 5.7×3.9 cm solid mass with a smooth surface in the posterior mediastinum. A neurogenic tumor was suspected, and the mediastinal tumor was resected through thoracotomy because it was strongly adherent. The postoperative course was good, and he was discharged from the hospital on postoperative day 3. Contrary to preoperative expectations, the tumor was pathologically diagnosed as a desmoid tumor. After 6 months postoperatively without any complications, no recurrence was observed.

Desmoid fibromatosis-a diagnostic dilemma.

PURPOSE: Desmoid fibromatosis in head and neck is infrequent and poses a significant challenge to the clinicians due to its non-specific characteristics. METHODS: This case report focuses on a 69-year-old male who presented to a tertiary healthcare center in Karnataka, India with a swelling in the oral cavity. RESULTS: Despite initial suspicions of malignancy based on clinical examination and findings on computed tomography imaging, subsequent histopathology and immunohistochemistry revealed an unexpected finding. CONCLUSION: The case highlights the importance of clinical suspicion and histopathological evaluation as well as the need for greater awareness to facilitate early diagnosis and appropriate management of desmoid fibromatosis. We also present a literature review of varied presentations of desmoid tumors afflicting various subsites of the head and neck.

Utility of LEF1 to differentiate desmoid fibromatosis from its histologic mimics.

Diagnosis of desmoid-type fibromatosis (DF) may be challenging on biopsy due to morphologic overlap with reactive fibrosis (scar) and other uniform spindle cell neoplasms. Evaluation of nuclear ß-catenin, a surrogate of Wnt pathway activation, is often difficult in DF due to weak nuclear expression and high background membranous/cytoplasmic staining. Lymphoid enhancer-factor 1 (LEF1) is a recently characterized effector partner of ß-catenin which activates the transcription of target genes. We investigated the performance of LEF1 and ß-catenin immunohistochemistry in a retrospective series of 156 soft tissue tumors, including 35 DF, 3 superficial fibromatosis, and 121 histologic mimics (19 soft tissue perineurioma, 8 colorectal perineurioma, 4 intraneural perineurioma, 26 scars, 23 nodular fasciitis, 6 low-grade fibromyxoid sarcomas, 6 angioleiomyomas, 5 neurofibromas, 5 dermatofibrosarcoma protuberans, 3 low-grade myofibroblastic sarcomas, 3 synovial sarcomas, 3 inflammatory myofibroblastic tumors, 2 schwannomas, and 1 each of Gardner-associated fibroma, radiation-associated spindle cell sarcoma, sclerotic fibroma, dermatofibroma, and glomus tumor). LEF1 expression was not only seen in 33/35 (94%) of DF but also observed in 19/23 (82%) nodular fasciitis, 7/19 (37%) soft tissue perineurioma, 2/3 (66%) synovial sarcoma, and 6/26 (23%) scar, as well as in 1 radiation-associated spindle cell sarcoma. The sensitivity and specificity of LEF1 IHC for diagnosis of DF were 94% and 70%, respectively. By comparison, ß-catenin offered similar sensitivity, 94%, but 88% specificity. Positivity for LEF1 and ß-catenin in combination showed sensitivity of 89%, lower than the sensitivity of ß-catenin alone (94%); however, the combination of both LEF1 and ß-catenin improved specificity (96%) compared to the specificity of ß-catenin alone (88%). Although LEF1 has imperfect specificity in isolation, this stain has diagnostic utility when used in combination with ß-catenin.

[A Case of Desmoid-Type Fibromatosis of the Mesentery of Small Intestine].

Desmoid-type fibromatosis is a relatively rare disease, often associated with familial adenomatous polyposis and a history of abdominal surgery. A 43-year-old male patient presented with abdominal pain and contrast-enhanced CT showed a mass in the lower abdomen. The mass was a 4×4×3 cm white, dense tumor with a wreath-like arrangement of eosinophilic spindle-shaped cells. Immunostaining showed KIT(-), CD34(-), desmin(-), ß-catenin(+), SMA(few+), and the diagnosis was desmoid-type fibrosis. Six months after surgery, there was no apparent recurrence.

Nirogacestat: First Approval.

