Two-week Course of Preoperative Radiotherapy for Locally Advanced Rectal Adenocarcinoma: 8 Years' Experience in a Single Institute.

OBJECTIVES: To evaluate local control and survival in locally advanced rectal adenocarcinoma patients who underwent a preoperative 2-week course of radiotherapy (RT) and to identify prognostic factors influencing the survival rate.

METHODS: We analyzed 377 consecutively treated patients with locally advanced (T3/T4 or node positive) rectal adenocarcinoma. All patients underwent a preoperative 2-week course of RT (30 Gy in 10 fractions) followed by curative surgery. Regression model was used to examine prognostic factors for the disease-free survival (DFS) and overall survival (OS) rates. The Statistical Analysis System software package, version 9.3, was used for analysis.

RESULTS: The median follow-up for all living patients was 63.8 months (range, 5.1 to 131.7). The 5-year DFS and OS rates were 64.5% (95% CI, 59.0-69.4) and 75.6% (95% CI, 70.5-80.0), respectively. The 5-year cumulative incidences of local recurrence and distant metastases were 5.4% (95% CI, 2.9-7.9) and 29.0% (95% CI, 23.9-30.1), respectively. The pathologic complete response rate was achieved in 17 patients (4.5%). The Multivariate Cox Regression model showed that factors affecting DFS were the surgical technique, pre-RT pathologic grade, ypT, ypN, and comorbidity; and factors improving OS were low anterior resection, low pre-RT grade, low ypT, and low ypN.

CONCLUSIONS: Patients treated with preoperative RT with 30 Gy in 10 fractions had similar local control, 5-year DFS and OS to reported long course RT regimen. The surgical technique, pre-RT pathologic grade, ypT, and ypN seemed to affect the OS. Further study on combining a 2-week course of preoperative RT with concurrent chemotherapy would be warranted.