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Osteosarcoma of the Spine and Pelvis: One hundred fifteen Patients of a Single Institution
E708
International Journal of Radiation Oncology Biology Physics
location included 29 patients with lower extremity, 6 upper extremity, and 1 neck. The most common histologies were undifferentiated pleomorphic sarcoma (44%), liposarcoma (14%), and myxofibrosarcoma (14%). The median tumor size was 9.5 cm (range, 1.5-22.1 cm) with 89% of patients presenting with high-grade histology. All patients had preoperative EBRT followed by surgical resection. Final surgical margins were negative in all patients. The median total EBRT dose was 50 Gy (range, 45-50.4 Gy). An intraoperative electron boost was delivered in 22% of patients with a median dose of 10 Gy (range, 10-12.5 Gy). Fifty percent of patients received chemotherapy. At a median follow-up of 18 months (range, 2-67 months), the 3-year OS, disease-free survival, and local control rates for all patients were 52.4% (95% CI: 19-77.7%), 52% (95% CI: 32.1-68.4%), and 82.6% (95% CI: 56.6-93.8%), respectively. A significant difference was observed in percent change in simple contrast (PZ0.0475) between patients with 95% pathologic necrosis (nZ9) and <95% necrosis (nZ27). Changes in simple deviation (PZ0.08), GLCM difference of variance (PZ0.09), and GLCM contrast (PZ0.08) showed a trend for significance. Conclusion: Changes in STS texture following NT can be used to identify pathologic responders to treatment prior to surgical resection. While this study involved analysis of only a portion of the tumor, our future work involves analysis of the entire tumor to identify additional imaging biomarkers as well as validating this analysis on a larger patient cohort. Author Disclosure: E.D. Miller: None. B.S. Erdal: None. X. Mo: None. L.M. Prevedello: None. R.D. White: None. M.X. Welliver: None.
who underwent surgery, positive margin (HRZ5.9, PZ0.004) and treatment without chemotherapy (HRZ6.3, PZ0.005) were associated with worse OS. Thirty-three (37.1%) patients had failure, including 18 patients with distant metastasis, 12 patients with local recurrence (LC), 1 patient with progression of primary disease, and 2 patients with regional recurrence. The median failure time is 14.2 months. Among patients with nonmetastatic disease, positive margins (HRZ3.5, PZ0.002) as one single negative factor for DFS. Among 12 patients who had LC, 10 (83.3%) of them had 1 mm or positive margins while the margins for the other 2 were not determined. Conclusion: Osteosarcoma in spine and pelvis are challenging bone sarcomas for management. For nonmetastatic disease, patients should be treated with wide excision of the tumor and adjuvant chemotherapy. Local control is highly affected by margin status. Author Disclosure: H. Wang: None. A. Jacobson: None. S. Goldberg: None. T. Stanton: None. D. Harmon: None. E. Choy: None. G. Cote: None. F.J. Hornicek: None. K. Raskin: None. T.F. DeLaney: None. G. Nielsen: None. Y.E. Chen: None.
3736 Osteosarcoma of the Spine and Pelvis: One hundred fifteen Patients of a Single Institution H. Wang,1 A. Jacobson,1 S. Goldberg,2 T. Stanton,2 D. Harmon,2 E. Choy,3 G. Cote,2 F.J. Hornicek,2 K. Raskin,4 T.F. DeLaney,1 G. Nielsen,4 and Y.L.E. Chen1; 1Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA, 2Massachusetts General Hospital, Boston, MA, 3Division of Hematology/Oncology, Department of Medicine, Massachusetts General Hospital, Boston, MA, 4Massachussets General Hospital, Boston, MA Purpose/Objective(s): Spine and pelvis are uncommon sites of involvement for osteosarcoma that pose unique challenges for treatment. Radiation therapy (RT) plays a greater role due to the difficulty of complete resection in these sites. We reviewed a large series of spine and pelvic osteosarcoma for treatment approach and clinical outcomes. Materials/Methods: Patients with osteosarcoma in their spine or pelvis who presented to our institution from 1964 to 2013 were identified. Kaplan-Meier analysis and Cox proportional hazards regression were used to analyze survival outcomes and prognostic factors. Results: Of 115 patients, the median age was 36 years, (range, 4-84). Twenty-six (22.6%) patients presented with metastatic disease, and 89 (77.4%) patients had nonmetastatic