Outcomes of osteosarcoma, chondrosarcoma and chordoma treated with image guided-intensity modulated radiation therapy.

BACKGROUND & PURPOSE: To evaluate the efficacy and toxicity of dose-escalated image guided-intensity modulated radiation therapy (IG-IMRT) in osteosarcoma (OGS), chondrosarcoma (CS) and chordoma (CH) of head and neck (H&N) and pelvis. METHODS AND MATERIALS: In this prospective non-randomized study, 65 patients of H&N or pelvic OGS (24), CS (7) and CH (34) mandating definitive or post-operative radiotherapy from May 2013 to December 2018 were included. Radiotherapy doses in definitive setting were 72.0 Gy for CH and 70.2 Gy for OGS and CS; while in post-operative setting it was 66.6 Gy and 64.8 Gy respectively (at 1.8 Gy per fraction). RESULTS: Planned doses of radiotherapy could be completed in 61 (93.8%) patients; with grade III or higher acute and late toxicities of 3% and 0% respectively. With a median follow-up of 52 (range 6-92) months, the five-year actuarial local control (LC) rates were 66% in OGS, 38.1% in CS and 75.9% in CH; while cause-specific survival (CSS) rates were 54.7%, 64.3% and 92.2% respectively. There was no statistically significant difference in outcomes for patients receiving definitive and post-operative radiotherapy. Locally controlled disease at first follow-up after radiotherapy was associated with improved CSS and OS in CS (p = 0.014) and CH (p < 0.001). Radiotherapy resulted in significant and sustained improvement in Musculoskeletal tumour society (MSTS) score and reduction in pain score. Salvage re-irradiation was feasible in local progression after radiotherapy, with good outcomes and tolerability. CONCLUSION: Dose-escalated IG-IMRT results in good LC & functional improvement with minimal toxicity in OGS, CS and CH.

Extraskeletal osteosarcoma with synchronous regional lymph node and soft tissue metastasis: a rare presentation of an uncommon tumour.

Extraskeletal osteosarcoma is a rare soft tissue neoplasm arising from mesenchymal elements with characteristic production of osteoid. These tumours are known to have high rate of distant metastasis and dismal prognosis. We present a rare case of extraskeletal osteosarcoma arising in medial aspect of knee joint with synchronous inguinal node and soft tissue metastasis. The patient was initially diagnosed as myositis ossificans at an outside institute and excised without prior imaging or biopsy. The patient presented to our hospital with recurrent lesion along with palpable inguinal lymph nodes and soft tissue metastasis in thigh. The patient underwent neoadjuvant chemotherapy and wide excision of the primary lesion, soft tissue metastasis and complete groin node dissection. We also discuss the importance of PET scan and intra-operative ultrasonography in the management of these lesions.