This thesis focus on the quality assurance in the surgical treatment of gastric cancer. This has been investigated using data of the CRITICS trial. In this randomized clinical patients underwent... Show moreThis thesis focus on the quality assurance in the surgical treatment of gastric cancer. This has been investigated using data of the CRITICS trial. In this randomized clinical patients underwent preoperative chemotherapy, followed by surgery, followed by adjuvant chemotherapy or chemoradiotherapy. Surgical quality in the CRITICS trial was investigated and was excellent (PART I). Furthermore, the influence of hospital volume on surgical quality and survival was analyzed using data of the CRITICS trial (PART II). Surgery performed in hospitals with high hospital volume was associated with better surgical quality and better survival. In part III of this thesis analyses were performed to analyze treatment strategy and survival in patients with resectable gastric cancer and in patients with metastatic gastric cancer. Show less
Bone metastases of the long bones can cause pain and pathologic fractures. Local treatment consists of radiotherapy or surgical stabilisation. The most appropriate treatment depends on many factors... Show moreBone metastases of the long bones can cause pain and pathologic fractures. Local treatment consists of radiotherapy or surgical stabilisation. The most appropriate treatment depends on many factors, including the symptoms, the location and extent of the lesion, the wishes and expectations of the patient, and the expected remaining survival. Survival estimation of patients with symptomatic long bone metastases is crucial to prevent over- and undertreatment. This thesis aimed to develop a prognostic model for estimating survival in patients with cancer and symptomatic metastases of the long bones, evaluate current (surgical) treatment modalities and trends, and provide rationale for future prospective randomized trials. As a result, the OPTIModel was developed: an easy-to-use prognostic model that categorises patients into four clinically relevant survival categories based on only three variables (tumour type, Karnofsky Performance Score, visceral/brain metastases). To enable easy use of the model, an app was created (OPTIModel). Futhermore, this thesis shows that almost all treatments of pathologic fractures are based on expert opinion and small, retrospective cohorts, as opposed to large, prospective (randomized) trials, which is interesting in an era of evidence based medicine. This confirms the need of a prospective, multicenter cohort, which was designed and implemented accordingly. Show less
As a result of our ageing population, breast cancer is becoming a disease of the elderly. Unfortunately, most studies investigating the efficacy of treatment do not include older patients and are... Show moreAs a result of our ageing population, breast cancer is becoming a disease of the elderly. Unfortunately, most studies investigating the efficacy of treatment do not include older patients and are not representative for the older population. In this thesis, we investigated whether there is variation in treatment and survival among older women with breast cancer in five European countries. Moreover, we study the long term efficacy of two types of adjuvant endocrine therapy in postmenopausal women. In addition, the effect of age and comorbidities on breast cancer death in the presence of competing mortality is studied. Finally, we investigate whether other endpoints in clinical studies might be more relevant for the older population and we introduce a new endpoint for clinical research in the older population with cancer. Show less
Uveal melanoma (UM) is an aggressive intraocular tumor with a high propensity to metastasize. Accurate prognostication is relevant for patient counselling, planning of follow-up and... Show moreUveal melanoma (UM) is an aggressive intraocular tumor with a high propensity to metastasize. Accurate prognostication is relevant for patient counselling, planning of follow-up and stratification of patients in clinical trials. Discoveries of prognostically relevant genetic markers in the last few decades have fuelled the advancement of prognostication in UM considerably. In this thesis, we explored ways of improving genetic prognostication in UM, evaluated the effect of irradiation on chromosome testing, and investigated the association of DNA repair genes and epigenetic regulators with prognosis. We reveal that chromosome markers of high malignancy such as monosomy 3 and chromosome 8q gain are less often observed in patients who die due to metastases at a late stage. We demonstrate that combining the AJCC staging and chromosome 3 and 8q status results in enhanced risk stratification. We provide evidence that supports the taking of biopsies before radiotherapy is applied since chromosome testing seems to fail more often in irradiated tumors. Furthermore, we show that evaluating the role of DNA repair and epigenetics in uveal melanoma can help in unraveling the biology of uveal melanoma and identifying new markers for prognostication. Show less
