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

PURPOSE

Desmoid tumor (DT) is a rare monoclonal, fibroblastic proliferation characterized by a variable and often unpredictable clinical course. Initial active surveillance is recommended by current guideline, and surgery is one of the main therapies for DT. Predicting the prognosis and outcome of active surveillance for intra-abdominal DT is pressing issue.

METHODS

The study included eighteen patients with intra-abdominal DT. Metabolic tumor volume (MTV), total lesion glycolysis (TLG), and maximum standardized uptake value (SUVmax) were measured. We analyzed their relationship with the outcome of active surveillance, as well as clinical, prognostic, and pathological data.

RESULTS

The MTV and TLG of recurrent DT were significantly higher than those of non-recurrent DT (P < 0.001 and P = 0.00, respectively). The ROC curve suggested that the appropriate cutoff values for distinguishing recurrent DT from non-recurrent DT were 760.8 for MTV (sensitivity = 1, specificity = 0.857 and AUC = 0.929), and 1318.4 for TLG (sensitivity = 1, specificity = 0.786, and AUC = 0.911). The cutoff values of MTV and TLG significantly correlated with PFS using the Kaplan-Meier method (P = 0.002 and P = 0.007, respectively). MTV and TLG could distinguish DTs with subsequent progression from stable ones (P = 0.004 and P = 0.004, respectively). The ROC curve suggested that the appropriate cutoff values for distinguishing DTs with subsequent progression from stable ones were 197.1 for MTV (sensitivity = 0.9, specificity = 1, and AUC = 0.900), and 445.45 for TLG (sensitivity = 0.9, specificity = 1, and AUC = 0.900).

CONCLUSION

Volume-based 18F-FDG-PET can predict prognosis of intra-abdominal DT. MTV and TLG can predict the outcome of active surveillance for intra-abdominal DT. MTV and TLG can potentially be predictors of surgical risk and difficulty.

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.

MR-guided focused ultrasound therapy of extra-abdominal desmoid tumors: a multicenter retrospective study of 105 patients

OBJECTIVE

To assess the safety and efficacy of magnetic resonance-guided focused ultrasound (MRgFUS) for the treatment extra-abdominal desmoids.

METHODS

A total of 105 patients with desmoid fibromatosis (79 females, 26 males; 35 ± 14 years) were treated with MRgFUS between 2011 and 2021 in three centers. Total and viable tumors were evaluated per patient at last follow-up after treatment. Response and progression-free survival (PFS) were assessed with (modified) response evaluation criteria in solid tumors (RECIST v.1.1 and mRECIST). Change in Numerical Rating Scale (NRS) pain and 36-item Short Form Health Survey (SF-36) scores were compared. Treatment-related adverse events were recorded.

RESULTS

The median initial tumor volume was 114 mL (IQR 314 mL). After MRgFUS, median total and viable tumor volume decreased to 51 mL (95% CI: 30-71 mL, n = 101, p < 0.0001) and 29 mL (95% CI: 17-57 mL, n = 88, p < 0.0001), respectively, at last follow-up (median: 15 months, 95% CI: 11-20 months). Based on total tumor measurements (RECIST), 86% (95% CI: 75-93%) had at least stable disease or better at last follow-up, but 50% (95% CI: 38-62%) of remaining viable nodules (mRECIST) progressed within the tumor. Median PFS was reached at 17 and 13 months for total and viable tumors, respectively. NRS decreased from 6 (IQR 3) to 3 (IQR 4) (p < 0.001). SF-36 scores improved (physical health (41 (IQR 15) to 46 (IQR 12); p = 0.05, and mental health (49 (IQR 17) to 53 (IQR 9); p = 0.02)). Complications occurred in 36%, most commonly 1st/2nd degree skin burns.

CONCLUSION

MRgFUS reduced tumor volume, reduced pain, and improved quality of life in this series of 105 patients with extra-abdominal desmoid fibromatosis.

CLINICAL RELEVANCE STATEMENT

Imaging-guided ablation is being increasingly used as an alternative to surgery, radiation, and medical therapy for the treatment of desmoid fibromatosis. MR-guided high-intensity focused ultrasound is an incisionless ablation technique that can be used to reduce tumor burden effectively and safely.

KEY POINTS

• Desmoid fibromatosis was treated with MR-guided high-intensity focused ultrasound in 105 patients. • MR-guided focused ultrasound ablation reduced tumor volume and pain and improved quality of life. • MR-guided focused ultrasound is a treatment option for patients with extra-abdominal desmoid tumors.

Desmoid Tumors: A Comprehensive Review

Desmoid tumors (DT) are rare, locally aggressive, fibroblastic soft-tissue tumors that are characterized by infiltrative growth and can affect organs and adjacent structures, resulting in substantial clinical burden impacting patients' health-related quality of life. Searches of PubMed, Embase, Cochrane, and key conferences were conducted in November 2021 and updated periodically through March 2023 to identify articles describing the burden of DT. Of 651 publications identified, 96 relevant ones were retained. Diagnosis of DT is challenging because of its morphologic heterogeneity and variable clinical presentation. Patients visit multiple healthcare providers, often facing delays in correct diagnosis. The low incidence of DT (estimated 3-5 cases per million person-years) limits disease awareness. Patients with DT experience a high symptom burden: up to 63% of patients experience chronic pain, which leads to sleep disturbance (73% of cases), irritability (46% of cases), and anxiety/depression (15% of cases). Frequently mentioned symptoms are pain, limited function and mobility, fatigue, muscle weakness, and swelling around the tumor. Overall, quality of life in patients with DT is lower than in healthy controls. There is no treatment approved by the US Food and Drug Administration for DT; however, treatment guidelines reference available options, such as active surveillance, surgery, systemic therapy, and locoregional therapy. Choice of active treatment may depend on tumor location, symptoms, and risk of morbidity. The substantial burden of illness of DT is related to difficulties in timely and accurate diagnosis, high symptom burden (pain and functional limitations), and decreased quality of life. There is a high unmet need for treatments that specifically target DT and improve quality of life.

