Iodine-125 brachytherapy for a desmoid tumor in the abdomen-thorax: A retrospective study.

PURPOSE: To investigate the safety and efficacy of iodine-125 seed implantation in the treatment of abdomen-thorax desmoid tumors (DTs). METHODS AND MATERIALS: Data from 14 DT patients who received brachytherapy with iodine-125 seeds were retrospectively collected from 2014 to 2020. The operation was completed using CT guidance and the treatment plan system (TPS). The number of lesions and the target dosimetry parameters were recorded. After brachytherapy, the lesions were evaluated using response evaluation criteria in solid tumors (RECIST). RESULTS: Fourteen patients with 18 lesions were enrolled in this study; eleven lesions were in the thorax, seven were in the abdomen, and the lesion gross tumor volume (GTV) was 82.10 cc (interquartile range [IQR]: 40.37, 203.42 cc). The median number of seeds was 88 (IQR: 35, 158), and the median prescription dose was 120 Gy (IQR: 115, 120 Gy). The D90 was 123 ± 16.7 Gy, the V90 was 97% (IQR: 95.00, 97.25%), and the V200 was 27% (IQR: 14.50, 33.00%). The median follow-up time for each lesion was 34 (IQR: 23, 67) months, and the local response rate was 100%. Following brachytherapy, the overall survival was 52.3 ± 30.72 months. One year after brachytherapy, one patient experienced persistent worsening of a brachial plexus injury; another received a ureteral stent. No brachytherapy-related complications were observed in the remaining patients. CONCLUSIONS: Iodine-125 brachytherapy is a novel treatment option for DT of the abdomen and thorax. Although it is a safe and effective treatment, the radiation dose of iodine-125 brachytherapy for DT-embedded organs at risk must be investigated further.

Radiation-induced Desmoid Tumor Development in the Radiotherapy Field in a Child With Pineoblastoma: A Case Report.

Although treatment-related secondary malignancies are rare, they are important problems after the treatment of childhood malignant diseases. Irradiation-induced sarcomas are the development of sarcoma different from the primary tumor after a latent period of ≥3 years or more in the radiotherapy field. Desmoid tumor is extremely rare as irradiation-induced tumor. A 7.5-year-old girl was referred to our hospital after a subtotal mass excision for a solid lesion with a cystic component located in the pineal gland. Pathologic examination revealed pineoblastoma. After surgery, craniospinal radiotherapy, and chemotherapy consisting of vincristine, cisplatin, and etoposide were performed. Painless swelling in the left parieto-occipital region ~75 months after the end of the treatment developed in the patient. A mass was detected in the intracranial but extra-axial region by radiologic imaging methods. Due to the total removal of the mass and the absence of a tumor in the surgical margins, she was followed up without additional treatment. The pathologic diagnosis was a desmoid tumor. She was followed up disease free for ~7 years after the primary tumor and ~7 months after the secondary tumor. Treatment-related desmoid tumor development after treatment for a central nervous system tumor in a child is extremely rare.

Disease and economic burden of surgery in desmoid tumors: a review.

INTRODUCTION: Desmoid tumors (DT) are soft-tissue tumors that infiltrate into surrounding structures with ill-defined margins. Although surgery is a potential treatment option, complete excision with negative margins is not often possible, the postsurgery recurrence rate is high, and surgery can result in disfigurement and/or loss of function. AREAS COVERED: We conducted a literature review to assess the burden of surgery in patients with DT, focusing on recurrence rates and functional deficits resulting from surgeries. Since economic data related to DT surgery is lacking, reviews of surgery costs in soft-tissue sarcomas and of general costs of amputations were conducted. Risk factors for DT recurrence after surgery are young age (<30 years), tumor location (extremities), tumor size (>5 cm in greatest diameter), positive resection margins, and history of trauma in the area of the primary tumor. Tumors in the extremities have the highest risk of recurrence (30%-90%). Lower rates of recurrences have been reported when radiotherapy was used after surgery (14%-38%). EXPERT OPINION: Although effective in specific cases, surgery may be associated with poor long-term functional outcomes and higher economic costs. Therefore, it is imperative to find alternative treatments with acceptable efficacy and safety profiles that do not adversely affect functional aspects in patients.

