Randomized clinical trial on preoperative radiotherapy 25 Gy in rectal cancer--treatment results at 5-year follow-up.

PURPOSE: The purpose of this study was to establish the influence of time interval between preoperative hyperfractionated radiotherapy (5 × 5 Gy) and surgery on long-term overall survival (5 years) and recurrence rate in patients with locally advanced rectal cancer operated on according to total mesorectal excision technique.

METHODS: The treatment group comprised 154 patients with locally advanced rectal cancer who were operated on between 1999 and 2006 in the 1st Department of General Surgery, Jagiellonian University, Cracow, Poland. The data on survival has been systematically collected until 31st of December 2010. In addition, the following aspects were analyzed: the significance of time interval between the end of radiotherapy and surgical treatment and its influence on downsizing, downstaging, rate of curative resections, and sphincter-sparing procedures. Patients were qualified to preoperative radiotherapy 5 × 5 Gy and then randomly assigned to subgroups with different time intervals between radiotherapy and surgery: one subgroup consisted of 77 patients operated on 7-10 days after the end of irradiation, and the second subgroup consisted of 77 patients operated on after 4-5 weeks. Both groups were homogenous in sex, age, cancer stage and localization, distal and circumferential resection margins, and number of resected lymph nodes.

RESULTS: The 5-year survival rate in patients operated on 7-10 days after irradiation was 63%, whereas in those operated on after 4-5 weeks, it was 73%-the difference was not statistically significant (log rank, p = 0.24). A statistically significant increase in 5-year survival rate was observed only in patients with downstaging after radiotherapy-90% in comparison with 60% in patients without response to neoadjuvant treatment (log rank, p = 0.004). Recurrence was diagnosed in 13.2% of patients. A lower rate of systemic recurrence was observed in patients operated on 4-5 weeks after the end of irradiation (2.8% vs. 12.3% in the subgroup with a shorter interval, p = 0.035). No differences in local recurrence rates were observed in both subgroups of irradiated patients (p = 0.119). The longer time interval between radiotherapy and surgery resulted in higher downstaging rate (44.2% vs. 13% in patients with a shorter interval, p = 0.0001) although it did not increase the rate of sphincter-saving procedures (p = 0.627) and curative resections (p = 0.132).

CONCLUSIONS: 1. Improved 5-year survival rate is observed only in patients with downstaging after preoperative irradiation dose of 25 Gy. 2. Longer time interval after preoperative radiotherapy 25 Gy does not improve the rate of sphincter-saving procedures and curative resections (R0) despite higher downstaging rate observed in this regimen.