"Caudal-to-cranial" plus "artery first" technique with beyond D3 lymph node dissection on the right midline of the superior mesenteric artery for the treatment of right colon cancer: is it more in line with the principle of oncology?

A multicenter prospective observational study of lymph node metastasis patterns and short-term outcomes of extended lymphadenectomy in right-sided colon cancer

Background

The lymph node metastasis rate in right-sided colon cancer is unknown, and the optimal central vascular ligation level remains controversial. We aimed to determine the lymph node metastasis rate and short-term results of radical surgery with extended lymph node dissection in right-sided colon cancer.

Methods

This prospective multicenter observational study included patients with stage II/III right-sided colon cancer from five cancer hospitals. The metastasis rate of each node station was analyzed according to tumor location and main feeding artery.

Results

Between April 2018 and August 2021, 208 patients underwent dissection around the superior mesenteric artery (SMA) and vein (SMV). In transverse colon cancer, 7.5% and 2.5% of metastases occurred around the SMV and SMA at the root of the middle colic artery (MCA), respectively; 6.7% and 6.7% at the root of the right colic artery. In caecal cancer, 1.9% of metastases occurred around the SMV and 1.9% around the SMA. In ascending colon cancer, the rate was 1.1% around the SMV. Of the tumors, 17% fed mainly by the ileocolic artery had node metastases along the middle or right colic artery, as did 66.7% fed mainly by the right colic artery and 41.2% fed by the MCA (p = 0.01). Postoperative complications occurred in 42 patients (20.2%).

Conclusion

Routine prophylactic extended lymphadenectomy around the SMA might not be necessary in caecum and ascending colon cancer. Dissection around the SMA may be necessary in cases of transverse colon cancer or when the feeding artery is the MCA.

Caudal-to-Cranial Approach for Right Colectomy with Complete Mesocolic Excision in Colon Cancer: A Systematic Review and Meta-analysis

BACKGROUND

A newly emerging approach "caudal to cranial" with complete mesenteric excision (CME) has recently been proposed for right colectomy in patients with right colon cancer. To date, only a few studies about this approach have appeared. Our study aims to investigate the safety and efficacy of this new technique.

METHODS

A systematic review of the literature was conducted to evaluate the evidence regarding short- and long-term outcomes after the caudal-to-cranial approach (CCA). Methodological Index for Non-Randomized Studies was used to evaluate methodological quality. The risk of bias was assessed using Robvis tool. Meta-analyses have been conducted for the outcomes of studies comparing CCA with other techniques.

RESULTS

We found six studies from 2017 to 2021 with a total of 594 patients. The postoperative complications and oncological outcomes were acceptable. Two studies comparing CCA to medial-to-lateral approach were included in the meta-analysis. No differences were found between the techniques regarding to operative time, length of hospital stay, overall morbidity, and number of lymph nodes.

CONCLUSION

Although the interpretation of our findings may be restrained by methodological limitations, risk of bias, and the absence of well-designed randomized controlled trials, CCA with CME in right-sided colon cancer may be a feasible and safe procedure.

"Caudal to cranial" versus "medial to lateral" approach in laparoscopic right hemicolectomy with complete mesocolic excision for the treatment of stage II and III colon cancer: perioperative outcomes and 5-year prognosis

The purpose of this study was to compare the "caudal to cranial" (CC) versus "medial to lateral" (ML) approach for laparoscopic right hemicolectomy. Pertinent data from all patients with stage II and III between January 2015 and August 2017 were entered into a retrospective database. A total of 175 patients underwent the ML (N = 109) or CC approach (N = 66). Patient characteristics were equivalent between groups. The CC group showed a shorter surgical time 170.00 (145.00, 210.00) vs. (206.50 (178.75, 226.25) min) than the ML group (p < 0.001). The time to oral intake was shorter in the CC group than in the ML group ((3.00 (1.00, 4.00) vs. 3.00 (2.00, 5.00) days; p = 0.007). For the total harvested lymph nodes, there was no statistical significance between the CC group 16.50 (14.00, 21.25) and the ML group 18.00 (15.00, 22.00) (p = 0.327), and no difference was found in the positive harvested lymph nodes (0 (0, 2.00) vs. 0 (0, 1.50); p = 0.753). Meanwhile, no differences were found in other perioperative or pathological outcomes, including blood loss and complications. For 5-year prognosis, overall survival rates were 75.76% in the CC group and 82.57% in the ML group (HR 0.654, 95% CI 0.336-1.273, p = 0.207); disease-free survival rates were 80.30% in the CC group and 85.32% in the ML group (HR 0.683, 95% CI 0.328-1.422, p = 0.305). Both approaches were safe and feasible and resulted in excellent survival. The CC approach was beneficial in terms of the surgical time and time to oral intake.