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

BACKGROUND: Desmoid tumor (DT) is rare and challenging, often affects the head and neck (HN) region in children, and its appropriate treatments are under-discussed. This study aimed to retrospectively evaluate the long-term effectiveness and safety of 125 I seed brachytherapy for pediatric DT in HN. PROCEDURE: Seven pediatric patients with a median age of three years who suffered from DT in HN treated with 125 I brachytherapy from January 2008 to June 2018 were included. Among these, five underwent sole brachytherapy and the others combined with surgery under prescription doses ranging from 10,000 to 12,000 cGy. The rate of local control (LC), complete response (CR), and partial response (PR) was calculated after evaluation by radiological and pathological means. Radiation-associated toxicities were also evaluated. RESULTS: The LC rate was 7/7 during the follow-up time ranging from 43 to 135 months and with a mean of 57 months. No recurrent lesion was found in the patients receiving surgery combined with brachytherapy. In patients treated with sole brachytherapy, the radiological PR rate and CR rate were 4/5 and 1/5, respectively. In those reaching radiological PR, 3/4 were pathological CR. Slight acute radiation-associated toxicities were observed in all patients, and no late or severe acute toxicity was observed. CONCLUSION: 125 I brachytherapy is effective and safe in the management of pediatric DT in HN as the sole modality or combined with surgery in the long term.

Successful treatment with radiation therapy for desmoid-type fibromatosis with unilateral hydronephrosis: a case report.

BACKGROUND: Desmoid-type fibromatosis is a rare disease that can result in hydronephrosis. Hydronephrosis associated with desmoid-type fibromatosis often requires surgery or ureteral stent insertion. Although radiation therapy is recommended for inoperable cases of desmoid-type fibromatosis, there has been no report of treatment for hydronephrosis associated with desmoid-type fibromatosis by radiation therapy alone. We herein report a case of successful treatment for inoperable recurrence of desmoid-type fibromatosis with unilateral hydronephrosis by radiation therapy alone. CASE PRESENTATION: A 43-year-old Japanese female underwent resection of desmoid-type fibromatosis in the right inguinal region and combined resection of the right external iliac vein 5 years before. Other treatment was not performed because of her pregnancy. Four years after surgery, desmoid-type fibromatosis recurred in the right pelvic wall. Cyclooxygenase-2 selective inhibitor treatment was given for 1 year, but her desmoid-type fibromatosis enlarged to more than 10 cm, and she had swelling of her right leg and hydronephrosis of her right kidney. The patient received 50.4 Gy in 28 fractions of prophylactic irradiation using 10 MV X-ray and 9 Gy in five fractions of a sequential boost for the recurrent desmoid-type fibromatosis. Although there was temporary tumor progression at 1 month after radiation therapy, slow regression of the tumor was seen. At 5 years after radiation therapy, there was no disease progression or severe complications. CONCLUSION: We experienced successful treatment for an inoperable case of desmoid-type fibromatosis with hydronephrosis. Moderate-dose radiation therapy alone is an effective and feasible approach for the management of hydronephrosis associated with desmoid-type fibromatosis.

Undervaluation of Radiotherapy for Gross Desmoid Tumors: The Need for Absolute Volume Assessment.

BACKGROUND/AIM: To compare absolute volume (AV) assessment according to Response Evaluation Criteria in Solid Tumors (RECIST) for the response evaluation of desmoid tumors (DTs) treated with radiotherapy. PATIENTS AND METHODS: Eighteen patients with DTs ≥3 cm in size were included. RESULTS: The median follow-up duration was 78.0 months. Five patients achieved a complete response according to RECIST, seven reached a partial response (PR), and one eventually exhibited progression. The overall response rate was 61%, the median time to PR was 8.0 months. Six patients achieved stable disease, although three developed progressions. Of the six patients with a PR, the median change in maximum diameter was -46%, and the median change in maximum volume was -84%. Three patients could have been diagnosed with progression at least 6 months earlier if the AV increment was considered. CONCLUSION: An AV assessment is essential for an accurate response assessment of DTs and radiotherapy seems feasible as a first-line treatment for DTs.

