- Email: [email protected]
Aggressive Fibromatosis Treated With Radiation Therapy: A Single Institution Experience With Adult Patients
Volume 99 Number 2S Supplement 2017 maximum and minimum were extracted from the SUV map and investigated as prognostic indicators for local or distant recurrence through independent t-tests. Significant weight fluctuations during EBRT occurred for 8 of the 37 patients, leading to physician initiated treatment re-planning prior to completion of EBRT treatment. Patient groups were defined for patients with (Group 1, 8 patients) and without (Group 2, 29 patients) significant weight fluctuations leading to re-planning. Kaplan-Meier (K-M) curves were generated for recurrence-free proportions where time of event was measured from the final HDR treatment date to the date of the follow-up exam when recurrence occurred or the patient was censored. These K-M curves were then compared through Cox regression. Results: At the time of follow-up visit (median of 12 months), 6 patients had local pelvic recurrence and 6 had distant recurrence. However, for the 8 patients who had significant weight fluctuation, 4 patients experienced recurrence. The minimum value from the SUV map was found to be a statistically significant indicator for recurrence through the independent t-test (pZ0.004). Cox regression found that patients in Group 2 had a hazard ratio of 0.204 (95% CI-0.051, 0.823; pZ0.025) for recurrence compared to patients in Group 1. Conclusion: The preliminary results obtained from this study suggest information collected prior to and during radiation treatment can provide indication of treatment outcomes. The minimum value of the CTV SUV map extracted from PET images prior to EBRT was identified as an indicator for recurrence. Furthermore, Cox regression demonstrated that patients with significant weight fluctuations were more likely to have recurrence. Early indicators for treatment outcome may play a vital role for the decision making process to adapt treatment plan for individual patients. Author Disclosure: R. Meerschaert: None. S.R. Miller: None. L. Zhuang: None.
3780 Toxicity of Concurrent and Sequential PD-1 Immune Check Point Inhibitors With Conventional and Hypofractionated Radiation Therapy in Patients with Metastatic Disease A.L.H. Arnett,1 L. Kottschade,2 T.J. Wilhite,2 R.S. Youland,1 C. Hocum,2 T.J. Whitaker,1 and S.S. Park1; 1Department of Radiation Oncology, Mayo Clinic, Rochester, MN, 2Mayo Clinic, Rochester, MN Purpose/Objective(s): The use of immune checkpoint inhibitors has become increasingly important in the treatment of metastatic disease. Concurrent and sequential application of both radiation and immunotherapy agents has been rapidly expanding in clinical practice. However, limited data exists regarding the safety and tolerability of combined treatment, particularly in the setting of extracranial stereotactic radiation and hypofractionated regimens. In this study, we evaluated the potential toxicities either concurrent or sequential treatment with radiation and PD-1 inhibitors. Materials/Methods: We retrospectively reviewed records from patients with metastatic melanoma, non-small cell lung cancer, squamous cell carcinoma of the skin, and renal cell carcinoma who were treated with at least one cycle of a PD-1 inhibitor and radiation within 3 months prior or after administration of immunotherapy. Relevant toxicities were recorded based on grade, severity, and timing. Results: We identified 76 patients who were treated with radiation and a PD-1 inhibitor. In total, 176 sites were treated. Of these radiation sites, 75 were treated concurrently with a PD-1 inhibitor. The remainder received radiation sequentially within 30 days or 60 days of PD-1 inhibitor administration. Median radiation dose administered was 30 Gy (range, 6-70 Gy), including patients who were treated with SBRT at doses of 70 Gy in 10 fractions (nZ1), 60 Gy in 5-10 fractions (nZ14), 45-50 Gy in 5-10 fractions (nZ21), 40 Gy in 5-10 fractions (nZ11), and 20-24 Gy in a single fraction (nZ11). Toxicities were generally mild and infrequent. In total, eleven patients (14.5%) reported Grade 1-2 immune-related adverse events. These included cough, fatigue, radiation dermatitis, mucositis, and wound healing complications. Only two patients experienced a Grade 3 adverse event. Of these, one patient experienced soft tissue necrosis in the
Poster Viewing E749 extremity after receiving 10 Gy in a single fraction, administered within 90 days after PD-1 inhibitor treatment. The other developed Grade 3 radiation dermatitis along the scalp after treatment with 36 Gy in 6 fractions, administered within 30 days after PD-1 inhibitor treatment. Notably, no episodes of pneumonitis were reported in this cohort. Conclusion: We observed minimal toxicities in patients who received both sequential or concurrent radiation and PD-1 inhibitor therapy. Both conventional and hypofractionation radiation regimens were well-tolerated in this cohort, suggesting that combinatorial therapy represents a low risk therapeutic option in appropriately selected patients with metastatic disease. Author Disclosure: A.L. Arnett: None. L. Kottschade: None. T.J. Wilhite: None. R.S. Youland: None. C. Hocum: None. T.J. Whitaker: None. S.S. Park: None.
