Pediatric Cancer

PV QA 3 - Poster Viewing Q&A 3

TU_25_3112 - Outcomes for Pediatric Osteosarcoma Patients Treated With Palliative Radiation Therapy

Tuesday, October 23
1:00 PM - 2:30 PM
Location: Innovation Hub, Exhibit Hall 3

Outcomes for Pediatric Osteosarcoma Patients Treated With Palliative Radiation Therapy
E. L. Chen, D. J. Merriott, S. S. Donaldson, and S. M. Hiniker; Department of Radiation Oncology, Stanford Cancer Institute, Stanford, CA

Purpose/Objective(s): Osteosarcoma is most often treated with chemotherapy combined with surgical resection, with radiotherapy (RT) generally reserved for recurrent disease or palliation of metastases. Though osteosarcoma is widely perceived to be a radioresistant disease, there are limited data regarding clinical outcomes after palliative RT and the effect of dose escalation in this setting. We evaluated treatment patterns and outcomes of pediatric osteosarcoma patients treated with palliative RT, focusing on the effects of dose on symptom alleviation and local control.

Materials/Methods: We performed a retrospective chart review of 24 pediatric osteosarcoma patients treated with radiotherapy at a single institution from 1997 to 2016. 23 (96%) patients had metastatic disease when irradiated and 1 (4%) had multiply recurrent primary disease. 22 (92%) patients had at least subtotal resection of their primary tumor and 2 (8%) had unresectable primary disease. The 24 patients received 40 total courses of RT. 3 patients (12.5%) underwent re-irradiation. 32 courses (80%) were treated with palliative symptom-alleviating intent. The median EQD2 of these 32 courses was 40.0 Gy (range: 20.0-60.4) and the median BED10 was 48.0 Gy (range: 24.0-72.5). Median number of fractions per course was 15 (range: 5-39). These 32 courses were delivered to 20 patients. Individual patients received a range of 1 to 6 total courses of radiation (median: 1) and a range of 1 to 5 palliative courses of radiation (median: 1).

Results: Of the 32 courses treated with palliative intent, 24 (75%) resulted in symptom improvement. The median time to response was 15.5 days (range: 3-43). Of the 24 courses that resulted in symptom improvement, 13 (54.2%) resulted in some degree of eventual symptom recurrence, 8 (33.3%) were lost to follow-up, and 3 (12.5%) had no symptom recurrence. The median duration of response was 77 days (range: 1-882). Higher dose delivered (EQD2) was positively correlated with duration of response (r=0.39, p=0.0003). Of the 32 courses with palliative intent, 14 (43.8%) were followed by repeat imaging of the treated site; 3 (21.4%) of these courses eventually had local failure by imaging. The median time to local failure by imaging was 394 days. Of the 20 patients who received palliative RT, 13 (65%) eventually expired due to disease-related causes, 6 (30%) were lost to follow-up, and 1 (5%) is alive without disease. The median survival after palliative RT was 142 days (range: 1-891). Only 1 (3.1%) course of palliative RT resulted in a grade 2+ toxicity.

Conclusion: Radiotherapy is an effective and well-tolerated method of symptom palliation in pediatric osteosarcoma patients, with higher doses correlating with longer symptom relief. The clinical efficacy of radiotherapy as well as the relatively long median survival of patients after initiation of palliative radiotherapy support its use in pediatric osteosarcoma patients and argue for further investigation in the definitive and adjuvant settings.

Author Disclosure: E.L. Chen: None. D.J. Merriott: None. S.S. Donaldson: None. S.M. Hiniker: None.

Send Email for Emily Chen


Assets

TU_25_3112 - Outcomes for Pediatric Osteosarcoma Patients Treated With Palliative Radiation Therapy



Attendees who have favorited this

Please enter your access key

The asset you are trying to access is locked. Please enter your access key to unlock.

Send Email for Outcomes for Pediatric Osteosarcoma Patients Treated With Palliative Radiation Therapy