The Role of Radiation Therapy for Symptomatic Desmoid Tumors.

OPINION STATEMENT: Desmoid tumors have a variable clinical course that ranges from indolence or spontaneous regression to an aggressive pattern marked by local invasion. Up to half may remain stable or regress; watchful waiting is the preferred approach in the initial management of desmoid tumors. Symptomatic or progressive tumors or those that may affect adjacent critical structures require surgery, radiotherapy, or systemic therapy. Although radiotherapy effectively controls desmoid tumors in most cases, concerns regarding late toxicity exist. Definitive radiotherapy for macroscopic disease is indicated when a non-morbid complete surgical resection cannot be accomplished and provides similar control rates to surgery plus radiotherapy but avoids toxicity from combined-modality treatment (surgery and radiotherapy). Adjuvant radiotherapy can be considered for microscopically involved margins, particularly for recurrent cases or when a future recurrence may be challenging to treat. Large size, extremity site, and younger age are poor prognostic factors after radiotherapy. In the extremity, radiotherapy may have superior outcomes to surgery. Younger patients, especially children, are challenging to manage as they are at particular risk for late toxicity due to the number of potential years at risk. For patients under 20 years old, for whom a non-morbid complete resection is not possible, we recommend systemic therapy as the first line of treatment. Although the long-term efficacy of systemic therapy is unproven, this strategy allows additional time for growth and development prior to radiotherapy. In younger patients and those with axial desmoid tumors adjacent to critical organs, consideration should be given to using proton therapy as the dosimetric advantages may mitigate some of the toxicity associated with conventional radiotherapy.

Radiotherapy in the treatment of aggressive fibromatosis: experience from a single institution.

BACKGROUND: Desmoid-type fibromatosis is a rare, potentially locally aggressive disease. Herein we present our experience in the treatment with radiotherapy. METHODS AND MATERIALS: In total 40 patients who received 44 treatments from 2009 to 2018 at the Heidelberg University Hospital with photons (N = 28) as well as protons (N = 15) and carbon ions (N = 1) were investigated. The median age at radiotherapy was 41 years [range 8-78]. Familial adenomatous polyposis (FAP) was confirmed for nine patients and 30 had a unifocal desmoid tumor. The localizations were abdominal wall, abdominopelvic cavity, thoracic wall, extremity, head and neck and trunk. The median prescribed dose was 54 Gy/ Gy (RBE) [range 39.6-66, IQR 50-60]. Eleven treatments were performed at the time of first diagnosis; 33 at the time of progression or recurrence. Post-operative radiotherapy was performed in 17 cases. The median planning target volume was 967 ml [84-4364 ml, IQR 447-1988]. Survival analysis was performed by the Kaplan-Meier Method. RESULTS: The median follow-up time was 32 months [1-153]. At the end of the follow-up interval all patients but one were alive. The estimated local progression free survival of the treated lesion in 3 and 5 years was 76.4% and 63,8%, respectively. The progression-free survival in 3 and 5 years was 72.3 and 58.4% and the overall survival was 97.4 and 97.4%, respectively. In case of macroscopic tumor (N = 31) before radiotherapy a partial remission was observed in 12 cases (38.7%) and a complete remission in 4 cases (12.9%). Progression was observed in 13 (29.5%) cases, predominantly at the margin of the planning target volume (PTV, N = 5, 38,4%) followed by progression within the PTV (N = 4, 30.8%). In univariate analysis multifocal localization was associated with impaired progression-free survival (p = 0.013). One patient developed a grade V gastrointestinal bleeding, otherwise no acute toxicity >°III was observed. Late toxicity was depending on the localization of the desmoid tumor and was especially severe in patients with FAP and abdominopelvine desmoids including gastrointesinal fistula, perforation and abscess. CONCLUSION: Radiotherapy in the treatment of desmoids can lead to long term control. Treatment of patients with abdominopelvine desmoids should be avoided, as the risk of higher-grade complications is substantial.

