Extra-abdominal Desmoid Tumors Research Articles

Initial treatment for surgery-naïve desmoid tumors by high intensity focused ultrasound.

Desmoid tumor (DT) is a rare proliferative disease occurring in connective tissues, characterized by high infiltration and recurrence rates. While surgery remains the primary treatment, its recurrence risk is high, and some extra-abdominal desmoid tumors are inoperable due to their locations. Despite attempts with radiotherapy and systemic therapy, the efficacy remains limited. We used low-power cumulative high-intensity focused ultrasound (HIFU) therapy as an initial treatment for desmoid tumor patients either ineligible or unwilling for surgery. Low-power cumulative HIFU employs slower heat accumulation and diffusion, minimizing damage to surrounding tissues while enhancing efficacy. Fifty-seven non-FAP desmoid tumor patients, previously untreated surgically, underwent low-power cumulative HIFU therapy. Among them, 35 had abdominal wall DT, 20 had extra-abdominal DT, and 2 had intra- abdominal DT, with an 85% median ablation ratio. Abdominal wall DT patients showed significantly better response rates (91.4% vs. 86%) and disease control rates (100% vs. 32%) than that of non-abdominal wall DT patients. Median event- free survival time was not reached after a median follow-up duration of 34 months. With its high response rate, durable efficacy, and mild adverse effects, our findings suggest that low-power cumulative HIFU presents a promising novel treatment for desmoid tumors, particularly abdominal wall DT patients.

Desmoid Tumors: Current Perspective and Treatment.

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.

Ultrasound-guided peripheral nerve blockade in high-intensity focused ultrasound ablation for extra-abdominal desmoid tumors: a case series.

Ultrasound-guided peripheral nerve blockade in high-intensity focused ultrasound ablation for extra-abdominal desmoid tumors: a case series.

MRI-based navigated cryosurgery of extra-abdominal desmoid tumors using skin fiducial markers: a case series of 15 cases

BackgroundPrecision surgery is becoming increasingly important in the field of Orthopaedic Oncology. Image-guided percutaneous cryosurgery (CRA) has emerged as a valid treatment modality for extra-abdominal desmoid tumors (EDTs). To date, most CRA procedures use CT-based guidance which fails to properly characterize tumor segments. Computer-guided MRI navigation can address this issue however, the lack of a fixed landmark for registration remains a challenge. Successful CRA correlates directly with precision approaches facilitated by intraoperative imaging guidance. This is the first study that attempts to assess the feasibility and efficacy of a novel approach of using skin fiducial markers to overcome the challenge of a MRI-based navigation CRA for symptomatic or progressive EDTs.MethodsIn this retrospective study conducted between 2018 and 2020, 11 patients at a single center with symptomatic or progressive EDTs were treated with CRA using intraoperative MRI navigation. Fifteen cryosurgery procedures were performed, each adhering to a personalized pre-operative plan. Total tumor size, viable and non-viable portions pre- and post-operation, and SF-36 questionnaire evaluating subjective health were recorded.ResultsAll CRAs demonstrated 100% adherence to the predetermined plan. Overall, tumor size decreased Median= -56.9% [-25.6, -72.4]) with a reduction in viable tissue, (Median= -80.4% [-53.3, -95.2]). Four patients required additional CRAs. Only one patient’s tumor did not reduce in size. One patient suffered from local muscle necrosis. Pre-operation, the average physical and mental scores 41.6 [29.4, 43] and 26.3 [17.6, 40.9] respectively. Post-operation, the average physical and mental scores were 53.4[38, 59.7] and 38 [31.2, 52.7] respectively.ConclusionThese findings provide an early indication of the feasibility and efficacy of performing percutaneous cryosurgery using skin fiducial marker registration for MRI-computed navigation to treat EDTs safely. Larger cohorts and multicenter evaluations are needed to determine the efficacy of this technique.

Efficacy of liposomal doxorubicin in patients with intra- and extra-abdominal desmoid fibromatosis.