Health-related Quality of Life of Patients With Non-Intra-abdominal Desmoid-Type Fibromatosis During Active Surveillance: Results of a Prospective Observational Study

OBJECTIVE

To examine the impact of an active surveillance (AS) approach on the health-related quality of life (HRQoL) of patients with desmoid-type fibromatosis (DTF).

BACKGROUND DATA

AS is recommended as initial approach in DTF patients. AS might however negatively affect HRQoL due to physical symptoms or stress and anxiety.

METHODS

In a prospective observational study, the GRAFITI trial (NTR4714), DTF patients were followed during an initial AS approach for 3 years. HRQoL was assessed by the EORTC QLQ-C30 at baseline, 6, 12 and 24-month follow-up. Patients who completed questionnaires at≥1-time point were included in this analysis of the secondary endpoint. A multivariable linear mixed-effects model with random intercept was conducted to assess trends of HRQoL scores over time and to explore the effect of treatment strategy on HRQoL.

RESULTS

All 105 patients enrolled in the GRAFITI trial were eligible for the HRQoL analyses. During 24-month follow-up, 75 patients (71%) continued AS and 30 patients (29%) started an active treatment (AT). DTF patients who continued AS demonstrated relatively stable HRQoL scores during follow-up. HRQoL scores of patients who started AT worsened compared to patients who continued AS, although no significant changes in HRQoL score over time were found in the mixed-model analyses. Overall, DTF patients who started AT scored significantly worse on pain (β=10.08, P =0.039) compared to patients who continued AS.

CONCLUSIONS

An initial AS approach did not impair HRQoL of DTF patients who continued AS over time, therefore providing further support for AS as the frontline approach in DTF patients. Longitudinal assessment of HRQoL should be part of clinical follow-up to identify patients who may need a change in treatment strategy.

A Nationwide Prospective Clinical Trial on Active Surveillance in Patients With Non-intraabdominal Desmoid-type Fibromatosis: The GRAFITI Trial

OBJECTIVE

To assess tumor behavior and the efficacy of active surveillance (AS) in patients with desmoid-type fibromatosis (DTF).

SUMMARY OF BACKGROUND DATA

AS is recommended as initial management for DTF patients. Prospective data regarding the results of AS are lacking.

METHODS

In this multicenter prospective cohort study (NTR4714), adult patients with non-intraabdominal DTF were followed during an initial AS approach for 3 years. Tumor behavior was evaluated according to Response Evaluation Criteria in Solid Tumors. Cumulative incidence of the start of an active treatment and progression-free survival (PFS) were calculated using the Kaplan-Meier method. Factors predictive for start of active treatment were assessed by Cox regression analyses.

RESULTS

A total of 105 patients started with AS. Median tumor size at baseline was 4.1cm (interquartile range 3.0-6.6). Fifty-seven patients had a T41A CTNNB1 mutation; 14 patients a S45F CTNNB1 mutation. At 3 years, cumulative incidence of the start of active treatment was 30% (95% confidence interval [CI] 21-39) and PFS was 58% (95% CI 49-69). Median time to start active treatment and PFS were not reached at a median follow-up of 33.7 months. During AS, 32% of patients had stable disease, 28% regressed, and 40% demonstrated initial progression. Larger tumor size (≥5 cm; hazard ratio = 2.38 [95% CI 1.15-4.90]) and S45F mutation (hazard ratio = 6.24 [95% CI 1.92-20.30]) were associated with the start of active treatment.

CONCLUSIONS

The majority DTF patients undergoing AS do not need an active treatment and experience stable or regressive disease, even after initial progression. Knowledge about the natural behavior of DTF will help to tailor the follow-up schedule to the individual patient.

Desmoid tumors located in the abdomen or associated with adenomatous polyposis: French intergroup clinical practice guidelines for diagnosis, treatment, and follow-up (SNFGE, FFCD, GERCOR, UNICANCER, SFCD, SFED, SFRO, ACHBT, SFR)

INTRODUCTION

Desmoid tumor (DT) of the abdomen is a challenging and rare disease. The level of evidence available to document their treatment is relatively low, however, recent publications of prospective studies have allowed to precise their management.

METHODS

This document is a summary of the French intergroup guidelines realized by all French medical and surgical societies involved in the management of DT located in the abdomen or associated with adenomatous polyposis. Recommendations are graded in four categories (A, B, C and D), according to the level of evidence found in the literature until January 2021.

RESULTS

When the diagnosis of DT is suspected a percutaneous biopsy should be performed when possible. A molecular analysis looking for pathogenic mutations of the CTNNB1 and APC genes should be systematically performed. When a somatic pathogenic variant of the APC gene is present, an intestinal polyposis should be searched. Due to a high rate of spontaneous regression, non-complicated DT should first benefit from an active surveillance with MRI within 2 months after diagnosis to assess the dynamic of tumor growth. The treatment decision must be discussed in an expert center, favoring the less toxic treatments which can include broad spectrum tyrosine kinase inhibitor or conventional chemotherapy (methotrexate-vinblastine). Surgery, outside the context of emergency, should only be considered for favorable location in an expert center.

CONCLUSION

French guidelines for DT management were elaborated to help offering the best personalized therapeutic strategy in daily clinical practice as the DT therapeutic landscape is complexifying. Each individual case must be discussed within a multidisciplinary expert team.

[Desmoid-type fibromatosis of the breast: about two cases and literature review]

Breast fibromatosis is a benign breast tumor of mesenchymal origin, accounting for 0.2% of breast tumors. This study reports two cases of breast fibromatosis highlighting its diagnostic, morphological, therapeutic and evolutionary features. In both cases, this tumor clinically and radiologically mimicked a cancer. Diagnostic confirmation was based on histological examination. Breast fibromatosis was characterized by local progression and a tendency to recurrence, hence the role of surgical excision with free surgical margins in our patients. The role of locoregional treatments (radiotherapy and cryotherapy) and medical treatments, in particular anti-estrogen therapy, is not clearly defined. In conclusion, breast fibromatosis must be known as it mimicks breast cancer and is characterized by a very high recurrence rate, without ever developing metastases.