disease. Seventeen patients were determined to be potentially RT associated. Specific anatomic distribution of the primary tumors were C spine (5, 4.3%), T spine (12, 10.4%), L spine (13, 11.3%), sacrum and coccyx (14, 12.1%), and pelvis (71, 61.7%). Histology subtypes were osteosarcoma NOS (69, 60.0%), chondroblastic osteosarcoma (35, 30.4%), fibroblastic osteosarcoma (6, 5.2%), small cell osteosarcoma (4, 3.5%), and parosteal osteosarcoma (1, 0.9%). Forty (34.8%) patients were treated with surgery without RT. Twenty patients were treated with preoperative RT, while 21 patients with surgery plus postoperative RT and 13 patients with surgery plus both pre- and postoperative RT. Nineteen patients were treated with RT alone without surgery and 2 patients received no surgery or RT. The median RT dose administered was 56 Gy (range, 16.2-77.4). Among 73 patients who received RT, 23 (31.5%) patients received RT dose over 66 Gy. With the median follow-up of 24.6 months, the 3- and 5-year overall survival (OS) were 70.9% (95%CI: 60.1-79.2) and 61.7% (95%CI: 49.8%-71.5), respectively. Among the patients who presented with nonmetastatic disease, multivariate analysis identified gGrade 3 (HRZ4.3, PZ0.014), no chemotherapy received (HRZ4.2, PZ0.003), and no surgical resection (HRZ8.2, PZ0.074) as worse prognostic factors for OS. Among patients
3737 Pencil Beam Scanning Proton Therapy for Extracranial Chondrosarcoma: Long-Term Follow-up From a Single Institution J.W. Snider, III,1,2 S. Stieb,1 D. Poelma-Tap,3 L. Placidi,1 F. Albertini,1 A. Bolsi,1 A.J. Lomax,1 U. Kliebsch,4 D.C. Weber,1 and R.A. Schneider1; 1 Paul Scherrer Institute, Villigen, Switzerland, 2University of Maryland Medical Center, Baltimore, MD, 3Radiotherapeutisch Instituut Friesland, Leeuwarden, Netherlands, 4Center for Proton Therapy, Paul Scherrer Institute, Villigen, Switzerland Purpose/Objective(s): Chondrosarcomas (ChSa) represent often large, locally aggressive tumors that commonly arise in the axial skeleton or pelvis. Complete surgical extirpation is rare, and local recurrences, unfortunately, remain common. Proximity to the spinal cord and other critical structures often compromises resection and/or the delivery of adjuvant radiation therapy. Pencil beam scanning proton therapy (PBS PT), however, allows for highly conformal, high dose delivery with limited highgrade toxicity. We investigated long-term clinical outcomes in patients treated for extracranial ChSa, with PBS PT, at our institution. Materials/Methods: Between 1999 and 2014, 33 patients (34 lesions) have been treated with PBS PT for extracranial ChSa; each has at least 1 year of follow-up (median 54 months, range, 14-180). Median patient age was 49 years (range, 23-72) and the female/male ratio was 1.8. The vast majority (28/32, 82%) received prescription doses of 68 Gy(RBE) or higher (median, 68.4 Gy(RBE)). Patients were treated for ChSa of the cervical (nZ10), thoracic (nZ19), or sacral (nZ1) spine, and the pelvis (nZ4). Twenty eight (82%) were treated with PBS PT alone, while 6 received combined modality (photon-proton) therapy. Surgical stabilization (SS) with metal implant in the treatment field was present in 14 patients. Results: Five-year actuarial local control (LC) was 58%, while progression-free (PFS) and overall survival (OS) were 52% and 68%, respectively. Five patients (15%) eventually developed distant metastasis. The presence of SS (nZ14) did not clearly correlate with long-term LC, PFS, or OS (P>0.1). In this series, the presence of gross residual disease (nZ20) at the time of PBS PT demonstrated a trend in predicting for both worse local control (PZ0.16) and overall survival (PZ0.058). Despite relatively large volume disease and resultant treatment volumes (median PTV1 353 mL, median PTV2 235 mL), high-grade toxicity was rarely encountered with 3% and 9% of patients having grade 3 or higher acute and late toxicity, respectively. Conclusion: A high rate of LC was observed after high dose, postoperative PBS PT with limited toxicity. Incomplete resection seems to prognosticate for worsened outcomes. Author Disclosure: J.W. Snider: None. S. Stieb: None. D. Poelma-Tap: None. L. Placidi: None. F. Albertini: None. A. Bolsi: None. A.J. Lomax: None. U. Kliebsch: None. D.C. Weber: None. R.A. Schneider: None.
