Prognostic factors in Japanese patients with colorectal cancer: the significance of large bowel obstruction--univariate and multivariate analyses.

In order to define prognostic factors in colorectal carcinoma, univariate and multivariate analyses were carried out on data from 113 Japanese patients treated in a typical general hospital in Japan. In the univariate analysis, a poor prognosis was seen in those with poorly differentiated adenocarcinoma, in tumors that perforated the visceral peritoneum or that invaded directly other organs or structures (T4), in metastasis to the nodes along the main vascular pedicle (N3), in lymphatic permeation, in blood vessel invasion, in peritoneal dissemination, in Dukes C stage, and in those with lesions presenting with large bowel obstruction. Of these, only lymph node metastasis and peritoneal dissemination had an independent prognostic significance when a multivariate Cox analysis was performed. The significant risk factors related to an obstructing tumor were determined by multivariate logistic regression analysis. The significant variables were patient's age, nodal involvement and peritoneal dissemination. Since lymph node metastasis and peritoneal dissemination proved significant in both multivariate analyses, we propose that the presence of large bowel obstruction is not an independent prognostic factor in patients with colorectal carcinoma. In poor-risk patients who have an obstructing tumor, a staged operation should be attempted for definitive curative surgery.