Familial adenomatous polyposis associated with desmoid tumors presenting with abdominal abscess: A case report and literature review

RATIONALE

Familial adenomatous polyposis (FAP) associated with desmoids tumors (DTs) complicated by abscess formation is rare. The management is not easy and the choice of the best treatment may be controversial.

PATIENT CONCERNS

A 33-year-old man was admitted to our hospital for abdominal pain, fever, chills, nausea, and vomiting. He had a family history of FAP, and history of abdominal surgery.

DIAGNOSES

An abdominal enhanced chest computed tomography (CT) scan revealed a soft tissue mass in the abdominal wall and an irregular mesenteric soft tissue mass with internal fistula and intra-abdominal abscess. A CT-guided biopsy of the abdominal wall mass revealed DTs.

INTERVENTIONS

The patient was given oral antibiotics for 6 months, and ultimately underwent surgery.

OUTCOMES

The patient had no evidence of recurrence on follow-up at 10 months.

LESSONS

This case indicates that for patients with FAP who have a history of abdominal surgery and a progressively enlarging mass and abscess in the abdomen, it is necessary to consider the possibility of DTs. FAP-related DTs are rarely complicated by abscess formation. Antibiotic therapy plus surgical resection of the tumor may be effective and make good prognosis.

What is the best front-line approach in patients with desmoid fibromatosis? - A retrospective analysis from a reference center

INTRODUCTION

Desmoid fibromatosis (DF) is a locally aggressive, not metastasizing tumor associated with high local recurrence rates. Surgery was a standard-of-care for DF treatment; however, recently, conservative treatment and active surveillance are preferred. This study aimed to evaluate the real-life outcomes of DF treatment.

MATERIALS AND METHODS

All consecutive patients diagnosed with DF and treated between 01.1999 and 12.2018 at one sarcoma reference institution were included in this retrospective analysis. Kaplan-Meier estimator, long-rank test, Cox regression model, and Chi2 tests were used for statistical analyses.

RESULTS

The analyses included 363 patients (254 female, 109 male). 195 patients (53.7%) underwent surgical resection, and 139 (38.3%) experienced a watch-and-wait approach with or without concomitant therapy with nonsteroid anti-inflammatory drugs (NSAIDs) in the first line. Disease recurrence/progression occurred in 43.2% of patients treated with surgery and 42.6% in the watch-and-wait group, resulting in 5-year event-free survival (EFS) rates of 60% and 55%, respectively. There was no difference in EFS between both groups (HR1.28, 95%CI 0.91-1.79). Surgery without prior biopsy and extra-abdominal wall location was associated with inferior outcomes.

CONCLUSIONS

Results of DF treatment in our center showed that watch-and-wait approach ± NSAIDs has similar efficacy to upfront surgery and allows to avoid unnecessary surgery in approximately half of the patients, primarily when tumors are located in unfavorable sites, like extremities.

SEOM Clinical Guideline of management of soft-tissue sarcoma (2020)

Soft-tissue sarcomas constitute an uncommon and heterogeneous group of tumors of mesenchymal origin. Diagnosis, treatment, and management should be performed by an expert multidisciplinary team. MRI/CT of the primary tumor and biopsy is mandatory before any treatment. Wide surgical resection with tumor-free tissue margin is the mainstay for localized disease. Radiotherapy is indicated in large, deep, high-grade tumors, or after marginal resection not suitable for re-excision. Perioperative chemotherapy should be discussed for high-risk sarcomas of the extremities and trunk-wall. In the case of oligometastatic disease, patients should be considered for local therapies. First-line treatment with anthracyclines (or in combination with ifosfamide) is the treatment of choice. Other drugs have shown activity in second-line therapy and in specific histological subtypes but options are limited and thus, a clinical trial should always be discussed.

[A Case of Pelvic Desmoid-Type Fibromatosis Treated by Radiation and Medication Therapies]

The treatment for desmoid-type fibromatosis involves surgical resection and medication therapy, but the standard treatment has not yet been established. In the West, the usefulness of radiation therapy has been reported. We encountered a patient with desmoid-type fibromatosis in the pelvis who was treated by radiation and medication therapies and achieved a good tumor reduction effect. The patient was a 70-year-old man. He had a 6-year history of pain in the right leg and had a palpable mass on the right side of the anus; he was admitted to our department. CT showed a 12×7×12 cm mass in the pelvis, and CT-guided needle biopsy revealed a desmoid-type fibromatosis. Because tumor exclusion resulted in obstruction of the rectum, radiation therapy(60 Gy in 30 Fr)was started after performing transverse colon colostomy; simultaneous medication therapy with a COX-2 inhibitor and the anti-allergic agent tranilast was administered. Cystic degeneration was observed 5 months after the end of radiation therapy, and after 12 months, the tumor volume had halved. Around 28 months after the end of radiation therapy, medication treatment has been continued with slow contraction.

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.

Follow-Up Protocols in Orthopedic Oncology

Little has been written about the specific timing and elements involved in the follow-up of orthopedic oncology patients1,2,7. The experience with bone tumor treatment at the First Clinic of the Istituto Rizzoli started 30 years ago and more than 15,000 patients have been treated to date. The increment of limb salvage surgery is linked with the improvements in imaging and surgical skills and with the availability of new reconstructive techniques. For this purpose it is mandatory to carry out meticulous monitoring of the patients. A large number of patients are still followed up to evaluate the results in terms of oncological and functional status. Based on this experience we developed a time schedule to better respond to the need for adequate patient evaluation.

Desmoid tumor of the abdominal wall A case report and literature review

BACKGROUND

Desmoid tumor is a rare soft tissues neoplasia characterized by local invasiveness and by a tendency towards local recurrence although not towards metastasization.

