Diagnosis and Surgery of Organ Metastases [antikvár]

CHAPTER 1 Clinicopathology of Tumor Metastasis* JÓZSEF TÍMÁR INTRODUCTION The issue of tumor metastasis obtained major attention in the turn of the 21st century due to the fact that oncologists face more and more the controversy of the clinical management of cancer: high success rate in the management of the primary tumors but a very low success rate in the field of the disseminated disease which usually means the organ-metastatic disease. However, malignant tumors also disseminate locally, sometimes that is as life-threatening as the organ-metastatic form (head and neck cancer). Other tumors use intracanalicular dissemination, such as ovarian cancer, which spreads along the peritoneal surface, and this type of dissemination is also an unsolved problem of oncology. Last but not least, one of the most usual form of dissemination and frequently the first form of it is the lymphatic spread, which again rarely leads to the death of the patient but in case of certain cancers (head and neck tumors) that is the only form of dissemination. Since the topic of this book is diagnosis and surgery of cancer metastasis the clinicopathology of this topic will focus on the organ metastatic disease. Although the author recognizes the importance of lymphatic spread and the diagnostic significance of tumor metastasis in lymph nodes from the point of view of staging of the disease, that issue will not be covered here and the reader is kindly asked to visit recent reviews on this topic. 1.1. MOLECULAR MECHANISM OF METASTASIS Uncontrolled tissue proliferation can result in benign or malignant tumors. There are several macroscopic and microscopic features which may help to distinguish between the two but the ultimate feature which has 100% specificity and 100% selectivity is the invasiveness of the tumor cells. However, tumor progression may not stop at this point but develop to a metastatic disease. Tumor (or malignant) progression can be considered both as a cascade of events and a continuous selection process (Fig. 1.1) (Fidler 1997). There are considerable similarities