International Journal of Radiation Oncology Biology Physics
location included 29 patients with lower extremity, 6 upper extremity, and 1 neck. The most common histologies were undifferentiated pleomorphic sarcoma (44%), liposarcoma (14%), and myxofibrosarcoma (14%). The median tumor size was 9.5 cm (range, 1.5-22.1 cm) with 89% of patients presenting with high-grade histology. All patients had preoperative EBRT followed by surgical resection. Final surgical margins were negative in all patients. The median total EBRT dose was 50 Gy (range, 45-50.4 Gy). An intraoperative electron boost was delivered in 22% of patients with a median dose of 10 Gy (range, 10-12.5 Gy). Fifty percent of patients received chemotherapy. At a median follow-up of 18 months (range, 2-67 months), the 3-year OS, disease-free survival, and local control rates for all patients were 52.4% (95% CI: 19-77.7%), 52% (95% CI: 32.1-68.4%), and 82.6% (95% CI: 56.6-93.8%), respectively. A significant difference was observed in percent change in simple contrast (PZ0.0475) between patients with 95% pathologic necrosis (nZ9) and <95% necrosis (nZ27). Changes in simple deviation (PZ0.08), GLCM difference of variance (PZ0.09), and GLCM contrast (PZ0.08) showed a trend for significance. Conclusion: Changes in STS texture following NT can be used to identify pathologic responders to treatment prior to surgical resection. While this study involved analysis of only a portion of the tumor, our future work involves analysis of the entire tumor to identify additional imaging biomarkers as well as validating this analysis on a larger patient cohort. Author Disclosure: E.D. Miller: None. B.S. Erdal: None. X. Mo: None. L.M. Prevedello: None. R.D. White: None. M.X. Welliver: None.
who underwent surgery, positive margin (HRZ5.9, PZ0.004) and treatment without chemotherapy (HRZ6.3, PZ0.005) were associated with worse OS. Thirty-three (37.1%) patients had failure, including 18 patients with distant metastasis, 12 patients with local recurrence (LC), 1 patient with progression of primary disease, and 2 patients with regional recurrence. The median failure time is 14.2 months. Among patients with nonmetastatic disease, positive margins (HRZ3.5, PZ0.002) as one single negative factor for DFS. Among 12 patients who had LC, 10 (83.3%) of them had 1 mm or positive margins while the margins for the other 2 were not determined. Conclusion: Osteosarcoma in spine and pelvis are challenging bone sarcomas for management. For nonmetastatic disease, patients should be treated with wide excision of the tumor and adjuvant chemotherapy. Local control is highly affected by margin status. Author Disclosure: H. Wang: None. A. Jacobson: None. S. Goldberg: None. T. Stanton: None. D. Harmon: None. E. Choy: None. G. Cote: None. F.J. Hornicek: None. K. Raskin: None. T.F. DeLaney: None. G. Nielsen: None. Y.E. Chen: None.
3736 Osteosarcoma of the Spine and Pelvis: One hundred fifteen Patients of a Single Institution H. Wang,1 A. Jacobson,1 S. Goldberg,2 T. Stanton,2 D. Harmon,2 E. Choy,3 G. Cote,2 F.J. Hornicek,2 K. Raskin,4 T.F. DeLaney,1 G. Nielsen,4 and Y.L.E. Chen1; 1Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA, 2Massachusetts General Hospital, Boston, MA, 3Division of Hematology/Oncology, Department of Medicine, Massachusetts General Hospital, Boston, MA, 4Massachussets General Hospital, Boston, MA Purpose/Objective(s): Spine and pelvis are uncommon sites of involvement for osteosarcoma that pose unique challenges for treatment. Radiation therapy (RT) plays a greater role due to the difficulty of complete resection in these sites. We reviewed a large series of spine and pelvic osteosarcoma for treatment approach and clinical outcomes. Materials/Methods: Patients with osteosarcoma in their spine or pelvis who presented to our institution from 1964 to 2013 were identified. Kaplan-Meier analysis and Cox proportional hazards regression were used to analyze survival outcomes and prognostic factors. Results: Of 115 patients, the median age was 36 years, (range, 4-84). Twenty-six (22.6%) patients presented with metastatic disease, and 89 (77.4%) patients had nonmetastatic disease. Seventeen patients were determined to be potentially RT