Postoperative pathological examination of colorectal cancer

The close cooperation of the surgeon and the pathologist in clinical practice and research of colorectal cancer was far established. The histopa-histopathological report has to include all important information in relation to tumour classification, prognostic factors and surgical procedure. This is the starting point for further treatment, estimation of prognosis and treatment results, indicator of oncological quality of surgical procedure and the most important contribution to increasing knowledge of clinical pathobiology related to colorectal cancer. To reach these goals the pathologist should follow some of up-dated histopathological protocols for the examination of specimen removed from patients with colorectal carcinoma. Most of the proposals and international standards are presented in detail. The applying of three main classifications for colorectal carcinoma is mandatory, i.e. histopathological classification, the disease stage (pathoanatomic extension) classification and residual disease classification. It seems that the first and most important step is R (residual disease) classification, serving as the most reliable determinant in further treatment, prognosis and in assessment of surgical treatment. The focus of surgery on R0 category subgroup of patients is presented in relation to the disease stage as second proven prognostic factor, strongly influencing the prognosis and adjuvant therapy options. The detection and significance of minimal residual disease, mainly occult micrometastases in examined lymph nodes are essential for more accurate staging of the disease. Our own data from pilot study confirmed the significant stage migration (Will Rogers phenomenon of "up-grading"). Using combination of serial sectioning and immunohistochemical reactivity of anti-cytokeratin antibody to scattered micrometastatic foci in lymph nodes and perirectal fat, we have shown the presence of minimal residual disease in 23.53% of R0 pT3 pN0 primary classified cases. Correlation to other probable and possible histological independent prognostic factors is discussed, as well as the most significant molecular prognostic markers.