11581 Background: Desmoid tumors (DT) or aggressive fibromatosis are rare growths of fibroblastic connective tissue that can be locally aggressive but without metastatic potential. Most cases are sporadic, but 5-20% of cases are associated with Familial adenomatous polyposis (FAP). Despite numerous systemic options, optimal choice is unclear, and there is a paucity of studies comparing efficacy based on tumor site. Liposomal doxorubicin (LD) can be an appealing option for DT patients (pts) given its favorable schedule and toxicity profile. In this study, we compared outcomes in pts with intra-abdominal (IA) and extra-abdominal (EA) DT who received LD. Methods: We identified pts with DT who were treated with LD between 1/2010 - and 2/2022 at two sarcoma centers. Tumor and pt characteristics and outcomes were clinically (symptom improvement) and radiologically (RECIST 1.1) assessed. Results: 40 pts with DT treated with LD were identified; 58% female and 42% male. Pt characteristics and outcomes are summarized in Table 1. Primary tumor site was IA in 21 (53%) pts. FAP was present more commonly in pts with IA vs EA DT, 8/21 (43%) and 4/19 (21%), respectively. In the IA cohort, LD was given as first (15/21, 71%), second (10%) or third (19%) line therapy. LD was used more commonly as a later line in the EA cohort with 16%, 52%, 16%, and 16% receiving it in first, second, third, and fourth lines, respectively. 37 pts were evaluable for response. Response rate in the IA cohort treated in first-line was 50% (8 of 16) and 10 of 12 evaluable pts had symptomatic improvement. No first-line responses were seen in the EA cohort. As later lines of therapy, 7/12 pts had disease control in the second line, 6/8 pts in the third line, and 1/2 pts in the fourth line with LD in the IA cohort. 1 patient had fourth line response to LD in the EA cohort. Disease control rate with LD was 72.5% across all pts. Reasons for early discontinuation of LD included progression or lack of symptom improvement (20%), allergic reaction (12.5%), adverse effects (7.5%), or infection (2.5%). No acute or long-term cardiotoxicity was reported. 2 pts had no signs of recurrence or symptoms at follow-up, 33 pts were alive with symptomatic DT, 1 patient died from disease, and 3 were lost to follow-up. Conclusions: In our study, LD provided tumor response, disease control, and symptomatic improvement regardless of location or prior therapy, with responses most frequently seen in IA DT in first line setting. Further studies should include comparison of efficacy, adverse effects, and patient-reported outcomes while accounting for tumor location and line of therapy. [Table: see text]

Abstract No. 175 Transarterial chemoembolization with Doxorubicin-eluting beads for extra-abdominal desmoid tumors: initial experience

To evaluate the efficacy and safety of Doxorubicin-eluting bead transarterial chemoembolization (DEB-TACE) in extra-abdominal desmoid tumor (DT)

Transarterial Chemoembolization with Doxorubicin Eluting Beads for Extra-Abdominal Desmoid Tumors: Initial Experience.

To evaluate the feasibility, efficacy, and safety of doxorubicin-eluting bead transarterial chemoembolization (DEB-TACE) as an alternative local treatment for extra-abdominal desmoid tumors (DTs). Eleven adult female patients (mean age = 40.1years) with symptomatic, progressively enlarging extra-abdominal DTs were determined ineligible for cryoablation after failing observation or systemic therapy and treated with a single session doxorubicin DEB-TACE. Six rectus sheath, one chest wall, three axilla, and one upper extremity DTs were included. The median follow-up was 155.0 ± 52.3days. Treatment response was assessed by MRIs and maximum visual analog scale (VAS). All procedures were technically successful without immediate complications. The average size of treated DT was 161.8ml (range: 28.3-420.0ml). The mean doxorubicin dose was 13.3mg/m2. All patients experienced skin changes which improved over time without treatments. No higher-grade adverse events were observed. Initial one-month follow-up MRI demonstrated partial to near-complete tumor necrosis, ranging from 1.4 to 97.6% (mean: 36.4%). Additional follow-up revealed a further reduction of overall tumor volume (mean: - 38.1%, p < 0.0001) and maximum VAS (mean: - 2.6, p = 0.0026) in 10 out of 11 patients (90.9%). After the first month, the residual tumors exhibited continued volume reduction in 10 out of 11 patients (mean: - 16.5%, p = 0.0230). There was also a significant decrease of T2 signal intensity within residual tumor on the latest follow-up (mean: - 29.6%, p = 0.0217), suggesting a reductionin tumor cellularity. DEB-TACE may be a safe and effective local treatment alternative in DT patients.

Cryotherapy in extra-abdominal desmoid tumors: A systematic review and meta-analysis.

