Primary tumour immune response and lymph node yields in colon cancer

Lymph node yield as a surrogate marker for tumour biology and prognosis in colon cancer

BACKGROUND

We interrogated two large national databases to explore the underlying mechanisms and institutional effects of the known association of enhanced survival with a higher lymph node yield (LNY) in non-metastatic colon cancer.

METHOD

Clinical and pathological data for stage I-III colon adenocarcinomas were extracted from the CORECT-R (England, 2010-2020) and SEER database (USA, 2000-2020). A lymph node (LN) cut-off for the lack of clinically significant increase in nodal positivity was identified. A multivariable Cox-regression model was developed to study the effect of LNY on overall survival. Furthermore, institutional variations in LNY and their impact on survival were explored.

RESULTS

Patients were retrospectively included from the CORECT-R (n = 84,116) and SEER (n = 287,974) databases. No significant increase in nodal positivity was noted after a LN cut-off of 9. However, improved survival was noted in node-negative and node-positive cancers beyond this cut-off. A 1% risk-reduction concerning overall survival was reported for every node counted. We identified ten outlying institutions across England with an observed LNY greater or less than the expected, with no impact on overall survival.

DISCUSSIONS

We advocate incorporating LNY into patient and clinician discussions as a surrogate marker of tumour biology and prognosis rather than using LNY as a quality indicator.

Optimal lymph node yield for long-term survival in elderly patients with right-sided colon cancer: a large population-based cohort study

BACKGROUND

Although the recommended minimal lymph node yield (LNY) in colon cancer is 12, this standard remains controversial in elderly patients with right-sided colon cancer (RSCC) due to insufficient evidence. This study aims to clarify this issue by assessing the relationship between LNY and long-term survival in elderly patients with RSCC.

METHODS

Data from the SEER database (split into 7:3 training and testing sets) and patients from the colorectal surgery departments of two tertiary hospitals in China (validation set) were analyzed. Elderly patients with stages I-III RSCC undergoing resection were included. The correlation between LNY and overall survival (OS) was evaluated by a multivariate model and the application of the restricted cubic spline curve (RCS). The odds ratios (ORs) for stage migration and the hazard ratios (HRs) for OS with increased LNY were estimated using Locally Weighted Scatterplot Smoothing (LOWESS), with structural breakpoints identified using the Chow test.

RESULTS

The distribution of LNY was similar across the training (median: 18, IQR [14, 23]), testing (median: 18, IQR [14, 23]), and validation (median: 17, IQR [14, 20]) sets. Increasing LNY was associated with significantly improved OS in all datasets (Training set: HR = 0.983; Testing set: HR = 0.981; Validation set: HR = 0.944, all P < 0.001) after adjusting for confounders. Cut-point analysis identified an optimal LNY threshold of 18, validated across datasets, effectively discriminating survival probabilities.

CONCLUSIONS

A higher LNY is associated with improved survival. Our findings robustly support 18 LNYs as the optimal threshold for assessing the quality of lymph node dissection and prognosis stratification in elderly patients with RSCC.

Impact of lymph node metastasis on immune microenvironment and prognosis in colorectal cancer liver metastasis: insights from multiomics profiling

BACKGROUND

This study aimed to investigate the prognostic impact of lymph node metastasis (LNM) on patients with colorectal cancer liver metastasis (CRLM) and elucidate the underlying immune mechanisms using multiomics profiling.

METHODS

We enrolled patients with CRLM from the US Surveillance, Epidemiology, and End Results (SEER) cohort and a multicenter Chinese cohort, integrating bulk RNA sequencing, single-cell RNA sequencing and proteomics data. The cancer-specific survival (CSS) and immune profiles of the tumor-draining lymph nodes (TDLNs), primary tumors and liver metastasis were compared between patients with and without LNM. Pathological evaluations were used to assess immune cell infiltration and histological features.

RESULTS

The CRLM patients with LNM had significantly shorter CSS than patients without LNM in two large cohorts. Our results showed that nonmetastatic TDLNs exhibited a greater abundance of immune cells, including CD4+ T cells, CD8+ T cells, and CD19+ B cells, whereas metastatic TDLNs were enriched with fibroblasts, endothelial cells, and macrophages. Immunohistochemical analysis confirmed elevated levels of CD3+ T cells, CD8+ T cells, and CD19+ B cells in nonmetastatic TDLNs. The presence of nonmetastatic TDLNs was associated with enhanced antitumor immune responses in primary tumors, characterized by a higher Klintrup-Makinen (KM) grade and the presence of tertiary lymphoid structures. Furthermore, liver metastasis in patients with nonmetastatic TDLNs were predominantly of the desmoplastic growth pattern (dHGP), while those with metastatic TDLNs were predominantly of the replacement growth pattern (rHGP).

