Technical outcomes of robotic-assisted surgery versus laparoscopic surgery for rectal tumors: a single-center safety and feasibility study.

PURPOSE: Robot-assisted surgery has a multi-joint function, which improves manipulation of the deep pelvic region and contributes significantly to perioperative safety. However, the superiority of robot-assisted surgery to laparoscopic surgery remains controversial. This study compared the short-term outcomes of laparoscopic and robot-assisted surgery for rectal tumors. METHODS: This single-center, retrospective study included 273 patients with rectal tumors who underwent surgery with anastomosis between 2017 and 2021. In total, 169 patients underwent laparoscopic surgery (Lap group), and 104 underwent robot-assisted surgery (Robot group). Postoperative complications were compared via propensity score matching based on inverse probability of treatment weighting (IPTW). RESULTS: The postoperative complication rates based on the Clavien-Dindo classification (Lap vs. Robot group) were as follows: grade ≥ II, 29.0% vs. 19.2%; grade ≥ III, 10.7% vs. 5.8%; anastomotic leakage (AL), 6.5% vs. 4.8%; and urinary dysfunction (UD), 12.1% vs. 3.8%. After adjusting for the IPTW method, although AL rates did not differ significantly between groups, postoperative complications of both grade ≥ II (odds ratio [OR] 0.66, 95% confidence interval [CI] 0.50-0.87, p < 0.01) and grade ≥ III (OR 0.29, 95% CI 0.16-0.53, p < 0.01) were significantly less frequent in the Robot group than in the Lap group. Furthermore, urinary dysfunction also tended to be less frequent in the Robot group than in the Lap group (OR 0.62, 95% CI 0.38-1.00; p = 0.05). CONCLUSION: Robot-assisted surgery for rectal tumors provides better short-term outcomes than laparoscopic surgery, supporting its use as a safer approach.

Possible role of p53/Mieap-regulated mitochondrial quality control as a tumor suppressor in human breast cancer.

Mitochondria-eating protein (Mieap), encoded by a p53-target gene, plays an important role in mitochondrial quality control (MQC). Mieap has been reported to have a critical role in tumor suppression in colorectal cancer. Here, we investigated its role as a tumor suppressor in breast cancer. The enforced expression of exogenous Mieap in breast cancer cells induced caspase-dependent apoptosis, with activation of both caspase-3/7 and caspase-9. Immunohistochemistry revealed endogenous Mieap in the cytoplasm in 24/75 (32%) invasive ductal carcinomas (IDC), 15/27 (55.6%) cases of ductal carcinoma in situ (DCIS) and 16/18 (88.9%) fibroadenomas (FA) (IDC vs DCIS; P = 0.0389, DCIS vs FA; P = 0.0234, IDC vs FA; P < 0.0001). In IDC, the Mieap promoter was methylated in 6/46 (13%) cases, whereas p53 was mutated in 6/46 (13%) cases. Therefore, the p53/Mieap-regulated MQC pathway was inactivated in 12/46 IDC (26.1%). Interestingly, all tumors derived from the 12 patients with Mieap promoter methylation or p53 mutations pathologically exhibited more aggressive and malignant breast cancer phenotypes. Impairment of p53/Mieap-regulated MQC pathway resulted in significantly shorter disease-free survival (DFS) (P = 0.021), although p53 status is more prognostic in DFS than Mieap promoter methylation. These results indicate that p53/Mieap-regulated MQC has a critical role in tumor suppression in breast cancer, possibly in part through mitochondrial apoptotic pathway.