Clinical and molecular studies of the effect of imatinib on advanced aggressive fibromatosis (desmoid tumor)

Clinical Challenges and Evolving Treatments in Desmoid Fibromatosis: A Single Institution Experience

Desmoid tumor (DT), also known as desmoid fibromatosis, is a rare, locally proliferative tumor characterized by an overgrowth of myofibroblastic cells. Due to the varied clinical presentation of DT, there are a multitude of treatment options. This study provides our institutional experience in characterizing and treating DT as well as patient outcomes. A retrospective review was performed for 49 patients diagnosed with DT. Patient demographics, tumor characteristics, treatment characteristics, and tumor recurrence were reported. We reported our institution's treatment trends over time, relative risk analysis for surgery, as well as univariate analysis for recurrence. Thirty-seven patients received surgery with an overall recurrence rate of 29.7% (11/37). In total, ten patients received medical therapy including tamoxifen/sulindac (n = 7), nirogacestat (n = 1), and sorafenib (n = 2). One patient has been followed with active surveillance. Relative risk for surgery and tumor recurrence was not significantly correlated with race, gender, location, or large tumor size > 5 cm. Four patients treated with medical therapy experienced tumor reduction and symptomatic improvement. Management of DT includes many surgical and non-surgical options. We noted a similar recurrence rate in patients who received surgical treatment to what has been reported in the literature roughly 33%. We also noted effective tumor control in patients receiving medical therapy. As such, surgery can be utilized in situations with well-demarcated DT which can be removed en bloc, while utilizing medical therapy for highly invasive tumors.

Desmoid tumors: Old and new drugs for a rare and challenging disease

There has been a paradigm shift in the treatment strategy for patients with desmoid tumor toward less invasive management using systemic therapies. In addition to older drugs, such as conventional chemotherapy and tyrosine kinase inhibitors, the newest class of medical agents—the gamma secretase inhibitors—have been included in the treatment armamentarium for patients with desmoid tumor, as nicely depicted in the latest consensus guideline from The Desmoid Tumor Working Group.

Adenomatous Polyposis Coli Gene Mutations, Risk Factors, and Long-term Outcomes Associated With Desmoid Tumors in Patients With Familial Adenomatous Polyposis After Colectomy in Japan

GOALS

To clarify the characteristics of desmoid tumors in Japanese patients with familial adenomatous polyposis after colectomy.

BACKGROUND

Few comprehensive reports have been published on desmoid tumors in Asian patients with familial adenomatous polyposis.

STUDY

This retrospective study included the data of 81 patients with familial adenomatous polyposis who underwent surgery between 1978 and 2021. The adenomatous polyposis coli gene mutation sites, risk factors, and long-term outcomes associated with desmoid tumors in Japanese patients with familial adenomatous polyposis after colectomy were analyzed.

RESULTS

No association was observed between the gene mutation sites and desmoid tumor development in 40 patients who underwent genetic analyses. The rate of desmoid tumor development was 30.3% in 66 patients. Multivariate analysis revealed that age below 32 years at colectomy (hazard ratio = 5.491, 95% confidence interval 1.820-16.50, P < 0.001) and familial adenomatous polyposis-related malignancies other than colorectal cancer (hazard ratio = 5.574, 95% confidence interval 2.075-14.98, P < 0.001) were independent risk factors for desmoid tumor development following colectomy. The 10-year disease-specific survival and overall survival rates for desmoid tumors were 92.9% and 76.9%, respectively. The median surveillance duration was 90 months.

CONCLUSIONS

Adenomatous polyposis coli gene mutation sites alone were not considered a factor for delaying or avoiding colectomy to prevent desmoid tumors in Japanese patients with familial adenomatous polyposis. The timing of colectomy and careful surveillance should be considered for managing patients at a high risk of developing desmoid tumors. Desmoid tumors in patients with familial adenomatous polyposis did not significantly impact prognosis, and pharmacological treatments are important for disease control.

Clinical Activity of TGF-β 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-β 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-β inhibitor, in this rare and difficult-to-treat desmoid tumor.

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.

Function-preserving surgery in sporadic desmoid-type fibromatosis of brachial plexus

Desmoid tumours of the brachial plexus are rare locally infiltrative aggressive, monoclonal, fibroblastic proliferations characterized by a variable and often unpredictable clinical course. Only 21 patients have been reported in the literature. We add another one, and report function-preserving surgery in a 34-year-old man with a desmoid tumour of the brachial plexus. The patient presented with paraesthesia and gradually progressive distal muscle weakness in the left upper limb. Electrodiagnostic studies revealed preganglionic changes in segments C8-D1. Contrast-enhanced magnetic resonance imaging showed an enhancing mass with irregular margins in the left paravertebral region encasing the subclavian artery, pre- and post-ganglionic C6-D1 nerve roots and trunks of the brachial plexus. Using an anterior transclavicular approach the tumour was decompressed, which led to a major improvement in paraesthesia and partial motor recovery. He was doing well at 6 months of follow-up. Histopathological examination showed findings consistent with desmoid tumour. A tailored multidisciplinary surgical approach, with the aim to preserve function over radiological clearance, is an acceptable treatment strategy in preserving patient's quality of life for such infiltrating desmoid tumours encasing the brachial plexus. Following surgery, observation and close radiological surveillance offer an optimal strategy without jeopardizing the quality of life.

Desmoid tumours (extra-abdominal), a surgeon's nightmare

Desmoid tumours are a rare fibroblastic proliferation of monoclonal origin, arising in deep soft-tissues. Histologically, they are characterized by locally aggressive behaviour and an inability to metastasize, and clinically by a heterogeneous and unpredictable course. Desmoid tumours can occur in any anatomical site, but commonly arise in the limbs. Despite their benign nature, they can be extremely disabling and sometimes life-threatening, causing severe pain and functional limitations. Their surgical management is complex and challenging, due to uncertainties surrounding the biological and clinical behaviour, rarity, and limited available literature. Resection has been the first-line approach for patients with a desmoid tumour but, during the last few decades, a shift towards a more conservative approach has occurred, with an initial 'wait and see' policy. Many medical and regional forms of treatment are also available for the management of this condition, and others have recently emerged with promising results. However, many areas of controversy remain, and further studies and global collaboration are needed to obtain prospective and randomized data, in order to develop an appropriate shared stepwise approach.