Certain risk factors for patients with desmoid tumors warrant reconsideration of local therapy strategies.

BACKGROUND: The objective of this study was to evaluate treatment outcomes for patients with desmoid tumors (DTs) receiving local therapy with surgery alone, radiation therapy (RT) alone, or combined modality therapy (RT and surgery). METHODS: This was a cross-sectional cohort study of 412 patients with nonmesenteric DTs who received local therapy at the authors' institution between 1965 and 2018. RESULTS: The median follow-up time was 95 months (range, 1-509 months). Local recurrence occurred in 127 patients (31%) at a median time of 21 months (interquartile range, 12-38 months). The 5-year local control (LC) rate was 67%. Patient or tumor factors that were significantly associated with poorer 5-year LC in a multivariable analysis included an age ≤ 30 years (57% vs 75% for an age > 30 years; hazard ratio [HR], 1.73; P = .004), an extremity location (57% vs 71% for a nonextremity location; HR, 1.77; P = .004), and large tumors (59% for >10 cm [HR, 2.17; P = .004] and 65% for 5.1-10 cm [HR, 1.71; P = .02] vs 76% for ≤5 cm). Subset analyses of these high-risk patients revealed no local therapy strategy to be superior for young patients ≤ 30 years old (HR for surgery, 1.42; P = .33; HR for RT, 1.36; P = .38) or for large tumors > 10 cm (HR for surgery, 1.55; P = .46; HR for RT, 0.91; P = .91). However, for patients with extremity tumors, surgery alone was significantly associated with inferior LC (HR for surgery, 5.15; P < .001; HR for RT, 1.51; P = .38). CONCLUSIONS: Local therapy provides durable tumor control in the majority of patients with DTs. However, young patients, patients with an extremity location, and patients with large tumors are at increased risk of recurrence. When active treatment is indicated, systemic therapy should perhaps be considered as a first-line option in these high-risk subsets. Prospective multi-institutional studies evaluating this strategy are warranted.

Definitive radiation therapy in patients with unresectable desmoid tumors: a systematic review.

BACKGROUND: Desmoid tumors are rare soft tissue tumors. Wide local excision has been the standard surgical treatment for desmoid tumors. However, this procedure results in high local recurrence rates, so non-surgical treatments should be considered. The aim of this systematic review was to evaluate the effect of radiation therapy on patients with desmoid tumors, especially those with unresectable disease. METHODS: We evaluated studies published between 1 January 1990 and 31 August 2017 and cited in PubMed and Ichushi (in Japanese). All studies evaluating the effect of radiation therapy on desmoid tumors were included. Data regarding radiation dose, recurrence and adverse events were recorded. RESULTS: Among 218 identified studies, only 6 were finally included in this review. Local control was achieved in 253 of 317 patients with unresectable or unresected tumors who underwent definitive radiation therapy (the crude rate of local control was 79.8%). Toxicity was evaluated in patients who underwent definitive radiation therapy or surgery plus radiation therapy. One of the most common acute complications was skin toxicity. Frequent late complications of radiation therapy included fibrosis/contracture/joint stiffness, skin disorders, lymphedema and pain. Six patients developed secondary malignancies in the radiation field. CONCLUSIONS: In patients treated unsuccessfully with surgery, watchful waiting and pharmacotherapy, radiation therapy may be an option as salvage therapy because of the high rate of local control. Because desmoid tumors frequently develop in young individuals, children and young patients who receive radiation therapy for the treatment of desmoid tumors should be followed up on a long-term basis with periodic monitoring for late radiation toxicities.

Radiation Therapy for Benign Disease: Arteriovenous Malformations, Desmoid Tumor, Dupuytren Contracture, Graves Ophthalmopathy, Gynecomastia, Heterotopic Ossification, Histiocytosis.