DISCUSSION

Etiology is not clear. Desmoid tumors originate from the monoclonal proliferation of one mesenchymal cell and develop in the context of fascial, muscular and aponeurotic tissue. They are free of capsule and do not usually metastatize, although they do present a high risk of local recurrence CONCLUSION: In the absence of a systematic data collection and of a clear distinction, in the existing databases, between primitive and recurrent lesions and between lesions of different sites, there are no standard guidelines for a correct management of desmoids.

KEY WORDS

Aggressive fibromatos Desmoid tumor, Soft tissue neoplasia.

[A Case of Familial Adenomatous Polyposis with a Desmoid Tumor Probably Communicating to the Intestinal Lumen That Was Successfully Treated with Non-Surgical Therapy]

A 44-year-old man with familial adenomatous polyposis underwent laparoscopic-assistedtotal proctocolectomy with ilealpouch anal anastomosis(IPAA). Computed tomography conducted 21 months after IPAA demonstrated bilateral hydronephrosis andan intra-abdominal mass with a maximal diameter of 22 cm, leading to a diagnosis of stage IV desmoid disease, according to the classification by Church and associates. Six courses of combination chemotherapy with doxorubicin plus dacarbazine were administered. Computed tomography after chemotherapy demonstrated marked shrinkage of the desmoidtumor with intraabdominal air andfluidcollection extending just below the skin of the ileostomy closure site. Stoollike fluidoverflowedspontaneously through the site of the ileostomy closure andthe abscess cavity was successfully drained. The patient was discharged 30 days after the start of drainage. The patient is doing well 10 months after the drainage without regrowth of the desmoid tumor, even though a cavity-like lesion encapsulatedby a thick wall remains.

Toward a new strategy in desmoid of the breast?

AIM

To report initial results of observation as well as surgery in patients with desmoid tumors (DTs) of the breast, a rare tumor for which data are scarce.

PATIENTS AND METHODS

The initial approaches were categorized as either front-line loco-regional treatment [(surgery or radiotherapy group, SRG) n = 20] or initial observation [(no surgery/no radiotherapy group, NSRG) n = 11].

RESULTS

A total of 27 women and 4 men were assessed between 1992 and 2013 and included in this study. Patient characteristics were adequately balanced in the 2 groups. Fifteen patients (48.4%) had a past history of breast surgery in the previous 24 months. The median initial DT size on MRI was 50 mm. The median follow-up was 36 months. In the SRG, 8/20 patients (40%) experienced recurrence. The median time to recurrence was 29 months. During the study period, 6 patients in the SRG (30%) received a mastectomy at the time of diagnosis (n = 3) or at relapse (n = 3), 7 patients (35%) received a thoracic wall resection and 8 patients (40%) received radiotherapy at the time of diagnosis (n = 2) or at recurrence (n = 5). In the NSRG, the median tumor size change was -4 mm (range -13 to +20). Three patients changed treatment strategies during the observation period; one received surgery, and 2 were administered anti-hormonal treatment.

CONCLUSIONS

Loco-regional treatments of breast DTs resulted in undesired disfigurement. Front-line observation yielded encouraging results and could enable the identification of patients who require loco-regional treatment. This strategy needs further evaluation.

Hyperthermia in the treatment of recurrent abdominal desmoid tumor

The most suitable management of recurrent abdominal desmoid tumor is still unclear. A case of recurrent huge abdominal desmoid tumor successfully treated by hyperthermia therapy is described. A 63-year-old man was operated upon for desmoid tumor in the retroperitoneum involving pancreas, posterior wall of the stomach and transverse mesocolon in 2007. In 2008, the tumor recurred and could not be resected because of the patient refused the operation. Several therapies using tamoxifen, anastrozole, imatinib mesylate and radiotherapy were all ineffective. The tumor grew bigger and bigger during a treatment period. Finally, hyperthermia treatment was applied to the tumor. The size of the recurrent desmoid tumor reduced 75% by hyperthermia treatment for 46-month. Base on this experience, we recommend hyperthermia as the treatment for patients with recurrent abdominal desmoid tumor that several therapeutic strategies did not achieve a remarkable response.

Intra-abdominal desmoid tumors: a case report

INTRODUCTION

Desmoid tumors are defined as a rare fibroblastic proliferative disease and may occur in any musculoaponeurotic or fascial tissue .

CASE REPORT

A 54-year-old man with FAP referred to our institution presenting fever and abdominal pain. Four years before a prophylactic colectomy with ileal-rectal anastomosis was done. Three years later a wide intraabdominal mass with desmoid characteristics was detected. In spite of therapy with tamoxifene the RM control showed an increase of mass dimension. Few days later the patient arrived in our istitute with fever and abdominal pain. Medical therapy didn't improve clinical symptoms and the patient underwent surgery.

DISCUSSION

Desmoid tumors are benign tumors, but not a benign disease. Most of these tumors occur sporadically, but about 5% arise in association with familial adenomatous polyposis. Intra-abdominal desmoid tumors remain asymptomatic until their growth and infiltration causes visceral compression. They can cause serious complications and treatment is often unsuccessful. Aggressive fibromatosis treatment should be evaluated and managed by a multidisciplinary team with expertise and experience in sarcoma, prior to initiation of therapy. In FAP, surgery has been recommended for abdominal wall tumors but there are only few indications for intra-abdominal disease like pain, bowel obstruction and desmoids perforation.

Multidisciplinary treatment of desmoid tumours in Gardner's syndrome due to a large interstitial deletion of chromosome 5q

BACKGROUND AND AIMS

Classic autosomal-dominant familial adenomatous polyposis (FAP) is clinically defined by the development of hundreds to thousands of colorectal adenomas beginning in childhood and adolescence. A variant of FAP characterized by polyposis in combination with osteomas or soft tissue tumours is called Gardner's syndrome. FAP is caused by germline inactivation of the APC (adenomatous polyposis coli) tumour-suppressor gene located on the long arm of chromosome 5 (5q21-5q22). Cytogenetically visible deletions of chromosome 5q encompassing APC have very rarely been reported. Here, we aimed to phenotypically and genetically characterize a patient with a heterozygous 5q deletion resulting in Gardner's syndrome.

