Oesophagogastric cancer: exploring the way to an individual approach

This thesis focuses on surgical- and multimodality treatment, patient selection and genetic profiling of oesophagogastric cancer. Part I of this thesis starts with a systematic review, in which several quality indicators for the surgical treatment of gastric cancer are identified. These indicators can be used in future quality assurance programs. Outcome analyses of a series of surgically treated gastric cancer patients showed that there are major differences in outcome between two histological subtypes. These differences should be taken into account in the approach of gastric cancer patients. Part I concludes with two studies in which it is shown that detecting progressive disease after neoadjuvant therapy using imaging modalities can improve the selection for surgical treatment. In part II, it is first shown that neoadjuvant chemoradiotherapy has been successfully implemented in the potentially curative treatment of oesophageal and oesophagogastric junction cancer. In gastric cancer there is room for improvement. The results of the next two studies show that the use of adjuvant chemoradiotherapy is a good treatment option for gastric cancer patients who have undergone a microscopically irradical resection. In part III it is shown that poor logistics can be a major cause for tissue loss in biobank projects of oesophageal cancer samples. The difficulties associated with collecting untreated oesophageal cancer samples can also partly explain the relative scarcity on genetic profiling studies in this cancer type. This thesis concludes with a study in which DNA copy number profiling is used to improve patient stratification and identification of therapeutic targets.