3781 Clinical Presentation and Patterns of Care in SCARE Soft Tissue Sarcoma M. Ashamalla,1 A. Guirguis,2 B.E. Mokhtar,2 and H. Ashamalla2; 1New York-Presbyterian Brooklyn Methodist Hospital, Brooklyn, NY, 2NewYorkPresbyterian Brooklyn Methodist Hospital, Brooklyn, NY Purpose/Objective(s): Soft tissue sarcomas (STS) represent 1% of all adult malignancies and are rarely associated with lymph node involvement. Five sarcoma histologies, identified by the mnemonic SCARE (Synovial, Clear cell, Angiosarcoma, Rhabdomyosarcoma and Epithelioid), are commonly associated with lymph node (LN) involvement. Our aims were to analyze the incidence of lymph node involvement of SCARE histologies and identify the patterns of care. Materials/Methods: Adults individuals (>18 - 90+) diagnosed with SCARE-STS between 2004-2014 were identified from the NCDB. We included the 5 histologies of interest and excluded all patients who received adjuvant therapy more than 180 days from diagnosis. Chi-square tests were used to compare demographic factors, tumor characteristics and therapy received. Results: 10,256 patients with SCARE-STS were identified. SCARE histologies comprised 34, 4, 35, 17 and 10% respectively. Of the total, 6% were located in the head and neck region, 17% in the upper extremities, 46% in the lower extremities and 30% in the trunk. Incidence of LN involvement in SCARE was 4.1, 23.5, 10.5, 21.4 and 19.4% respectively. Incidence of distant metastases was highest in rhabdomyosarcoma (27%) and lowest in synovial sarcoma (13%). Despite the lowest incidence of LN involvement (4.1%), synovial sarcoma demonstrated the highest correlation between nodal disease and distant metastases (33.3%), the highest of all SCARE histologies. Of all subtypes, chemotherapy was used in 47, 19, 32, 62 and 31% respectively. In patients with positive LN, use of chemotherapy was highest in rhabdomyosarcoma (77.4%) and lowest in clear cell sarcoma (28%). Radiation was given most often in synovial sarcoma (52%) and least often in clear cell sarcoma (26%). Multivariate analysis and survival data will be presented. Conclusion: An analysis of lymph node involvement in SCARE-STS revealed surprisingly less lymph node involvement (4.1%) in synovial sarcoma than previously believed, while confirming the high likelihood of lymph node involvement in the remaining four subtypes, thus supporting the mnemonic CARE. Notably, the use of chemotherapy in these 5 histologies is higher than that historically reported for other STS subtypes. Author Disclosure: M. Ashamalla: None. A. Guirguis: None. B.E. Mokhtar: None. H. Ashamalla: None.