METHODS AND RESULTS

A 26-year-old female patient with mild mental handicap and dysmorphic features due to a cytogenetically visible deletion on chromosome 5q (microscopically estimated region 5q14-5q23) presented at our tertiary referral centre because of mild adenomatous polyposis (<500 polyps). Twenty months after prophylactic proctocolectomy with definitive ileostomy, three rapidly growing desmoids were observed. Tumour-associated complications necessitated a multidisciplinary approach including medical treatment, surgery and radiation therapy. The characterization of the deletion by comparative genomic hybridization identified a large 5q deletion expanding over a 20-Mb region (5q21.3-5q23.3) including the APC gene.

CONCLUSION

Chromosome deletions must be suspected in patients presenting with FAP together with mental handicap and dysmorphic features. This case also impressively shows that FAP-associated desmoids need multimodal treatment taking into account the patient's individual symptoms, disease progression and tumour location.

Extra-abdominal desmoid fibromatosis--a sarcoma unit review of practice, long term recurrence rates and survival

INTRODUCTION

Desmoid fibromatosis (DF) carries a significant morbidity and a recognised mortality. Despite this there are currently limited diagnostic or treatment algorithms specific to cases of extra-abdominal DF. Historically surgical excision has formed the cornerstone of treatment. Recently however a paradigm shift has meant many practitioners now adopt a more conservative approach, placing emphasis on active surveillance, function preserving resections, and non-surgical oncologic therapies.

METHODS

We performed an 8-year retrospective review of all cases of extra-abdominal DF managed within our region to assess the consistency of diagnostics, management and long-term outcome.

RESULTS

47 eligible cases were identified. Mean age at diagnosis was 41.3 years (1-81 years). Disease location and speciality of diagnosing practitioners were varied. Management was generally inconsistent. Variation was seen in imaging, biopsy techniques, MDT involvement and management. At a median follow up of 4.9 years our local recurrence rate was 19%.

DISCUSSION

The optimal management of DF is unknown. This has led to a lack of formalised guidance for practitioners managing this challenging condition, resulting in inconsistencies and areas for improvement in current management. We propose a diagnostic pathway which may improve consistency of care, reduce potentially unnecessary surgery and the associated morbidity, and significantly increase the rate of complete (R0) surgical resections when surgery is deemed appropriate whilst not significantly worsening oncological outcome. Specifically we propose all cases should be imaged appropriately (usually with MRI), undergo a planned biopsy (by radiologically guided core needle biopsy) and be managed centrally in conjunction with multidisciplinary sarcoma units.

[Effect of transarterial chemoembolization for recurrent desmoid tumor - a case report]

Desmoid fibromatosis is classified as a benign soft tissue tumor regardless of its local invasive behavior and its, local recurrence rate is 57-85% after local resection. A 19 y/o male patient with post-operative recurrence of a desmoid tumor in the shoulder was initially treated by arterial embolization; however, no improvement of symptoms was obtained. As second-line treatment, 20 mg of epirubicin, 50 mg of cisplatin and 250 mg of 5-FU were infused to tumor-related arteries and embolization was performed with a super absorbent polymer microsphere. After a single session of treatment, reduction of tumor size and improvement of symptoms were achieved. The same treatment was repeated three times without major complications. Considerable reduction of tumor was obtained after treatment. Chemo-embolization should be considered for the postoperative recurrence of desmoid fibromatosis, in order to prevent loss of function and maintain a high QOL for the patient.

Update on desmoid tumors

Desmoid tumors (DTs) are histologically benign proliferations of stromal cells but may grow locally aggressive. Overall, DTs are rare (0.03% of all neoplasms). A minority of DTs is associated with Gardner syndrome and mutations of the familial adenomatous polyposis (FAP) gene. Most spontaneous DTs are associated with mutations of the beta-catenin gene. This mutation results in the activation of Wnt/catenin signaling. Due to their variable clinical presentation and behavior, no standard approach for DTs can be recommended. In most cases of DTs of the extremities surgical extirpation is indicated, whereas in many other cases, a multimodal and multidisciplinary concept should be followed. In this review article, we discuss the diagnosis, pathogenesis, and treatment options for DTs, including targeted therapy with tyrosine kinase inhibitors.

[Mesenterial fibrosis--could it be desmoidi?]

Desmoid tumors are rare benign fibrous tumors, which have a tendency to invade locally. A minority of desmoids are mesenterial. The symptoms of mesenterial desmoids are misleading, and diagnosis can be delayed. A complete surgical excision is the preferred treatment, but the mesenterial location of the tumor makes radical surgery complicated. Patients whose tumors are not amenable to surgical treatment, have been treated with antiestrogens, nonsteroidal anti-inflammatorics and various chemotherapeutics. Good responses have been observed with pegylated liposomal doxorubicin. In most cases, the quality of life can be maintained even in incurable situations.

An evaluation of brachytherapy and external beam radiation used with wide-margin surgical resection in the treatment of extra-abdominal desmoid tumors

Surgical resection has had control rates of 53% to 77% in the treatment of extra-abdominal desmoid tumors. Surgical excision combined with external beam radiation therapy (EBRT) has had local control rates of up to 83% in some series. The purpose of this study was to evaluate the effectiveness of resection combined with radiotherapy (brachytherapy, EBRT, or both) in the treatment of extra-abdominal desmoid tumors. We retrospectively reviewed the charts of 24 consecutive patients (27 histologically confirmed extra-abdominal desmoid tumors). Patients were included in the study if they had a lesion that was potentially resectable with a wide margin, allowing for limb salvage, and if they did not have a contraindication to radiotherapy. Limb functioning was assessed with the Musculoskeletal Tumor Society (MSTS) scoring system. Seventeen patients (7 men, 10 women) with 19 tumors met the inclusion criteria. Mean age at diagnosis was 23.4 years. Follow-up (mean, 4.28 years) involved serial clinical examinations and magnetic resonance imaging of tumor sites. After surgery, the tumors were treated with brachytherapy (n = 6), EBRT (n = 10), or both (n = 3). Two of the 17 tumors in patients with negative margins of resection recurred locally (local control rate, 88.2%). Mean MSTS score was 29/30 (96.7%). The role of surgery, radiotherapy, chemotherapy, hormone therapy, and other treatments for extra-abdominal desmoid tumors is not well defined. When wide-margin resection and radiotherapy can be performed with limb preservation surgery, local control and complication rates compare favorably with those of other reported methods of treatment. Given the results and limitations of our study, we cannot make a definitive recommendation as to which modality--brachytherapy or EBRT--should be used in the treatment of extra-abdominal desmoid tumors.

