A nationwide study of 3,792 patients in Taiwan found that neoadjuvant radiotherapy followed by surgery may improve survival in patients with resectable locally advanced rectal cancer but significantly increased the risk of permanent diverting stomas, particularly in upper rectal tumors.

In the study, researchers compared outcomes between patients with stage II or III rectal cancer who received neoadjuvant radiotherapy (NRT) or underwent surgery alone. Using a target trial emulation design with propensity score matching, the researchers ensured comparability between the two groups.

The patients treated with NRT had a higher 3-year overall survival rate compared with those treated with surgery alone (88.5% vs 85.2%, hazard ratio [HR] = 0.74, 95% confidence interval [CI] = 0.59–0.92). There were no statistically significant differences in local recurrence rates (5.7% vs 6.6%, HR = 0.78, 95% CI = 0.55–1.11).

However, NRT was associated with increased diverting stoma creation during surgery (65.5% vs 41.0%) and a higher rate of permanent stoma at 3 years (20.6% vs 11.1%, relative risk [RR] = 1.91, 95% CI = 1.62–2.25).

“More than 25% of these stomas remained for at least 3 years,” wrote lead study author Po-Chuan Chen, MD, and colleagues from the National Cheng Kung University Hospital, raising concerns about long-term quality of life.

Subgroup analysis showed that the oncologic benefits of NRT varied by tumor height. Patients with lower rectal tumors (< 5 cm from the anal verge) had improved survival (HR = 0.66, 95% CI = 0.46–0.96) and reduced recurrence (HR = 0.53, 95% CI = 0.30–0.95). In contrast, no survival benefit was observed for upper rectal tumors (> 10 cm), which had the highest risk of permanent stoma (RR = 3.54, 95% CI = 1.44–8.69).

“Patients undergoing NRT prior to surgery were more likely to undergo diverting stoma creation,” the study authors noted, adding that “the risk was most pronounced in upper rectal cancer.”

The study highlighted the importance of tumor height in treatment planning and suggested that selective use of radiotherapy may reduce the risk of overtreatment in certain patients. Advances in surgical technique may further mitigate the need for routine NRT in some cases.

The authors reported no conflicts of interest.

Source: JAMA Network Open