IntroductionDesmoid tumor is a locally-invasive neoplasm that causes significant morbidity. There is recent interest in cryotherapy for treatment of extra-abdominal desmoid tumors. This systematic review assesses evidence on safety and efficacy of cryotherapy in the treatment of extra-abdominal desmoid tumors.Materials and methodsThe systematic review was conducted with reference to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Literature search was performed using MEDLINE and the Cochrane Central Register of Controlled Trials. 9 full text papers were reviewed and meta-analysis was performed for measures of safety, efficacy and symptom relief.ResultsThe estimated pooled proportion of major and minor complications was 4.2% (95% CI, 1.8–9.6; I 2 = 0%) and 10.2% (95% CI, 5.7–17.8; I 2 = 0%) respectively. The estimated pooled proportion of non-progressive disease rate of all studies was 85.8% (95% CI, 73.4–93.0; I 2 = 32.9%). The estimated progression free survival rate at 1 year was 84.5% (95% CI:74.6–95.8) and 78.0% at 3 years (95% CI: 63.8–95.3). As for pain control, the estimated pooled proportion of patients with decrease in visual analogue scale (VAS) > = 3 for those with VAS > = 3 before treatment for 2 studies was 87.5% (95% CI, 0.06–100; I 2 = 71.5%) while 37.5% to 96.9% of patients were reported to have experienced partial or complete symptom relief in the other studies.ConclusionCryotherapy is a safe and effective treatment modality for extra-abdominal desmoid tumors with efficacy similar to those treated with traditional strategies in the short to medium term.

Extra-abdominal desmoid fibromatosis: An evaluation of clinical factors affecting local recurrence rates.

The aim of this study was to determine the prognostic factors for recurrence in patients with extra-abdominal desmoid tumors (EDTs) treated surgically. This single-institution, retrospective study included patients with a histologically-proven extra-abdominal desmoid tumor between 2007 and 2018. The demographic characteristics (age, sex) of the patients, tumor characteristics (region, size, proximity to neurovascular structures, margins), treatment management (surgery and/or adjuvant radiotherapy), and clinical results were analyzed. The effects of these possible prognostic factors on overall and disease-free survival rates and the risk of local recurrence were evaluated. Evaluation was made of 22 patients (16 females, 6 males) with a mean age at diagnosis of 34.7 years (range = 22-76 years). The mean follow-up was 104 months (range = 4.8-168). Tumor localization was in the upper extremity in 4 patients (18.1%), the lower extremity in 11 (50.0%), and the trunk in 7 (31.8%). The mean tumor size (maximum diameter) was 5.2 cm (range = 0.6-13 cm; median = 5.8 cm), and the mean tumor volume was 181.3 ± 531.4 ml. All the 22 patients were treated surgically along with adjuvant radiotherapy (RT) administered to 8 in addition to surgery for the primary treatment of the tumor. Following primary surgery, resection margins were R0 in 11 patients, R1 in 9 and R2 in 2. Local recurrence (LR) developed in 6 patients (27.2%) during the follow-up period. Recurrence-free survival rate (RFS) was 90.9% at one year, 74.1% at 5 years, and 61.7% at 10 years. During the follow-up, no patient died, and distant metastasis was not detected. Tumor length, resection margins, and adjuvant RT were observed to influence the risk of local recurrence (P < 0.05). The results of this study have demonstrated that tumor size ≥ 5 cm and the presence of microscopic or macroscopic positive surgical margins can increase the risk of LR, and adjuvant RT can reduce the development of LR in the management of EDT.

The Clinical Features of Multicentric Extra-abdominal Desmoid Tumors.

Extra-abdominal desmoid tumors often occur in the necks, shoulder, chest wall, back, arm, buttock, thigh and leg. Multicentric extra-abdominal desmoids are rather rare and seem to have other clinical features. The aim of our study was to investigate clinical features, especially multicentric occurrence of extra-abdominal desmoid tumors. A total of 135 patients diagnosed with extra-abdominal desmoid were enrolled in this study from January 2005 to December 2019 at the Cancer Institute Hospital of The Japanese Foundation for Cancer Research. The operative procedure was principally wide excision. The clinicopathological factors [e.g., age, gender, pain, restriction of range of motion (ROM), tumor site, tumor size, surgical margin, multicentric occurrence, local recurrence, tumoral regression] were collected and assessed by univariate analysis. We assessed how multicentric occurrence influenced clinicopathological factors of desmoid tumors. The median follow-up was 39.9 months (range=0.29-259 months). Among 135 patients, 20 had multicentric occurrence. Multicentric extra-abdominal desmoids occurred in the neck in six cases, shoulder in four, chest wall in three, back in three, thigh in two and leg in two. In the case of multicentric occurrence on thighs and legs, tumors arose not in the anterior compartment but in the posterior compartment. Univariate analysis showed association of multicentric extra-abdominal desmoids with high local recurrence (p=0.0003), restriction of ROM (p=0.0012) and tumor size larger than 5 cm (p=0.04) but surgical margins were not correlated with local recurrence (p=0.37). Surgery should be performed in those who have severe pain or restriction of ROM. A 'Wait and see' policy is a first-line management, especially for those with multicentric extra-abdominal desmoids.