New treatments for desmoid tumors

PURPOSE OF REVIEW

Desmoid tumor is a rare disease of intermediate malignancy characterized by a locally aggressive monoclonal, fibroblastic proliferation and accompanied by a variable and often unpredictable clinical course. The purpose of this review is to give an overview on the emerging new systemic treatment options for this intriguing disease for which no established or approved drugs are available yet.

RECENT FINDINGS

Over decades, surgical resection has been the established initial treatment approach; however, more recently, a paradigm shift has been introduced towards a more conservative treatment strategy. Almost 10 years ago, The Desmoid Tumor Working Group has initiated a consensus process initially in Europe and then globally with the intention to harmonize the therapeutic strategy amongst clinicians and set up management recommendations for desmoid tumor patients.

SUMMARY

This review will summarize and focus on the latest emerging impressive data on the use of gamma secretase inhibitors in this disease paving a possible future perspective in the treatment armamentarium for desmoid tumor patients.

A Review of the Clinical Presentation, Outcomes, and Treatments of Patients Having Desmoid Tumors

Desmoid tumors (DTs) are deep fibroblastic neoplasms that arise from musculo-aponeurotic stromal elements. DTs may result in significant morbidity by infiltrating vital anatomic structures. Their mortality is often due to the local aggressiveness, most commonly when intra-abdominal in location. Some indolent DTs can be observed expectantly; infiltrative tumors require an aggressive and multidisciplinary approach and are offered conservative therapies such as nonsteroidal anti-inflammatory drugs or antiestrogens when surgery is not feasible. Comparably, chemotherapy is considered for those cases not amenable to surgery or radiation. Bowel resection and at times intestinal transplantation may be necessary. However, DTs may recur postsurgery making long-term management of these patients. Herein, we review the genetics, clinical presentations, outcomes, and treatments of DTs.

Cytopathology of rare gastric mesenchymal neoplasms: A series of 25 cases and review of literature

BACKGROUND

Gastrointestinal stromal tumour (GIST) is the most common mesenchymal neoplasm arising in the stomach. However, a number of other rare mesenchymal neoplasms do occur at this anatomic site, which often presents a diagnostic challenge for cytopathologists on endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA). Our study aims to selectively present the clinico-radiological and cytopathological characteristics of these rare "non-GIST" neoplasms, as well as their differential diagnoses.

MATERIAL AND METHODS

We performed a 20 year retrospective search in the cytopathology database of our two large medical institutions for non-GIST mesenchymal neoplasms arising in the stomach and diagnosed on EUS-FNA. Data regarding the patients' demographics and radiological findings were analysed. All available cytopathology specimens were reviewed. The cytomorphological characteristics and the accompanying immunohistochemical stains, when available, were subsequently analysed.

RESULTS

Twenty-five cases of gastric mesenchymal tumours were selectively included in the study after excluding all cases of GIST (n = 113) diagnosed on FNA. These cases included 10 leiomyomas (40%), eight schwannomas (32%), five glomus tumours (20%), one perivascular epithelioid cell neoplasm, and one desmoid tumour. The specimen cellularity was variable and ranged from hypocellular to highly cellular. Most smears were composed of spindle cells with a few showing epithelioid morphology. Cell blocks were available in 20 cases and a range of immunohistochemical ancillary studies were performed. DOG-1, c-KIT, smooth muscle actin (SMA), and S100-protein were the most common immunomarkers done.

CONCLUSION

Our study highlights important cytomorphological characteristics of rare mesenchymal neoplasms arising in the stomach. In the appropriate clinical setting and with the help of immunohistochemistry, an accurate diagnosis of these neoplasms can be achieved.

Molecular pathogenesis of desmoid tumor and the role of γ-secretase inhibition

Desmoid tumor (DT) is a rare, soft tissue neoplasm associated with an unpredictable clinical course. Although lacking metastatic potential, DT is often locally aggressive and invasive, causing significant morbidity. Both sporadic DT and familial adenomatous polyposis (FAP)-associated DT are linked to constitutive activation of the Wnt signaling pathway with mutations in the β-catenin oncogene CTNNB1 or the tumor suppressor gene APC, respectively. Cross-talk between the Notch and Wnt pathways, as well as activation of the Notch pathway resulting from dysregulation of the Wnt pathway, suggest a possible therapeutic target for DT. Due to the role γ-secretase plays in Notch signaling through cleavage of the Notch intracellular domain (with subsequent translocation to the nucleus to activate gene transcription), γ-secretase inhibitors (GSIs) have emerged as a potential treatment for DT. Two GSIs, nirogacestat (PF-03084014) and AL102 are in later-stage clinical development; nirogacestat is being evaluated in a phase 3, randomized, placebo-controlled trial while AL102 is being evaluated in a phase 2/3, dose-finding (part A) and placebo-controlled (part B) trial. This review summarizes current understanding of the molecular pathogenesis of DT focusing on dysregulation of the Wnt signaling pathway, crosstalk with the Notch pathway, and the potential therapeutic role for GSIs in DT.

The Role of Pharmacotherapeutic Agents in Children with Desmoid Tumors

Desmoid tumors (DT) are rare fibroblastic, soft-tissue tumors that do not metastasize but can aggressively infiltrate tissues causing significant chronic discomfort and/or functional impairment. In the pediatric population, the incidence of DT is greatest during infancy and adolescence but can occur at any age. Dysregulated β-catenin, most commonly resulting from mutations in either CTNNB1 or germline APC (adenomatous polyposis coli) drives DT. Most cases are sporadic but some are associated with predisposition syndromes such as familial adenomatous polyposis (FAP). Historically, treatment has been surgery. However, the recurrence rate after surgery can be high. Various systemic cytotoxic chemotherapy regimens used in other soft-tissue sarcomas have been applied to DT with differing results. Given the chronic and rarely life-threatening nature of this disease and the potential short- and long-term toxicity of these regimens, especially in children, alternative non-cytotoxic interventions have been investigated. Molecularly targeted agents such as tyrosine kinase and gamma secretase inhibitors have shown activity against DT. Innovative local control therapies are being employed as alternatives to surgery and radiation. Periods of prolonged stability and spontaneous regression in the absence of therapy in some patients has prompted wider adoption of an upfront active surveillance approach in the appropriate setting. This review will briefly summarize the epidemiology, pathophysiology, and clinical presentation of DT in children, then focus on historical, current, and future pharmacotherapeutic management and finally, propose areas for future study.

