Purpose: Compared to paediatric cancer patients adolescents and young adults may have disadvantaged access to care. Therefore we investigated the correlation of patient, tumour and institutional characteristics with the outcome of osteosarcoma in this age group.

Method: Analysis of consecutive patients aged 15–24 years with newly diagnosed high-grade osteosarcoma entered into the Cooperative Osteosarcoma Study Group(COSS) registry 1980–2004 and treated in pediatric (PO) or medical oncology institutions (MO). Standardised multimodal therapy according to a COSS-protocol. Event-free survival rates (EFS) evaluated in relation to patient demographics and registering institution (MO vs PO and treatment volume as: < 1, 1–3 or > 3 osteosarcoma/year).

Results: 944 patients identified (median age: 17.35 years; range: 15.01–24.99; 79% aged < 20 years). Patients > 20 years were more likely than younger patients to be treated in centers with low treatment volume (p< .0001) and MO (p< .0001) but otherwise comparable. After a median follow-up of 5.59 years (range: 0.12 – 27.92) for all patients and 8.08 years (range: 0.19 – 27.92) for 617 survivors, actuarial 5/10 year event-free survival probability (EFS) was 58%/54%. Upon univariate analysis of the total cohort neither of the institutional variables correlated significantly with EFS. There was a correlation between treatment in PO and improved EFS for patients > 20 years (p=.001) and for those with primary metastases (p=.009). Upon multivariate testing type of center (odds ratio: 1.26; p=.022) but not treatment volume were significant.

Conclusion: Within a framework of standardised regimens and consultation supportby our group’s infrastructure, similar EFS-probabilites were obtained regardless of institutional treatment volumes. Observed variations in outcome between PO and MO may be partly due to different distributions of presenting factors but deserve further investigation.

The experience of radiotherapy (RT) in the local treatment of osteosarcoma (OS) is limited. Data of 100 patients with RT for OS from the international COSS-Registry (1980–2007) were analysed. Survival and local control rates at five years were calculated. Univariate and multivariate analyses were performed.

The COSS-registry includes 3500 patients with histo-logically proven OS. A total of 175 patients were irradiated over the period of 1980 to 2007, 100 patients were eligible. Median age was 18 (3–66) years. Indication for RT was a primary tumor in 66, a local recurrence in 11 and metastases in 23 patients. 94 Patients got external photontherapy, 2 pats. protontherapy, 2 pats. neutrontherapy, and 2 pats. intraoperative RT. Seventeen patients received a samarium-153-EDTMP therapy. Median dose for external RT was 55.8 Gy All patients were treated with chemotherapy in accordance to different COSS-protocols.

Median follow-up is 1.5 (0.2–23) years. Overall survival rates at 5 years for the whole group, for treatment of primary tumours, local recurrence, and metastases are 36 %, 55%, 15%, and 0% respectively. Local control rate for combined surgery and RT is significantly better than for RT alone (48% vs. 22%, p=0.002). Local control for treatment of primary tumours, local recurrence, and metastases are 40%, 17%, and 0% respectively. Prognostic factors for survival are indication for RT, RT plus surgery vs. RT alone and localisation. Prognostic factors for local control are indication for RT, and RT plus surgery vs. RT alone.

Radiotherapy is an important option for local treatment of unresectable OS, after intralesional resection, or symptomatic metastases. Survival prognosis of these patients is poor. Combination of surgery, radiotherapy, and chemotherapy can be curative. Prognostic factors were identified.

The development of local recurrence after multimodal treatment of osteosarcoma is associated with a very poor prognosis. The importance of clear surgical margins has been demonstrated in multiple studies, however up to date there are no studies defining which margin width is safe from an oncological perspective. The purpose of this retrospective analysis was to evaluate whether margin width or other surgical and tumour-related factors influence the development of local recurrence in osteosarcoma patients.

The files of 1867 consecutive patients with high-grade central osteosarcoma of the extremities, the pelvic bones and the shoulder girdle, who had achieved a complete surgical remission during combined-modality therapy on neoadjuvant Cooperative Osteosarcoma Study Group (COSS) protocols between 1986 and 2005, were reviewed. Of those, the data required were available for 1369 patients, who were the subject of this analysis. Eighty of these patients developed a local recurrence during the course of their illness.

The median surgical margin width amounted to 45 mm (range, 0 to 140 mm) in the local recurrence (LR) group and 50 mm (range, 0 to 350 mm) in the non-local recurrence (NLR) group (p=0.106). No statistically significant difference between the two groups was found regarding tumour size (mean, 10.38 cm and 9.53 cm respectively, p=0.169), T-status (p=0.225) and presence of pathological fracture (p=0.231). However infiltration of the soft tissue beyond the periosteum was documented in 58.8% of the patients with local recurrence and only in 36.9% of the rest (p=0.003). Furthermore, in 50% of the LR group the biopsy had been performed in a centre other than the one performing the definitive tumour resection, compared to 30.2% of the NRL group (p=0.001).

In conclusion, the absolute metric width of surgical margins does not define oncological safety. Local recurrence is more likely to develop in patients with soft tissue infiltration beyond the periosteum or those biopsied in a centre other than the one performing the tumour resection.