3782 Aggressive Fibromatosis Treated With Radiation Therapy: A Single Institution Experience With Adult Patients J.E. Bates,1 M.S. Rutenberg,1,2 C.G. Morris,1,2 D.J. Indelicato,1,2 C.P. Gibbs,3 M. Scarborough,3 and R.A. Zlotecki1; 1Department of Radiation Oncology, University of Florida College of Medicine, Gainesville, FL, 2University of Florida Health Proton Therapy Institute,
E750
International Journal of Radiation Oncology Biology Physics
Jacksonville, FL, 3Department of Orthopaedics and Rehabilitation, University of Florida College of Medicine, Gainesville, FL
Materials/Methods: Patients with stage I-III STS of the extremity diagnosed from 2003- 2011 treated with pre-operative RT were retrieved from the National Cancer Data Base. No patients received chemotherapy. TTPRT was delineated by the number of days from diagnosis to initiation of pre-operative RT. TTPRT was categorized into 4 groups, 0-30 days, 31-60 days, 61-90 days and greater than 90 days. The effect of TTPRT on margin status and survival was determined by using logistic regression and Cox regression models (MVA), respectively. Results: 7069 patients were treated with pre-operative RT followed by resection and included in the analysis. Forty percent received RT within 30 days, 35% received RT within 31-60 days, 11% received RT within 61-90 days and 14% received RT greater than 90 days from the time of diagnosis. TTPRT of 31-60 days versus 30 days (HR 1.17; 95% CI 1.09-1.26, p<0.001) and >90 days versus 30 days (HR 1.19; 95% CI 1.09-1.32, p<0.001) increased the risk of positive margins at the time of resection. In addition, to TTPRT, age > 65 (HR 1.29; 95% CI 1.06-1.57, pZ0.009) and stage (HR 1.001; 95% CI 1.000-1.003, pZ0.008) also predicted for increased risk of positive margins. On MVA, TTPRT of 31-60 days versus 30 days (HR 1.10; 95% CI 1.02-1.20, pZ0.02) and >90 days versus 30 days (HR 1.17; 95% CI 1.05-1.30, pZ0.006) led to increased risk of mortality after resection. In addition, stage (HR 1.002; 95% CI 1.001-1.005, pZ0.001) predicted for increased mortality. Conclusion: TTPRT independently affects the propensity for positive margins at the time of resection and leads to increased mortality. As such, efforts should be made to ensure that patients with localized STS treated with pre-operative RT should initiate treatment in a timely manner to avoid poorer outcomes. Author Disclosure: M. Bedi: None. J. Charlson: None. C.M. Ellison: None. C. Johnstone: Employee; Medical College of WI. K. Turaga: None.
Purpose/Objective(s): Aggressive fibromatosis (desmoid tumor) is subject to varied and sometimes controversial management. The purpose of this study is to report the long-term disease control and toxicity outcomes in a large case series of patients treated with radiotherapy for this rare tumor. Materials/Methods: We retrospectively analyzed 69 consecutive adult patients treated with radiotherapy at a single institution over a 40-year period (1975 to 2015). The median age was 41 years old (range, 31 e 80). Sixty-seven percent of patients were female; 65% were white. Fifty-five percent of patients were treated with radiation therapy at initial presentation for unresectable disease, primarily due to close anatomic proximity to vital structures. A minority of patients (16%) had 3 or more surgeries before radiotherapy. Further, 75% of patients had gross disease present at the time of radiation. Data on tumor size was available for 57 patients; the median maximum linear dimension was 8 cm (range, 2 e 22 cm). The median total radiotherapy dose was 54 Gy (range, 35 Gy e 70 Gy). Twicedaily fractionation (typically 1.2 Gy per fraction) was used in 36% of patients. Median follow-up was 14.2 years (range, 0.3 e 41.5 years). Cox proportional hazards modeling was used to compare the risk of local recurrence between various demographic, tumor, and treatment characteristics. Age