Evolving strategies for management of desmoid tumor

Desmoid tumors (DTs) are rare soft tissue mesenchymal neoplasms that may be associated with impairments, disfigurement, morbidity, and (rarely) mortality. DT disease course can be unpredictable. Most DTs are sporadic, harboring somatic mutations in the gene that encodes for β-catenin, whereas DTs occurring in patients with familial adenomatous polyposis have germline mutations in the APC gene, which encodes for a protein regulator of β-catenin. Pathology review by an expert soft tissue pathologist is critical in making a diagnosis. Magnetic resonance imaging is preferred for most anatomic locations. Surgery, once the standard of care for initial treatment of DT, is associated with a significant risk of recurrence as well as avoidable morbidity because spontaneous regressions are known to occur without treatment. Consequently, active surveillance in conjunction with pain management is now recommended for most patients. Systemic medical treatment of DT has evolved beyond the use of hormone therapy, which is no longer routinely recommended. Current options for medical management include tyrosine kinase inhibitors as well as more conventional cytotoxic chemotherapy (e.g., anthracycline-based or methotrexate-based regimens). A newer class of agents, γ-secretase inhibitors, appears promising, including in patients who fail other therapies, but confirmation in Phase 3 trials is needed. In summary, DTs present challenges to physicians in diagnosis and prognosis, as well as in determining treatment initiation, type, duration, and sequence. Accordingly, evaluation by a multidisciplinary team with expertise in DT and patient-tailored management are essential. As management strategies continue to evolve, further studies will help clarify these issues and optimize outcomes for patients.

Percutaneous Cryoablation Provides Disease Control for Extra-Abdominal Desmoid-Type Fibromatosis Comparable with Surgical Resection

PURPOSE

The aim of this study was to determine outcomes and prognostic factors for patients with primary and locally recurrent extra-abdominal desmoid tumors who underwent percutaneous cryoablation, and to compare with patients treated with surgery.

METHODS

Group characteristics were compared using Fisher's exact test, and propensity score matching was performed using the nearest-neighbor approach. Kaplan-Meier and log-rank analyses were used to evaluate the variation in first local recurrence and disease control, while multivariate Cox regression was used to identify factors associated with first local recurrence. All statistical tests were two-sided and a p-value of 0.05 was considered statistically significant.

RESULTS

Twenty-two cryoablation patients were matched with 33 surgical patients (n = 55). Median follow-up after cryoablation was 16.3 months versus 14.9 months after surgery. Two-year local recurrence-free survival (LRFS) was 59% after cryoablation and 71% after surgery, and median LRFS was 26.6 months after cryoablation but was not reached after surgery. Two-year disease control for all patients was 85%, however median disease control was not reached in either the cryoablation or surgery groups. There was no significant difference in LRFS or disease control between matched cryoablation and surgical patients. No local recurrences occurred after the first cryoablation in patients with zero or one of the following risk factors: tumor size > 5 cm, age ≤ 25 years, or locally recurrent disease. All patients with two or more of these risk factors recurred locally after the first cryoablation.

CONCLUSION

Percutaneous cryoablation of primary and locally recurrent extra-abdominal desmoid tumors provides freedom from first local recurrence and long-term disease control comparable with surgery.

Desmoid fibromatosis in the pharyngeal wall: A case report and literature review

Desmoid fibromatosis (DF) is one of the rarest locally aggressive growing benign tumor entities. We present an overview of the literature and a rare clinical case of a 22-year-old female patient, who was diagnosed with aggressive DF in the left pharyngeal wall at the age of 4 years old.

Spindle Cell Tumors of the Pleura and the Peritoneum: Pathologic Diagnosis and Updates

A diverse group of both benign and malignant spindle cell tumors can involve the pleura or the peritoneum. Due to their rarity and overlapping morphologic features, these tumors can pose considerable diagnostic difficulty in surgical pathology. As these tumors differ in their prognosis and clinical management, their correct pathologic diagnosis is critical. In addition to histologic assessment, select immunohistochemical and molecular tools can aid the distinction among these tumors. In this review, we consider some of the major histologic differential diagnosis of spindle cell tumors involving these serosal membranes. This list of tumors includes: solitary fibrous tumor, inflammatory myofibroblastic tumor, desmoid fibromatosis, synovial sarcoma, sarcomatoid carcinoma, spindle cell melanoma, dedifferentiated liposarcoma, epithelioid hemangioendothelioma, and sarcomatoid mesothelioma. We describe their salient clinicopathologic and genetic findings, with a review on some of the recent discoveries on their molecular pathogenesis.

Molecular targeted therapy for advanced or metastatic soft tissue sarcoma

Soft tissue sarcomas are a form of rare and heterogeneous neoplasms with high recurrence rate and mortality. Over the past decades, less progress has been achieved. Surgical management with or without adjuvant/neoadjuvant radiotherapy is still the first-line treatment for localized soft tissue sarcomas, and chemotherapy is the additional option for those with high-risk. However, not all patients with advanced or metastatic soft tissue sarcomas benefit from conventional chemotherapy, targeted therapy takes the most relevant role in the management of those resistant to or failed to conventional chemotherapy. Heterogeneous soft tissue sarcomas vary from biological behavior, genetic mutations, and clinical presentation with a low incidence, indicating the future direction of histotype-based even molecule-based personalized therapy. Furthermore, increasing preclinical studies were carried out to investigate the pathogenesis and potential therapeutic targets of soft tissue sarcomas and increasing new drugs have been developed in recent years, which had started opening new doors for clinical treatment for patients with advanced/metastatic soft tissue sarcomas. Here we sought to summarize the concise characteristics and advance in the targeted therapy for the most common subtypes of soft tissue sarcomas.

Desmoid fibromatosis: is the current picture changing?

Desmoid fibromatosis is a locally aggressive tumor with an unpredictable clinical course. Surgery was once the mainstay of treatment, but the treatment protocol has been constantly evolving and currently active surveillance is the front-line approach. There have been significant insights into the molecular biology with the addition of mutational analysis of CTNNB1 adding to prognostic information. We present a review of the literature with current practice guidelines, also including novel therapeutic targets and ongoing clinical trials, to unravel the next step in the management of sporadic desmoid fibromatosis.