Desmoid tumors: clinical features and treatment options for advanced disease

Desmoid tumors describe a rare monoclonal, fibroblastic proliferation characterized by a variable and often unpredictable clinical course. Although histologically benign, desmoids are locally invasive and associated with a high local recurrence rate, but lack metastatic potential. On the molecular level, desmoids are characterized by mutations in the β-catenin gene, CTNNB1, or the adenomatous polyposis coli gene, APC. Proof of a CTNNB1 mutation may be useful when the pathological differential diagnosis is difficult and location might be predictive for disease recurrence. Many issues regarding the optimal treatment of patients with desmoids remain controversial; however, surgery is the therapeutic mainstay, except if mutilating and associated with considerable function loss. Postoperative radiotherapy reduces the local recurrence rate, in cases of involved surgical margins. Because of the heterogeneity of the biological behavior of desmoids, including long periods of stable disease or even spontaneous regression, treatment needs to be individualized to optimize local tumor control and preserve patients' quality of life. Therefore, the application of a multidisciplinary assessment with multimodality treatment forms the basis of care for these patients. Watchful waiting may be the most appropriate management in selected asymptomatic patients. Patients with desmoids located at the mesentery or in the head and neck region could present with life-threatening complications and often need more aggressive treatment. This review describes treatment options and management strategies for patients with desmoid tumors with a focus on advanced disease.

Evaluation of estrogen receptor alpha, estrogen receptor beta, progesterone receptor, and cKIT expression in desmoids tumors and their role in determining treatment options

The present study evaluates the protein expression of estrogen receptor alpha (ERalpha), estrogen receptor beta (ERbeta), progesterone receptor (PR) and cKIT in a wide number of desmoids tumors and their role in determining treatment options. Fifty-nine cases classified as muscle aponeurotic fibromatosis were selected. Samples were grouped by tumor location in: head and neck, extremity and abdominal/trunk; type of resection of the primary tumor (complete resection with adequate margins, marginal resection and resection with inadequate margins); type of treatment (exclusive surgery, surgery followed by radiation therapy and surgery followed by tamoxifen or cyclooxygenase inhibitor). A tissue microarray (TMA) was built and the immunohistochemical reactions were performed against ERalpha, ERbeta, PR, and c-kit. All cases were negative for ERalpha, PR and c-KIT. 53/59 cases were positive for ERbeta. No significant difference was observed among clinical variables and the ERbeta status. The estimated 5 and 10 year local recurrence free survival (LRFS) for the patients with complete or marginal resection was 75% and 75%, respectively. Tumor location (p = 0.006) and type of resection (p = 0.001) were predictive of local relapse in the univariate analysis. All patients treated with post-operative tamoxifen were LRFS (p = 0.035). Head and neck and extremities lesions showed higher recurrence rates compared to abdominal/trunk lesions. Marginal resection was associated with local recurrence. In conclusion, although this is a retrospective study, the results presented can contribute to better understanding of the mechanisms under desmoid tumor development and can propose tamoxifen as a therapeutic option to be tested in prospective trials.

Cortical desmoid and the four clinical scenarios

We reviewed four patients diagnosed with a cortical desmoid lesion at the distal posterior medial femur. Each case reflects a clinical scenario that can be present. Cortical desmoid is a benign, self-limited entity which occasionally can exhibit aggressive radiologic features. Here, we present the specific imaging features in association with patients history and clinical findings facilitating establishment of correct diagnosis. Exact diagnosis is important in order to avoid unnecessary biopsy and complicated therapeutic strategies.

[Abdominal desmoid tumor: pathologic and therapeutic concepts]

BACKGROUND

Abdominal desmoid tumors arise in young adults between 20 and 40 years. They are characterized by a local recurrence in 20 to 30% of cases.

AIM

review the clinical and pathologic features of this entity, look for the expression of immunohistochemical markers (actine, desmine, CD34, vimentin) and also to estimate the expression of two potential targets therapy; the hormonal receptors and the CD117.

METHODS

From 1990 to 2004, three cases of abdominal desmoid tumors were diagnosed in the Pathologic laboratory of the Charles Nicole Hospital of Tunis.

RESULTS

The study concerned three women 62, 35 and 30 year-old. All the patients were operated and the size of tumours varied to 5 to 7cm. The CD117 and the hormonal receptors were negative in every case. None of the patients presented local recurrence.

CONCLUSION

Abdominal desmoid tumors are locally aggressive but never give metastasis. The negativity of these lesions to the CD117 and in the hormonal receptors does not imply resistance in the hormonal treatment by anti-estrogens.

[Treatment of desmoid tumour in head and neck]

OBJECTIVE

To find out the suitable therapy for the patient of desmoid tumour in head and neck.

METHODS

Forty-four patients with desmoid tumours of the head and neck treated at Cancer Hospital of Fudan University between 1987 and 2002 were identified from inpatient tumour database. Patients were classified into three groups: operation group (15 cases); operation + radiation group (12 cases); radiation group (17 cases). All patients were prospectively followed. Clinicopathologic features and treatment modalities were evaluated.

RESULTS

In the group of operation, four of operation group had recurrences 26.7% (4/15). In the group of radiation, three of radiation group had recurrences 17.6% (3/17). And the recurrence of operation + radiation group was 23.5% (4/17). No patient died of their disease.

CONCLUSION

For desmoid tumors of the head neck, operation + radiation was recommended, and the benefits of radiation therapy were demonstrated.

