Nowadays, biomaterials can be used to maintain or replace several functions of the human body being constricted or lost due to tumors, fractures, injuries as well as chronic diseases, infections or simply aging. Titanium and its alloys, i.e. Ti6Al4V are the most common materials (70 to 80%) used for structural orthopedic implants due to their unique combination of good mechanical properties, corrosion resistance and biocompatibility. Addition of β-stabilizers, e. g. niobium (Nb), can improve the mechanical properties of such titanium alloys further, simultaneously offering excellent biocompatibility. Previous studies concerning biocompatibility analyses with niobium and especially Ti-42Nb specimens are rarely described; none for niobium and Ti-42Nb powders examining human cell viability, collagen and interleukin synthesis. In this in vitro study, human osteoblasts were cultured on different roughened niobium specimens (Nb Amperit, Nb Ampertec), Nb sheets and spherical Ti-42Nb (sintered and 3D-printed by selective laser melting, SLM) and compared with forged Ti6Al4V specimens. Furthermore, human osteoblasts were incubated with particulates of the Nb and Ti-42Nb specimens in three particle concentrations over four and seven days to imitate influence of wear debris against the background of osteolysis and aseptic implant loosening. Thereby, the specimens with the roughest surfaces, i.e. Ti-42Nb and Nb Ampertec, revealed excellent and similar results concerning cell viability (WST-1 test, live-dead staining) and collagen-I synthesis superior to forged Ti6Al4V. Examinations with particulate debris disclosed a significant dose-dependent influence of all powders with Nb Ampertec showing the highest decrease of cell viability and collagen-I synthesis. Furthermore, interleukin expression was only slightly increased for all powders. In summary, from a cell-biological point of view Nb Ampertec (sintered Nb) and Ti-42Nb materials seem to be superior alternatives for medical applications compared to common materials like forged Ti6Al4V.

Standard therapy for soft-tissue sarcomas remains complete resection, irresectable tumours or tumours after resection with gross residual disease are a special challenge. For primary radiotherapy with median 60 Gy local control rates of 30–45% have been reported. We analysed retrospectively 11 cases of radiochemotherapy with single-agent Ifosfamide in patients with macroscopic soft-tissue sarcomas.

The patients were treated in irresectable high risk situations: T2-tumours (100%), G3 (73%), localisation at the trunk (82%). Radiation therapy was performed with median 60 Gy (50 to 72.6 Gy) in 1.8–2.0 Gy single fraction dose, once daily, five times a week. During the first and fifth week the concommittant chemotherapy with 1.0/1.5 gr/m2/d Ifosfamide on five days was added. Two patients received trimodal therapy with additional hyperthermia. The therapy was completed in 73% of the patients. Average local control time was 91 months, median disease-free-survival/overall-survival was 8/26 months. Five-year rates for local control/disease free survival/overall survival were 70%/34%/34%. Long-term tumor control could be achieved in three patients. The median disease free survival is dependant on the histological tumor grading (21 vs 8 months for G2 vs G3 tumors, no statistical significance due to small patient numbers). The limited prognosis is mainly caused by systemic treatment failure.

Concomitant radiochemotherapy with Ifosfamide in patients with macroscopic soft-tissue-sarcomas yields a good local control rate of 70% compared to previously published 30% in definitive radiotherapy with similar radiation doses. Additional simultaneous chemotherapy should be considered for irresectable soft tissue sarcomas or tumors after resection with gross residual disease, if the applicable radiation dose is limited due to close vicinity of organs at risk. A decrease of systemic failure with additional chemotherapy might be speculated.