Are Metastatic Central Lymph Nodes (D3 volume) in right-sided Colon Cancer a Sign of Systemic Disease? A sub-group Analysis of an Ongoing Multicenter Trial

Abstract

Objective: Assess outcomes of patients with right-sided colon cancer with metastases in the D3 volume after personalized surgery.

Background: Patients with central lymph node metastasis (D3-PNG) are considered to have a systemic disease with a poor prognosis. A 3-dimensional definition of the dissection volume allows the removal of all central nodes.

Materials and methods: D3-PNG includes consecutive patients from an ongoing clinical trial. Patients were stratified into residual disease negative (D3-RDN) and residual disease positive (D3-RDP) groups. D3-RDN was further stratified into 4 periods to identify a learning curve. A personalized D3 volume (defined through arterial origins and venous confluences) was removed " en bloc" through medial-to-lateral dissection, and the D3 volume of the specimen was analyzed separately.

Results: D3-PNG contained 42 (26 females, 63.1 SD 9.9 y) patients, D3-RDN:29 (17 females, 63.4 SD 10.1 y), and D3-RDP:13 (9 females, 62.2 SD 9.7 y). The mean overall survival (OS) days were D3-PNG:1230, D3-RDN:1610, and D3-RDP:460. The mean disease-free survival (DFS) was D3-PNG:1023, D3-RDN:1461, and D3-RDP:74 days. The probability of OS/DFS were D3-PNG:52.1%/50.2%, D3-RDN:72.9%/73.1%, D3-RDP: 7.7%/0%. There is a significant change in OS/DFS in the D3-RDN from 2011-2013 to 2020-2022 (both P =0.046) and from 2014-2016 to 2020-2022 ( P =0.028 and P =0.005, respectively).

Conclusion: Our results indicate that surgery can achieve survival in most patients with central lymph node metastases by removing a personalized and anatomically defined D3 volume. The extent of mesenterectomy and the quality of surgery are paramount since a learning curve has demonstrated significantly improved survival over time despite the low number of patients. These results imply a place for the centralization of this patient group where feasible.

FIGURE 1

Showing composition of D3 volume after extended D3 mesenterectomy. FF: Front flap; BF: Back flap. D1/D2: D1/D2 volume; D3: D3 volume. The picture in the upper left corner shows the D3 volume after dissecting it from the main specimen. The main picture shows the operative area with separate marked D1/D2 volume and D3 volume in relation to the superior mesenteric artery and superior mesenteric vein. *From “Banipal et al. Copyright 2022 by Springer Nature. Reprinted under Creative Commons attribution 4.0 international license.

FIGURE 2

3D segmentation of the D3 volume. A, Mimics 3D mask. B, An axial MIP of the same case. GTH indicates gastrocolic trunk of Henle; ICA, ileocolic artery; ICV, ileocolic vein; IMV, inferior mesenteric vein; IV, ileal vein; JV, jejunal vein; LyNoCo, lymph node conglomerate; LyNo, lymph node; MCA, middle colic artery; MCV, middle colic vein; MIP, maximal intensity projection; RCA, right colic artery.

FIGURE 3

Kaplan Meier curves showing the 5-year overall survival and 5-year disease-free survival. A, Represents the overall survival. B, represents the disease-free survival. D3-RDP indicates residual disease positive; D3-RDN, residual disease negative.

FIGURE 4

Graphical illustration of learning curves in different time periods in relation to 5-year overall survival and 5-year disease-free survival. A, Represents the probability of 5-year overall survival in different time periods. B, Represents the probability of 5-year disease-free survival in different time periods. D3-PNG indicates positive nodes in the D3 volume (Continued line); D3-RDN, residual disease negative (Long dotted line). D3-RDP, residual disease positive (Short dotted line).