Systemic therapy of aggressive fibromatosis in children and adolescents: Report of the Cooperative Weichteilsarkom Studiengruppe (CWS)

The significance of margins in pediatric Non-Rhabdomyosarcoma soft tissue sarcomas: Consensus on surgical margin definition harmonization from the INternational Soft Tissue SaRcoma ConsorTium (INSTRuCT)

BACKGROUND

Margin status following surgery in children, adolescents, and young adults with soft tissue sarcomas is controversial and has been defined differently by various specialties, with definitions changing over time and by cooperative group. The International Soft Tissue Sarcoma Consortium (INSTRuCT) is a collaboration of the Children's Oncology Group (COG) Soft Tissue Sarcoma Committee, European pediatric Soft Tissue sarcoma Study Group (EpSSG), and the European Cooperative Weichteilsarkom Studiengruppe (CWS) devoted to improving patient outcomes by pooling and mining cooperative group clinical trial data.

METHODS

The INSTRuCT non-rhabdomyosarcoma soft tissue sarcoma (NRSTS) working group aimed to develop international harmonized recommendations regarding surgical margin assessment and definitions in children and adolescents with soft tissue tumors.

RESULTS AND CONCLUSION

This review addresses accepted principles and areas of controversy, including the perspectives of surgeons, pathologists, radiation oncologists, and pediatric oncologists, to develop a framework for building common guidelines for future research.

Long-term result of 125 I seed brachytherapy for pediatric desmoid tumor in the head and neck

BACKGROUND

Desmoid tumor (DT) is rare and challenging, often affects the head and neck (HN) region in children, and its appropriate treatments are under-discussed. This study aimed to retrospectively evaluate the long-term effectiveness and safety of ¹²⁵ I seed brachytherapy for pediatric DT in HN.

PROCEDURE

Seven pediatric patients with a median age of three years who suffered from DT in HN treated with ¹²⁵ I brachytherapy from January 2008 to June 2018 were included. Among these, five underwent sole brachytherapy and the others combined with surgery under prescription doses ranging from 10,000 to 12,000 cGy. The rate of local control (LC), complete response (CR), and partial response (PR) was calculated after evaluation by radiological and pathological means. Radiation-associated toxicities were also evaluated.

RESULTS

The LC rate was 7/7 during the follow-up time ranging from 43 to 135 months and with a mean of 57 months. No recurrent lesion was found in the patients receiving surgery combined with brachytherapy. In patients treated with sole brachytherapy, the radiological PR rate and CR rate were 4/5 and 1/5, respectively. In those reaching radiological PR, 3/4 were pathological CR. Slight acute radiation-associated toxicities were observed in all patients, and no late or severe acute toxicity was observed.

CONCLUSION

¹²⁵ I brachytherapy is effective and safe in the management of pediatric DT in HN as the sole modality or combined with surgery in the long term.

Pediatric Non-Rhabdomyosarcoma Soft Tissue Sarcomas: Standard of Care and Treatment Recommendations from the European Paediatric Soft Tissue Sarcoma Study Group (EpSSG)