associated. Specific anatomic distribution of the primary tumors were C spine (5, 4.3%), T spine (12, 10.4%), L spine (13, 11.3%), sacrum and coccyx (14, 12.1%), and pelvis (71, 61.7%). Histology subtypes were osteosarcoma NOS (69, 60.0%), chondroblastic osteosarcoma (35, 30.4%), fibroblastic osteosarcoma (6, 5.2%), small cell osteosarcoma (4, 3.5%), and parosteal osteosarcoma (1, 0.9%). Forty (34.8%) patients were treated with surgery without RT. Twenty patients were treated with preoperative RT, while 21 patients with surgery plus postoperative RT and 13 patients with surgery plus both pre- and postoperative RT. Nineteen patients were treated with RT alone without surgery and 2 patients received no surgery or RT. The median RT dose administered was 56 Gy (range, 16.2-77.4). Among 73 patients who received RT, 23 (31.5%) patients received RT dose over 66 Gy. With the median follow-up of 24.6 months, the 3- and 5-year overall survival (OS) were 70.9% (95%CI: 60.1-79.2) and 61.7% (95%CI: 49.8%-71.5), respectively. Among the patients who presented with nonmetastatic disease, multivariate analysis identified gGrade 3 (HRZ4.3, PZ0.014), no chemotherapy received (HRZ4.2, PZ0.003), and no surgical resection (HRZ8.2, PZ0.074) as worse prognostic factors for OS. Among patients
3737 Pencil Beam Scanning Proton Therapy for Extracranial Chondrosarcoma: Long-Term Follow-up From a Single Institution J.W. Snider, III,1,2 S. Stieb,1 D. Poelma-Tap,3 L. Placidi,1 F. Albertini,1 A. Bolsi,1 A.J. Lomax,1 U. Kliebsch,4 D.C. Weber,1 and R.A. Schneider1; 1 Paul Scherrer Institute, Villigen, Switzerland, 2University of Maryland Medical Center, Baltimore, MD, 3Radiotherapeutisch Instituut Friesland, Leeuwarden, Netherlands, 4Center for Proton Therapy, Paul Scherrer Institute, Villigen, Switzerland Purpose/Objective(s): Chondrosarcomas (ChSa) represent often large, locally aggressive tumors that commonly arise in the axial skeleton or pelvis. Complete surgical extirpation is rare, and local recurrences, unfortunately, remain common. Proximity to the spinal cord and other critical structures often compromises resection and/or the delivery of adjuvant radiation therapy. Pencil beam scanning proton therapy (PBS PT), however, allows for highly conformal, high dose delivery with limited highgrade toxicity. We investigated long-term clinical outcomes in patients treated for extracranial ChSa, with PBS PT, at our institution. Materials/Methods: Between 1999 and 2014, 33 patients (34 lesions) have been treated with PBS PT for extracranial ChSa; each has at least 1 year of follow-up (median 54 months, range, 14-180). Median patient age was 49 years (range, 23-72) and the female/male ratio was 1.8. The vast majority (28/32, 82%) received prescription doses of 68 Gy(RBE) or higher (median, 68.4 Gy(RBE)). Patients were treated for ChSa of the cervical (nZ10), thoracic (nZ19), or sacral (nZ1) spine, and the pelvis (nZ4). Twenty eight (82%) were treated with PBS PT alone, while 6 received combined modality (photon-proton) therapy. Surgical stabilization (SS) with metal implant in the treatment field was present in 14 patients. Results: Five-year actuarial local control (LC) was 58%, while progression-free (PFS) and overall survival (OS) were 52% and 68%, respectively. Five patients (15%) eventually developed distant metastasis. The presence of SS (nZ14) did not clearly correlate with long-term LC, PFS, or OS (P>0.1). In this series, the presence of gross residual disease (nZ20) at the time of PBS PT demonstrated a trend in predicting for both worse local control (PZ0.16) and overall survival (PZ0.058). Despite relatively large volume disease and resultant treatment volumes (median PTV1 353 mL, median PTV2 235 mL), high-grade toxicity was rarely encountered with 3% and 9% of patients having grade 3 or higher acute and late toxicity, respectively. Conclusion: A high rate of LC was observed after high dose, postoperative PBS PT with limited toxicity. Incomplete resection seems to prognosticate for worsened outcomes. Author Disclosure: J.W. Snider: None. S. Stieb: None. D. Poelma-Tap: None. L. Placidi: None. F. Albertini: None. A. Bolsi: None. A.J. Lomax: None. U. Kliebsch: None. D.C. Weber: None. R.A. Schneider: None.