and radiation dose were evaluated using a dichotomous model. Results: Overall survival rates at 5, 10, and 15 years were 98.2%, 92.6%, and 83.0%. The local control rates at 5, 10, and 15 years were 88.9%, 87.0%, and 87.0%, respectively. On univariate analysis, age <40 years was associated with inferior local control (5-year local-regional control rate, 78% versus 97%; hazard ratio Z 4.4; 95% confidence interval Z 1.0 e 30.0; p Z 0.048), a trend which was maintained on multivariate analysis (p Z 0.048). Neither the presence of gross disease nor recurrent disease was associated with an increased risk of recurrence. There was no statistically significant difference in local control between patients who received <55 Gy and those who received 55 Gy (p Z 0.70). A total of 39% of patients developed grade 3 or higher acute or late treatment-related toxicity; the most common toxicity was lymphedema, occurring in 13% of patients. The second most common toxicity was pain/paresthesia, occurring in 12% of patients. There were 2 in-field fractures identified. Treatment toxicities were more frequent in patients who received surgery before RT (47%) relative to those who did not (32%), although this finding was not statistically significant (p Z 0.32). Conclusion: Moderate-dose radiation is associated with high rates of local control and acceptable toxicity. Radiotherapy should be considered the standard of care for adult patients with recurrent or unresectable aggressive fibromatosis. Author Disclosure: J.E. Bates: None. M.S. Rutenberg: None. C.G. Morris: None. D.J. Indelicato: Expert Witness; Mateer Harbert PA. Honoraria; Mayo Clinic, University of Cincinnati. Consultant; LEK Consulting, Maximus Federal Services. Travel Expenses; IBA. ; Pediatric Proton Foundation. C. Gibbs: None. M. Scarborough: None. R.A. Zlotecki: None.
3783 The Impact of Increasing Time to Pre-Operative Radiation on Outcomes in Patients with Soft Tissue Sarcomas M. Bedi,1 J. Charlson,1 C.M. Ellison,1 C. Johnstone,1 and K. Turaga2; 1 Medical College of Wisconsin, Milwaukee, WI, 2University of Chicago, Chicago, IL Purpose/Objective(s): Pre-operative radiation (RT) followed by resection in soft tissue sarcomas (STS) of the extremity yields excellent rates of local control and survival. It is unknown, however, if the interval from diagnosis to the initiation of pre-operative RT impacts disease outcomes. The aim of this study is to assess the effect of increasing time to preoperative RT (TTPRT) on margin status and mortality in patients (pts) with localized STS of the extremity.
3784 Optimal Management of Subcutaneous Myxofibrosarcoma: Impact of Initial Surgical Intervention on Oncologic Outcomes Y.L.E. Chen,1 R. Miao,1 K.A. Raskin,2 F.J. Hornicek,2 A. Jacobson,3 T.F. DeLaney,1 and A.B. Haynes3; 1Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA, 2Department of Orthopaedic Surgery, Massachusetts General Hospital, Boston, MA, 3 Massachusetts General Hospital, Boston, MA Purpose/Objective(s): Subcutaneous myxofibrosarcoma present a unique challenge for local control. Often mistaken as benign or well encapsulated lesions, these are often resected nononcologically and associated with high local recurrence. Materials/Methods: We retrospectively reviewed the outcomes of patients with subcutaneous myxofibrosarcoma in an IRB approved protocol. Clinicopathological, treatment details, and oncologic outcomes were analyzed. Results: 22 consecutive patients with subcutaneous myxofibrosarcoma were identified from 1994 to 2015. A large proportion of patients (10, 45.5%) had family history of cancers or sarcomas. Four (18%) had prior malignancies including 2 sarcomas. Median age at diagnosis was 64.5 years (18-87). 