This paper describes the standard of care for patients with non-rhabdomyosarcoma soft tissue sarcomas (NRSTS) and the therapeutic recommendations developed by the European paediatric Soft tissue sarcoma Study Group (EpSSG). NRSTS form a very mixed group of mesenchymal extraskeletal malignancies. Their rarity, heterogeneity, and aggressiveness make the management of children and adolescents with these tumors complex and challenging. The overall cure rate for patients with NRSTS is around 70%, but survival depends on several prognostic variables, such as histotype and tumor grade, extent of disease and stage, tumor size, and tumor site. While surgery remains the mainstay of treatment for most of these tumors, a multimodal therapeutic approach including radiotherapy and chemotherapy is required in many cases. The EpSSG NRSTS 2005 study was the first prospective protocol tailored specifically to NRSTS. Together with the ARST0332 study developed by the North-American Soft Tissue Sarcoma Committee of the Children's Oncology Group (COG), the EpSSG NRSTS 2005 study currently represents the benchmark for these tumors, establishing risk-adapted standards of care. The EpSSG has developed common treatment recommendations for the large group of adult-type NRSTS (including synovial sarcoma), and specific treatment recommendations for other particular adult-type histologies (ie, alveolar soft-part sarcoma, clear cell sarcoma and dermatofibrosarcoma protuberans); other highly malignant tumors with a biology and clinical behavior differing from those of adult-type NRSTS (ie, rhabdoid tumors and desmoplastic small round cell tumor); and soft tissue tumors of intermediate malignancy (ie desmoid-type fibromatosis, inflammatory myofibroblastic tumors, and infantile fibrosarcoma). New effective drugs are needed for patients whose NRSTS carries the worst prognosis, ie, those with unresectable tumors, metastases at diagnosis, or relapsing disease. Progress in this area relies on our ability to develop international integrated prospective collaborations, both within existing pediatric oncology networks and, importantly, between the communities of specialists treating pediatric and adult sarcoma.

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.

Infantile myofibromatosis: Excellent prognosis but also rare fatal progressive disease. Treatment results of five Cooperative Weichteilsarkom Studiengruppe (CWS) trials and one registry

BACKGROUND

Infantile myofibromatosis (IM) is a rare benign soft tissue tumor and often a self-limiting disease but rarely includes life-threatening complications. Little is known about optimal treatment of primary localized (LD) and multifocal disease (MFD).

METHODS

Treatment and outcome of 95 children with IM registered within five Cooperative Weichteilsarkom Studiengruppe (CWS) trials and one registry (1981-2016) were evaluated.

RESULTS

LD was diagnosed in 71 patients at a median age of 0.4 years (range 0.0-17.7). MFD was present in 24 patients. The mainstay of treatment was watch-and-wait strategy (w&w) after initial biopsy or resection. Low-dose chemotherapy (CHT) was administered to 16/71 (23%) patients with LD and eight of 24 (33%) patients with MFD, imatinib was added in two. A delayed resection was possible in eight of 71 (11%) and five of 24 (21%) patients with LD and MFD, respectively. Overall, patients were alive in complete remission (n = 77) and partial remission (n = 10) at a median follow-up time of 3.4 years after diagnosis (range 0.01-19.4); no data available (n = 5). Three patients died of progressive disease (PD) despite CHT. Gender, tumor size, and location correlated with a favorable event-free survival (EFS) in patients with LD. The 5-year EFS and overall survival of patients with LD were 73% (±12, confidence interval [CI] 95%) and 95% (±6, CI 95%), respectively; for MFD 51% (±22, CI 95%) and 95% (±10, CI 95%).

CONCLUSION

Prognosis is excellent in patients with LD and MFD. Targeted treatment needs to be evaluated for rare fatal PD.

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.

Treatment Concepts and Challenges in Nonrhabdomyosarcoma Soft Tissue Sarcomas

Pediatric nonrhabdomyosarcoma soft tissue sarcomas (NRSTSs) encompass a heterogeneous group of mesenchymal tumors with more than 50 histologic variants. The incidence of NRSTS is greater than rhabdomyosarcoma; however, each histologic type is rare. The treatment schema for all NRSTSs is largely surgical. The treatment is a risk-adapted approach based on tumor size, localization, tumor grade, and presence of metastases. Low-grade tumors are mainly managed by surgery alone, whereas for high-grade tumors a multimodal treatment concept is necessary. The multimodal treatment consists of tumor biopsy, chemotherapy, local treatment (surgery ± radiotherapy), and immunotherapy in selected conditions.

Upfront surgery is not advantageous compared to more conservative treatments such as observation or medical treatment for patients with desmoid tumors

Background

This study compared the clinical and functional outcomes of patients initially treated with observation or medical treatment with those of patients treated with local treatment (surgery alone or surgery with adjuvant radiotherapy) to confirm whether observation or medical treatment is an appropriate first-line management approach for patients with desmoid tumors.

