Non-haematogenic tumours arising primarily in the bone are rare. They are classified based on their histomorphology. Within the osteofibrous group the spectrum ranges from benign, exclusively... Show moreNon-haematogenic tumours arising primarily in the bone are rare. They are classified based on their histomorphology. Within the osteofibrous group the spectrum ranges from benign, exclusively fibrous lesions to high-grade osteosarcoma. These osteofibrous tumours show histological variability in a given entity as well as similarities between entities. The purpose of this thesis was to reveal the meaning of the phenotypic spectrum of osteofibrous tumours. In retrospect, the histological subtype of osteosarcoma is a predictive factor for response to chemotherapy, late relapse and risk of a hereditary cancer syndrome, but not for survival. However, the poor histological response of chondroblastic osteosarcomas to neo-adjuvant chemotherapy did not translate in a lower survival rate. On the other hand, overlapping histological and/or clinical parameters between certain tumour entities such as for example adamantinoma and Ewing sarcoma, and desmoplastic fibroma of bone and desmoid type fibromatosis of soft tissue, does not justify to classify these tumours as part of one disease entity as was demonstrated in this thesis. Thus, the correct classification, reclassification of known entities on new insights and sub-classification on phenotypic differences, when related with biological behaviour, has implications for clinical practice and disease management, and contributes to optimal patient care. Show less
Prognostic factors are used for making treatment decisions regarding adjuvant systemic therapy. The major prognostic variables that are used in clinical practice are the number of positive axillary... Show morePrognostic factors are used for making treatment decisions regarding adjuvant systemic therapy. The major prognostic variables that are used in clinical practice are the number of positive axillary lymph nodes and tumour size. A number of other variables are associated with disease recurrence and survival as well. In particular UPA and PAI-1 appear to be strong prognostic variables. No differences in prognostic value of oestrogen receptor and progesterone receptor detected by immunocytochemical assay or enzyme immuno assay were found. In the study presented no significant association between mitotic counts and disease recurrence or survival was found, which was explained by the favourable tumour characteristics of the group of patients and the associated low number of events. Several tools have been developed to make individualised estimates of baseline prognosis and absolute survival benefit of adjuvant systemic therapy. Two of these tools, Adjuvant! and Numeracy, were compared. Adjuvant! was the preferred prognostic model. The administration of adjuvant chemotherapy concurrently with radiotherapy appeared too toxic. As anthracyclin-containing regimens have become standard for adjuvant chemotherapy in early breast cancer which are considered more toxic than the regimens studied the concurrent administration of adjuvant chemotherapy and radiotherapy is dissuaded. Show less
