The effect of pericolic lymph nodes metastasis beyond 10 cm proximal to the tumor on patients with rectal cancer

A modified method for precise anastomosis during laparoscopic low anterior resection for rectal cancer: the first clinical experience and application

BACKGROUND

There is no criterion to guide and evaluate the anastomosis of laparoscopic low anterior resection (LAR). We developed a new technique for precise anastomosis. This study endeavored to evaluate the effectiveness and safety of this new technology.

METHODS

Patients with mid-low rectal cancer who underwent laparoscopic LAR in our department were enrolled retrospectively between January 1, 2021 and July 1, 2023. During the LAR, the distance between the sacral promontory and the rectal stump was measured and used to determine the length of the sigmoid colon, which was preserved for anastomose. The demographic characteristics and short-term outcomes were analyzed.

RESULTS

Forty-nine patients (26 men, 23 women) with low and middle rectal cancer were retrospectively enrolled in the study. The distance of the tumor from the anal verge was 6.4 ± 2.7 cm. The operative time was 193 ± 42 min. All patients underwent precise anastomosis, among which 12 patients underwent freeing of the splenic flexure of the colon. According to our criteria, there was no redundant or tense state of the colon anterior to the sacrum after the anastomosis. Only one patient had a postoperative anastomotic leak (Grade B). All 15 patients receiving neoadjuvant chemoradiotherapy underwent terminal ileostomy. No postoperative death occurred within 30 days of the surgery. The median follow-up time in our study was 12 months. One patient developed a single metastasis in the right lobe of the liver in the eighth month after surgery and underwent microwave radiofrequency ablation, which did not recur in the four months of postoperative follow-up, and the rest of the patients survived disease-free without recurrence of metastasis.

CONCLUSIONS

Precise measurement of the proximal colon of the anastomosis can ensure accurate and convenient colorectal anastomosis and this may be a technique worthy of clinical application. However, its effectiveness needs to be further verified in a multicenter clinical trial.

Lymph node stain after radical resection of rectal cancer mainly increased the harvest of mini lymph node: A randomized controlled trial

AIM

The lymph node status plays an important role in rectal cancer, which depends on adequate lymph node harvest. Lymph node stain techniques increase the lymph node harvest. The aim of this prospective study is to investigate which subgroups of lymph nodes harvested were increased mostly.

METHODS

From May 2020 to May 2022, 172 stage II-III rectal cancer patients were randomized to methylene blue (MB) stained group or unstained group to retrieve the lymph nodes. Methylene blue solution was injected into the inferior mesenteric artery, we dissected lymph nodes by palpation and sight. The lymph nodes were divided into 3 groups depending on the anatomy (main lymph nodes, superior rectal and perirectal lymph nodes (SPLNs), and pericolic lymph nodes located beyond 10 cm proximal to the tumor), and 3 groups depending on the short diameter of the nodes (big: ≥ 5 mm, small: 5-2 mm, mini: ≤ 2 mm).

RESULTS

The number of lymph nodes harvested with MB was significantly higher (22.0 (14.8, 32.0) vs 14.5 (11.0, 22.0); p < 0.001) without difference in positive patients or number of positive nodes. The positive rate of the big node was 3.5%, the small node was 1.9%, and the mini node was 0.2%. In the subgroup analysis, the median number of mini lymph nodes in the MB-stained group was significantly more than that of the unstained group (median (IQR): 9.0 (6.0, 14.0) vs 4.0 (2.0,6.0), p < 0.001); and the median number of SPLNs in the MB-stained group were significantly more than that of the unstained group (median (IQR): 15.0 (9.0, 19.0) vs 10.0 (6.0, 13.3), p < 0.001); these differences were existing in both patients with and without neoadjuvant treatments.

CONCLUSION

Intra-arterial injection of MB can significantly increase the number of lymph nodes harvested in rectal cancers, especially those mini lymph nodes. However, methylene blue staining did not significantly increase the number of positive lymph nodes and the proportion of patients with more than 12 lymph nodes, or affect lymph node staging accuracy after radical resection of rectal cancer.