Prognostic factors in adolescents and young adults (AYA) with high risk soft tissue sarcoma (STS) treated by adjuvant chemotherapy: a study based on pooled European Organisation for Research and Treatment of Cancer (EORTC) clinical trials 62771 and 62931

Abstract

Background: We conducted a retrospective study, pooling data from two clinical trials in high risk soft tissue sarcoma (STS) patients, with the objective of comparing two different age groups: 15-29 years (adolescents and young adults (AYA) population) and ≥ 30 years. The aim was to determine prognostic factors for the AYA population.

Methods: Patients selected for analysis were treated in two randomised trials of adjuvant chemotherapy in STS (European Organisation for Research and Treatment of Cancer (EORTC) 62771 and 62931). A total of 793 patients were included with a median follow-up (FU) of 8.74 years (AYA population: n=161, median FU 9.46 years; patients ≥ 30 years: n=632, median FU 8.62 years). Study endpoints were overall survival (OS) and relapse-free survival (RFS). The variables of the multivariate analysis were gender, subtype and grade, tumour size and localisation (limb versus other), absence or presence of local recurrence and treatment (control arm versus adjuvant chemotherapy).

Results: Patients' characteristics were globally similar with two exceptions, histological subtype (p=0.0043) and tumour size (p<.0001). The commonest sarcoma subtype in the AYA population was synovial sarcoma (29%), whereas leiomyosarcoma (18%), malignant fibrous histiocytoma (MFH, presently being termed undifferentiated pleomorphic sarcoma (UPS), 16%) and liposarcoma (15%) were more frequent in patients ≥ 30 years. For OS, independent favourable prognostic factors were low grade and small tumour size for both groups; radical resection and MFH or liposarcoma subtype were favourable factors for patients ≥ 30 years only. For RFS, favourable prognostic factors were small tumour size and low grade for both groups; tumour location in the extremities was a favourable factor for the AYA population only, whereas radical resection and adjuvant chemotherapy treatment were favourable factors for patients ≥ 30y ears only.

Conclusions: Significant differences could be found concerning prognostic factors between the AYA population and older patients. Interestingly, adjuvant chemotherapy was associated with improved RFS only in patients ≥ 30 years. The results may have further implications for the treatment of STS patients in different age groups, as well as the design of future clinical trials.