Although the use of ionizing radiation in malignant conditions has been well established, its application in benign conditions has not been fully accepted and has been inadequately recognized by health care providers outside of radiation therapy. Most frequently, radiation therapy in these benign conditions is used along with other treatment modalities, such as surgery, in instances where the condition causes significant disability or could even lead to death. Radiation therapy can be helpful for inflammatory/proliferative disorders. This article discusses the current use of radiation therapy in some of the more common benign conditions.

Radiotherapy in the treatment of primary or recurrent unresectable desmoid tumors of the neck.

Purpose: Desmoid tumors are locally aggressive nonmalignant soft tissue tumors, which frequently recur after therapy. The optimal treatment is still controversial because of the lack of large research. A few studies have reported the effects of other treatments in one lesion when surgery is not possible or would cause notable functional impairment. Our aim was to examine the outcome of radiotherapy (RT) in the treatment of primary or recurrent unresectable desmoid tumors of the neck. Materials: A retrospective analysis was performed on 30 patients between 1/2008 and 12/2017, with 3 primary and 27 recurrent unresectable desmoid tumors of the neck. All cases were reviewed by pathologists. Results: The median follow-up time was 50.5 months (range 2-126 months). Radiotherapy doses varied from 50 to 66 Gy (median 60 Gy, 23/30 patients) with all fraction size of 2 Gy. The objective response rate (ORR: CR or PR) to definitive RT was 56.7% (17/30 patients). On Chi-square statistic, ORR was significantly influenced by tumor size (≤5 cm versus >5 cm) (p = .046). Age (≤ 40 versus >40 years) (p = .804), gender (p = .629), and RT dose (≤60 versus >60 Gy) (p = .613) were not significantly associated with ORR. The most common acute side effects of the radiation-related complication were grade 1-2 skin toxicities. Conclusion: Radiotherapy is a valuable option in the management of primary or recurrent unresectable DTs of the neck with good local control. Multi-institutional and prospective studies are warranted to further validate our findings.

Postoperative radiotherapy in primary resectable desmoid tumors of the neck: a case-control study.

PURPOSE: Desmoid tumors (DTs) are rare soft tissue tumors, which frequently recur after surgery. The optimal treatment approach is still controversial due to lack of randomized data. The purpose of the study was to review a relative large series of DTs of the neck with emphasis on the value of postoperative radiotherapy (RT). METHODS: A total of 68 patients with DTs of the neck region with or without postoperative RT between 1/2008 and 12/2017 were included. They were individually matched for factors including age, gender, tumor size and margin status with a cohort of patients who underwent operative without postoperative RT. The event-free survival (EFS) was compared in the two groups. RESULTS: For the study, 34 patients and 34 matched control subjects were identified. The two groups did not differ in terms of age (p = 0.810), gender (p = 0.328), tumor size (p = 0.803) and margin status (p = 0.799). Patients who received surgery plus RT had a significantly higher 3­year EFS than those who received surgery alone (74.6% vs. 13.3%, P < 0.001). Factors including postoperative RT and margin status were independent factors of EFS. The values of P were <0.001 and 0.003 and the hazard ratios (95% confidence interval) were 11.929 (4.732-30.072) and 0.299 (0.133-0.671), respectively. None of the patients treated with RT developed serious complications. CONCLUSIONS: According to our results, postoperative radiotherapy is an effective treatment in desmoid tumors of the neck. Multi-institutional and prospective studies are warranted to further validate our findings.

Long-Term Outcomes for Patients With Desmoid Fibromatosis Treated With Radiation Therapy: A 10-Year Update and Re-evaluation of the Role of Radiation Therapy for Younger Patients.