Methods

We retrospectively reviewed the medical records of 99 patients with histologically confirmed primary desmoid tumors treated between 1978 and 2018. The median follow-up period was 57 months. We evaluated event-free survival, defined as the time interval from the date of initial diagnosis to the date of specific change in treatment strategy or recurrence or the last follow-up.

Results

An event (specific change in treatment strategy or recurrence) occurred in 28 patients (28.3%). No significant difference in event-free survival was found between the first-line observation/medical treatment and local treatment groups (p = 0.509). The median Musculoskeletal Tumor Society score of the patients treated with first-line local treatment was 29 (interquartile range [IQR], 23–30), whereas that of the patients managed with first-line observation or medical treatment was 21 (IQR, 19–29.5). First-line observation or medical treatment was more frequently chosen for larger tumors (p = 0.045). In the patients treated with local treatment, local recurrence was not related to the surgical margin (p = 0.976).

Conclusion

Upfront surgery is not advantageous compared to more conservative treatments such as observation or medical treatment for patients with desmoid tumors.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-020-03897-9.

Genetic testing and surveillance in infantile myofibromatosis: a report from the SIOPE Host Genome Working Group

Infantile myofibromatosis (IM), which is typically diagnosed in young children, comprises a wide clinical spectrum ranging from inconspicuous solitary soft tissue nodules to multiple disseminated tumors resulting in life-threatening complications. Familial IM follows an autosomal dominant mode of inheritance and is linked to PDGFRB germline variants. Somatic PDGFRB variants were also detected in solitary and multifocal IM lesions. PDGFRB variants associated with IM constitutively activate PDGFRB kinase activity in the absence of its ligand. Germline variants have lower activating capabilities than somatic variants and, thus, require a second cis-acting hit for full receptor activation. Typically, these mutant receptors remain sensitive to tyrosine kinase inhibitors such as imatinib. The SIOPE Host Genome Working Group, consisting of pediatric oncologists, clinical geneticists and scientists, met in January 2020 to discuss recommendations for genetic testing and surveillance for patients who are diagnosed with IM or have a family history of IM/PDGFRB germline variants. This report provides a brief review of the clinical manifestations and genetics of IM and summarizes our interdisciplinary recommendations.

Desmoid with biweekly methotrexate and vinblastine shows similar effects to weekly administration: A phase II clinical trial

Low-dose methotrexate (MTX) plus vinblastine (VBL) chemotherapy is an effective treatment for desmoid-type fibromatosis (DF). However, previous reports have described a weekly regimen, with no reports available on a biweekly one. The aim of this study was to determine the clinical outcomes of a biweekly regimen in a cohort prospectively treated in our single institution. Since 2010, we have prospectively treated refractory DF patients with biweekly MTX (30 mg/m² ) + VBL (6 mg/m² ). Efficacy, progression-free survival (PFS), and correlating factors were analyzed. Adverse events (AEs) were recorded. In total, 38 patients received low-dose MTX + VBL therapy, and its efficacy was assessed in 37 of them. Nineteen (51%) patients showed partial response (PR). Clinical benefit rate was 95%. PFS at 5 y was 80.8%. In PR cases, median time to response was 10 mo. Longer duration of therapy was significantly associated with the response of PR (P = .007) by univariate analysis. There was no clear association between various clinicopathological factors, including tumor size, location, catenin beta-1 (CTNNB1) mutation status with effect. Only 3 AEs of grade 3/4 were observed. Tumor regrowth after MTX + VBL discontinuation was observed in 5 (20%) of 25 patients. Biweekly administration of MTX + VBL chemotherapy was well tolerated compared with weekly administration, and its efficacy was anticipated in DF patents, although the time needed to achieve a response may be relatively long. The treatment interval should be determined taking into account both the condition of the tumor and the patient's preference.