CONCLUSIONS

This research highlights the adverse prognostic impact of LNM on patients with CRLM and reveals potential related mechanisms through multiomics analysis. Our research paves the way for further refinement of the AJCC TNM staging system for CRLM in clinical practice.

Predicting Regional Lymph Node Metastases at CT in Microsatellite Instability-High Colon Cancer

Background Early identification of lymph node metastasis is crucial for microsatellite instability-high (MSI-H) colon cancer caused by deficient mismatch repair, but accuracy of CT is poor. Purpose To determine whether CT-detected lymph node distribution patterns can improve lymph node evaluation in MSI-H colon cancer. Materials and Methods This two-center retrospective study included patients with MSI-H colon cancer who underwent pretreatment CT and radical surgery (development set, December 2017-December 2022; test set, January 2016-January 2024). Lymph node characteristics associated with pathologic lymph node metastasis (pN+), including clinical lymph node stage (cN) and distribution patterns (vascular distribution, jammed cluster, and partial fusion), were selected (logistic regression and Kendall tau-b correlation) to create a distribution-based clinical lymph node stage (dcN) in the development set. Diagnostic performance was verified in the test set. Interobserver agreement was assessed by using Fleiss κ. Clinical value of dcN was assessed using univariable logistic analysis among patients in the treatment set receiving neoadjuvant immunotherapy (August 2017-February 2024). Results The study included 368 patients (median age, 60 years [IQR, 50-70 years]; 211 male): 230 from the development set (median age, 59 years [IQR, 49-70 years]), 86 from the test set (median age, 66 years [IQR, 55-79 years]), and 52 from the treatment set (median age, 54 years [IQR, 42-65 years]). Only jammed cluster and partial fusion were associated with higher odds of pN+ (odds ratio, 78.9 and 21.5, respectively; both P < .001). dcN outperformed cN in the test set (accuracy, 90% [78 of 87] vs 46% [40 of 87]; P < .001; specificity, 97% [55 of 57] vs 26% [15 of 57]; P < .001). Interobserver agreement was moderate for dcN (κ = 0.67) and poor for cN (κ = 0.48). dcN was associated with a complete response after neoadjuvant immunotherapy (odds ratio, 0.05; P < .001). Conclusion dcN showed high performance for identifying regional lymph node metastases and helped predict complete response after neoadjuvant immunotherapy in MSI-H colon cancer using a surgical reference standard. © RSNA, 2025 Supplemental material is available for this article. See also the editorial by Lev-Cohain and Sosna in this issue.

Prognostic significance of tumor deposit counts in stage III colorectal cancer based on T/N staging and chemotherapy status: A retrospective cohort study

Background

We aimed to evaluate the impact of tumor deposit (TD) count on cancer-specific survival (CSS) and disease-free survival (DFS) in stage III colorectal cancer (CRC) patients stratified by T and N staging, and further explore its impact on chemotherapy effect.

Method

We determined the optimal TD cut-off value for stage III CRC patients from the SEER database utilizing X-tile analysis, and retrospectively analyzed the clinicopathological data of 443 patients from the First Affiliated Hospital of Wenzhou Medical University from 2019 to 2020. Chi-square (χ2) tests compared categorical variables. Kaplan-Meier assessed CSS and DFS. Cox regression model evaluated prognostic factors on CSS and DFS.

Results

2TD is the optimal cutoff value for prognosis in Stage III CRC, in the low-risk group (T1-T3 and N1), ≥3TD patients faced higher cancer-specific mortality (HR = 3.445, 95%CI = 1.254-9.465, P = 0.017) and recurrence risks (HR = 1.934, 95%CI = 1.095-3.416, P = 0.024) vs. 1-2TD, while 1-2TD and no-TD patients showed no difference in survival. In the high-risk group (T4 or N2), both ≥3TD and 1-2TD patients had poor prognosis. Chemotherapy reduced cancer-specific mortality in both groups (1-2TD: HR = 0.347, 95%CI = 0.138-0.870, P = 0.024; ≥3TD: HR = 0.272, 95%CI = 0.077-0.960, P = 0.043) but did not significantly improve recurrence risk (1-2TD: P = 0.177; ≥3TD: P = 0.058).

Conclusion

TD indicates poor prognosis in stage III CRC, with ≥3 TD significantly worsening survival, yet the prognosis remains poor in TD-positive patients with high-risk (T4 or N2) regardless of TD count. Moreover, TD count does not influence chemotherapy's mortality benefit.

