The Effects of Short-Course Preoperative Irradiation on Local Recurrence Rate and Survival in Rectal Cancer : A Population-Based Nationwide Study

• BACKGROUND: Preoperative irradiation with 5 x 5 Gy in randomized trials reduces local recurrence rate and may improve survival in patients with resectable rectal cancer. OBJECTIVE: The aim of this study was to determine whether the same favorable effects could be observed in a population-based study. DESIGN: This study was conducted via a retrospective analysis of prospectively collected data from the Swedish Rectal Cancer Registry. SETTINGS: This study examined population-based data from Sweden. PATIENTS: All newly diagnosed rectal cancers in Sweden are reported to the Swedish Rectal Cancer Registry. INTERVENTIONS: Between 1995 and 2001, 6878 patients (stages I-III) were operated on with an anterior resection, an abdominoperineal resection, or a Hartmann's procedure. Short-course irradiation was given to 41% of patients preoperatively. To reduce bias, patients operated on with a Hartmann's procedure or older than 75 years were excluded when 5-year survival was analyzed (n = 3466). Tumors were analyzed according to height (0-5 cm, 6-10 cm, 11-15 cm). MAIN OUTCOME MEASURES: Five-year cumulative local recurrence and survival rates. RESULTS: The 5-year cumulative local recurrence rate was 6.3% (95% CI 5.4-7.4) for patients receiving preoperative irradiation and 12.1% (95% CI 10.8-13.5) for patients not receiving preoperative irradiation. Multivariate analyses indicated the risk of local recurrence was 50% lower for patients receiving preoperative irradiation compared with patients not receiving irradiation (hazard ratio = 0.50; 95% CI 0.40-0.62). Among patients younger than 76 years and operated on with an anterior resection or abdominoperineal resection, the 5-year cumulative survival rate was 0.70 (95% CI 0.69-0.72). Disease-free and overall survivals were higher in irradiated patients, and the difference was statistically significant in low tumors. CONCLUSIONS: In this population-based analysis, the favorable effect of preoperative short-course irradiation on local recurrence rates, seen in randomized trials, was confirmed for the entire Swedish population irrespective of tumor height and stage. Data also suggested an effect on 5-year survival, especially in patients with low tumors (0-5 cm).

Nyckelord

Rectal cancer

Colon and rectal surgery

Radiation oncology

MEDICINE

MEDICIN

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