Extra-abdominal primary fibromatosis: Aggressive management could be avoided in a subgroup of patients

OBJECTIVE

To evaluate the impact of surgery as first-line treatment on event-free survival (EFS) of primary aggressive fibromatosis.

PATIENTS AND METHODS

Treatments were categorized into: surgery with or without radiotherapy and nonsurgical strategies with systemic treatment alone or wait and see policy. Eighty-nine patients had initial resection of their primary tumour followed by postoperative radiotherapy in 13 cases. Twenty-three did not undergo surgery but received systemic treatment or watch and wait policy.

RESULTS

Median follow-up was 76 months. Overall 3 years EFS was 49%. In the univariate analysis, patients with microscopically complete surgery had a similar outcome to patients in the no-surgery group (3 years EFS of 65% and 68%, respectively). Gender, age, tumour size, treatment period and strategy (surgery versus no-surgery) were not statistically significant. Quality of resection according to margins and the tumour site were the only prognostic factors. There was a significant correlation between tumour site and quality of surgery (p=0.0002).

CONCLUSIONS

A subset of patients with extra-abdominal fibromatosis could be managed with a nonaggressive policy, as growth arrest concerned 2/3 of nonoperated patients. When surgery is finally necessary, it should be performed with the aim of achieving negative margins.

The management of desmoids in patients with familial adenomatous polyposis (FAP)

Desmoids are rare in the general population but occurs in between 10 to 20% of patients with familial adenomatous polyposis (FAP). This risk is about 852 times the risk for the population at large. Desmoids are benign neoplasms that are capable of infiltrating locally with a high risk of recurrence (25-65%) even after extirpating surgery. Desmoids in FAP may occur extra-abdominally, or within the abdominal wall or most commonly intra-abdominally within the mesentery or retroperitoneal. Desmoids are a major problem in patients with FAP. Mortality from desmoids is high in such patients and ranges from 18 to 31%, compared to peri-ampullary carcinomas at about 22% and cancer in the retained rectum at only about 8%. Simple drug treatment with tamoxifen or NSAIDS like sulindac should be used as first line treatment as it carries a response in 30-50% of patients. Surgery should be reserved for extra-abdominal tumours alone and only when needed. Surgery for intra-abdominal desmoids should really only be attempted for intestinal obstruction or ureteric obstruction. Dacarbazine-Doxorubicin chemotherapy may have dramatic response in some cases. Genetic transfer may unlock this disease in future and may give patients with FAP and severe desmoids hope for the future.

Extra-abdominal desmoid tumour of the leg

Extra-abdominal desmoid tumour is a rare tumour and only a few cases occurring in the limbs have been reported. A 35-year-old woman presented with gradually increasing swelling in the upper leg. She had a mild, dull, aching pain in the tumour. Wide local excision was done and the tumour was found mainly in the subcutaneous tissue, which histopathologically proved to be an extra-abdominal desmoid tumour. This case had an abnormal radiological appearance of peripheral calcification of tumour and saucer-shaped lesion in the underlying tibial cortex. The patient had no recurrence at two years follow-up.

Assessment of endostatin gene therapy for familial adenomatous polyposis-related desmoid tumors

Constitutive activation of the Wnt signaling pathway is a hallmark of many cancers, including familial adenomatous polyposis (FAP)-related desmoid tumors. Endostatin is a well-known antiangiogenic protein that has been described recently as a potential inhibitor of this signaling pathway. Here, we show that endostatin directly induces apoptosis and inhibits the Wnt signaling pathway in colorectal cancer cell lines bearing mutations on the adenomatous polyposis coli (APC) gene as a model of FAP-related malignant cells. We then explore the relationship between apoptosis and inhibition of this pathway and show that they are not correlated. These results seem to contradict a well-recognized study, showing that reintroduction of the APC cDNA in APC-deficient cells leads to apoptosis. To reconcile our conclusions with the literature, we further show that a truncated fragment of APC capable of inhibiting the Wnt signaling pathway in SW480 cells is incapable of inducing apoptosis in these cells, confirming that APC-mediated apoptosis is uncoupled to the inhibition of the Wnt signaling pathway. Finally, we show that endostatin directly induces cell death on primary FAP-related desmoid tumor cells in culture. This phenomenon is also independent of the inhibition of the Wnt signaling pathway. Considering the current lack of effective treatment against desmoid tumors, we advocate that endostatin gene therapy represents an attractive new therapeutic approach for this disease.

MRI and Biologic Behavior of Desmoid Tumors in Children

OBJECTIVE

The outcome of desmoid tumor in children cannot be reliably predicted on the basis of histologic findings. We sought to determine whether the postoperative presence of residual or recurrent tumor can be predicted on the basis of demographic variables and baseline MRI features of the tumor. We also aimed to determine how imaging features change during adjuvant treatment and how the imaging features relate to the histologic features.

MATERIALS AND METHODS

Two radiologists retrospectively reviewed images from 281 MRI examinations performed at baseline and during postoperative therapy for desmoid tumor. The examinations had been performed on 17 children treated between September 1991 and March 2003. Tumor volume; distinctness of margins; involvement of bone and neurovascular bundle; and T1-weighted, T2-weighted, and STIR signal intensity and contrast enhancement pattern were recorded. Baseline imaging and demographic features were correlated with the postoperative presence of residual or recurrent tumor. Imaging changes during follow-up were compared with treatment response and outcome. The imaging features of eight tumors were compared with percentage cellularity and collagen deposition in biopsy samples obtained within 30 days of imaging.

RESULTS

Baseline involvement of the neurovascular bundle approached significance as a predictor of the presence of residual or recurrent tumor (p = 0.08). Other baseline imaging and demographic features were not predictive (p > or = 0.4). Changes in imaging features were variable during follow-up. T2-weighted and STIR signal intensity may be correlated with percentage cellularity and collagen deposition.

CONCLUSION

MRI has limited value in prediction of the postoperative presence of residual or recurrent desmoid tumor in children. It is useful, however, for detecting disease and monitoring postoperative adjuvant therapy.

