[Impacts of participation in surgical clinical trial on safety and survival outcomes in patients with right-sided colon cancer].

Objective: To explore the impact on safety and prognosis in patients with right-sided colon cancer participating in surgical clinical research. Methods: This retrospective cohort study utilized data from a randomized controlled trial (RELARC study) conducted by the colorectal surgery group at Peking Union Medical College Hospital in which laparoscopic complete mesocolic excision (CME) was compared with D2 radical resection for the management of right-sided colon cancer. The eligibility criteria were age 18-75 years, biopsy-proven colon adenocarcinoma, tumor located between the cecum and right 1/3 of the transverse colon, enhanced chest, abdomen, and pelvic CT scans suggesting tumor stage T2-T4N0M0 or TanyN+ M0, and having undergone radical surgical treatment from January 2016 to December 2019. Exclusion factors included multiple primary colorectal cancers, preoperative stage T1N0 or enlarged central lymph nodes, tumor involving surrounding organs requiring their resection, definite distant metastasis or otherwise unable to undergo R0 resection, history of any other malignant tumors within previous 5 years, intestinal obstruction, perforation, or gastrointestinal bleeding requiring emergency surgery, and assessed as unsuitable for laparoscopic surgery. Patients who had participated in the RELARC study were included in the RELARC group, whereas those who met the inclusion criteria but refused to participate in the RELAEC study were included in the control group. The main indicators studied were the patient's baseline data, surgery and perioperative conditions, pathological characteristics, adjuvant treatment, and postoperative follow-up (including average frequency of follow-up within the first 3 years) and survival (including 3-year disease-free survival rate (DFS) and 3-year overall survival rate (OS). Differences in these indicators between the RELARC and control groups were compared. Results: The study cohort comprised 290 patients, 173 in the RELARC group (RELARC-CME group, 82; RELARC-D2 group, 91) and 117 in the control group (CME control group, 72; D2 control group, 45). There was a significantly higher proportion of overweight patients (BMI ≥24 kg/m²) in the RELARC-CME than in the CME control group (67.1% [55/82] vs. 33.3% [24/72], χ²=17.469, P<0.001). There were no other statistically significant differences in baseline characteristics (all P>0.05). No significant disparities were found between the CME and D2 groups in terms of operation duration, intraoperative blood loss, rate of conversion to open surgery, combined organ resection, intraoperative blood transfusion, or intraoperative complications (all P>0.05). There was a trend toward Clavien-Dindo grade II or higher postoperative complications in the RELARC-CME group (24.4% [20/82]) than in the CME control group (18.1% [13/72]); however, this difference was not statistically significant (χ²=0.914, P=0.339). Similarly, the difference in this rate did not differ significantly between the RELARC-D2 group (25.3% [23/91]) and D2 control group (24.4% [11/45], χ²=0.011, P=0.916). The median duration of postoperative follow-up was significantly shorter in the RELARC groups than in the corresponding control groups. Specifically, the median duration of follow-up was 4.5 (4.5, 4.5) months in the RELARC-CME and 7.2 (6.0, 9.0) months in the CME control group (Z=-10.608, P<0.001). Similarly, the median duration of follow-up was 4.5 (4.5, 4.5) months in the RELARC-D2 group as opposed to 8.3 (6.6, 9.0) months in the D2 control group (Z=-10.595, P<0.001). The 3-year DFS rate (91.5%) and OS rate (96.3%) tended to be higher in the RELARC-CME group than in the CME control group (84.7% and 90.3%, respectively). The 3-year DFS rate (87.9%) and OS rate (96.7%) tended to be higher in the RELARC-D2 group than in the D2 control group (81.8% and 88.6%, respectively); however, these differences were not statistically significant (all P>0.05). Subgroup analysis according to pathological stage revealed that patients in the RELARC-D2 group with pN0 stage achieved a significantly superior 3-year OS rate than did those in the D2 control group (100% vs. 88.9%, P=0.008). We identified no statistically significant differences in survival rates between the remaining subgroups (all P>0.05). Conclusions: A high-quality surgical clinical trial with close follow-up can achieve perioperative safety and a trend toward improved survival outcomes.