PURPOSE: To update our experience with long-term outcomes in patients with desmoid fibromatosis treated with radiation therapy (RT) and to characterize factors associated with increased risk of local recurrence. METHODS AND MATERIALS: We reviewed the records of 209 consecutive patients with desmoid fibromatosis treated with RT, either alone or as combined-modality therapy (CMT) with surgery, at our institution from 1965 to 2015. RESULTS: Median follow-up time was 98 months (range, 1-509 months). The 5- and 10-year local control (LC) was 71% and 69%, respectively. Fifty-nine patients (28%) experienced a local recurrence at a median time of 23 months (interquartile range, 15-38 months). Among all patients, on multivariable analysis, adjusting for anatomic site, size, age, treatment era (>2005 vs ≤2005), treatment approach (RT alone vs CMT), and an interaction between age and treatment, we found only age ≤30 years (hazard ratio [HR], 2.94; P = .005; 95% confidence interval [CI], 1.38-6.27) and large tumor size >10 cm (HR, 2.51; P = .03; 95% CI, 1.09-5.78) to be correlated with poorer LC. Notably, for patients receiving RT alone, the 5-year LC was 43% for patients ≤30 years old versus 75% for >30 years old (P < .001). On multivariable analyses, for patients receiving RT alone, the only factor associated with inferior LC was age ≤30 years (HR, 2.87; P = .001; 95% CI, 1.51-5.47). The same was true for patients treated with CMT; age ≤30 years was the only factor associated with inferior LC (HR, 5.36; P = .01; 95% CI, 1.40-20.58). CONCLUSIONS: Among all patients with desmoid fibromatosis, RT is an effective local therapy for tumor control. However, young patients ≤ 30 years have notably high rates of local recurrence regardless of treatment strategy, which requires further study. Treatment decisions should be risk-adapted by large referral centers with multidisciplinary expertise in desmoid management.

Optimal radiotherapy strategy for primary or recurrent fibromatosis and long-term results.

PURPOSE: Although locally invasive or recurrent fibromatosis is primarily treated with surgery, radiotherapy (RT) produces local control for recurrent/unresectable tumors or those with positive surgical margins. Herein, we describe our updated institutional experience with RT to treat fibromatosis. METHODS: Forty-seven patients with fibromatosis received RT between 1990 and 2015, and were followed for ≥12 months. Eight patients received RT for gross tumors, and 39 received postoperative RT after single/multiple prior surgeries. A median dose of 54 Gy was prescribed for definitive RT; 48.6, 50.4, and 54 Gy were prescribed for R0, R1, and R2 resected tumors, respectively. Recurrences were classified as in-field, marginal, or out-field. Prognostic factors were also evaluated. RESULTS: Seven recurrences were noted, including 2 in-field, 4 marginal, and 1 out-field, after a median follow-up of 60 months. In-field recurrences occurred in 1 patient who received 40.5 Gy of salvage RT after postoperative recurrence and another who received 45 Gy for R1 resection after multiple prior operations. All marginal failures were due to insufficient clinical target volume (CTV) margins regardless of dose (3 with 45 Gy and 1 with 54 Gy). On multivariate analysis, a CTV margin ≥5 cm and dose >45 Gy were significant predictors of non-recurrence (p = 0.039 and 0.049, respectively). Subgroup analysis showed that patients with both an CTV margin ≥5 cm and a dose >45 Gy showed a favorable outcome. CONCLUSIONS: RT is a valuable option for treating aggressive fibromatosis; doses ≥45 Gy and a large field produce optimal results. For in-field control, a higher dose is more necessary for gross residual tumors than for totally excised lesions.

Radiation Therapy as an Alternative Treatment for Desmoid Fibromatosis.

AIM: To determine the outcome after radiation therapy for desmoid fibromatosis. MATERIALS AND METHODS: A retrospective review of 50 patients treated between 1988 and 2016 in a specialised bone and soft tissue tumour clinic. RESULTS: The median age at the time of radiation therapy was 36.8 years (range 15.1-69.0) and the median follow-up time was 51 months. Forty-three patients underwent radiation therapy as the definitive treatment with a median dose of 56 Gy (range 30-58.8 Gy). The median dose for the seven patients treated with postoperative radiation therapy was 50.4 Gy (range 48-56 Gy). Eleven patients (22%) developed progressive disease after radiation therapy at a median time of 41 months (range 12-113 months). The recurrences were within the radiation therapy field in four patients and outside the field in seven patients. One patient developed a radiation-induced malignancy 20 years after treatment. CONCLUSIONS: Radiation therapy is an alternative treatment in the management of desmoid fibromatosis. It should be considered in patients for whom surgical resection is not feasible, or as adjuvant therapy after surgery with involved margins where any further recurrences would cause significant morbidity.

