Laparoscopic curative surgery for T3 rectal cancer with uninvolved circumferential resection margin on magnetic resonance imaging without neo-adjuvant treatment: Findings from a 3-year follow-up study

Objectives: The choice of optimal initial treatment strategies for low-risk locally advanced rectal cancer remains controversial. This study evaluates the safety of oncologic and survival outcomes of laparoscopic curative surgery without neoadjuvant chemoradiotherapy (nCRT) in patients with T3 rectal cancer, uninvolved circumferential resection margin on magnetic resonance imaging (mrCRM). Material and Methods: This longitudinal cohort study included 109 patients with T3 rectal cancer (≤ 12cm from the anal verge (AV), except for cT3c at low rectum) having an uninvolved mrCRM. All participants underwent radical surgery without nCRT and were followed for a minimum of three years post-surgery. Data on short-term outcomes, pathologic outcomes, local recurrence (LR), distant metastasis (DM), overall survival (OS), and disease-free survival (DFS) were collected. Results: The median number of dissected lymph nodes was 12 (interquartile range: IQR = 10-14), the mean number of metastatic lymph nodes was 0.8 (standard deviation: SD = 1.65), and the lymph node ratio (LNR) was 0.06. Pathological CRM (pCRM) was involved in 3 cases (2.8%), and proximal and distal margins were R0 in all 109 cases. LR and DM rates were 5.5% and 11%, respectively. The 3-year and 5-year OS rates were 93.5% and 88.6% while the 3-year and 5-year DFS rates were 91.5% and 73.7%, respectively. LR was significantly correlated with involved pCRM (hazard ratio HR:3.28), violated mesorectum (HR:2.02), and anastomotic leakage (HR:1.86), while involved pCRM (HR:5.39) and violated mesorectum (HR:4.43) were significant predictors for DM. Conclusion: Upfront laparoscopic curative surgery without nCRT for T3a/b/c rectal cancer (≤ 12cm from anal verge(AV), except for cT3c at low rectum) with uninvolved mrCRM was safe, yielding favourable oncologic outcomes and survival rates.