Rectal Cancer: Complete Radiotherapy Dose Improves Overall Survival
Incomplete neoadjuvant radiotherapy is associated with worse overall survival in patients with locally advanced rectal cancer.
Incomplete neoadjuvant radiotherapy is associated with worse overall survival among patients with locally advanced rectal cancer, according to a study published in JAMA Surgery.1
Patients with colorectal cancer who fail to complete chemotherapy have inferior outcomes. There are, however, limited data on the impact of incomplete neoadjuvant radiotherapy delivery.
To evaluate whether incomplete radiotherapy delivery is associated with worse clinical outcomes and survival, researchers analyzed National Cancer Database data from 17,600 patients with stage II to III rectal adenocarcinoma who received neoadjuvant chemoradiotherapy prior to surgical resection between 2006 and 2012. Patients were considered to have completed radiotherapy if they received 45.0 to 50.4 Gy and were classified as having incomplete delivery if they received preoperative doses less than 45.0 Gy.
Five percent of patients received incomplete doses of neoadjuvant radiation. Among those who did not achieve complete dosing, median radiation dose was 34.2 Gy.
After adjusting for multiple variables, investigators found that female sex (adjusted odds ratio [OR] 0.69; 95% CI, 0.59-0.81; P < .001) and receiving radiotherapy at a different hospital than the one where surgery was performed (OR, 0.72; 95% CI, 0.62-0.85; P < .001) carried a 30% lower likelihood of having a complete radiation dose.
Private insurance status was associated with a 60% increased likelihood of completing radiotherapy (OR, 1.60; 95% CI, 1.16-2.21; P = .004).
Significantly more patients who received a complete course of radiotherapy were alive at 5 years compared with those who received an incomplete course (73.2% vs 63.0%; P < .001).
The findings suggest that patients with locally advanced rectal cancer who achieve a target radiotherapy dose of 45.0 to 54.0 Gy have improved survival.
- Freischlag K, Sun Z, Adam MA, et al. Association between incomplete neoadjuvant radiotherapy and survival for patients with locally advanced rectal cancer. JAMA Surg. 2017 March 8. doi: 10.1001/jamasurg.2017.0010 [Epub ahead of print]