Rationale for the use of tyrosine kinase inhibitors in the treatment of paediatric desmoid-type fibromatosis

In children with desmoid-type fibromatosis (DTF) in whom disease progression occurs after an initial watch-and-wait strategy, prolonged low-dose chemotherapy using vinblastine and methotrexate (VBL-MTX) is currently the standard of care. These conventional drugs have been prospectively evaluated but their efficacy and safety profiles are limited, and alternative therapeutic options are therefore essential. Based on the results of clinical trials, the use of tyrosine kinase inhibitors (TKIs) in the treatment of DTF is currently considered only in adult patients. TKIs such as imatinib show superior therapeutic efficacy to VBL-MTX and tolerable short-term side effects for the treatment of adult DFT, supporting the concept of the use of TKIs for the treatment of paediatric DFT. Moreover, new-generation TKIs, such as pazopanib and sorafenib, have shown improved therapeutic efficacy compared to imatinib in adult non-comparative studies. A tolerable safety profile of TKI therapy in children with disease entities other than DTF, such as leukaemia, has been reported. However, the efficacy and, in particular, the long-term safety of TKIs, including childhood-specific aspects such as growth and fertility, for the treatment of children with DTF should be investigated prospectively, as DFT therapy requires long-term drug exposure.

Targeted therapy in advanced desmoid tumors: Current perspectives

Background

Desmoid tumors/aggressive fibromatosis (DTs/AF) are cytological bland fibrous neoplasms originating from the musculoaponeurotic structures throughout the body. The exact cause still remains unknown, however, they may present sporadically or as a manifestation of a hereditary syndrome called familial adenomatous polyposis (FAP). Although they lack the capacity to establish metastases, DTs/AF may be devastated and occasionally fatal. As a result of the heterogeneity of DTs/AF, treatment needs to be individualized to improve local tumor control and maintain patients’ quality of life. Therefore, after a multidisciplinary approach, all treatment options should be discussed with patients. Where systemic chemotherapy has been shown to be unsuccessful with marked side effects in case of advanced DTs/AF, new therapeutic options are needed.

Methods

A Medline search was conducted and published articles in different studies from 2000 to the present were reviewed.

Conclusion

More research is needed to illustrate both the prognostic and predictive factors of the targeted therapy and the value of their combinations with or without other treatment modalities to get the best result for the treatment of advanced DTs/AF.

Extra-abdominal desmoid tumor fibromatosis: a multicenter EMSOS study

Background

Extra-abdominal desmoid tumor fibromatosis (DTF) is a rare, locally aggressive soft tissue tumour. The best treatment modality for this patient cohort is still object of debate.

Questions/purpose

This paper aimed to (1) to compare the outcomes of DTF after different treatment modalities, (2) to assess prognostic factors for recurrence following surgical excision, and (3) to assess prognostic factors for progression during observation.

Methods

This was a retrospective multicenter study under the patronage of the European Musculoskeletal Oncology Society (EMSOS). All seven centres involved were tertiary referral centres for soft tissue tumours. Baseline demographic data was collected for all patients as well as data on the diagnosis, tumour characteristics, clinical features, treatment modalities and whether they had any predisposing factors for DTF.

Results

Three hundred eighty-eight patients (240 female, 140 male) with a mean age of 37.6 (±18.8 SD, range: 3–85) were included in the study. Two hundred fifty-seven patients (66%) underwent surgical excision of ADF, 70 patients (18%) were observed without therapy, the residual patients had different conservative treatments. There were no significant differences in terms of tumour recurrence or progression between the different treatment groups. After surgical excision, younger age, recurrent disease and larger tumour size were risk factors for recurrence, while tumours around the shoulder girdle and painful lesions were at risk of progression in the observational group.

Conclusion

Local recurrence rate after surgery was similar to progression rates under observation. Hence, observation in DTF seems to be justified, considering surgery in case of dimensional progression in 2 consecutive controls (3 and 6 months) and in painful lesions, with particular attention to lesions around the shoulder girdle.

Desmoid Fibromatosis: Management in an Era of Increasing Options

PURPOSE OF REVIEW

Desmoid fibromatosis (DF) is a locally aggressive clonal neoplasm with locally aggressive behavior and no metastatic potential. Historical treatment of DF has consisted primarily of up-front surgery when feasible. In recent years, recognition that DF can spontaneously stabilize or involute has allowed for many patients to be managed with watchful waiting rather than intervention. This review is intended to review recent developments in the treatment of DF.

RECENT FINDINGS

Recent studies have demonstrated prospectively that patients with DF often have improvement in their lesions without intervention, enabling an initial period of surveillance as a standard option for patients with mild symptoms. Given the lengthening list of effective systemic treatments, including sorafenib, pazopanib, and experimental agents, there has been a less reliance on local therapies for those patients who require treatment. For patients with DF that require treatment, there is a growing list of options that includes radiation therapy (RT), percutaneous ablation, and a growing list of systemic agents with favorable toxicity profiles.

Efficacy and safety of apatinib for patients with advanced extremity desmoid fibromatosis: a retrospective study

PURPOSE

Desmoid fibromatosis (DF) is a locally aggressive connective-tissue tumor arising in deep soft tissues. Although multiple therapeutic modalities have been demonstrated effective for DF, there is no standard systemic treatment for progressive and recurrent DF. As a part of systemic treatment, tyrosine kinase inhibitors have shown promising activity against DF with tolerable toxicity profiles. Thus, the aim of this study was to investigate the efficacy and safety of apatinib, a novel multi-target angiogenesis inhibitor, in patients with DF.

METHODS

We retrospectively analyzed the medical records of patients with advanced extremity DF regularly treated with apatinib between October 2017 and January 2020 in our center. Apatinib was initially administered with a dose of 250 mg daily and the dose was adjusted according to the toxicity. Tumor response was assessed by the Response Evaluation Criteria in Solid Tumors 1.1 criteria. The primary endpoint was progression-free survival (PFS); objective response rates and drug-related adverse events were also evaluated.

RESULTS

A total of 22 (6 male, 16 female) patients with advanced extremity DF were included. The mean medication time was 17 months. None of the patients reached a complete response, but ten (45.5%) patients achieved partial response, and 11 patients (50%) achieved stable disease. One (4.5%) patient developed progressive disease, and the 1-year PFS rate was 95.2%. The disease control rate was 95.4% (21/22) and the objective response rate was 45.5% (10/22). Meanwhile, 18 (81.8%) patients with a tumor shrinkage were accompanied by a decreased signal intensity of lesions in T2-weighted magnetic resonance imaging. The most frequent adverse events included hand-foot syndrome (n = 7, 31.8%), fatigue (n = 6, 27.2%), local pain (n = 4, 18.1%), diarrhea (n = 4, 18.1%).

CONCLUSION

Apatinib is an effective and well-tolerated option for patients with advanced extremity DF. Indeed, further prospective, randomized studies with larger cases are required to fully explore the clinical utility of apatinib in DF.

