Colorectal carcinoma: evaluation of histologic grade and factors influencing prognosis.

We analyzed 246 patients with adenocarcinoma of colorectum treated with "curative" surgery alone. In reviewing these cases it is apparent that patients with poorly differentiated tumor (Grade 3) have an increased likelihood of deep invasion of tumor through the bowel wall and lymph node metastases compared to well (Grade 1) or moderately differentiated tumor (Grade 2). Poor differentiation of the tumor, deep penetration through the bowel wall and lymph node metastases appear to represent unfavorable prognostic indices in patients operated upon. Age, sex, size of primary tumor, and large bowel site of tumor origin were unrelated to the prognosis. Compared to Grade 1 and 2 tumors, patients with Grade 3 lesions had more local recurrences and/or distant metastases. These findings suggest that histologic grading is an important adjunct to the clinical evaluation and treatment planning of patients with colorectal carcinoma.