Definition and reporting of lymphadenectomy and complete mesocolic excision for radical right colectomy: a systematic review

BACKGROUND

Several procedures have been proposed to reduce the rates of recurrence in patients with right-sided colon cancer. Different procedures for a radical right colectomy (RRC), including extended D3 lymphadenectomy, complete mesocolic excision and central vascular ligation have been associated with survival benefits by some authors, but results are inconsistent. The aim of this study was to assess the variability in definition and reporting of RRC, which might be responsible for significant differences in outcome evaluation.

METHODS

PRISMA-compliant systematic literature review to identify the definitions of RRC. Primary aims were to identify surgical steps and different nomenclature for RRC. Secondary aims were description of heterogeneity and overlap among different RRC techniques.

RESULTS

Ninety-nine articles satisfied inclusion criteria. Eight surgical steps were identified and recorded as specific to RRC: Central arterial ligation was described in 100% of the included studies; preservation of mesocolic integrity in 73% and dissection along the SMV plane in 67%. Other surgical steps were inconstantly reported. Six differently named techniques for RRC have been identified. There were 35 definitions for the 6 techniques and 40% of these were used to identify more than one technique.

CONCLUSIONS

The only universally adopted surgical step for RRC is central arterial ligation. There is great heterogeneity and consistent overlap among definitions of all RRC techniques. This is likely to jeopardise the interpretation of the outcomes of studies on the topic. Consistent use of definitions and reporting of procedures are needed to obtain reliable conclusions in future trials. PROSPERO CRD42021241650.

Risk factors of chylous ascites and its relationship with long-term prognosis in laparoscopic D3 lymphadenectomy for right colon cancer

BACKGROUND

Chylous ascites (CA) after laparoscopic D3 lymphadenectomy for right colon cancer is not rare. However, the risk factors for CA have not been fully explored. Few studies have investigated the effect of CA on long-term prognosis.

METHODS

The clinical data of patients with right colon cancer who underwent laparoscopic D3 lymphadenectomy in five centers from January 2013 to December 2018 were retrospectively collected. Univariate and multivariate analyses were performed to determine the clinicopathological factors associated with CA. Then, the long-term prognosis of patients with and without CA was compared by propensity score matching and Kaplan-Meier survival analysis.

RESULTS

The incidence of CA was 4.4% (48/1090). Pathological T stage (p = 0.025), dissection along the left side of the superior mesenteric artery (p < 0.001) and the number of retrieved lymph nodes (p < 0.001) were independent risk factors for CA. After propensity score matching, 48 patients in the CA group and 353 patients in the non-CA group were enrolled. Kaplan-Meier survival analysis indicated that CA was not associated with overall survival (p = 0.454) and disease-free survival (p = 0.163). In patients with stage III right colon cancer, there were no significant differences in overall survival (p = 0.501) and disease-free survival (p = 0.254).

CONCLUSIONS

Pathological T stage, number of retrieved lymph nodes, and left side dissection along the superior mesenteric artery were independent risk factors for CA after laparoscopic D3 lymphadenectomy. CA does not impair the oncological outcomes of patients.

Laparoscopic Complete Mesocolic Excision with Central Vascular Ligation (CME + CVL) for Right-Sided Colon Cancer: A New "Superior Mesenteric Artery First" Approach

PURPOSE

It remains a technical challenge to perform "superior mesenteric artery (SMA) first" approach for laparoscopic right hemicolectomy with complete mesocolon excision (CME) as the vascular anatomy of the right colon varies a lot, which may cause difficulty in early location of SMA and the risk of vascular damage during central vascular ligation (CVL). The purpose of this study was to describe a new "SMA first" approach for laparoscopic CME with CVL in right hemicolectomy with Treitz's ligament and ileocolic vascular pedicle as the anatomical landmarks for early identification of and exposure of SMA.

METHODS

This procedure was performed on 21 patients with right colon cancer between March 2020 and August 2021. To start, the transverse mesocolon was retracted to expose the ligament of Treitz, and the pedicle of ileocolic vessels was anteriorly grasped. Next, the peritoneum near the right border of the ligament of Treitz was divided along the left side of SMA until the peritoneum below the ileocolic vessels. Next, the mesenteric lymphatic adipose tissue outside of the sheath of SMA was dissected from medial to lateral. Then, laparoscopic right hemicolectomy with complete mesocolic excision (CME) was performed. Patients' preoperative baseline characteristics and intraoperative and postoperative complications were examined.