The Landmark Series: Desmoid

Desmoid-type fibromatosis represents a challenge in the landscape of surgical oncology, for several reasons. The tumors can be infiltrative and locally aggressive, surgery may be morbid, and patients are usually young, and thus treatment sequelae must be managed for decades. Desmoids do not have metastatic potential, therefore management strategies for desmoids have evolved to employ frontline treatments that are largely non-operative. In fact, with unpredictable and benign behavior, we now recognize that desmoids can also stabilize and regress, making active observation an option for many patients. Moreover, many medical therapies are active in the disease. We reviewed landmark studies describing contemporary issues that affect treatment recommendations for desmoid patients: prognostic factors, indication to active surveillance, role of surgical margins, postoperative radiotherapy, and the most recent expert consensus papers.

CRYODESMO-O1: A prospective, open phase II study of cryoablation in desmoid tumour patients progressing after medical treatment

BACKGROUND

Desmoid tumours (DTs) are rare tumours originating from musculoaponeurotic structures. Although benign, they may be locally aggressive, leading to pain and disability. European Society for Medical Oncology (ESMO) guidelines recommend frontline watchful waiting and medical treatment in progressing tumours. Cryoablation is an interventional radiology technique that is suitable for DT patients (pts) on the basis of repeated cycles of freezing, leading to cell death.

METHODS

CRYODESMO-01 (ClinicalTrials.gov Identifier: NCT02476305) is a prospective, open-label, non-randomised, non-comparative, multicenter study assessing cryoablation in non-abdominopelvic progressing DT. Inclusion criteria were: pts ≥18 y.o., confirmed DT accessible to cryoablation (≥90% destruction), measurable lesion conforming to modified response evaluation criteria in solid tumours (mRECIST), progressive disease after ≥2 lines of medical therapy or with functional symptoms/pain, adequate biological parameters, informed consent, and affiliation to a medical insurance scheme. The primary end-point was the non-progression rate at 12 months; secondary end-points included safety, quality of life (QoL), assessment of pain and functional status.

FINDINGS

50 pts were enrolled (78% female) from four French centres and all were treated. The mean age was 41 y.o. (19-73). The median number of prior treatments was 2.00 [1-4] including non-steroidal anti-inflammatory drugs (NSAIDs), hormone therapy, chemotherapy, and anti-angiogenics. Tumour location included limbs (36%), trunk (60%), and cervical area (4%). The median tumour largest diameter was 89 mm. The rate of non-progressing disease at +12 months was 86% [confidence level (CI) 95% 73-94%]. Median PFS was not reached at a median follow-up of 31 months. Grade 1 and 2 toxicity occurred in 32.8% and 44.5% of patients, grade 3-4 in 22% and no Grade 5 toxicity was observed. Cryoablation significantly improved functional status and pain scores.

INTERPRETATION

Cryoablation demonstrated feasibility in progressive DT pts. The study met is primary end-point with 86% of non-progressive disease at +12 months, with reduced pain, better functional status, and encouraging long-term disease control.

Desmoid tumors: To treat or not to treat, That is the question

Desmoid tumors (DTs) are a rare disease of intermediate malignancy characterized histologically by a locally aggressive, monoclonal, fibroblastic proliferation and clinically by a variable and often unpredictable course. For decades, surgical resection has been the standard initial treatment approach; however, more recently, a paradigm shift toward a more conservative treatment strategy has been introduced. More than 5 years ago, The Desmoid Tumor Working Group started a consensus initiative in Europe with the aim of harmonizing the strategy among clinicians and setting up treatment recommendations for patients with DTs. This review summarizes the latest joint, global, evidence-based guideline approach to DT management. Moreover, a number of gray areas in the treatment recommendations are discussed, and possible future perspectives on the treatment armamentarium for patients with DTs are presented.

Safety and efficacy of gamma-secretase inhibitor nirogacestat (PF-03084014) in desmoid tumor: Report of four pediatric/young adult cases

Systemic therapy for pediatric desmoid tumors has been challenged by a lack of high-quality clinical evidence and potential adverse effects. The gamma-secretase inhibitor nirogacestat has shown promising efficacy in adults. We report four cases of pediatric and young adult desmoid tumor patients (three with familial adenomatous polyposis [FAP] syndrome) who received nirogacestat on compassionate use. After a median of 13.5 months (range 6-18), three had durable benefit: a complete response (Case 1); a partial response (Case 2); stable disease (Case 3). The fourth had disease progression after a partial response. No patient experienced grade 3 or 4 adverse events.

The Activity and Safety of Anlotinib for Patients with Extremity Desmoid Fibromatosis: A Retrospective Study in a Single Institution

Purpose

Desmoid fibromatosis (DF) is an aggressive fibroblastic neoplasm with a high propensity for local recurrence. Although multiple therapeutic modalities seem effective for DF, the standard systemic treatment for symptomatic and progressive DF remains controversial. As targeted therapy, tyrosine kinase inhibitors have been recently reported to contribute to the treatment of DF. Thus, the purpose of this study was to assess the efficacy and safety of anlotinib, a novel multi-kinase angiogenesis inhibitor, in patients with DF.

Patients and Methods

We retrospectively collected the clinical medical records of patients with extremity DF who received anlotinib between January 2019 and January 2020 in our center. Anlotinib was started with a dose of 8 mg daily and adjusted according to the drug-related toxicity. Tumor response was assessed by the Response Evaluation Criteria in Solid Tumors 1.1 criteria. Progression-free survival (PFS) was identified as the primary endpoint and analyzed using the Kaplan–Meier method.

Results

In total, 21 (6 male, 15 female) consecutive patients with DF were enrolled. The median medication time was nine months (Q1, Q3: 7.5, 10.5). None of the patients achieved a complete response, but eight (38.1%) patients achieved a partial response and ten patients (47.6%) achieved disease stability. Three (14%) patients developed progressive disease and the 3-, 6-, and 12-month PFS rates were 95.2%, 90.5%, and 84.0%, respectively. The disease control rate was 86.0% (18/21) and the objective response rate was 38.1% (8/21). Moreover, 15/21 (71.4%) patients achieved a reduction in tumor size, accompanied with a decrease in T2-weighted signal intensity on magnetic resonance imaging and clinical benefit.

Conclusion

Anlotinib was effective against DF with an acceptable safety profile, and significantly slowed the disease progression. Further, multicenter studies with a longer follow-up time are needed to characterize fully the clinical application of anlotinib in DF.

