Preoperative radiotherapy improves survival for patients undergoing total mesorectal excision for stage T3 low rectal cancers.

Colorectal cancer is a leading cause of morbidity and mortality and ranks second to cancers of the lung and breast as a cause of death in men and women, respectively. Although endoscopic screening programs may reduce the incidence of cancer and the stage at which cancer is diagnosed, many patients present at an advanced stage of the disease. The 5-year survival rate of patients undergoing curative surgery is often only 50%, and local recurrence has been reported in as many as 35% to 40%. 1–4 Thus, radiotherapy has been investigated as an adjuvant therapy for rectal cancer in an effort to reduce rates of local recurrence and improve overall survival. In 1988, a meta-analysis of six randomized controlled trials of preoperative radiotherapy (PRT) failed to show a significant beneficial effect on survival. 5 More recent randomized studies have suggested that PRT may be of benefit for rectal cancer. 2 This evolution in opinion has been supported by another more recent meta-analysis. 6 Thus, there is increasing clinical evidence to support the biologic rationale of giving radiotherapy before surgery, 7 at a time when the small bowel is freely mobile and not fixed in the pelvis by postoperative adhesions. Although these studies suggest that PRT should be used more frequently for patients about to undergo rectal cancer surgery, several concerns have led many surgeons to be hesitant about freely recommending this form of therapy. The first is the difficulty of accurately knowing the tumor stage preoperatively, so as to select the best candidates for PRT. Clinical examination, endoluminal ultrasound, and computed tomography have been utilized to define the more advanced lesions that might derive most benefit from PRT. There is no consensus to the best test, but endoluminal ultrasound is becoming favored as the best and easiest test for low, nonobstructing tumors. Furthermore, once tumor stage has been defined, there are no definitive guidelines as to which stage lesions should receive PRT. The second and more important issue is that there are no data concerning the effect of PRT for patients who have undergone a total mesorectal excision (TME). None of the randomized trials published to date have described formal TME, and in these trials, local recurrence rates in the surgery-only arms have been on the order of 25% to 50%, 1–4,6 much higher than the expected 4% to 9% seen with a formal TME. 8–12 Thus, many surgeons feel that PRT may subject patients to unnecessarily increased morbidity and mortality, especially when performed with a three-field technique. This is particularly so for small rectal tumors that can easily be removed by a TME technique. Nevertheless, until the completion of studies like the Dutch Colorectal Surgical study, which incorporates TME and preoperative radiation, 13 prospective data will not be available. In an effort to address the above concerns, we examined the effect of PRT on the 5-year survival and 5-year local recurrence rates for patients undergoing surgery for stage T3 cancers within 8 cm of the anal verge. The primary analysis was performed for tumors staged as T3 by postoperative pathology. A second analysis was performed as a control, using a cohort of patients staged as T3 by preoperative endoluminal ultrasound performed before PRT.