95.5% present with a palpable mass and 13.6 % present with pain. Pathologic diagnosis was established by unplanned excision (9, 40.9%), FNA (5, 22.7%), core biopsy (5, 22.7%), incisional biopsy (2, 0.1%), or planned excisional biopsy (1, 4.5%). Most were located in the lower extremity (12, 54.5%), followed by upper extremity/shoulder (7, 31.8%), trunk (2, 13.6%), and breast (1, 4.5%). 10 patients had tumors Z< 5 cm and 12 were > 5 cm. None had nodal or distant metastases on presentation. Median tumor size was 5.45 cm (2-11.9 cm). On pathology, 14 were grade 3 (63.6%), 7 grade 2 (31.8%), and 1 grade 1 (4.5%). Five cases (22.7%) had clear dermal involvement. Patients were treated with surgery, no RT (10, 45.5%), surgery -> postop RT (5, 22.7%), preop RT -> surgery -> postop RT (4, 18.2%), preop RT -> surgery (1, 4.5%), surgery -> RT -> surgery (2, 9.1%). On surgical resection, positive
3780 Toxicity of Concurrent and Sequential PD-1 Immune Check Point Inhibitors With Conventional and Hypofractionated Radiation Therapy in Patients with Metastatic Disease A.L.H. Arnett,1 L. Kottschade,2 T.J. Wilhite,2 R.S. Youland,1 C. Hocum,2 T.J. Whitaker,1 and S.S. Park1; 1Department of Radiation Oncology, Mayo Clinic, Rochester, MN, 2Mayo Clinic, Rochester, MN Purpose/Objective(s): The use of immune checkpoint inhibitors has become increasingly important in the treatment of metastatic disease. Concurrent and sequential application of both radiation and immunotherapy agents has been rapidly expanding in clinical practice. However, limited data exists regarding the safety and tolerability of combined treatment, particularly in the setting of extracranial stereotactic radiation and hypofractionated regimens. In this study, we evaluated the potential toxicities either concurrent or sequential treatment with radiation and PD-1 inhibitors. Materials/Methods: We retrospectively reviewed records from patients with metastatic melanoma, non-small cell lung cancer, squamous cell carcinoma of the skin, and renal cell carcinoma who were treated with at least one cycle of a PD-1 inhibitor and radiation within 3 months prior or after administration of immunotherapy. Relevant toxicities were recorded based on grade, severity, and timing. Results: We identified 76 patients who were treated with radiation and a PD-1 inhibitor. In total, 176 sites were treated. Of these radiation sites, 75 were treated concurrently with a PD-1 inhibitor. The remainder received radiation sequentially within 30 days or 60 days of PD-1 inhibitor administration. Median radiation dose administered was 30 Gy (range, 6-70 Gy), including patients who were treated with SBRT at doses of 70 Gy in 10 fractions (nZ1), 60 Gy in 5-10 fractions (nZ14), 45-50 Gy in 5-10 fractions (nZ21), 40 Gy in 5-10 fractions (nZ11), and 20-24 Gy in a single fraction (nZ11). Toxicities were generally mild and infrequent. In total, eleven patients (14.5%) reported Grade 1-2 immune-related adverse events. These included cough, fatigue, radiation dermatitis, mucositis, and wound healing complications. Only two patients experienced a Grade 3 adverse event. Of these, one patient experienced soft tissue necrosis in the
Poster Viewing E749 extremity after receiving 10 Gy in a single fraction, administered within 90 days after PD-1 inhibitor treatment. The other developed Grade 3 radiation dermatitis along the scalp after treatment with 36 Gy in 6 fractions, administered within 30 days after PD-1 inhibitor treatment. Notably, no episodes of pneumonitis were reported in this cohort. Conclusion: We observed minimal toxicities in patients who received both sequential or concurrent radiation and PD-1 inhibitor therapy. Both conventional and hypofractionation radiation regimens were well-tolerated in this cohort, suggesting that combinatorial therapy represents a low risk therapeutic option in appropriately selected patients with metastatic disease. Author Disclosure: A.L. Arnett: None. L. Kottschade: None. T.J. Wilhite: None. R.S. Youland: None. C. Hocum: None. T.J. Whitaker: None. S.S. Park: None.