Nirogacestat (OGSIVEO™) is an oral, selective, reversible, small molecule γ-secretase inhibitor developed by SpringWorks Therapeutics, Inc. γ-Secretase is a multi-subunit protease complex that cleaves multiple transmembrane protein complexes, including Notch and membrane-bound B-cell maturation antigen (BCMA). Inhibition of γ-secretase may result in growth inhibition of tumour cells overexpressing Notch, and preservation of membrane-bound BCMA may increase target density for BCMA-targeted therapy. In November 2023, nirogacestat was approved in the USA for use in adult patients with progressing desmoid tumours who require systemic treatment. This article summarizes the milestones in the development of nirogacestat leading to this first approval for the systemic treatment of desmoid tumours.

Clinical Activity of TGF-ß Inhibitor Vactosertib in Combination with Imatinib in Desmoid Tumors: A Multicenter Phase Ib/II Study.

PURPOSE: The study was to determine the activity and safety of the TGF-ß inhibitor vactosertib in combination with imatinib in patients with desmoid tumors. PATIENTS AND METHODS: In this investigator-initiated, open-label, multicenter, phase Ib/II trial, patients with desmoid tumors not amenable to locoregional therapies (surgery and/or radiotherapy) or with disease progression following at least one treatment were enrolled. Participants were administered 400 mg imatinib daily in combination with vactosertib (5 days on and 2 days off, twice a day) every 28 days. In phase Ib, the vactosertib dose was set at 100 mg (level -1) and 200 mg (level 1) to determine the recommended phase II dose (RP2D). Phase II assessed the efficacy, with the primary endpoint being progression-free rate (PFR) at 16 weeks. RESULTS: No dose-limiting toxicities were observed during phase Ib; therefore RP2D was defined at doses of 400 mg imatinib daily in combination with 200 mg vactosertib. Of the 27 patients evaluated, 7 (25.9%) achieved a confirmed partial response and 19 (70.4%) were stable. The PFR at 16 weeks and 1 year were 96.3% and 81.0%, respectively. Most toxicities were mild to moderate myalgia (n = 10, 37%), anemia (n = 10, 37%), and nausea (n = 9, 33.3%). Common grade 3 to 4 toxicities included neutropenia (n = 6, 22.2%) and anemia (n = 5, 18.5%). CONCLUSIONS: The vactosertib and imatinib combination was well tolerated, with promising clinical activity in patients with progressive, locally advanced desmoid tumors. This is the first study investigating a novel target agent, a TGF-ß inhibitor, in this rare and difficult-to-treat desmoid tumor.

Giant Intrathoracic Desmoid Tumor - a Case Report.

Desmoid tumors are soft tissue neoplasms arising from fascial and muscle-aponeurotic structure. These tumors are locally aggressive and have a high recurrence rate, even after complete resection. We present the case of a female with a giant intrathoracic desmoid tumor. She underwent complete surgical resection with no disease recurrence. Desmoid tumors' natural history is not well defined and is often enigmatic, making these tumors difficult to manage. Currently, for intrathoracic desmoid tumors, medical treatment is the recommended approach, nevertheless, surgery can be considered in selected patients.

18F-FDG PET/CT and 99mTc-MDP Bone Scintigraphy Findings of Multifocal Desmoid Fibromatosis.

ABSTRACT: Desmoid fibromatosis, also called desmoid tumors, is a group of locally aggressive fibromatous proliferative disorders. They represent less than 3% of all soft tissue sarcoma and are multifocal in approximately 10% of cases. However, there are only a few cases in the literature describing 18F-FDG PET/CT and 99mTc-MDP bone scan features of extra-abdominal desmoid fibromas, and all were solitary bone lesions. Herein, we presented a unique case of multifocal desmoid fibromatosis of bone illustrating the prospective value of 18F-FDG PET/CT and 99mTc-MDP bone scan in the evaluation of desmoid tumors.

Volume-based 18F-FDG PET/CT predicts prognosis and outcome of active surveillance for intra-abdominal desmoid tumor.