Long-term Outcomes of Oral Vinorelbine in Advanced, Progressive Desmoid Fibromatosis and Influence of CTNNB1 Mutational Status

PURPOSE

Desmoid-type fibromatosis (DF) are locally aggressive neoplasms, with a need for effective systemic treatment in case of progression to avoid the short- and long-term complications of local treatments.

EXPERIMENTAL DESIGN

We retrospectively analyzed the outcomes of adult patients with DF treated with oral vinorelbine (90 mg once weekly) at Gustave Roussy Cancer Institute (Villejuif, Paris, France). Only patients with documented progressive disease according to RECIST v1.1 for more than 3 months (±2 weeks) before treatment initiation were included.

RESULTS

From 2009 to 2019, 90 out of 438 patients with DF were eligible for this analysis. Vinorelbine was given alone in 56 patients (62%), or concomitantly with endocrine therapy in 34 patients, for a median duration of 6.7 months. A partial response was observed in 29% and stable disease in another 57%. With a median follow-up of 52.4 months, the median time to treatment failure (TTF) was not reached. Progression-free rates at 6 and 12 months were 88.7% and 77.5%, respectively. Concomitant endocrine therapy was associated with longer TTF in women [HR, 2.16; 95% confidence interval (CI), 1.06-4.37; P = 0.03). Among 64 patients with documented CTNNB1 mutational status, p.S45F or p.S45P mutations were associated with longer TTF compared with p.T41A or wild-type tumors (HR, 2.78; 95% CI, 1.23-6.27; P = 0.04). Toxicity profile was favorable, without grade 3-4 toxicity, except for one grade 3 neutropenia.

CONCLUSIONS

Oral vinorelbine is an effective, affordable, and well-tolerated regimen in patients with advanced, progressive DF. Prolonged activity was observed in patients with tumors harboring CTNNB1 p.S45F or p.S45P mutations.

Fibromatosis of the breast: a 10-year multi-institutional experience and review of the literature

BACKGROUND

Breast fibromatosis is a rare clinical entity, but poses significant diagnostic and therapeutic challenges. In light of recent changes in management practices, the aim was to review our institutional experience of breast fibromatosis and provide a review of current available literature on such management.

METHODS

A search of pathological databases within two tertiary institutions for all patients diagnosed with fibromatosis of the breast over a 10-year period (2007-2016) was performed. Clinicopathological characteristics and modes of treatment were recorded for each patient. Concurrently a comprehensive literature search was performed and studies relating to breast fibromatosis and its management were identified and reviewed.

RESULTS

Sixteen patients were identified. Median age at diagnosis was 42 (range 21-70) and all patients were diagnosed with core biopsy. The most useful imaging modality in diagnosis was ultrasonography and magnetic resonance imaging. 13/16 were treated surgically whilst 3/16 were treated using a watch-and-wait approach. 6/13 (46%) required re-excision of margins and 2/13 (15%) had recurrence after surgery. On review of the literature, there is no dedicated guideline in place for the management of breast fibromatosis. Currently a 'watch and wait' approach is favoured over surgical intervention due to high levels of recurrence and associated surgical morbidity. All cases should be discussed at a sarcoma multidisciplinary team meeting and tyrosine kinase inhibitors should be considered in advanced cases.

CONCLUSIONS

Breast fibromatosis is rare but affects young patients. Active surveillance is now favoured over surgical resection due to high recurrence rates and extensive morbidity. Dedicated guidelines are required to ensure best outcomes.

Recent Advances in Desmoid Tumor Therapy

The desmoid tumor is a locally aggressive proliferative disease within the family of soft-tissue sarcomas. Despite its relatively good prognosis, the clinical management of desmoid tumors requires constant multidisciplinary evaluation due to its highly variable clinical behavior. Recently, active surveillance has being regarded as the appropriate strategy at diagnosis, as indolent persistence or spontaneous regressions are not uncommon. Here, we review the most recent advances in desmoid tumor therapy, including low-dose chemotherapy and treatment with tyrosine kinase inhibitors. We also explore the recent improvements in our knowledge of the molecular biology of this disease, which are leading to clinical trials with targeted agents.

Soft-tissue sarcoma in adults: An update on the current state of histiotype-specific management in an era of personalized medicine

Soft-tissue sarcomas (STS) are rare tumors that account for 1% of all adult malignancies, with over 100 different histologic subtypes occurring predominately in the trunk, extremity, and retroperitoneum. This low incidence is further complicated by their variable presentation, behavior, and long-term outcomes, which emphasize the importance of centralized care in specialized centers with a multidisciplinary team approach. In the last decade, there has been an effort to improve the quality of care for patients with STS based on anatomic site and histology, and multiple ongoing clinical trials are focusing on tailoring therapy to histologic subtype. This report summarizes the latest evidence guiding the histiotype-specific management of extremity/truncal and retroperitoneal STS with regard to surgery, radiation, and chemotherapy.

[Biology and signaling pathways involved in the oncogenesis of desmoid tumors]

Desmoid tumors (TDs) are derived from mesenchymal stem cells and their pathogenesis is strongly linked to the Wingless/Wnt cascade where the deregulation of β-catenin plays a major role. A mutation of the CTNNB1 encoding β-catenin is found in the majority of sporadic TD cases and constitutional mutations of APC have been described in heritable forms in patients with familial adenomatous polyposis (FAP). Estrogens could also play a role in pathogenesis and this is the basis for the use of hormone therapy. Other signaling pathways have been involved in the development of TDs such as Notch, Hedgehog, JAK/STAT, PI3 Kinase/AKT and mTOR. Metalloproteases are expressed in TDs and play a role in invasiveness. TGF-ß, as a growth factor, stimulates the transcriptional activity of β-catenin. Future studies will need to focus on better describing and understanding the immune environment of TDs. One of the major difficulties for the experimental study of TDs is the virtual absence of a preclinical model, either in vitro or in vivo. This is partly why the interactions between the different signaling pathways presented here and their consequences for the development of TDs are still poorly understood.

Evolving Practice Patterns Over Two Decades (1993-2013) in the Management of Desmoid-type Fibromatosis in British Columbia

AIMS

Due to the rarity and varied natural history of desmoid-type fibromatosis, evidence-based treatment standards for this disease remain lacking. This study evaluated outcomes in patients with desmoid-type fibromatosis managed at a Canadian institution over two decades.