3781 Clinical Presentation and Patterns of Care in SCARE Soft Tissue Sarcoma M. Ashamalla,1 A. Guirguis,2 B.E. Mokhtar,2 and H. Ashamalla2; 1New York-Presbyterian Brooklyn Methodist Hospital, Brooklyn, NY, 2NewYorkPresbyterian Brooklyn Methodist Hospital, Brooklyn, NY Purpose/Objective(s): Soft tissue sarcomas (STS) represent 1% of all adult malignancies and are rarely associated with lymph node involvement. Five sarcoma histologies, identified by the mnemonic SCARE (Synovial, Clear cell, Angiosarcoma, Rhabdomyosarcoma and Epithelioid), are commonly associated with lymph node (LN) involvement. Our aims were to analyze the incidence of lymph node involvement of SCARE histologies and identify the patterns of care. Materials/Methods: Adults individuals (>18 - 90+) diagnosed with SCARE-STS between 2004-2014 were identified from the NCDB. We included the 5 histologies of interest and excluded all patients who received adjuvant therapy more than 180 days from diagnosis. Chi-square tests were used to compare demographic factors, tumor characteristics and therapy received. Results: 10,256 patients with SCARE-STS were identified. SCARE histologies comprised 34, 4, 35, 17 and 10% respectively. Of the total, 6% were located in the head and neck region, 17% in the upper extremities, 46% in the lower extremities and 30% in the trunk. Incidence of LN involvement in SCARE was 4.1, 23.5, 10.5, 21.4 and 19.4% respectively. Incidence of distant metastases was highest in rhabdomyosarcoma (27%) and lowest in synovial sarcoma (13%). Despite the lowest incidence of LN involvement (4.1%), synovial sarcoma demonstrated the highest correlation between nodal disease and distant metastases (33.3%), the highest of all SCARE histologies. Of all subtypes, chemotherapy was used in 47, 19, 32, 62 and 31% respectively. In patients with positive LN, use of chemotherapy was highest in rhabdomyosarcoma (77.4%) and lowest in clear cell sarcoma (28%). Radiation was given most often in synovial sarcoma (52%) and least often in clear cell sarcoma (26%). Multivariate analysis and survival data will be presented. Conclusion: An analysis of lymph node involvement in SCARE-STS revealed surprisingly less lymph node involvement (4.1%) in synovial sarcoma than previously believed, while confirming the high likelihood of lymph node involvement in the remaining four subtypes, thus supporting the mnemonic CARE. Notably, the use of chemotherapy in these 5 histologies is higher than that historically reported for other STS subtypes. Author Disclosure: M. Ashamalla: None. A. Guirguis: None. B.E. Mokhtar: None. H. Ashamalla: None.
