We reviewed the medical records of 101 patients who underwent extended resection for locally advanced colorectal carcinoma between 1965 and 1989. Preoperative symptoms related to the genitourinary system were present in 46 patients. Malignant invasion of genitourinary structures by colorectal carcinoma was found in 43 of these 46 patients (93%). In contrast, 51% of the patients without such symptoms had malignant invasion of contiguous structures. Preoperative intravenous pyelography, computerized tomographic scans, and cystoscopy correctly predicted the presence or absence of malignant invasion in 89%, 83%, and 87% of patients, respectively. Tumor-positive resection margins had a negative impact on survival (mean survival: 11.4 months). The 5-year actuarial survival rate for the patients who underwent a curative extended resection (margins tumor negative) was 54%. A thorough preoperative evaluation can identify a significant number of patients with colorectal cancer extending into adjacent organs and structures. Such evaluation is vital for operative planning and patient preparation, since an appropriate extended resection can produce long-term local control and patient survival.