MATERIALS AND METHODS

Records of 227 patients with desmoid-type fibromatosis referred from 1990 to 2013 were retrospectively reviewed to investigate management strategies including active surveillance, surgery, radiation therapy, cryoablation, and systemic therapy, including tamoxifen and chemotherapy.

RESULTS

Thirty-two per cent of cases were men, median age 40 years, median tumour size 5.4 cm. Initial treatments were surgery (79%), tamoxifen (13%), radiation therapy (5.0%), chemotherapy (1.8%) and cryoablation (1.2%). Active surveillance was used upfront in 26% of cases, most after 2005. At a median follow-up of 77 months, one patient died of disease, 13 died of unrelated causes and the remainder were alive with no evidence of disease (56%), stable/responding disease (33%) or progressive disease (4%). The recurrence rate was 25% after upfront surgery. Response rates and disease control rates were 40% and 76% for active surveillance; 68% and 96% for radiation therapy; 31% and 67% for tamoxifen; and 53% and 80% for chemotherapy. On univariable analysis, factors associated with a higher recurrence after initial surgery were young age (P = 0.012), male gender (P = 0.012) and extremity location (P = 0.005). On multivariable analysis, only young age was significantly associated with recurrence risk (P = 0.010).

CONCLUSIONS

Active surveillance was associated with spontaneous regression and long-term disease control consistent with other studies. Primary radiation therapy appeared to provide a similar response and disease control compared with systemic treatments and may be a viable option for patients who are not candidates for surgery or active surveillance.

Activated Signaling Pathways and Targeted Therapies in Desmoid-Type Fibromatosis: A Literature Review

Desmoid-type fibromatosis (DTF) is a rare, soft tissue tumor of mesenchymal origin which is characterized by local infiltrative growth behavior. Besides "wait and see," surgery and radiotherapy, several systemic treatments are available for symptomatic patients. Recently, targeted therapies are being explored in DTF. Unfortunately, effective treatment is still hampered by the limited knowledge of the molecular mechanisms that prompt DTF tumorigenesis. Many studies focus on Wnt/β-catenin signaling, since the vast majority of DTF tumors harbor a mutation in the CTNNB1 gene or the APC gene. The established role of the Wnt/β-catenin pathway in DTF forms an attractive therapeutic target, however, drugs targeting this pathway are still in an experimental stage and not yet available in the clinic. Only few studies address other signaling pathways which can drive uncontrolled growth in DTF such as: JAK/STAT, Notch, PI3 kinase/AKT, mTOR, Hedgehog, and the estrogen growth regulatory pathways. Evidence for involvement of these pathways in DTF tumorigenesis is limited and predominantly based on the expression levels of key pathway genes, or on observed clinical responses after targeted treatment. No clear driver role for these pathways in DTF has been identified, and a rationale for clinical studies is often lacking. In this review, we highlight common signaling pathways active in DTF and provide an up-to-date overview of their therapeutic potential.

Intra-abdominal desmoid tumors mimicking gastrointestinal stromal tumors - 8 cases: A case report

BACKGROUND

Intra-abdominal desmoid tumors (DTs) can mimic recurrence or progression of gastrointestinal stromal tumors (GISTs). Differential diagnosis is important to avoid unnecessary or inappropriate treatment.

CASE SUMMARY

All 8 patients experienced surgical resection of GIST, and median time to diagnosis of DT was 1.8 years after surgical resection. All sites of DT were in the peritoneum around the surgical sites of GIST. The following clinical suspicion coupled with radiological findings contributed to the suspicion of intra-abdominal DTs: (1) Occurrence of a new single lesion in the peritoneum around the surgical sites of GIST; (2) uncontrolled lesion with imatinib while other lesions being controlled with imatinib; (3) well-defined ovoid shaped lesion with delayed or mild enhancement and absence of necrosis, hemorrhage, and cystic change on computed tomography; and (4) a lesion showing mild or no hypermetabolic activity on 18fluorodeoxyglucose-positron emission tomography, contrary to initially hyperactive lesion of GIST. All DTs were surgically removed except for one unresectable DT and only one DT recurred at another site of peritoneum, which was also surgically removed.

CONCLUSION

Intra-abdominal DT should be a differential diagnosis for a new single lesion in patients with GIST.

Autophagy inhibition overcomes sorafenib resistance in S45F-mutated desmoid tumors

BACKGROUND

Desmoid tumors (DTs) are rare and understudied fibroblastic lesions that are frequently recurrent and locally invasive. DT patients often experience chronic pain, organ dysfunction, decrease in quality of life, and even death.

METHODS

Sorafenib has emerged as a promising therapeutic strategy, which has led to the first randomized phase 3 clinical trial devoted to DTs. Concurrently, we conducted a comprehensive analysis of sorafenib efficacy in a large panel of desmoid cell strains to probe for response mechanism.

RESULTS

We found distinctive groups of higher- and lower-responder cells. Clustering the lower-responder group, we observed that CTNNB1 mutation was determinant of outcome. Our results revealed that a lower dose of sorafenib was able to inhibit cell viability, migration, and invasion of wild-type and T41A-mutated DTs. Apoptosis induction was observed in those cells after treatment with sorafenib. On the other hand, the lower dose of sorafenib was not able to inhibit cell viability, migration, or invasion or to induce apoptosis in the S45F-mutated DTs. The investigation of autophagy showed the dependency of S45F-mutated DTs on this pathway as a part of cell survival mechanism. Significantly, when autophagy was inhibited genetically or pharmacologically in the S45F mutant cell strains, sensitivity to sorafenib was restored.

CONCLUSIONS

Our findings suggest that the response to sorafenib differs when comparing S45F-mutated DTs and T41A-mutated or wild-type DTs. Furthermore, the combination of hydroxychloroquine and sorafenib enhances the antiproliferative and proapoptotic effects in S45F-mutated DT cells, suggesting that profiling β-catenin status could guide clinical management of desmoid patients who are considering sorafenib treatment.