RESULTS

The median operative time was 180 min, and the median intraoperative blood loss was 50 ml (interquartile range 40-90). Chylous leakage occurred in four patients, and all the patients resolved with percutaneous drainage. The total harvested lymph nodes was 21.0 (range 16-27). The median times to first flatus and liquid diet intake were both 3.0 days. The median number of postoperative hospital days was 10.0 days. No severe postoperative complications, such as abdominal infection, anastomotic leakage, or bleeding, were observed.

CONCLUSIONS

This new "SMA first" approach is safe and technically feasible for laparoscopic CME with CVL in right hemicolectomy.

The Medial Border of Laparoscopic D3 Lymphadenectomy for Right Colon Cancer: Results from an Exploratory Pilot Study

BACKGROUND

Opinions vary on the medial border of D3 lymphadenectomy for right colon cancer. Most surgeons place the medial border along the left side of the superior mesenteric vein, but some consider the left side of the superior mesenteric artery as the medial border.

OBJECTIVES

This study investigated the clinical outcomes of laparoscopic D3 lymphadenectomy for right colon cancer with the medial border along the left side of superior mesenteric artery.

DESIGN

This was a retrospective study.

SETTINGS

The study was conducted in specialized colorectal cancer department of 5 tertiary hospitals.

PATIENTS

Patients receiving laparoscopic D3 lymphadenectomy for right colon cancer from January 2013 to December 2018 were included.

MAIN OUTCOME MEASURES

After propensity score matching, 307 patients receiving laparoscopic D3 lymphadenectomy along the left side of the superior mesenteric artery were assigned to the superior mesenteric artery group and 614 patients were assigned to the superior mesenteric vein group. Univariate, multivariate, and Kaplan-Meier analyses were performed to assess the clinical data.

RESULTS

The short-term outcomes were similar between the 2 groups; however, the superior mesenteric artery group had a higher rate of chylous leakage (p < 0.001). More lymph nodes were harvested from the superior mesenteric artery group than from the superior mesenteric vein group (p = 0.001). The number (p = 0.005) of metastatic lymph nodes and the lymph node ratio (p = 0.041) in main nodes were both higher in the superior mesenteric artery group. The 2 groups had similar long-term survival, but the superior mesenteric artery group tended to show better disease-free survival in patients with stage disease III (p = 0.056).

LIMITATIONS

This was a retrospective, nonrandomized study.

CONCLUSION

Laparoscopic D3 lymphadenectomy along the left side of the superior mesenteric artery, except for a higher rate of chylous leakage, had short-term outcomes comparable to the superior mesenteric vein group. The superior mesenteric artery group tended to achieve better disease-free survival in patients with stage III disease, but further study is required to better elucidate differences in these approaches because risks/benefits do exist.

Laparoscopic right hemicolectomy with complete mesocolic excision plus D3 lymphadenectomy (CME + D3): a new medial approach for central vascular ligation

Due to the high risk of vascular injuries, it remains a technical challenge and time-consuming procedure for surgeons to perform CME and D3 lymph node dissection in laparoscopic right hemicolectomy. To overcome this difficulty, we developed a novel method of the vessel's management for central vascular ligation (CVL). The key feature of this new approach focused on vascular dissection in two aspects. The first one was to expose the superior mesentery vein (SMV) and the branches of the superior mesentery artery (SMA) at their roots from left to right after dividing the peritoneum near the left border of SMV, which has the advantage of exposing SMV and controlling bleeding. The second was to selectively ligate the colic tributaries of gastrocolic trunk of Henle (GTH) after expanding its surrounding spaces. We named this technique the "new approach (NA)". Thirty-eight patients who underwent laparoscopic right hemicolectomy with the new approach (NA) were retrospectively analyzed and compared with data from 35 patients, who underwent the conventional medial approach (TA) performed by the same surgical team from April 2017 to March 2021. There was no significant difference between the two groups in baseline data (all p > 0.05). All 38 operations were completed with this procedure successfully. The NA approach was associated with a shorter operation time (190.5 min vs.215.5 min; P < 0.05) and a smaller blood loss (50 ml vs. 95 ml; P < 0.05) compared with the conventional approach. Two cases of vascular injuries occurred in the TA group and had been managed laparoscopically. The lymph nodes count (15 vs. 16; P > 0.05) was not significantly different; additionally, no difference was observed regarding anastomotic leakage (both n = 0) and postoperative complications (3/31 vs. 3/30; P > 0.05). No mortality was observed. NA is feasible and can be an optional method of vessel's management in laparoscopic CME and D3 lymphadenectomy for right-sided colon cancer.

Modified complete mesocolic excision with central vascular ligation by the squeezing approach in laparoscopic right colectomy

PURPOSE

Complete mesocolic excision (CME) and central vascular ligation (CVL) are becoming the standard procedure in laparoscopic right-sided colectomy. However, the approach to CME and CVL has not been established, although several useful approaches have been reported. The squeezing approach described herein is a novel procedure to perform modified CME and CVL in laparoscopic right colectomy.