PURPOSE: Desmoid tumor (DT) is a rare monoclonal, fibroblastic proliferation characterized by a variable and often unpredictable clinical course. Initial active surveillance is recommended by current guideline, and surgery is one of the main therapies for DT. Predicting the prognosis and outcome of active surveillance for intra-abdominal DT is pressing issue. METHODS: The study included eighteen patients with intra-abdominal DT. Metabolic tumor volume (MTV), total lesion glycolysis (TLG), and maximum standardized uptake value (SUVmax) were measured. We analyzed their relationship with the outcome of active surveillance, as well as clinical, prognostic, and pathological data. RESULTS: The MTV and TLG of recurrent DT were significantly higher than those of non-recurrent DT (P < 0.001 and P = 0.00, respectively). The ROC curve suggested that the appropriate cutoff values for distinguishing recurrent DT from non-recurrent DT were 760.8 for MTV (sensitivity = 1, specificity = 0.857 and AUC = 0.929), and 1318.4 for TLG (sensitivity = 1, specificity = 0.786, and AUC = 0.911). The cutoff values of MTV and TLG significantly correlated with PFS using the Kaplan-Meier method (P = 0.002 and P = 0.007, respectively). MTV and TLG could distinguish DTs with subsequent progression from stable ones (P = 0.004 and P = 0.004, respectively). The ROC curve suggested that the appropriate cutoff values for distinguishing DTs with subsequent progression from stable ones were 197.1 for MTV (sensitivity = 0.9, specificity = 1, and AUC = 0.900), and 445.45 for TLG (sensitivity = 0.9, specificity = 1, and AUC = 0.900). CONCLUSION: Volume-based 18F-FDG-PET can predict prognosis of intra-abdominal DT. MTV and TLG can predict the outcome of active surveillance for intra-abdominal DT. MTV and TLG can potentially be predictors of surgical risk and difficulty.

CTNNB1 mutation-driven hybrid tumor: desmoid fibromatosis with an unusual associated epithelioid component arising in association with a neuromuscular choristoma.

CTNNB1 mutations play important roles in the development of soft tissue tumors, such as desmoid fibromatosis (DF), sinonasal tract angiofibroma, sinonasal glomangiopericytoma, intranodal palisaded myofibroblastoma, neuromuscular choristoma (NMC), and the recently reported pseudoendocrine sarcoma. Here, we report a unique hybrid soft tissue tumor with classic DF, unusual epithelioid component, and NMC in a 23-year-old female. The classic DF and NMC and the unusual epithelioid component and NMC were locally intermixed and closely related to each other. Immunohistochemically, the DF, unusual epithelioid component, and NMC exhibited nuclear positivity for ß-catenin to varying degrees. More critically, all of the above components harbored identical CTNNB1 p.Ser45Pro missense mutations. To the best of our knowledge, this is the only reported CTNNB1 mutation-driven hybrid tumor with DF, unusual epithelioid component, and NMC. The present case further confirmed that CTNNB1-mutational soft tissue tumors are highly heterogeneous, but the morphological spectrum is wide and consecutive.

Desmoid Tumors: Current Perspective and Treatment.

OPINION STATEMENT: Desmoid tumors are rare tumors with a tendency to infiltrate locally. The lack of a standard treatment approach makes choosing the most appropriate treatment for patients challenging. Most experts recommend watchful observation for asymptomatic patients as spontaneous regression of tumor is observed in up to 20% of patients. Upfront resection of the desmoid tumor has fallen out of favor due to high morbidity and high relapse rates associated with the tumor. Systemic therapy has evolved over several decades. Where chemotherapy, hormonal therapy, and non-steroidal anti-inflammatory drugs were used over the last several decades, tyrosine kinase inhibitors came to the forefront within the last decade. Most recently, gamma-secretase inhibitors have shown significant clinical benefit in patients with desmoid tumors, bringing forth an entirely new mechanistic approach. Several Wnt pathway inhibitors are also under development. Invasive approaches like cryoablation have also shown clinical benefit in patients with extra-abdominal desmoid tumors in recent years. The recent approval of nirogacestat has ushered in a new era of treatment for patients diagnosed with desmoid tumors. Several new molecules are expected to be approved over the coming years.

Trauma and sporadic desmoid tumor development: An approach toward real incidence and aspects of causality.