Abdominal desmoid tumors

Desmoid tumors are rare, benign, fibromatous lesions that are the result of abnormal proliferation of myofibroblasts. Desmoid tumors can be classified as extra-abdominal and abdominal. Abdominal desmoid tumors are either superficial or intraabdominal. These tumors are associated with a high recurrence rates, even if their microscopic characters indicate a benign disease; their biologic behavior often indicates rather a "malignant" disease, which can cause even the death. Intraabdominal desmoid tumors can engulf surrounding viscera and vessels, thereby greatly complicating their surgical treatment. Management is multidisciplinary. Simple observation is a reasonable management option for asymptomatic patients; spontaneous regression of these tumors may be observed. Complete excision is the treatment of choice for tumors causing symptoms or complications. Surgery should be minimized as much as feasible, while at the same time achieving free margins. Adjuvant therapy should be considered in selected cases; the role of other management options (including gene transfer therapy) is currently under intensive investigation.

[Aggressive fibromatosis of the head and neck in children (a report of three cases)]

OBJECTIVE

To discuss the therapy of aggressive fibromatosis of head and neck in children.

METHOD

Three cases of aggressive fibromatosis of head and neck were analyzed retrospectively.

RESULT

Total tumor removal was achieved in all cases and the diagnosis was confirmed pathologically. No recurrence was found during follow-up.

CONCLUSION

Aggressive fibromatosis is a rare, benign but locally infiltrative condition. Complete surgical removal was a chief treatment. But it was sometimes impossible in the head and neck area because of associated growth problems. Cosmic problems and facial deformity were the main obstacles of surgery.

Optimizing Treatment of Desmoid Tumors

Purpose

This study compared a large series of desmoid patients treated at a single institution to a previously published series from the same institution to determine if patient population characteristics, treatment approaches, and clinical outcomes had undergone change over the two study periods.

Materials and Methods

Data from a prospective soft tissue tumor database was used to analyze clinical courses of 189 desmoid patients treated at The University of Texas M.D. Anderson Cancer Center (UTMDACC) from 1995 to 2005 as compared with 189 UTMDACC desmoid patients treated between 1965 and 1994.

Results

A nearly three-fold increase in annualized UTMDACC desmoid referral volume with significantly higher percentages and numbers of primary desmoid tumor referrals to UTMDACC was observed in the most recent study period. Significantly increased systemic therapy use and decreased reliance on surgery alone was observed more recently. While the recent series patients had higher rates of macroscopic residual disease and equivalent rates of positive microscopic margins after definitive surgery, the estimated 5-year local recurrence rate of 20% was improved compared with the 30% rate observed in the earlier series.

Conclusion

Increased awareness of the complex multidisciplinary management needed for desmoid tumor control may underlie significantly increased numbers of referrals to UTMDACC, especially primary untreated desmoids. Increased neoadjuvant treatments may be associated with improved desmoid patient outcomes. These trends should be supported, particularly if personalized molecular-based therapies are to be rapidly and effectively deployed for the benefit of those afflicted by this rare and potentially debilitating disease.

Fibromatosis: benign by name but not necessarily by nature

Aggressive fibromatoses, also known as desmoid tumours, are rare fibrous tissue proliferations with a tendency for slow, local infiltrative growth. There is an association with Gardner's syndrome and familial adenomatous polyposis. Histologically they are fairly bland with no abnormal mitoses or necrosis. They do not metastasize, but can cause significant morbidity through their locally destructive effects. Magnetic resonance imaging is the method of choice for diagnosis, pre-treatment planning and post-treatment follow-up. Surgical excision with a wide margin is the treatment of choice. However, there is a tendency for local recurrence and repeated excision may result in a poor functional or cosmetic outcome. Radiotherapy is used to reduce local recurrence rates after excision and is also used to treat inoperable tumours. Long-lasting remissions can be obtained. Treatment is now planned using modern three-dimensional conformal techniques, similar to those used in soft tissue sarcoma management. There is no definite dose-response relationship, but doses of 50-60 Gy in 1.8-2 Gy fractions are recommended. Systemic therapy has been used for lesions not controlled by surgery or radiotherapy, or less commonly, as a primary treatment. Tamoxifen and non-steroidal anti-inflammatory agents are used most often as they are relatively non-toxic, but there is limited experience with cytotoxic chemotherapy and biological agents. There are no randomised trials to help guide the management of this locally aggressive 'benign' tumour and treatment decisions are best made by the local soft tissue sarcoma multidisciplinary team.

Response from authors: A 10-year review of surgery for desmoid disease associated with familial adenomatous polyposis (Br J Surg 2006; 93: 1258-1264)

No Abstract.

Current ideas in desmoid tumours

Desmoid tumours are rare neoplasms of fibroblastic origin which arise with disproportionate frequency in patients with familial adenomatous polyposis (FAP). They are thought to develop in about 10-25% of FAP patients and may be the leading cause of death amongst those who have undergone colectomy. Risk factors include trauma, having a distal germline APC mutation, having a family history of desmoids, and probably oestrogens. In very high-risk individuals there may be a case for delay of colectomy or chemoprophylaxis at the time of surgery. Desmoids are now known to be true neoplasms but with normal telomere length and telomerase activity. FAP-associated tumours seem to carry biallelic APC mutations, one of which lies in the distal part of the gene. Such loss of wild-type APC seems to occur relatively late in tumour development. It is likely that beta-catenin plays an important role in tumourigenesis. FAP-associated desmoids tend to arise in the abdomen or abdominal wall. CT scanning gives the best information on tumour anatomy whilst T2-weighted MRI indicates likely behaviour. Treatment may simply consist of observation. Otherwise, usual first-line therapy is with sulindac with or without an anti-oestrogen. Cytotoxic chemotherapy is an option in unresectable tumours. Surgery is a reasonable first-line treatment in abdominal wall tumours but is risky for intra-abdominal tumours and may necessitate massive small bowel resection. Desmoids are the greatest remaining challenge in the management of FAP and further research into their aetiology needs to be combined with multicentre clinical trials of new treatments in order to improve management of the disease.