Targeted next generation sequencing of pancreatic solid pseudopapillary neoplasms show mutations in Wnt signaling pathway genes

Solid pseudopapillary neoplasms of the pancreas are rare neoplasms that have been shown to harbor recurrent somatic pathogenic variants in the beta-catenin gene, CTNNB1. Here, we used targeted next generation sequencing to analyze these tumors for other associated mutations. Six cases of solid pseudopapillary neoplasms were studied. DNA extracted from formalin-fixed paraffin embedded tissue blocks was analyzed using the Ion Torrent platform, with the 50-gene Ampliseq Cancer Hotspot Panel v2 (CHPv2), with further variant validation performed by Sanger sequencing. Four tumors (67%) were confirmed to harbor mutations within CTNNB1, two with c.109T > G p.(Ser37Ala) and two with c.94G > A p.(Asp32Asn). One case showed a frameshift deletion in the Adenomatous Polyposis Coli gene, APC c.3964delG p.(Glu1322Lysfs*93) with a variant allele frequency of 42.6%. Sanger sequencing on non-tumoral tissue confirmed the variant was somatic. The patient with the APC mutation developed metastasis and died. In addition to the four cases harboring CTNNB1 variants, we found a case characterized by poor outcome, showing a rare frameshift deletion in the APC gene. Since the APC product interacts with beta-catenin, APC variants may, in addition to CTNNB1, contribute to the pathogenesis of solid pseudopapillary neoplasms via the Wnt signaling pathway.

Targeted therapy of desmoid-type fibromatosis: mechanism, current situation, and future prospects

Desmoid-type fibromatosis (DF) is a rare monoclonal fibroblastic proliferation that is characterized by locally infiltrative but rarely metastatic lesions. Tyrosine kinase and γ-secretase inhibitors are primarily used in the targeted therapy of DF. The use of these drugs, however, is mainly based on the recommendations of retrospective studies with small sample sizes. Previous studies that focused on the mechanism, efficacy, and safety of targeted therapy for DF were reviewed to provide references for clinical applications and research. The efficacy and safety of targeted therapy were compared with those of other systemic therapy options. Targeted therapy does not provide considerable advantages in efficacy and safety over other medical treatments and is usually applied after the failure of antihormonal therapies, nonsteroidal anti-inflammatory drugs, and chemotherapy. Further studies are required to explore the mechanism, indications, and appropriate drug dosage of the targeted therapy of DF.

Sorafenib for Advanced and Refractory Desmoid Tumors

BACKGROUND

Desmoid tumors (also referred to as aggressive fibromatosis) are connective tissue neoplasms that can arise in any anatomical location and infiltrate the mesentery, neurovascular structures, and visceral organs. There is no standard of care.

METHODS

In this double-blind, phase 3 trial, we randomly assigned 87 patients with progressive, symptomatic, or recurrent desmoid tumors to receive either sorafenib (400-mg tablet once daily) or matching placebo. Crossover to the sorafenib group was permitted for patients in the placebo group who had disease progression. The primary end point was investigator-assessed progression-free survival; rates of objective response and adverse events were also evaluated.

RESULTS

With a median follow-up of 27.2 months, the 2-year progression-free survival rate was 81% (95% confidence interval [CI], 69 to 96) in the sorafenib group and 36% (95% CI, 22 to 57) in the placebo group (hazard ratio for progression or death, 0.13; 95% CI, 0.05 to 0.31; P<0.001). Before crossover, the objective response rate was 33% (95% CI, 20 to 48) in the sorafenib group and 20% (95% CI, 8 to 38) in the placebo group. The median time to an objective response among patients who had a response was 9.6 months (interquartile range, 6.6 to 16.7) in the sorafenib group and 13.3 months (interquartile range, 11.2 to 31.1) in the placebo group. The objective responses are ongoing. Among patients who received sorafenib, the most frequently reported adverse events were grade 1 or 2 events of rash (73%), fatigue (67%), hypertension (55%), and diarrhea (51%).

CONCLUSIONS

Among patients with progressive, refractory, or symptomatic desmoid tumors, sorafenib significantly prolonged progression-free survival and induced durable responses. (Funded by the National Cancer Institute and others; ClinicalTrials.gov number, NCT02066181 .).

Subsequent Development of Desmoid Tumor after a Resected Gastrointestinal Stromal Tumor

Desmoid tumors (deep fibromatosis) of the mesentery are rare mesenchymal tumors. They are often misdiagnosed, especially with a previous history of resection for gastrointestinal stromal tumor (GIST). Immunohistochemistry can help differentiate between these two tumors. In this article, we present a case we had encountered: a Desmoid tumor developing in a patient with a history of GIST 3 years ago. It is the first case of GIST with subsequent development of Desmoid tumor to be reported in Saudi Arabia. We discuss the two entities of Desmoid tumor and GIST by comparing their definitions, clinical presentations, histological features, immunohistochemistry stains, molecular pathogenesis, prognosis, and treatment. We also discuss the relationship between GIST and the subsequent development of Desmoid tumors and compare our case with case reports in literature.

An update on the management of sporadic desmoid-type fibromatosis: a European Consensus Initiative between Sarcoma PAtients EuroNet (SPAEN) and European Organization for Research and Treatment of Cancer (EORTC)/Soft Tissue and Bone Sarcoma Group (STBSG)

Desmoid-type fibromatosis is a rare and locally aggressive monoclonal, fibroblastic proliferation characterized by a variable and often unpredictable clinical course. Currently, there is no established or evidence-based treatment approach available for this disease. Therefore, in 2015 the European Desmoid Working Group published a position paper giving recommendations on the treatment of this intriguing disease. Here, we present an update of this consensus approach based on professionals' AND patients' expertise following a round table meeting bringing together sarcoma experts from the European Organization for Research and Treatment of Cancer/Soft Tissue and Bone Sarcoma Group with patients and patient advocates from Sarcoma PAtients EuroNet. In this paper, we focus on new findings regarding the prognostic value of mutational analysis in desmoid-type fibromatosis patients and new systemic treatment options.

Role of Nonsteroidal Anti-inflammatory Drug in Treatment of Extra-abdominal Desmoid Tumors

Background

We retrospectively reviewed the outcomes of patients who had been treated with meloxicam for the extra-abdominal desmoid tumors and evaluated the correlation between clinical outcome and clinic pathological variables.

Methods

Twenty patients treated with meloxicam were followed up every 3 to 6 months. Meloxicam administration was planned at 15 mg/day orally for 6 months.

Results

Of the 20 patients evaluated, according to Response Evaluation Criteria in Solid Tumors criteria, there were five patients with partial response (25.0%), eight with stable disease (40.0%), and seven with tumor progression (35.0%). The cumulative probability of dropping out from our nonsurgical strategy using meloxicam was 35.0% at 1 year and 35.0% at 5 years.

Conclusions

The present study suggests that conservative treatment would be a primary treatment option for this perplexing disease even though we were not able to determine that the use of a cyclooxygenase-2 inhibitor would have an additional influence on the natural course of a desmoid tumor.