Radiation Therapy for Aggressive Fibromatosis: The Association Between Local Control and Age.

PURPOSE: Radiation therapy (RT) is often used in the treatment of unresectable or recurrent aggressive fibromatosis (also known as desmoid tumor) typically with excellent local control. Prior reports have suggested that local control in pediatric patients with aggressive fibromatosis is poor. We aimed to report a long-term single-institution experience with the radiotherapeutic treatment of these tumors with a focus on age-dependent outcomes. METHODS AND MATERIALS: A total of 101 patients treated with RT for aggressive fibromatosis between 1975 and 2015 at a single institution were identified. A variety of demographic and treatment-related variables were abstracted from patients' medical records. Kaplan-Meier analyses were performed to investigate the relationship between these variables and local control. RESULTS: Overall survival was excellent (98% and 95% at 5 and 10 years, respectively); local control was likewise excellent (82% and 78% at 5 and 10 years, respectively). Patients aged <20 years at diagnosis had significantly worse 5-year local control than those aged >40 years at diagnosis (72% vs 97%; hazard ratio, 9.0; P = .009). Patients treated with once-daily fractionation had significantly improved 5-year local control compared with those treated with twice-daily fractionation (90% vs 73%; hazard ratio, 0.3; P = .008). Neither the presence of gross versus microscopic residual disease, initial versus recurrent presentation, number of prior surgical procedures, nor tumor size had any effect on 5-year local control. In a total of 36.6% of patients, Common Terminology Criteria for Adverse Events grade 3 or 4 toxicity developed following treatment; the frequency of toxicities was reduced in patients treated during or after 1995 (24.5%) relative to those treated prior to 1995 (51.9%, P = .02). CONCLUSIONS: RT for aggressive fibromatosis offers excellent local control and should remain the standard of care for patients with unresectable or recurrent disease. Younger patients have diminished local control relative to older patients, suggesting possible biological differences contributing to radioresistance in the pediatric and young adult population.

Radiotherapy in desmoid tumors : Treatment response, local control, and analysis of local failures.

BACKGROUND: Desmoid tumors (aggressive fibromatosis) are rare soft tissue tumors which frequently recur after surgery. Desmoid tumors arise from musculoaponeurotic tissue in the extremities, head and neck, abdominal wall, or intra-abdominally. Our aim was to examine the outcome of radiotherapy of desmoid tumors in a single institution series. PATIENTS AND METHODS: We evaluated 41 patients with desmoid tumors treated with 49 radiotherapies between 1987 and 2012. Radiologic images for response evaluation were reassessed and responses to treatment registered according to RECIST criteria 1.1. For patients with local failures radiation dose distribution was determined in each local failure volume using image co-registration. Recurrences were classified as in-target, marginal, or out-of-target. Prognostic factors for radiotherapy treatment failure were evaluated. RESULTS: Radiotherapy doses varied from 20-63 Gy (median 50 Gy) with a median fraction size of 2 Gy. The objective response rate to definitive radiotherapy was 55% (12/22 patients). Median time to response was 14 months. A statistically significant dose-response relation for definitive and postoperative radiotherapy was observed both in univariate (p-value 0.002) and in multivariate analysis (p-value 0.02) adjusted for potential confounding factors. Surgery before radiotherapy or surgical margin had no significant effect on time to progression. Nine of 11 (82%) local failures were classified as marginal and two of 11 (18%) in-target. None of the recurrences occurred totally out-of-target. CONCLUSIONS: Radiotherapy is a valuable option for treating desmoid tumors. Radiotherapy dose appears to be significantly associated to local control.