Pathologic studies in colorectal cancer. A guide to the surgical pathology examination of colorectal specimens and review of features of prognostic significance.

The results of a careful and systematic examination of surgical specimens from patients with tumors of the colorectum play an important role in patient care and the assessment of prognosis. An accurate and detailed gross examination of the specimen is important. Photographs and line drawings are very useful. Proper handling of the specimen and fixation for 24 to 48 hours are essential before satisfactory blocks can be taken for sectioning. Lymph nodes adjacent to the lesion and at the point of ligation of the vascular pedicle should be removed for sectioning. Multiple blocks of the tumor and adjacent tissues should be taken for histologic study. All blocks should be appropriately labeled and properly identified. I have found the use of large sections of the entire lesion a very satisfactory method of studying cancers and polyps; in such preparations the anatomic relationships remain undisturbed. The pathology report should include information on the site or sites of tumor, the size, configuration, and circumference of the bowel wall involved, obstruction, distance of the resected margin from the tumor, depth of infiltration, tumor grade, tumor margin, local inflammatory reaction, lymph node involvement and location, and venous and perineural invasions. There is evidence in the literature to suggest that all of the above pathologic features are either essential or desirable for pathology reports and have varying degrees of prognostic value. The literature on the prognostic value of immunomorphologic features in nontumorous regional lymph nodes is contradictory. Cortical, paracortical, and sinus hyperplasia have been reported to be both associated with or to have no relation to prognosis. However, careful documentation of the changes in lymph nodes may in time shed light on their value, if any, with regard to survival. We have found a standardized pathology reporting system very useful in compiling data and evaluating patient prognosis. Moreover, this system of reporting can be used as a method of quality control in establishing minimum standards for data collection, as originally suggested by Buckwalter and Kent. In a regional multiinstitutional study such as ours, differences attributable to subjective variations among different observers are likely to occur, and may have some bearing when different pathologic features are eventually correlated with survival.