Pathological Evaluation, Classification, and Staging of Colorectal Cancers

This chapter provides an overview of the pathological evaluation, classification, and staging of the colorectal cancers. A crucial part of the management of patients with colorectal cancers is a thorough pathological evaluation. Understanding the steps involved in this process may obviate misunderstandings. Any pathological evaluation begins with the gross (macroscopic) examination of the tissue specimen, followed by tissue processing and microscopic evaluation. This chapter summarizes the histological findings in each of the main categories of colorectal neoplasia – namely, carcinomas, sarcomas, and lymphomas. Following diagnosis, colorectal cancer staging is a key element in documenting the extent of the disease and determining the appropriate course of treatment. The most common clinically used cancer staging system is the tumor node metastasis (TNM) system, which is reviewed. We hope that this chapter will offer oncology colleagues an overview of the process of the pathological evaluation of the colorectal cancers.