Without treatment, familial adenomatous polyposis (FAP) patients will inevitably develop colorectal cancer (CRC) during lifetime. Yet, surgical trauma is a high risk of desmoid tumor (DT), one of the main causes of death in FAP patients. So far, the timing for colectomy is primarily based on the clinician\'s experience and the patient\'s preference; most patients undergo surgery at mid-20\'s. In this study, we analyzed the germline mutation distribution in 35 FAP patients from different families, 16 of them diagnosed with DTs. We also investigated the association between the molecular alterations and the clinicopathological features. Capture-based targeted sequencing using a panel of 520 genes was performed on tumor tissue and paired normal mucosa or white blood cells from 18 FAP probands who were initially diagnosed with CRC. Of all 35 FAP patients, 30 (85.7%) of them harbored germline APC mutations scattered from codon 161 to 1578. The mutations in the 16 DT patients scattered from codon 457 to 1578. All three patients with the mutation at the 3\' of 1444 codon were diagnosed with DT. The percentage of high-risk DT (stage III or IV) harboring mutations at the 5\' of 1062 or 1062-1578 was 14.3% and 77.8%, respectively, and all three patients with 3\' of 1399 codon mutation had high risk. In addition, by using public database, we compared 140 FAP patients with DT to all 1880 FAP patients on the Leiden Open Variation Database and found that the odd ratio of DT in codon 159 to 495 was 0.34, while in codon 1310 to 2011 was 2.36. Compared to sporadic CRCs, the somatic spectrum of FAP CRCs was similar to the early onset CRCs, with higher TP53 (94.1%) and lower somatic APC mutations (65.7%), but the KRAS mutation rate was the highest (58.5%). One of the 18 FAP CRCs was identified as microsatellite instability-high (MSI-H), with tumor mutation burden (TMB) of 115.65 mut/Mb. Given that no TP53 mutations were detected in the low- and high-grade adenomas, ctDNA TP53 sequencing might be used for the close monitoring before FAP colectomy. In conclusion, except mutations at the 5\' end of APC (5\' to 495), all FAP patients need to consider the risk of DT after colectomy. The chance of life-threating DTs was higher in patients with 3\' 1062 codon mutation and peaked in patients with 3\' 1399 codon mutation. Scheduled monitoring of TP53 ctDNA is proposed to be a novel tool for optimizing the operation time.

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.

This study was undertaken to clarify the risk factors, including the mutation status of CTNNB1, for the local recurrence after surgery of the rare disease desmoid-type fibromatosis. It was designed as a multiinstitutional joint research project with 7 major centers in Japan participating. The committee members of 7 major medical centers specializing in bone and soft tissue tumors formed this study group to develop clinical care guidelines. Of 196 cases with specimens and medical records collected from the 7 institutions, 88 surgically treated ones were analyzed regarding clinicopathologic prognostic factors including CTNNB1 mutation status. Excluding R2 cases (n = 3), 5-year local recurrence-free survival (LRFS) was 52.9%. No case had received pre- or postoperative radiotherapy. Univariate analysis revealed that extremity location (P < .001) and larger size (8 cm or more, P = .036) were significant adverse risk factors for LRFS. Multivariate analysis indicated that extremity location (P < .001) was a significantly adverse factor in addition to recurrent tumor (P = .041), S45F mutation (P = .028), and R1 surgical margin (P = .039). Preoperative drug treatment, including nonsteroidal antiinflammatory drugs, did not reduce the incidence of local recurrence (P = .199). This is the first study to analyze the factors correlating with outcomes of surgical treatment, including CTNNB1 mutation status, in a relatively large number of cases from an Asian country. Tumor location was found to be the most influential prognostic factor for local recurrence, similar to the results from Europe and North America. The development of more sensitive method(s) for determination of CTNNB1 mutation is a priority for future study.

Desmoid-type fibromatosis is an uncommon disease which mimics sarcoma but is more locally aggressive but with less metastatic potential than sarcoma. Diagnosis is difficult and treatment protocols have changed to include more non-surgical options as compared with sarcoma. This is a retrospective study of the clinical presentation, imaging findings, treatment given, and outcomes of pathologically proven desmoid-type fibromatosis patients who presented to government medical college Kozhikode.

Desmoid tumors can be safely managed with watchful waiting, including either observation alone or tamoxifen/NSAIDs. Surgery at first presentation can be associated with significant treatment burden.
Immediate surgery was historically recommended for desmoid tumors. Recently, watchful waiting, (tamoxifen/NSAIDs or observation alone), has been advocated.
All diagnoses of desmoid tumor within the Alberta Cancer Registry from August 2004 to September 2015 were identified. Patients with FAP were excluded. Demographics, tumor characteristics and treatment and outcome data were collected. Outcomes were compared between immediate surgery and watchful waiting. The effect of abdominal wall site on progression and recurrence and the effect of microscopic margin on recurrence were assessed with Fisher\'s exact test.
We identified 111 non-FAP patients. Median follow-up was 35 months from diagnosis. 74% were female. Mean age was 42. Fifty (45%) underwent watchful waiting, of whom 21(42%) progressed, with median PFS of 10 months. Fifty-three (48%) underwent resection at presentation, of whom 8 (15%) recurred, with median disease-free survival of 22 months. Abdominal wall lesions were equally represented in both groups, and equally likely to progress on watchful waiting (50% vs 39%, p = 0.53), but there was a trend toward decreased recurrence after surgery. (5% vs 23%, p = 0.08). Microscopic margin had no effect on recurrence (14% of margin negative vs 20% of margin positive, p = 1.0).
Watchful waiting was successful in 58% of patients, and a further 28% only required one aggressive treatment thereafter, for a total of 86%. Surgery had a favorable recurrence rate (15%), but some recurrences were associated with significant treatment burden. Treatment should be tailored to individual patients in a multidisciplinary setting. A trial of observation appears warranted in most patients. Recurrence rate was not affected by positive margins.

