Proof of concept: prognostic value of the plasmatic concentration of circulating cell free DNA in desmoid tumors using ddPCR

Novel insights into biomarkers of progression in Desmoid tumor

Desmoid tumor (DT) is a rare neoplasm characterized by the proliferation of myofibroblastic cells that infiltrates and invades adjacent tissues. Due to its locally aggressive and recurrent nature, DT often causes local symptoms and can be challenging to manage clinically. Therefore, identifying biomarkers that can predict the progression of DT and guide treatment decisions is critical. This review summarizes several biomarkers that have been implicated in active surveillance (AS) and the prediction of postoperative recurrence and attempts to elucidate their underlying mechanisms. Some of these novel markers could provide prognostic value for clinicians, and ultimately help facilitate optimal and accurate therapeutic decisions for 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.

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.

Lower Rate of CTNNB1 Mutations and Higher Rate of APC Mutations in Desmoid Fibromatosis of the Breast: A Series of 134 Tumors

Desmoid fibromatosis (DF) is a rare, locally aggressive, nonmetastasizing fibroblastic/myofibroblastic tumor with a tendency to recur and an unpredictable clinical course. A "wait-and-see" policy is the new standard of care. DF are characterized by activating alterations of the wnt/β-catenin pathway: CTNNB1 or adenomatous polyposis coli gene (APC) mutations (these mutations being mutually exclusive). Desmoid-type fibromatosis of the breast (DFB) is rare with an incidence of 0.2% of breast tumors. The diagnosis of DFB is difficult, as it must be distinguished from metaplastic carcinoma and other spindle cell lesions. Sequencing of 128 DFB identified a lower rate of CTNNB1 mutations using Sanger (65.6%) or Sanger+next-generation sequencing (77.7%) and a higher rate of APC mutations (11.8%) than in all-site DF. By excluding patients with familial adenomatous polyposis (n=2), the rate of APC mutations in DFB was high (10.7%). The distribution of CTNNB1 mutations in DFB was different from all-site DF, with a higher rate of T41A (68.9%), a lower rate of S45F (5.7%), and a similar rate of S45T (12.6%). By combining the 2 molecular techniques in a 2-step manner (Sanger, then next-generation sequencing), we increased the detection rate of CTNNB1 mutations and lowered the rate of wild-type tumors from 34.4% to 9.8%, therefore improving the diagnosis of DFB. The identification of the exon 3 CTNNB1 mutation in breast spindle cell lesions is a highly specific tool for the diagnosis of DFB, in addition to extensive immunohistochemical analysis. Our study also underlines the importance of APC in DFB tumorigenesis. These findings have significant implications for patient care and management.

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.

The role of patients' associations

The role of patient groups has grown steadily stronger since the first General Meeting of cancer patients in 1999 and the emergence of the rare diseases issue in the mid-eighties. This article demonstrates the role of a patient group (SOS DESMOIDE) gathering people suffering from a rare disease (the desmoid tumor) in the stimulation of scientific and medical research as well as the improvement of patient care, information and support provided to patients. It substantiates these elements with numerous socio-medico-psychological surveys, scientific publications and medical research implemented by medical teams and supported, even sometimes initiated, by SOS DESMOIDE. This research effort illustrates the significant impact of a partnership between patients and physicians-researchers on medical and scientific breakthroughs in a specific pathological field.

Breast desmoid tumor management in France: toward a new strategy

PURPOSE

Desmoid tumors (DTs) are rare tumors that originate from myofibroblastic tissue. Recently, initial wait and see was recommended (ESMO guidelines Ann Oncol 2017) in the most frequent locations. This study investigates the outcome of breast desmoid tumor (BDT) according to the initial strategy.

METHOD

Data from all consecutive patients treated from a BDT in four referral centers were collected. Only intra-mammary desmoid tumors were included. A pathological review and a molecular analysis (CTNNB1 gene mutation) were performed (National re-reading network of sarcomas-RRePS). Patients were grouped according to initial strategy: surgery group (SG) and active surveillance group (ASG).

RESULTS

A total of 63 patients (61 women, 2 men) met the inclusion criteria. Median age was 50 years (16-86). CTNNB1 mutation was found in 61% (n = 36). SG included 46 patients (73%) (41 partial mastectomies, 2 mastectomies, and 3 mastectomies associated to parietectomies). Surgical margins were positive in 15 patients (33.3%). Median follow-up of SG was 24.9 (0.5-209) months; and 4 patients (8.7%) developed recurrence. ASG included 17 patients (27%). Their median follow-up was 42.2 (0-214) months, and 15 patients (88.2%) did not require any additional treatment. Six patients (35%) had a spontaneous regression, 9 patients (52%) were stable, and 2 patients presented a significant progression that was treated by partial mastectomy.

CONCLUSION

This study supports an initial nonsurgical approach to BDTs followed by surgery based on tumor growth in select cases, which is consistent with current ESMO recommendations.

Liquid biopsy and PCR-free ultrasensitive detection systems in oncology (Review)

In oncology, liquid biopsy is used in the detection of next-generation analytes, such as tumor cells, cell-free nucleic acids and exosomes in peripheral blood and other body fluids from cancer patients. It is considered one of the most advanced non-invasive diagnostic systems to enable clinically relevant actions and implement precision medicine. Medical actions include, but are not limited to, early diagnosis, staging, prognosis, anticipation (lead time) and the prediction of therapy responses, as well as follow-up. Historically, the applications of liquid biopsy in cancer have focused on circulating tumor cells (CTCs). More recently, this analysis has been extended to circulating free DNA (cfDNA) and microRNAs (miRNAs or miRs) associated with cancer, with potential applications for development into multi-marker diagnostic, prognostic and therapeutic signatures. Liquid biopsies avoid some key limitations of conventional tumor tissue biopsies, including invasive tumor sampling, under-representation of tumor heterogeneity and poor description of clonal evolution during metastatic dissemination, strongly reducing the need for multiple sampling. On the other hand, this approach suffers from important drawbacks, i.e., the fragmentation of cfDNA, the instability of RNA, the low concentrations of certain analytes in body fluids and the confounding presence of normal, as well as aberrant DNAs and RNAs. For these reasons, the analysis of cfDNA has been mostly focused on mutations arising in, and pathognomonicity of, tumor DNA, while the analysis of cfRNA has been mostly focused on miRNA patterns strongly associated with neoplastic transformation/progression. This review lists some major applicative areas, briefly addresses how technology is bypassing liquid biopsy limitations, and places a particular emphasis on novel, PCR-free platforms. The ongoing collaborative efforts of major international consortia are reviewed. In addition to basic and applied research, we will consider technological transfer, including patents, patent applications and available information on clinical trials aimed at verifying the potential of liquid biopsy in cancer.