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

The aim of this study was to determine outcomes and prognostic factors for patients with primary and locally recurrent extra-abdominal desmoid tumors who underwent percutaneous cryoablation, and to compare with patients treated with surgery. Group characteristics were compared using Fisher's exact test, and propensity score matching was performed using the nearest-neighbor approach. Kaplan-Meier and log-rank analyses were used to evaluate the variation in first local recurrence and disease control, while multivariate Cox regression was used to identify factors associated with first local recurrence. All statistical tests were two-sided and a p-value of 0.05 was considered statistically significant. Twenty-two cryoablation patients were matched with 33 surgical patients (n=55). Median follow-up after cryoablation was 16.3 months versus 14.9 months after surgery. Two-year local recurrence-free survival (LRFS) was 59% after cryoablation and 71% after surgery, and median LRFS was 26.6 months after cryoablation but was not reached after surgery. Two-year disease control for all patients was 85%, however median disease control was not reached in either the cryoablation or surgery groups. There was no significant difference in LRFS or disease control between matched cryoablation and surgical patients. No local recurrences occurred after the first cryoablation in patients with zero or one of the following risk factors: tumor size > 5cm, age ≤ 25years, or locally recurrent disease. All patients with two or more of these risk factors recurred locally after the first cryoablation. Percutaneous cryoablation of primary and locally recurrent extra-abdominal desmoid tumors provides freedom from first local recurrence and long-term disease control comparable with surgery.

Percutaneous cryoablation for advanced and refractory extra-abdominal desmoid tumors

To assess efficacy and safety of percutaneous cryoablation (CA) for advanced and refractory extra-abdominal desmoid tumors. This retrospective study reviewed 30 consecutive patients with symptomatic desmoid tumors evolving after "wait and watch" periods, and despite medical treatment, treated by CA between 2007 and 2019. Progression free survival (PFS), objective response rate, pain reduction (decreased of visual analogic scale pain (VAS)[Formula: see text] 3 or disappearance of pain), total volume lesion (TVL) and complications were documented. Kaplan Meier method was used to outline PFS. Paired sample t test was used to compare volume of tumors before treatment and at 1 and 3year. With a median follow-up of 18.5months (range 6-93months, interquartile range (IQR): 12-55), the PFS was 85.1% at 1year and 77.3% at 3years. Objective response was obtained for 80% of patients with a complete response for 43% patients. Pain reduction was obtained for 96.7% (95% confidence interval (95% CI): 90.3, 100) of patients. Median volume of desmoid tumor before treatment was 124.1cm3 (range 2-1727cm3, IQR: 54-338cm3). Median change of TLV after ablation was 66.6% (95% CI: 37.2, 72.3; p = 0.002) at 1year and 76.4% (95% CI: 59.1, 89.8; p = 0.002) at 3year. Adverse events rate was 36.6%, the most common was edema and temporary increase of pain in the days following CA. Four patients experienced a major complication (13.3%): 2 skin necrosis, 1 infection and 1 brachial plexopathy. CA is an effective treatment for advanced and refractory extra-abdominal desmoid tumor, that induces durable responses.

A Rare Case of Extra-abdominal Desmoid Fibromatosis of the Mandible in a 9-Year-Old Child

AbstractDesmoid tumors are tumors of the fibrous tissue that are benign, which most commonly occur in the abdominal walls of females who are of childbearing age. The most common location for extra-abdominal desmoid tumors is the shoulder and the upper limb. They show no tendency for metastasis but are locally very aggressive. Here we report a rare case of extra-abdominal desmoid fibromatosis in the mandible of a child.

