ESTRO 2024 - Abstract Book

S2083

Clinical - Sarcoma, skin cancer, melanoma

ESTRO 2024

Ewing Sarcoma is rare bone sarcoma that most commonly affects children, teenagers and young adults and makes up around 14% of all bone sarcoma’s 1 . Treatment for this disease requires a multimodality treatment using a combination of chemotherapy, radiotherapy and surgery. In cases where surgery is not an option definitive radiotherapy is used in combination with chemotherapy. Since 2018 the Christie Hospital has been treating patients with Ewing’s Sarcoma that have been referred via the NHS proton portal. A total of 23 TYA/adult patients have been treated with definitive proton beam therapy (PBT) plus chemotherapy as of June 2023. We describe the outcomes, demographics, and grade 3+ toxicities.

Material/Methods:

Patient data was collected for all patients that have completed PBT. Follow up data was collected at baseline, on treatment, 6 weeks, 6 months, 1 year, 2 years and 3 years. Patient demographics were taken from hospital records, and the treatment management system. We have excluded patients who had < 6 months follow-up.

Results:

We have treated a total of 23 patients (M:10 F:13) with an age range of 16-52 years old (mean: 27). Most common sites treated are spine(16), pelvis (4) and head and neck (3). Volume of initial disease ranged from 2.2-2069 cc (456cc) with the total irradiated volume ranging 30.3-3718.1cc (1037.6cc). Total dose delivered was 50.4-60Gy with most common dose given being 59.4Gy. Follow up ranged from 6-36 months. 2 patients had small volume lung metastasis at baseline. At the time of analysis 1 patient had locally relapsed (16 months post PBT), 4 patients had developed new metastatic disease and 2 patients had died both with metastatic disease. No grade 4 toxicity was recorded in the acute phase of treatment and the only grade 4 toxicity was retinopathy in one patient 3 years post treatment who had recurrent disease in the head and neck. The most common acute Grade 3 toxicity was a skin reaction (n=2) but in all these patients it had resolved by 6 week follow up. 2/3 of the patients who had treatment to the head and neck had acute grade 3 oral mucositis. 2 patients went in to early menopause G3 1 year post radiotherapy. Of note 2 patient who had pelvic radiotherapy developed osteonecrosis of the femoral head requiring hip replacements 3 years post radiotherapy. One patient developed grade 3 peripheral neuropathy at 3 years.

Conclusion:

Radiation treatment alone has so far shown to be an effective method of local control when surgery is not suitable for patients. Proton therapy provides acceptable treatment toxicity in the acute phase of treatment. Long term side effects are expected, and further long term follow up is needed to assess this.

Keywords: Definitive,Protons,Ewings

References:

1-Sarcoma Uk (2023) website: https://sarcoma.org.uk/about-sarcoma/what-is-sarcoma/types-of-sarcoma/ewing sarcoma/