eP207 - Upfront Surgery versus Preoperative Chemoradiotherapy : Comparison of Survival Analysis for Stage II–III Resectable Rectal Cancer

Purpose/Background: The current international guidelines recommend neoadjuvant chemoradiotherapy (nCRT) followed by total mesorectal excision (TME) for locally advanced rectal cancer. Although nCRT decreases the risk of local recurrence, it does not improve survival and increases the likelihood of preoperative overtreatment. We investigated whether upfront TME in patients with locally advanced rectal cancer can be offered without compromising oncological outcomes.Methods/Interventions: From January 2015 to December 2020, resectable locally advanced stage II/III rectal cancer patients who received upfront surgery with TME (upfront TME group) and nCRT followed by TME (nCRT group) were analyzed retrospectively. Long-term survival analyses were compared between the two groups. The primary endpoint was 5-year disease-free survival (DFS). The secondary endpoint was 5-year local recurrence-free survival (LRFS), distant metastasis-free survival (DMFS), and overall survival.Results/Outcomes: A total of 348 patients were included in the analysis, 138 (39.7%) underwent upfront TME, and 210 (60.3%) received nCRT followed by TME. The median follow-up duration was 39 months (interquartile range, 25–60). Compared to the nCRT group, the upfront TME group demonstrated a significantly better 5-year DFS (43% vs. 22%, p = 0.0007) and DMFS (88% vs. 70%, p = 0.01). 5-year LRFS and OS did not differ between groups. There was no difference in positive pathological circumferential resection margin, R0 resection rate, adjuvant chemotherapy, or 30-day postoperative morbidity in both treatment groups. Univariate cox regression analysis for disease-free survival in all patients revealed pre-op MRF involvement (HR =1.58; 95% CI, 0.98–2.55; p =0.06), T3 (HR =3.83; 95% CI, 0.49–29.7; p =0.2), T4 (HR =6.45; 95% CI, 0.78–53.6; p =0.08), N1 (HR =2.28; 95% CI, 0.79–6.57; p =0.13), and N2 tumor (HR =1.08; 95% CI, 0.21–5.58; p =0.93) as the worse prognostic factors.Conclusion/

Discussion: This study showed no difference in local recurrence and overall survival rate. nCRT may not be required for all stage II/III rectal cancer patients, especially for cT1-2/N1 or cT3N0 without MRF involvement. Upfront TME without neoadjuvant chemoradiotherapy can be considered in selected locally advanced rectal cancer patients with comparable prognosis."Table 1: Baseline Characteristics

Table 1: Baseline Characteristics
Table 2: Pathological Report, Postoperative Treatment and Morbidity

Table 2: Pathological Report, Postoperative Treatment and Morbidity
Survival Outcome

Survival Outcome
Table 5: Risk Factors Associated with Disease-Free Survival

Table 5: Risk Factors Associated with Disease-Free Survival
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