Breast Fibromatosis Case Series and Literature Review

Fibromatosis or desmoid tumor is a benign tumor that rarely affects the breast. It represents 0.2% of all breast tumors and 4% of all extra-abdominal desmoid tumors. Wide local excision with adequate safety margins is considered the standard of care. We report three cases of breast fibromatosis who were presented to and operated in the sultan Qaboos University. All of these cases underwent wide local excision. After close regular follow up now for six months no local recurrence was reported.

Cryoablation of Extra-Abdominal Desmoid Tumors: A Single-Center Experience with Literature Review.

Cryoablation (CA) has gained popularity in the treatment of benign and malignant musculoskeletal tumors. While extra-abdominal desmoid (EAD) tumors are not malignant, they remain challenging to treat because of their high local recurrence rate. We reviewed all EAD tumors treated with CA at our institution between November 2012 and March 2020. Fourteen procedures were performed on nine females and one male (mean age, 33 ± 18 years) as either first-line (n = 4) or salvage therapy (n = 6) with curative intent (n = 8) or tumor debulking (n = 2). Mean tumor size was 63.6 cm3 (range, 3.4–169 cm3). Contrast-enhanced MRI was performed before treatment and at 3-, 6-, and 12-month follow-up. Treatment outcome was based on the change in enhanced tumor volume (ET-V). For curatively treated patients, the mean ET-V change was −97 ± 7%, −44 ± 143%, and +103 ± 312% at 3, 6, and 12 months, respectively. For debulking patients, the mean ET-V change was −98 ± 4%, +149 ± 364%, and +192 ± 353% at 3, 6, and 12 months, respectively. During a mean follow-up of 53.7 months (range, 12–83 months), one grade III and one grade IV complication were noted. We found CA to be safe and well tolerated in patients with EAD.

Trends in Musculoskeletal Ablation: Emerging Indications and Techniques

Image-guided percutaneous thermal ablation plays an increasingly important role in the multidisciplinary management of musculoskeletal lesions. Established indications for ablation in this setting include the treatment of osteoid osteomas, palliation of painful skeletal metastases, local control of oligometastatic disease, and consolidation of bone tumors at risk for fracture. Emerging indications include the treatment of symptomatic soft tissue masses such as extra-abdominal desmoid tumors and abdominal wall endometriosis. This review will discuss considerations in patient selection and preprocedural workup, ablation technology and techniques, strategies to avoid complications, and expected outcomes of ablation in the musculoskeletal system.

Magnetic Resonance-Guided Focused Ultrasound: A Brief Review With Emphasis on the Treatment of Extra-abdominal Desmoid Tumors.

Magnetic resonance-guided focused ultrasound (MRgFUS) utilizes high-intensity focused ultrasound to noninvasively, thermally ablate lesions within the body while sparing the intervening tissues. Magnetic resonance imaging provides treatment planning and guidance, and real-time magnetic resonance thermometry provides continuous monitoring during therapy. Magnetic resonance-guided focused ultrasound is ideally suited for the treatment of extra-abdominal desmoid fibromatosis due to its noninvasiveness, lack of ionizing radiation, low morbidity, and good safety profile. Conventional treatments for these benign tumors, including surgery, radiation, and chemotherapy, can carry significant morbidity. Magnetic resonance-guided focused ultrasound provides a safe and effective alternative treatment in this often-young and otherwise healthy patient population. While there is considerable experience with MRgFUS for treatment of uterine fibroids, painful bone lesions, and essential tremor, there are few reports in the literature of its use for treatment of benign or malignant soft tissue tumors. This article reviews the principles and biologic effects of high-intensity focused ultrasound, provides an overview of the MRgFUS treatment system and use of magnetic resonance thermometry, discusses the use of MRgFUS for the treatment of extra-abdominal desmoid tumors, and provides several case examples.

Percutaneous cryoablation for the treatment of extra-abdominal desmoid tumors.

