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Evaluation of long term toxicity profile in young patients treated with particle therapy for chordoma at CNAO. Chordomas are rare slow-growing tumors characterized by a locally aggressive growth pattern, representing 50-60% of bone tumors. The 50–60% of cases are localized in the sacrum-coccix followed by skull-base (25–30%), cervical (10%) and thoracolumbar tract (5 %). The site of origin is commonly located nearby organs performing important functions. The main treatment for chordoma is still represented by radical surgery. In most cases the resection with wide margins is complicated by severe dysfunctions that can be highly disabling with remarkable impact on quality of life (QoL) and socio-economics contribution, especially in young patients. In the last decades particle therapy seems to be a safe alternative to radical surgery in sacral chordoma, and the best radiotherapy technique in post-operative treatment of skull-base and spine chordoma in terms of local control and lower late effects. Aim of the study is to evaluate toxicity and quality of life in young patients undergoing hadrontherapy for chordoma.

Between June 2012 and December 2018, 36 young pts with median age of 36 years (9-40) with histologically proven chordoma, were treated with charged particle therapy using active scanning beam delivery system at CNAO. We treated 22 skull-base chordomas, 9 spine chordomas (level from C1 to L5) and 5 sacral chordomas (level S1-S3 and below). 17 pts were treated with proton therapy (PT) median dose 74Gy RBE (range 36-74) while 19 pts with carbon ion therapy (CIRT) with median dose 70.4Gy RBE (range 64-73.6). We evaluated toxicity according to CTCAE v.4 and investigated QoL using EORTC QLQ-C30 questionnaires.

Median follow-up time was 26 months. Late G3 toxicity was observed in 2 patients with skull-base chordoma (skin ulceration with consequential synthesis media exposure and seizures). Temporal lobe necrosis G2 was observed in 4 patients, G1 in 2 patients. Six patients with spine/sacral chordoma developed neurosensitive peripheral neuropathy: 3 patients experienced G1 toxicity, 3 patients G2 toxicity. No one showed bladder or bowel dysfunctions. No patient had walking impairment. 

These data seem to confirm an encouraging long-term toxicity profile in young patients treated with particle therapy for chordoma, taking into account the lower late severe side effects compared to the disabilities expected from aggressive surgery. All patients were able to keep working and having a normal social life after treatment. Nevertheless a longer follow is required to confirm our preliminary results.