Desmoid-type fibromatosis, also called desmoid tumor, is a locally aggressive myofibroblastic neoplasm that usually arises in deep soft tissue with significant potential for local recurrence. It displays an unpredictable clinical course. β-Catenin, the genetic key player of desmoid tumors shows nuclear accumulation due to mutations that prevent its degradation leading to activation of Wnt signaling and myofibroblastic cell proliferation. The corresponding hot spot mutations are located in exon 3 of the CTNNB1 gene or alternatively, in the APC tumor suppressor gene, most often as a germline mutation. Multifocal desmoid tumors are very rare and clinical characteristics are poorly understood. Here we present six sporadic and one familial case of multifocal desmoid tumors. Four female and three male patients, aged between 7 and 30 years (mean 18.4 years) were identified in a cohort of 1392 cases. Tumors were located in (distal) extremities, thorax, breast, abdominal wall, shoulder, and neck. Four cases showed a CTNNB1 mutation and one an APC germline mutation. In two sporadic cases no CTNNB1 mutation was identified. Four patients showed (multiple) recurrences and one patient was lost to follow-up. In conclusion, multifocal desmoid tumors are a very rare disease and may occur in sporadic cases that are characterized by recurrent CTNNB1 mutations. However, the underlying pathogenesis of multifocal desmoid tumors remains poorly understood with often aggressive clinical behavior and challenging therapeutical management.

Desmoid-type fibromatosis (DF) is a aggressive (myo)fibroblastic neoplasm with an infiltrative growth and a tendency to local recurrence. Resection of the tumour and/or radiation were proposed as principal treatment. The aim of this retrospective study was to analyze the local control rates focusing on the effect of surgical margins and radiotherapy.
From 1981 to 2014, 44 patients had been treated. Fifty four therapies had been applied, in 50 cases surgery +/- radiation therapy, NSAIDs or chemotherapy. In 4 cases a conservative approach was chosen. Thirty seven patients had primary, 17 recurrent disease. Endpoint was either local recurrence (LR), progression of residual disease or rare non-metastatic secondary lesions at the same extremity.
The mean age was 39,4 years. In 17 cases a R0, in 27 a R1 and in 6 cases a R2 resection was achieved. Four patients were treated conservatively. All together in 21 cases radiotherapy, in 5 NSAIDs, in 3 imatinib and in 2 cases each tamoxifen or chemotherapy had been applied. The median follow-up was 119 months. 5-year recurrence free survival after resection was 78%. 10 (20.4%) patients developed LR between 5 and 42 months after therapy. Recurrent disease was a negative factor on LR. Margins, radiotherapy, sex, or size of the tumour had no significant impact on LR. Patients younger than 40 years had a significant higher risk of LR.
Surgical margins are less important than keeping function. Radiotherapy might be an option in unresectable lesions, the role of adjuvant radiotherapy is controversially discussed.

Aim of this study is to evaluate the outcome of long-term conservative treatment with sulindac and high-dose selective estrogen receptor modulators (SERMs) for sporadic and FAP-associated desmoid tumors. Desmoids are very rare tumors in the general population but occur frequently in FAP patients, being encountered in 23-38 %. Treatment of desmoids is still most controversial since response cannot be predicted and they are prone to develop recurrence. This study included all desmoid patients that were treated and followed at our institution and had completed at least 1 year of treatment. Response was defined as stable size or regression of desmoid size between two CT or MRI scans. A total of 134 patients were included. 64 (47.8 %) patients had a confirmed diagnosis of FAP, 69 (51.5 %) patients were sporadic. Overall 114 (85.1 %) patients showed regressive or stable desmoid size. Patients with previous history of multiple desmoid-related surgeries showed less-favorable response. The mean time to reach at least stable size was 14.9 (±9.1) months. After regression or stabilization, medication was tapered in 69 (60.5 %) of the treated patients with only one long-term recurrence after >10 years. The results of this study fortify the role of sulindac and high-dose SERMs as an effective and safe treatment for both, sporadic and FAP-associated desmoid tumors. While invasive treatment frequently results in high recurrence rates, high morbidity and high mortality, this conservative treatment is successful in most patients. The recurrence rate is negligible with no desmoid-related mortality in this large series. Therefore surgical resection, especially for mesenteric desmoids, should be deferred favoring this convincingly effective, well tolerated regimen.

OBJECTIVE: Desmoid-type fibromatosis (desmoid) is a locally aggressive (myo)fibroblastic lesion. It represents one of the more common fibrous tumours in children and adolescents. The head and neck region is more often involved than in adults.
RESULTS: We investigated the clinicopathological and genetic characteristics of seven paediatric desmoids at this anatomical site, including two cases of desmoplastic fibroma located in the mandible. There were two females and five males with an age range of 1.5-8 years. The sites of the soft tissue lesions were sinonasal (n = 4) and paramandibular (n = 1). All cases showed typical morphology and nuclear β-catenin expression. CTNNB1 gene sequencing, performed successfully in five cases, revealed mutations in three cases with one p.T41A (bone lesion), one p.S37A and one novel mutation, p.D32V (sinonasal soft tissue lesions). Six patients were treated by excision with positive margins in five cases. Follow-up, available for six patients (median 4 years), showed no evidence of disease in four cases, slow progression in one case, and recurrence with stable disease in the last case.
CONCLUSIONS: Our study provides evidence of genetic similarities in desmoid and desmoplastic fibroma. Additionally, we expanded the spectrum of mutations in CTNNB1 with one novel desmoid mutation.