PROMIS Function Scores Are Lower in Patients Who Underwent More Aggressive Local Treatment for Desmoid Tumors

BACKGROUND

Desmoid tumors of the extremities often present with pain and functional limitation, but treatment can lead to morbidity and recurrence is common. The impact of treatment with respect to traditional "oncologic" metrics (such as recurrence rate) has been studied extensively, with a shift in recent years away from local therapies as first-line management; however, little is known about the association between treatment modality and long-term functional outcomes for patients with this benign disease.

QUESTIONS/PURPOSES

In a retrospective review of consecutive patients treated at two institutions, we asked: (1) Is event-free survival (EFS) different between patients who undergo local treatment and those who do not for primary as well as for recurrent desmoid tumors? (2) What treatment-related factors are associated with worse Patient-reported Outcomes Measurement Information System (PROMIS) function scores at a minimum of 1 year after treatment?

METHODS

Between 1991 and 2017, 102 patients with desmoid tumors of the extremities (excluding those of the hands and feet) were treated at two institutions; of those, 85 patients with 90 tumors were followed clinically for at least 1 year (median [range] 59 months follow-up [12 to 293]) and were included in the present analysis. We attempted to contact all patients for administration of PROMIS function (Physical Function Short Form [SF] 10a and Upper Extremity SF v2.0 7a) and Pain Interference (SF 8a) questionnaires. Complete survey data (minimum 1 year follow-up) were available for 46% (39 of 102) of patients with 40 tumors at a median of 125 months follow-up; only these patients were included in PROMIS data analyses. Though there was no formal institutional treatment algorithm in place during the study period, surgical resection typically was the preferred modality for primary tumors; radiation therapy and systemic treatments (including cytotoxic or hormonal agents earlier in the study period, and tyrosine kinase inhibitors later) were often added for recurrent or very symptomatic disease. We coded treatment for each patient into discrete episodes, each defined by a particular treatment strategy: local treatment only (surgery and/or radiation), systemic treatment only, local plus systemic treatment, or observation; treatment episodes rendered at other institutions (that is, before referral) were not included in the analyses. Treatment failure was defined as recurrence after surgical resection, or clinically significant radiologic and/or symptomatic progression after systemic treatment, and EFS was defined as time from treatment initiation to treatment failure or final follow-up. Episodes of treatment for recurrent tumors were analyzed in a pooled fashion, wherein discrete treatment episodes for patients with multiple recurrences were included separately as independent events. We analyzed 56 primary tumors (54 patients), and 101 discrete treatment episodes for recurrent tumors (88 patients). Kaplan-Meier survival curves were constructed separately for the primary and recurrence cohorts, both comparing EFS among patients who received any local treatment (local treatment and local plus systemic treatment groups) versus those who did not (systemic treatment and observation groups). PROMIS function data were analyzed on the bases of patient- and treatment-specific variables, including the PROMIS Pain Interference score as a potential explanatory variable.

RESULTS

Within both the primary and recurrence cohorts, there were no differences between the local treatment, systemic treatment, and local plus systemic treatment groups with respect to gender, age, axillary/hip girdle location, or tumor volume. Among primary tumors, 5-year EFS was 44% (95% CI 24 to 80) for the systemic-only group versus 15% (95% CI 5 to 44) for the local treatment group (p = 0.087). Within the pooled recurrence treatment episode cohort, 5-year EFS after systemic-only treatment was 70% (95% CI 52 to 94) versus 56% among patients receiving any local treatment (95% CI 44 to 70; p = 0.46). PROMIS function scores were lowest among patients who underwent two or more resections (39 versus 51 versus 47 for ≥2, 1, and 0 resections, respectively; p = 0.025); among those who received both surgery and radiation at any point, either concurrently or in separate treatment episodes, as compared with those who did not (39 versus 46; p = 0.047); and among those with higher levels of pain interference (38 versus 47 for pain interference scores > 50 versus < 50; p = 0.006).

