Survival Benefit of Preoperative Versus Postoperative Radiotherapy in Metastatic Rectal Cancer Treated With Definitive Surgical Resection of Primary Tumor: A Population Based, Propensity Score-Matched Study

Abstract

Preoperative chemoradiation followed by surgery has been recommended as a standard treatment for patients with stage II/III rectal cancer. However, the optimal sequencing of radiotherapy for metastatic rectal cancer remains unclear. Between 2004 and 2014, patients diagnosed with metastatic rectal cancer who underwent the resection of primary site and received radiotherapy were retrospectively selected using the Surveillance, Epidemiology, and End Results (SEER) database. The propensity score matching analyses were used to lessen the effects of confounding factors including age, sex, race, marital status, serum carcinoembryonic antigen level, histologic type, differentiation status, tumor size, T stage, N stage and resection of the distant lesions. The cancer-specific survival (CSS) were compared based on the sequencing of radiotherapy. Ultimately, 686 matched pairs were formed for comparison of preoperative versus postoperative radiotherapy. The 5-year CSS estimates were 33.4% (95% CI: 28.9%-37.9%) and 26.8% (95% CI: 22.7%-30.9%) for patients underwent preoperative radiotherapy followed by resection of primary lesion and postoperative radiotherapy after surgery, respectively. Patients underwent preoperative radiotherapy had better CSS as compared to patients received postoperative radiotherapy (p<0.001 for log-rank test). Multivariate analysis demonstrated that preoperative radiotherapy group was associated with significantly decreased risk for cancer death (HR=0.820, 95% CI: 0.712-0.945, p=0.006). Preoperative radiotherapy was superior to postoperative radiotherapy in patients with metastatic rectal cancer. Therapeutic strategy for these patients should be further explored.

Mutated DNA Damage Repair Pathways Are Prognostic and Chemosensitivity Markers for Resected Colorectal Cancer Liver Metastases

“…Both factors have been reported to correlate significantly independent of treatment with shorter OS in mCRC (56,57). On the other hand, the higher preoperative CEA levels and more patients undergoing direct surgeries presented in the subgroup without good oxaliplatin TRC are also negatively correlated with the survival of mCRC (58)(59)(60)(61). Therefore, when all patients carrying FA pathway mutations were considered as a whole in survival analyzes, the positive effect of chemotherapeutic response may have been compromised by other negative factors listed above, especially in small populations as in this study.…”

The survival impact of radiotherapy on synchronous metastatic rectal cancer: metastatic site can serve for radiotherapy-decision

“…More important, the metastatic site seems to represent a malignancy with a different biological characteristics [7]. However, many studies analyzed metastatic rectal cancer as a whole without considering the metastatic site [8,9], which may provide an inaccurate conclusion.…”

Effect of interval between neoadjuvant chemoradiotherapy and surgery on oncological outcomes in poor responders with locally advanced rectal cancer: a retrospective cohort study

“…Compared with postoperative CRT, neoadjuvant CRT had the advantages of improved resectability and local control, as well as less therapeutic toxicity 1 , 2 . Our previous study demonstrated that preoperative radiotherapy was superior to postoperative radiotherapy in terms of oncological outcomes in metastatic rectal cancer patients who received definitive surgical resection of the primary tumor 3 .…”