Outcomes of patients receiving radiation for carcinoma of the rectum. Results of the 1988-1989 patterns of care study.

BACKGROUND: Clinical trials of surgical adjuvant treatment for patients with rectal carcinoma (RC) indicate that postoperative radiation therapy with concurrent chemotherapy (CRT) is superior to postoperative radiation alone (RT) or surgery alone. Whether preoperative treatment is superior to postoperative treatment is controversial. This Patterns of Care Study (PCS) surveyed patients with RC treated with radiation during the years 1988-1989 to determine the national practice standards and outcomes and to compare these results with those of clinical trials.

METHODS: A national survey of 73 institutions was conducted using 2-stage cluster sampling, and specific information on 406 patients with RC who received radiation at 69 facilities was collected. Follow-up information on 215 patients was subsequently collected by mail survey. There were no significant differences between the known prognostic indicators or treatment-related variables for patients for whom follow-up was available compared with the variables for patients for whom follow-up was not available. Follow-up ranged from 0 to 8.44 years with a median of 4 years. One hundred fifty-four patients (71%) received postoperative treatment, either RT (37%) or CRT (34%); and 40 (18%) received preoperative treatment, either RT (15%) or CRT (3%). Ninety-six patients (45%) received chemotherapy, and for 86% of those patients chemotherapy was administered concurrently with radiation.

RESULTS: Survival was stage-dependent (85% Stage I, 69% Stage II, and 54% Stage III at 5 years, P = 0.04). Survival was also substage-dependent, and patients with C(1) cancer had significantly higher 5-year survival than those with C(2)/C(3) cancer (89% vs. 48%, P = 0.008). Local failure was similar for Stage II and Stage III patients (10% vs. 11% at 5 years, respectively). In multivariate analyses, only stage and use of chemotherapy were significant to survival (Stage III vs. Stage I and II, relative risk [RR] = 2.52, and chemotherapy vs. no chemotherapy, RR = 0.46). A significantly higher 5-year survival rate was seen with postoperative CRT than with postoperative RT (69% vs. 50%, P = 0. 011). Preoperative radiation resulted in a significantly higher 5-year survival rate than postoperative radiation (85% vs. 50%, P = 0.0006), but not compared with postoperative CRT. Survival and local failure did not differ according to radiation therapy interruption or the interval between surgery and radiation.

CONCLUSIONS: Stage is an important prognostic indicator for survival, and among patients with Stage III malignancies survival in the substage C(1) is significantly higher than in the substages C(2) and C(3). As has been demonstrated in randomized trials, adjuvant postoperative CRT is superior to postoperative RT for patients with RC in this national study. These nationwide results of adjuvant treatment are comparable to those reported in randomized trials. The use of CRT was the only treatment-related factor that resulted in a significant reduction in the risk of death.