3782 Aggressive Fibromatosis Treated With Radiation Therapy: A Single Institution Experience With Adult Patients J.E. Bates,1 M.S. Rutenberg,1,2 C.G. Morris,1,2 D.J. Indelicato,1,2 C.P. Gibbs,3 M. Scarborough,3 and R.A. Zlotecki1; 1Department of Radiation Oncology, University of Florida College of Medicine, Gainesville, FL, 2University of Florida Health Proton Therapy Institute,
E750
International Journal of Radiation Oncology Biology Physics
Jacksonville, FL, 3Department of Orthopaedics and Rehabilitation, University of Florida College of Medicine, Gainesville, FL
Materials/Methods: Patients with stage I-III STS of the extremity diagnosed from 2003- 2011 treated with pre-operative RT were retrieved from the National Cancer Data Base. No patients received chemotherapy. TTPRT was delineated by the number of days from diagnosis to initiation of pre-operative RT. TTPRT was categorized into 4 groups, 0-30 days, 31-60 days, 61-90 days and greater than 90 days. The effect of TTPRT on margin status and survival was determined by using logistic regression and Cox regression models (MVA), respectively. Results: 7069 patients were treated with pre-operative RT followed by resection and included in the analysis. Forty percent received RT within 30 days, 35% received RT within 31-60 days, 11% received RT within 61-90 days and 14% received RT greater than 90 days from the time of diagnosis. TTPRT of 31-60 days versus 30 days (HR 1.17; 95% CI 1.09-1.26, p<0.001) and >90 days versus 30 days (HR 1.19; 95% CI 1.09-1.32, p<0.001) increased the risk of positive margins at the time of resection. In addition, to TTPRT, age > 65 (HR 1.29; 95% CI 1.06-1.57, pZ0.009) and stage (HR 1.001; 95% CI 1.000-1.003, pZ0.008) also predicted for increased risk of positive margins. On MVA, TTPRT of 31-60 days versus 30 days (HR 1.10; 95% CI 1.02-1.20, pZ0.02) and >90 days versus 30 days (HR 1.17; 95% CI 1.05-1.30, pZ0.006) led to increased risk of mortality after resection. In addition, stage (HR 1.002; 95% CI 1.001-1.005, pZ0.001) predicted for increased mortality. Conclusion: TTPRT independently affects the propensity for positive margins at the time of resection and leads to increased mortality. As such, efforts should be made to ensure that patients with localized STS treated with pre-operative RT should initiate treatment in a timely manner to avoid poorer outcomes. Author Disclosure: M. Bedi: None. J. Charlson: None. C.M. Ellison: None. C. Johnstone: Employee; Medical College of WI. K. Turaga: None.
Purpose/Objective(s): Aggressive fibromatosis (desmoid tumor) is subject to varied and sometimes controversial management. The purpose of this study is to report the long-term disease control and toxicity outcomes in a large case series of patients treated with radiotherapy for this rare tumor. Materials/Methods: We retrospectively analyzed 69 consecutive adult patients treated with radiotherapy at a single institution over a 40-year period (1975 to 2015). The median age was 41 years old (range, 31 e 80). Sixty-seven percent of patients were female; 65% were white. Fifty-five percent of patients were treated with radiation therapy at initial presentation for unresectable disease, primarily due to close anatomic proximity to vital structures. A minority of patients (16%) had 3 or more surgeries before radiotherapy. Further, 75% of patients had gross disease present at the time of radiation. Data on tumor size was available for 57 patients; the median maximum linear dimension was 8 cm (range, 2 e 22 cm). The median total radiotherapy dose was 54 Gy (range, 35 Gy e 70 Gy). Twicedaily fractionation (typically 1.2 Gy per fraction) was used in 36% of patients. Median follow-up was 14.2 years (range, 0.3 e 41.5 years). Cox proportional hazards modeling was used to compare the risk of local recurrence between various demographic, tumor, and treatment characteristics. Age and radiation dose were evaluated using a dichotomous model. Results: Overall survival rates at 5, 10, and 15 years were 98.2%, 92.6%, and 83.0%. The local control rates at 5, 10, and 15 years were 88.9%, 87.0%, and 87.0%, respectively. On univariate analysis, age <40 years was associated with inferior local control (5-year local-regional control rate, 78% versus 97%; hazard ratio Z 4.4; 95% confidence interval Z 1.0 e 30.0; p Z 0.048), a trend which was maintained on multivariate analysis (p Z 0.048). Neither the presence of gross disease nor recurrent disease was associated with an increased risk of recurrence. There was no statistically significant difference in local control between patients who received <55 Gy and those who received 55 Gy (p Z 0.70). A total of 39% of patients developed grade 3 or higher acute or late treatment-related toxicity; the most common toxicity was lymphedema, occurring in 13% of patients. The second most common toxicity was pain/paresthesia, occurring in 12% of patients. There were 2 in-field fractures identified. Treatment toxicities were more frequent in patients who received surgery before RT (47%) relative to those who did not (32%), although this finding was not statistically significant (p Z 0.32). Conclusion: Moderate-dose radiation is associated with high rates of local control and acceptable toxicity. Radiotherapy should be considered the standard of care for adult patients with recurrent or unresectable aggressive fibromatosis. Author Disclosure: J.E. Bates: None. M.S. Rutenberg: None. C.G. Morris: None. D.J. Indelicato: Expert Witness; Mateer Harbert PA. Honoraria; Mayo Clinic, University of Cincinnati. Consultant; LEK Consulting, Maximus Federal Services. Travel Expenses; IBA. ; Pediatric Proton Foundation. C. Gibbs: None. M. Scarborough: None. R.A. Zlotecki: None.
