Extended Lymphadenectomy in Colon Cancer Is Debatable

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.

Selective central vascular ligation (D3 lymphadenectomy) in patients undergoing minimally invasive complete mesocolic excision for colon cancer: optimizing the risk-benefit equation

AIM

Complete mesocolic excision (CME) with central vascular ligation (CVL) has been advocated for right colon adenocarcinoma (RC), but the radicality of vascular dissection remains controversial. Our aim is to report outcomes of selective CVL (D3 lymphadenectomy) during minimally invasive CME for RC.

METHOD

A prospective database identified patients who were treated for RC between 2009 and 2016. Minimally invasive CME was standard. The radicality of lymphadenectomy was defined as high ligation (HL) versus CVL based on operative reports and videos. Two blinded radiologists independently evaluated the pre- and postoperative CT scans for radiographically abnormal nodes.

RESULTS

Of 197 patients who underwent CME, HL was performed in 56 (28%) and CVL in 141 (72%). There were no baseline differences in age, sex, body mass index, American Society of Anesthesiologists score or pathological staging, and there were no major intra-operative complications in either group (including no major vascular injuries). The median total number of nodes retrieved was 27 and 31 (P = 0.011) in HL and CVL groups, resepctively, with pathologically positive nodes identified in 33.9% and 39.8% (P = 0.704), respectively. Preoperative imaging identified abnormal cN3 nodes in 1.5% of patients; all of whom underwent CVL. No abnormal cN2 or cN3 nodes remained on postoperative imaging. The 60-day mortality was 0.5%, and major morbidity was 4%. One patient (0.5%) had an anastomotic recurrence after a median follow-up of 22 months.

CONCLUSION

With imperfect preoperative clinical nodal staging, and in the absence of randomized data, the low morbidity and oncological outcomes observed support the approach of CME with HL as a minimum standard, with CVL (D3 lymphadenectomy) in selected cases.

Lymphatic Drainage of the Splenic Flexure Defined by Intraoperative Scintigraphic Mapping

BACKGROUND

The optimal surgical management of splenic flexure cancer is debated, partly because of an incomplete understanding of the lymphatic drainage of this region.

OBJECTIVE

This study aimed to evaluate the normal lymphatic drainage of the human splenic flexure using laparoscopic scintigraphic mapping.

DESIGN

This was a clinical trial.

SETTINGS

The study was conducted at a single tertiary care center.

PATIENTS

Thirty consecutive patients undergoing elective colorectal resections without splenic flexure pathology were recruited.

INTERVENTION

Technetium-99m was injected subserosally at the splenic flexure.

MAIN OUTCOME MEASURES

Lymphatic scintigraphic mapping was undertaken at 15, 30, and 60 minutes using a laparoscopic gamma probe at the left branch of the middle colic, left colic, inferior mesenteric, and ileocolic (control) lymphovascular pedicles.

RESULTS

Lymphatic drainage at 60 minutes was strongly dominant in the direction of the left colic pedicle (96% of patients), with a median gamma count of 284 (interquartile range, 113-413), versus the left branch of the middle colic count of 31 (interquartile range, 15-49; p < 0.0001). This equated to a median 9.2-times greater flow to the left colic versus the middle colic. Counts at the left colic were greater than all of the other mapped sites at 15, 30, and 60 minutes (p < 0.001), whereas middle colic and inferior mesenteric artery counts were equivalent. The protocol increased operative duration by 20 to 30 minutes without complications.

LIMITATIONS

These results report lymphatic drainage from patients with normal splenic flexures, and caution is necessary when extrapolating to patients with splenic flexure cancers.

CONCLUSIONS

The lymphatic drainage of the normal splenic flexure is preferentially directed toward the left colic in the high majority of cases. Retrieving these nodes should be prioritized in splenic flexure cancer resections, with important secondary emphasis on left middle colic nodes, supporting segmental (left hemicolectomy) resection as the procedure of choice. Additional development of colonic sentinel node mapping using these techniques may contribute to individualized surgical therapy morbidity. See Video Abstract at http://links.lww.com/DCR/A495.