BackgroundDesmoid tumors are rare locally invasive, benign neoplasms that develop along aponeurotic structures. Current treatment is complicated by associated morbidity and high recurrence rates.MethodsA retrospective, single‐institution review identified 23 patients (age: 16‐77) with extra‐abdominal desmoid tumors who received CT‐guided percutaneous cryoablation as either a first‐line (61%) or salvage (39%) treatment in 30 sessions between 2014 and 2018. Median maximal lesion diameter was 69 mm (range: 11‐209). Intent was curative in 52% and palliative in 48%. Contrast‐enhanced cross‐sectional imaging was obtained before and after treatment in addition to routine clinical follow‐up.ResultsTechnical success was achieved in all patients. The median follow‐up was 15.4 months (3.5‐43.4). Symptomatic improvement was demonstrated in 89% of patients. At 12 months, the average change in viable volume was −80% (range −100% to + 10%) and response by modified response evaluation criteria in solid tumors (mRECIST) was CR 36%, PR 36%, and SD 28% No rapid postablation growth or track seeding was observed. Four patients underwent repeat cryoablation for either residual or recurrent disease. Two patients sustained a major procedural complication consisting of significant neuropraxia.ConclusionCryoablation for desmoid tumors demonstrates a high degree of symptom improvement and local tumor control on early follow‐up imaging with relatively low morbidity.

03:45 PM Abstract No. 301 Percutaneous cryoablation for the treatment of extra-abdominal desmoid tumors

Desmoid tumors are a rare form of locally invasive, benign neoplasms that develop along aponeurotic structures with high recurrence rate after surgical resection. The purpose of this study was to evaluate the safety and efficacy of cryoablation for local disease control. A retrospective search of our single-institution database identified 23 patients with extra-abdominal desmoid tumors who were treated with percutaneous cryoablation as both de novo (61% pts) and salvage (39% pts) treatment in 28 sessions between 2014 and 2018. Mean lesion diameter was 7.0 cm, ranging from 1.1 - 14.0 cm. 48% of patients were treated with the goal of complete ablation, while 52% were treated for palliative debulking. Patient age ranged from 16 to 77 years. Tumors were treated in the abdominal wall, chest wall, shoulder girdle, upper extremity, hip girdle, lower extremity, and head and neck. Imaging was evaluated for baseline tumor size, MR characteristics, and enhancing tumor volume. Technical success was achieved in 100% of patients. 90% of patients who were symptomatic on presentation showed clinical improvement following ablation. One patient suffered a major procedural complication consisting of significant neuropraxia. The average imaging follow-up was 14.6 months (SD ± 10.9). Of 11 patients with follow-up imaging at 12 months, the enhancing tumor volume showed either complete response (CR) or partial response (PR) in all patients (CR 27%, PR 73%), and the total lesion volume showed either CR or PR in 9 of 11 patients. No treatments demonstrated rapid post-ablation growth or track seeding. Three patients underwent repeat cryoablation for either residual or progressive disease. Cryoablation for desmoid tumors demonstrates a high degree of symptom improvement and local tumor control on early follow-up imaging with relatively few side effects. Study limitations include variable follow-up, small sample size, and the retrospective nature of this case series; however, further studies should be pursued as these data provide promising results.

P2.16-29 Clinical Outcomes of Surgically Resected Extraabdominal Chest Wall Desmoid Tumors

Extraabdominal chest wall desmoid tumors are uncommon soft tissue tumors. This study was performed to examine the outcomes of patients with extraabdominal chest wall desmoid tumors and adjacent structures treated with surgery. A detailed retrospective clinicopathological study was performed in 17 patients (8 men and 9 women) treated in our institution for extraabdominal desmoid tumors of the chest wall between March 2001 and June 2017. The patients had a median age of 44 years (range, 17-62 years), and the mean pathological diameter of the resected tumors was 92.1mm. Complete resection was performed in 13 of the 17 patients (76.5%). One patient had positive microscopic margin and three had gross residual disease. Chest wall reconstruction surgery was necessary in five patients (29%), synthetic patches were used in two patients, muscle flaps in two patients, and a metal plate in one patient. Complications were found in one patient, and there were no cases of operative mortality. Five patients (29%) received postoperative adjuvant therapy (only radiotherapy in three, radiotherapy and chemotherapy in two). Follow-up was complete in all patients and ranged from 9 to 202 months (median 76 months). One of the three patients with gross residual disease showed no change in tumor size during the 114 month follow-up period. Recurrences were found in five patients (29%), four of whom were treated by surgery. Second or more operations were performed in three of these patients. All sites of recurrence were around structures the first resected tumors. The mean recurrence time was 20.8 months after surgery. Desmoid tumors of the chest wall are locally aggressive tumors with a high recurrence rate. Surgical treatment requires wide radical resection. Multicentric and long-term investigations would be helpful for management of desmoid tumors because of the low prevalence rate of this disease.