CONCLUSIONS

Patients treated with local modalities (surgery and/or radiation, with or without additional systemic therapy) did not experience improved EFS as compared with those treated without local modalities; this was the case for both the primary and the recurrent tumor cohorts. However, PROMIS function scores were lowest among patients who underwent two or more surgical interventions and among those treated with surgery and radiation at any time, suggesting that more aggressive local treatment may be associated with poorer long-term functional outcomes. Prospective collection of patient-reported outcomes data at multiple time points will allow for more direct correlations between treatment modality and impact on function and will help to elucidate the ideal management strategy for these benign but often-symptomatic tumors.

LEVEL OF EVIDENCE

Level III, therapeutic study.

[Systemic treatment for management of aggressive fibromatosis in both adult and children: Level of evidence and unsolved questions]

We summarize here available data about systemic treatments of desmoids tumors, as well in adult patients as pediatric patients. Until 2018, the level of evidence associated with these treatments (NSAI, hormonal therapies, tyrosine kinase inhibitors, chemotherapy) was very low, based on retrospective studies or non-randomized phase 2 trials with limited number of cases. In 2018-2019, 2 large randomized trials have been published, including one large superiority phase 3 trial comparing sorafenib to placebo. This trial clearly demonstrates the clinical benefit of sorafenib over placebo (level of evidence IA). To conclude, wait-and-see policy must be the first-line approach, systemic treatment is indicated in case of disease progression. Randomized trials are feasible in this exceptional disease.

Desmoid-type fibromatosis of the head and neck in children: A changing situation

INTRODUCTION

Desmoid-type fibromatosis (DF) is a rare benign lesion known for its local aggressiveness. The tumor management still remains under debate. Primary head and neck (HN), represents the second most prevalently affected sitein children with DF. This study aims to analyze the specificity of HN-DF in children, focusing on long-term effects of the tumor and therapies.

METHODS

This retrospective multicenter study analyzed children treated for a HN-DF between 1993 and 2013. All medical files were reviewed and their outcomes analyzed according to the initial therapies provided.

RESULTS

Sixteen children were selected. Mandibular and submandibular areas were the main locations (11 cases). Eight children underwent chemotherapy as first-line therapy with tumor control in 3 cases and 5 cases needing additional treatment. Six children underwent primary surgery: isolated in 3 cases and with additional treatment after tumor progression in 3 cases. A wait-and-see attitude was adopted for 2 children without any additional treatment in 1 case, and followed by additional chemotherapy in the other case. Total burden of treatment to control the disease was a biopsy (1 case), surgery (3 unique cases, 1 multiple case), surgery with chemotherapy (6 cases), and exclusive medical therapies (5 cases). Surgical postoperative sequelae were facial palsy (cases of parotid gland affection), XI^th cranial nerve sacrifice or sensory impairment.

CONCLUSION

HN-DF is a local and extensive disease that is difficult to control with surgery alone. Sequelae are frequent due to the initial tumor location or therapies. Initial conservative strategies need to be discussed in a multidisciplinary way in order to try to control the disease with the minimal morbidity.

[Pediatric tumors with spindle cell morphology]

Spindle cell tumors in childhood are rare lesions with a heterogeneous morphological picture and clinical course, ranging from benign lesions to fully malignant tumors. The clinical assessment of these tumors is often challenging since some of them show fast growth dynamics but are utterly benign, while a subset of slow-growing tumors can represent malignant entities. Due to the rarity of these tumors as well as the overlapping morphology and the often uncharacteristic immunohistochemical profiles, the pathologic diagnosis is often also difficult. This review gives an overview of some of the more common pediatric spindle cell tumors. In addition to the morphological features and immunohistochemical aspects, specific molecular changes are discussed. Here, some of the newly described translocations that may imply therapeutic options, are presented.