Complete mesocolic excision and extended (D3) lymphadenectomy for colonic cancer: is it worth that extra effort? A review of the literature

PURPOSE

Recent interest in complete mesocolic excision (CME) with central vascular ligation (CVL) or extended (D3) lymphadenectomy (EL) for curative resection of colon cancer has been driven by published series from experienced practitioners showing excellent survival outcomes and low recurrence rates. In this article, we attempt to clarify the role of CME or EL in modern colorectal surgery.

METHODS

A narrative review of the evidence for CME and EL in the curative treatment of colon cancer.

RESULTS

The principal of CME surgery, similar to total mesorectal excision (TME) for rectal cancer, is the removal of all lymphatic, vascular, and neural tissue in the drainage area of the tumour in a complete mesocolic envelope with intact mesentery, peritoneum and encasing fascia. Extended (D3) lymphadenectomy (EL) is based on similar principles. Sound anatomical and oncological arguments are made to support the principles of removing the tumor contained within an intact mesocolic facial envelope together with an extended lymph node harvest. Excellent oncological outcomes with minimal morbidity and mortality have been reported. This has led to calls for the standardisation of surgery for colon cancer using CME. However, there is conflicting evidence regarding the prognostic benefit of greater lymph node harvests and the evidence for an oncological benefit of CME is limited by methodology flaws and several potential confounding factors.

CONCLUSIONS

Although there is a reasonable anatomical and oncological basis for these techniques, there are no randomised controlled trials from which to draw confident conclusions and there is insufficient consistent high quality evidence to recommend widespread adoption of CME.

Linking surgical specimen length and examined lymph nodes in colorectal cancer patients

AIM

The number of examined lymph nodes (NLN) was associated with survival of stages II and III colorectal cancer (CRC) patients. Guidelines recommend examining at least 12 lymph nodes. This study investigated the influence of surgical specimen length on lymph node harvest and compliance with international guidelines.

MATERIALS AND METHODS

This population-based study included 4,724 cases of surgically treated CRC that were diagnosed from 2002 to 2008. Multivariate analyses were performed for the main study variables (age, gender, diagnosis at screening or in symptomatic patients, cancer site, staging, grading, number of positive nodes, neo-adjuvant treatment for rectal cancer, hospital were surgery was performed). Fractional polynomial models investigated the relationship between continuous variables and outcomes.

RESULTS

The NLN increased over time reaching ≥12 NLN in 64% of cases at the end of the study period. More NLN were associated with young age, right colon cancer, pT3-T4 disease, stages II and III and high grade. Fewer NLN were associated with short surgical specimen length and neo-adjuvant treatment in rectal cancer patients. Use of laparoscopy increased sharply over time.

CONCLUSIONS

NLN increased over time in accordance with international guidelines. Surgical specimen length correlated with NLN which may determine therapeutic choices, particularly in stage II colon cancer. When harvested lymph nodes are under 10 in number and all are negative, chemotherapy is always recommended. As specimen lengths <20 cm were associated with a high risk of inadequate NLN counts, patients are at risk of over-treatment.

Is low tie ligation truly reproducible in colorectal cancer surgery? Anatomical study of the inferior mesenteric artery division branches

AIM

Curative surgery is the standard treatment for colorectal cancer. The ligation level of the inferior mesenteric artery (IMA) is still debated, as neither low tie (LT) nor high tie ligation (HT) has shown any benefit on the patients' overall survival. We examined whether LT is standardizable and easily reproducible from an anatomical point of view.

METHOD

One hundred CT angiographies of healthy patients were analysed for the anatomy of the IMA and its division branches: left colic artery (LCA), sigmoid arteries trunk and superior rectal artery. Data analysed comprised angles between the IMA and the aorta, diameters of the IMA and its branches, repartition of the branches and distances between the origin of the branches and the origin of the IMA.

RESULTS

IMA anatomy showed no variation. In contrast, its division branches showed important variability in terms of distance to the origin and repartition: in 19.9% of the patients, the IMA directly splits into three branches, and in 17.6% of the patients, the LCA originated at more than 5 cm from the origin of the IMA. These frequent variations led us to assume that the standardization of LT is very difficult in a context of neoplasm, where the quality of the lymphadenectomy is fundamental.

CONCLUSION

The division branches of the IMA are extremely subject to interindividual variations, making it difficult if not impossible to reproduce identically a surgical procedure based on their anatomy. HT appears to us as the only relevant procedure for colorectal cancer.