OBJECTIVES: The development of desmoid tumors (DT) is associated with trauma, which is an aspect with medicolegal relevance. The objective of this study was to analyze the proportion and type of trauma (surgical, blunt/fracture, implants), its lag time, and mutations of the CTNNB1 gene in patients with sporadic DT. METHODS: We analyzed a prospectively kept database of 381 females and 171 males, median age at disease onset 37.7 years (females) and 39.3 years (males) with a histologically confirmed DT. Patients with germline mutation of the APC gene were excluded. Details of the history particularly of traumatic injuries to the site of DT were provided by 501 patients. RESULTS: In 164 patients (32.7%), a trauma anteceding DT could be verified with a median lag time of 22.9 months (SD, 7.7 months; range, 9-44 months). A prior surgical procedure was relevant in 98 patients, a blunt trauma in 35 patients, a punctuated trauma (injections, trocar) in 18 patients, and site of an implant in 10 patients. In 220 patients, no trauma was reported (43.9%), and 58 females (11.6%) had a postpregnancy DT in the rectus abdominis muscle. In 42 patients (8.4%), data were inconclusive. The distribution of mutations in the CTNNB1 gene (codon 41 vs. 45) was similar in patients with and without a history of trauma before DT development. CONCLUSIONS: A significant subgroup of patients suffers from a trauma-associated DT, predominantly at a prior surgical site including implants to breast or groin, accounting for 77.9% of the cases, whereas blunt trauma was responsible in 22.1%. We found no data to support that trauma-associated DT have different molecular features in the CTNNB1 gene.

Risk factors for local recurrence of upper extremity desmoid tumors.

INTRODUCTION: Upper extremity (UE) desmoid tumors are locally aggressive neoplasms with high recurrence rates. Our study sought to analyze the demographics and treatment strategies of UE desmoid tumors and identify risk factors for recurrence. MATERIALS AND METHODS: A retrospective review of 52 patients with histologically confirmed UE desmoid tumors treated at our institution between 1990 and 2015 was conducted. Survival was assessed using the Kaplan-Meier method and the Cox proportional hazards model was used for risk factor analysis. RESULTS: For the entire cohort, median age was 40 (29-47) years, 75% were female, and 48% had local recurrence. The median tumor size was 45 (15-111) cm3 on imaging. Twenty-two patients had a previous resection. The most common treatments were surgery alone (50%) and surgery with adjuvant radiotherapy (21%). Tumor size ≥5 cm and tumor volume ≥40 cm3 on imaging were associated with increased recurrence (p = 0.006 and p = 0.005, respectively). Age and sex were not associated with local recurrence. Patients with a tumor size ≥5 cm were 2.6 times more likely to present with recurrence. At the 10-year mark, a lower local recurrence-free survival was seen in patients with tumors ≥5 cm (72.2% vs. 36.3%, p = 0.042) or ≥40 cm3 (67.2% vs. 32.7%, p = 0.034). CONCLUSION: In our study, only tumor dimensions appeared to modify recurrence risk.

PDGFRß Signaling Cooperates with ß-Catenin to Modulate c-Abl and Biologic Behavior of Desmoid-Type Fibromatosis.

PURPOSE: This study sought to identify ß-catenin targets that regulate desmoid oncogenesis and determine whether external signaling pathways, particularly those inhibited by sorafenib (e.g., PDGFRß), affect these targets to alter natural history or treatment response in patients. EXPERIMENTAL DESIGN: In vitro experiments utilized primary desmoid cell lines to examine regulation of ß-catenin targets. Relevance of results was assessed in vivo using Alliance trial A091105 correlative biopsies. RESULTS: CTNNB1 knockdown inhibited hypoxia-regulated gene expression in vitro and reduced levels of HIF1α protein. ChIP-seq identified ABL1 as a ß-catenin transcriptional target that modulated HIF1α and desmoid cell proliferation. Abrogation of either CTNNB1 or HIF1A inhibited desmoid cell-induced VEGFR2 phosphorylation and tube formation in endothelial cell co-cultures. Sorafenib inhibited this activity directly but also reduced HIF1α protein expression and c-Abl activity while inhibiting PDGFRß signaling in desmoid cells. Conversely, c-Abl activity and desmoid cell proliferation were positively regulated by PDGF-BB. Reduction in PDGFRß and c-Abl phosphorylation was commonly observed in biopsy samples from patients after treatment with sorafenib; markers of PDGFRß/c-Abl pathway activation in baseline samples were associated with tumor progression in patients on the placebo arm and response to sorafenib in patients receiving treatment. CONCLUSIONS: The ß-catenin transcriptional target ABL1 is necessary for proliferation and maintenance of HIF1α in desmoid cells. Regulation of c-Abl activity by PDGF signaling and targeted therapies modulates desmoid cell proliferation, thereby suggesting a reason for variable biologic behavior between tumors, a mechanism for sorafenib activity in desmoids, and markers predictive of outcome in patients.