METHODS

The squeezing approach features retroperitoneal mobilization followed by cranial mesocolic mobilization and lymph node dissection using a cranial approach followed by a caudal approach. Dissection of the regional lymph nodes along with central vascular ligation was performed along the anterior wall of the superior mesenteric vein. In total, 177 patients (mean age, 70.6 years; male-to-female ratio, 90:87) who underwent laparoscopic right-sided colectomy were retrospectively assessed. Descriptive statistics for patient characteristics were calculated.

RESULTS

The mean operative time and blood loss were 169 min and 37 mL, respectively. Seven patients (4.0%) required conversion to open surgery, and major postoperative complications occurred in five patients (2.8%) with no anastomotic leakage. Histological R0 resection was achieved in all cases of stages 0-III colon cancer. The 5-year recurrence-free survival rates were 100% (n = 19), 100% (n = 40), 87% (n = 46), and 81% (n = 43) in pathological stages 0, I, II, and III, respectively. Node recurrence occurred in one case near the root of the middle colic artery.

CONCLUSION

The novel squeezing approach in laparoscopic right colectomy could be safely performed in terms of the technical and oncological aspects.

The role of apical lymph node metastasis in right colon cancer

BACKGROUND

The role of apical lymph node (APN) metastasis in colorectal cancer remains controversial. The main purpose of this study is to explore the prognostic value of APN metastasis in patients with right colon cancer.

METHODS

This is a retrospective study of patients with stage III right colon cancer between April 2007 and December 2016. Patients who underwent resection of right colon cancers with D3 lymph node dissection were divided into APN-positive (APN+) and APN-negative (APN-) groups according to the postoperative pathological presence or absence of APN metastasis. Relapse-free survival (RFS) and overall survival (OS) between groups were compared after Cox regression analysis and 1:1 propensity score matching (PSM).

RESULTS

A total of 254 patients were included in this study: 28 (11.0%) were APN+ and 226 (89.0%) were APN-. Before matching, the rates of elevated carcinoembryonic antigen (CEA), T3-4 tumor invasion, and N2 lymph node metastasis were significantly higher in the APN+ group (CEA ≥ 5 ng/mL, 53.6% vs. 37.6%, p < 0.001; T3-4, 92.9% vs. 85.4%, p < 0.001; N2 metastasis, 57.1% vs. 20.4%, p < 0.001), and APN+ tumors were associated with significantly higher postoperative relapse rates (39.3% vs. 21.2%; p = 0.03), especially with lung metastases (14.3% vs. 4.0%; p = 0.019), which conferred worse RFS (p = 0.013), although OS was similar (p = 0.078). However, after PSM, there were no apparent between-group differences in RFS (p = 0.29) or overall survival rate (p = 0.637). The Cox regression analysis indicated that lymphatic vessel infiltration and depth of invasion were independent risk factors for OS, while APN+ status was not a significant predictor for RFS or OS.

CONCLUSIONS

APN metastasis was not a prognostic indicator for RFS or OS in right colon cancer. However, APN+ patients with elevated CEA levels and deeper tumor invasion should be closely monitored for lung metastasis during postoperative follow-up.

Optimal extent of central lymphadenectomy for right-sided colon cancers: is lymphadenectomy beyond the superior mesenteric vein meaningful?

PURPOSE

The objective of the current study was to assess the therapeutic benefit of lymphadenectomy according to the extent of lymphadenectomy.

METHODS

Patients undergoing colectomy for right-sided colon cancer were identified. Distribution of lymph node metastases (DLNM) of 1, 2 and 3 were defined as lymph node metastasis (LNM) in the pericolic nodes, the intermediate nodes and the front of the SMV near the origin of the major artery, respectively. The therapeutic index (TI) was calculated based on the frequency of LNM and the 5 year overall survival (OS) rate of patients with LNM.

RESULTS

Among 344 patients who met the inclusion criteria, roughly half had LNM (n = 150, 43.7%). While 107 (31.1%) and 30 (8.7%) patients had DLNM1 and DLNM2, respectively, only 13 patients (3.8%) were defined as DLNM3. However, there was no significant difference in 5 year OS by DLNM (DLNM1 71.1%, DLNM2 78.7%, DLNM3 50.4%, p = 0.61). Overall, the TI of lymphadenectomy for D3 area was approximately 1/10 of the TI for D1 (1.9 vs.22.1), given the low frequency of LNM (3.8%) and poor 5 year OS of patients with LNM (50.4%). This trend was consistent irrespective of primary tumor locations.

CONCLUSION

The survival benefit from central lymphadenectomy namely D3 was low among patients with right-sided colon cancers.