REVIEWS — Tumour micrometastases: the influence of angiogenesis

Introduction: Many cancer patients have undetected micrometastatic disease at first presentation which ultimately progresses. Angiogenesis—the development of an independent blood supply—is a key event in the growth of metastases. Improved understanding of the influence of angiogenesis on micrometastatic growth may lead to new therapeutic intervention. Methods: This study examines current concepts of the significance of micrometastases and the role of angiogenesis in their development and destruction. A comprehensive review of the literature on micrometastasis and angiogenesis was performed using the Medline database between 1966 and 1999. Conclusions: Advances in technology have improved our ability to diagnose metastatic disease, but micrometastases in loco-regional lymph nodes and at distant sites can only be detected by sophisticated histological techniques. While the significance of micrometastases remains controversial, there is increasing evidence that micrometastatic status provides useful prognostic information and should be part of standard staging techniques. Anti-angiogenic therapy has the potential to favourably influence management of certain cancers by manipulating a number of key events in the metastatic process.