3783 The Impact of Increasing Time to Pre-Operative Radiation on Outcomes in Patients with Soft Tissue Sarcomas M. Bedi,1 J. Charlson,1 C.M. Ellison,1 C. Johnstone,1 and K. Turaga2; 1 Medical College of Wisconsin, Milwaukee, WI, 2University of Chicago, Chicago, IL Purpose/Objective(s): Pre-operative radiation (RT) followed by resection in soft tissue sarcomas (STS) of the extremity yields excellent rates of local control and survival. It is unknown, however, if the interval from diagnosis to the initiation of pre-operative RT impacts disease outcomes. The aim of this study is to assess the effect of increasing time to preoperative RT (TTPRT) on margin status and mortality in patients (pts) with localized STS of the extremity.
3784 Optimal Management of Subcutaneous Myxofibrosarcoma: Impact of Initial Surgical Intervention on Oncologic Outcomes Y.L.E. Chen,1 R. Miao,1 K.A. Raskin,2 F.J. Hornicek,2 A. Jacobson,3 T.F. DeLaney,1 and A.B. Haynes3; 1Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA, 2Department of Orthopaedic Surgery, Massachusetts General Hospital, Boston, MA, 3 Massachusetts General Hospital, Boston, MA Purpose/Objective(s): Subcutaneous myxofibrosarcoma present a unique challenge for local control. Often mistaken as benign or well encapsulated lesions, these are often resected nononcologically and associated with high local recurrence. Materials/Methods: We retrospectively reviewed the outcomes of patients with subcutaneous myxofibrosarcoma in an IRB approved protocol. Clinicopathological, treatment details, and oncologic outcomes were analyzed. Results: 22 consecutive patients with subcutaneous myxofibrosarcoma were identified from 1994 to 2015. A large proportion of patients (10, 45.5%) had family history of cancers or sarcomas. Four (18%) had prior malignancies including 2 sarcomas. Median age at diagnosis was 64.5 years (18-87). 95.5% present with a palpable mass and 13.6 % present with pain. Pathologic diagnosis was established by unplanned excision (9, 40.9%), FNA (5, 22.7%), core biopsy (5, 22.7%), incisional biopsy (2, 0.1%), or planned excisional biopsy (1, 4.5%). Most were located in the lower extremity (12, 54.5%), followed by upper extremity/shoulder (7, 31.8%), trunk (2, 13.6%), and breast (1, 4.5%). 10 patients had tumors Z< 5 cm and 12 were > 5 cm. None had nodal or distant metastases on presentation. Median tumor size was 5.45 cm (2-11.9 cm). On pathology, 14 were grade 3 (63.6%), 7 grade 2 (31.8%), and 1 grade 1 (4.5%). Five cases (22.7%) had clear dermal involvement. Patients were treated with surgery, no RT (10, 45.5%), surgery -> postop RT (5, 22.7%), preop RT -> surgery -> postop RT (4, 18.2%), preop RT -> surgery (1, 4.5%), surgery -> RT -> surgery (2, 9.1%). On surgical resection, positive