Level of Inferior Mesenteric Artery Ligation in Sigmoid Colon and Rectal Cancer Surgery: Analysis of Apical Lymph Node Metastasis and Recurrence

Impact of D3 lymph node dissection on short-term and long-term outcomes in elderly patients with colon cancer

BACKGROUND

The oncologic impact of D3 lymph node dissection (LND) for colon cancer (CC) has been reported to be favorable. However, D3 LND is potentially more invasive than non-D3 LND, and whether it is beneficial for elderly patients with CC remains unclear. This study aimed to evaluate the perioperative safety and short- and long-term oncologic outcomes of D3 LND in elderly patients with CC.

METHODS

Subjects were 442 elderly patients aged ≥ 70 years who underwent curative surgery for pathologic stage (pStage) I-III CC between 2011 and 2022. Background clinical factors and short- and long-term outcomes were compared between patients who received D3 LND (D3 group; n = 363) and those who received non-D3 LND (non-D3 group; n = 79).

RESULTS

The D3 group had a significantly higher number of retrieved lymph nodes (median 20 vs. 12, p < 0.001) and a lower rate of postoperative complications (18% vs. 32%, p = 0.040) than the non-D3 group. In the overall cohort, overall survival (OS) did not differ between the two groups. Among pStage III patients, however, OS was significantly better (69.8% vs. 34.1%, p = 0.028), and RFS tended to be better (60.7% vs. 42.6%, p = 0.075) in the D3 group than in the non-D3 group. Multivariable analysis revealed that D3 LND was independently associated with better OS (HR 0.477; 95% CI 0.245-0.931, p = 0.030) and tended to be associated with better RFS (HR 0.588; 95% CI 0.329-1.051, p = 0.073).

CONCLUSION

D3 LND is safe and effective in improving the prognosis of elderly patients with pStage II/III CC.

Dynamic Prediction of Rectal Cancer Relapse and Mortality Using a Landmarking-Based Machine Learning Model: A Multicenter Retrospective Study from the Italian Society of Surgical Oncology-Colorectal Cancer Network Collaborative Group

Background: Almost 30% of patients with rectal cancer (RC) who submit to comprehensive treatment experience relapse. Surveillance plays a leading role in early detection. The landmark approach provides a more flexible and dynamic framework for survival prediction. Objective: This large retrospective study aims to develop a machine learning algorithm to profile the patient prognosis, especially the risk and the onset of RC relapse after curative resection. Methods: A cohort of 2450 RC patients were analyzed using landmark analysis. Model A applied a classical cause-specific Cox approach with a landmarking approach, while Model B implemented a landmarking-based RSF (random survival forest) competing risk algorithm. The two models were compared in terms of predictive and interpretative ability. A bootstrapped validation strategy was employed to validate the model's performance and prevent overfitting. The best-performing hyperparameters were selected systematically, ensuring the model's robustness within the landmark approach. The study assessed these factors' importance and interactions using RSF and compared the predictive accuracy to that of the classical Cox model. Results: Model B outperformed Model A (mean C-index 0.95 vs. 0.78), capturing complex interactions and providing dynamic, individualized relapse predictions. Clinical factors influencing survival outcomes were identified across time with the landmark approach allowing for more accurate and timely predictions. Conclusions: The landmark approach offers an improvement over traditional methods in survival analysis. By accommodating time-dependent variables and the evolving nature of patient data, this approach provides a precise tool for profiling RC survival, thereby supporting more informed and dynamic clinical decision-making.

Low ligation of the inferior mesenteric artery in robotic mid-low rectal cancer surgery: a comparative study from a single-center

Laparoscopic total mesorectal excision is the main surgical approach for treating rectal cancer, but there is still no clear consensus on the issue of low ligation of the inferior mesenteric artery during the procedure. Robotic surgery has been shown to have certain advantages over laparoscopic surgery in multiple studies, but further research is needed to better understand the outcomes of robotic surgery in the context of low ligation procedures. In this study, we included 1590 patients with mid-low rectal cancer. Among them, 942 patients underwent low ligation surgery (LL), divided into 138 in the robotic group and 804 in the laparoscopic group. The high ligation surgery (HL) group consisted of 648 patients. The results of LL vs HL showed that the LL group had faster bowel movement recovery (P = 0.003), lower anastomotic leak rate (P = 0.032), and lower International Prostate Symptom Score (IPSS) at 6 months postoperatively (P < 0.001). The results of Rob-LL vs Lap-LL showed that the Rob-LL group had longer operative time (P < 0.001), less blood loss (P = 0.001), more lymph nodes retrieved (P = 0.045), and lower Wexner score at 2 weeks postoperatively (P = 0.029). The concept of low ligation of the inferior mesenteric artery is a promising surgical approach that can accelerate the patient's functional recovery. When combined with robotic technology, it may offer more benefits than laparoscopic techniques.