Number of Lymph Nodes Examined as a Prognosis Factor in Patients With Stage II or III Colon Cancer

BACKGROUND

Lymph node (LN) examination is important for staging colorectal cancer. Examining < 12 LN has been associated with a poor prognosis. However, surgical and pathological advances have led to increase examined LN, necessitating the reassessment of the best cutoff for prognosis.

PATIENTS AND METHODS

We reviewed patients with stage II-III colon cancer from the Yonsei Cancer Center Registry (YCC) database and the Netherlands Cancer Registry (NCR). The optimal LN cutoff was determined by comparison with hazard ratio (HR) in 12 LN. We compared higher vs. lower LN cutoff effects on a 6-year overall survival (OS).

RESULTS

From 2005 to 2015, the proportion with < 12 LN decreased significantly (P < .001). There was no significant association between 6-year OS and LN yield in all stages II-III patients (HR = 1.21, P = .116), stage II (HR = 1.39, P = .068), and stage III (HR = 1.18, P = .297) colon cancer based on the standard 12 LN examined, whereas the 20 LN cutoff examined was associated with a significant increase in 6-year OS in all patients (HR = 1.51, P < .001). Multivariate regression revealed a significant decrease in 6-year OS in stage II (HR = 1.39, P = .026) and stage III (HR = 1.47, P < .001) with < 20 LN yield. In the NCR, < 20 LN was associated with poorer 6-year OS in stage II-III patients (HR = 1.25, P < .001), stage II (HR = 1.43, P < .001), and stage III (HR = 1.13, P = .007).

CONCLUSION

Over the past decade, inadequate LN examinations have significantly decreased. Compared to < 12 LN, < 20 LN examined is more associated with a worse prognosis in patients who underwent surgery.

Beta-2-microglobulin positive tumor cells and CD8 positive lymphocytes are associated with outcome in post-neoadjuvant colorectal cancer resections

Locally advanced colorectal cancers are treated with neoadjuvant therapy (NAT), which has been shown to alter the characteristics of the tumor including size, lymph node yield, and histologic grade. We seek to interrogate the effect of NAT on the immune microenvironment. We compared 190 patients with colorectal adenocarcinoma treated with NAT with those without NAT (n = 926). We evaluated clinicopathologic and molecular factors and performed immunohistochemistry and quantification on tissue microarrays for HLA class I/II proteins, beta-2-microglobulin (B2M), CD8, CD163, LAG3, PD-L1, and FoxP3. Patients in the NAT group were younger (60.9 vs 67.9, p < 0.001) and more often male (59.5 vs. 47.9, p = 0.004) than those in the non-NAT group. Tumors in the NAT group were smaller (3.5 vs 4.7 cm, p < 0.001), less often high grade (6.5% vs. 16.2%, p = 0.001), more frequently in the rectum (68.9% vs. 6.6%, p < 0.001) and associated with lower lymph node yields (p = 0.002); however, the incidence of extramural venous invasion, perineural invasion, and AJCC stage 3-4 disease were not different. Immune cells positive for CD8 (p = 0.011) were significantly lower in the NAT group. A high number of CD8+ cells and higher expression of B2M in tumor cells showed a significant survival benefit in both NAT and non-NAT group. NAT is associated with an immune-low tumor environment. CD8+ cells and tumor B2M expression may help identify a subset of immune high-tumors following NAT. This identification could aid in determining patients who may benefit from conservative management of colorectal carcinomas.

Lymph Node Yield and Long-Term Mortality Risk in Patients with Colon Cancer: A 20-Year Follow-Up National Study

BACKGROUND

Lymph node status is a well-established prognostic factor for colon cancer, but the optimal number of nodes for accurate staging remains unclear. This study explored the relationship between lymph node yield (LNY) and 5-year mortality rates in colon cancer patients in New Zealand.

METHODS

Data from the New Zealand Cancer Registry were retrospectively analyzed for patients with TNM stage I, II, and III colon cancer between August 2003 and December 2021, with follow-up until January 2024. The primary outcome was the 5-year all-cause mortality rate, with LNY, age, sex, ethnicity, tumor site, district health board (DHB), and the number of positive nodes as covariates. Statistical analyses included univariate analysis, Cox regression modeling, and chi-squared tests.

RESULTS

LNY was a significant predictor of 5-year mortality risk (hazard ratio 0.985, p < 0.0001), adjusted for age, sex, ethnicity, tumor site, and DHB. The strongest association between LNY and mortality rate was observed at 12 nodes. Further increases in LNY beyond 22 nodes did not lead to statistically significant differences in mortality rates. Lymph node ratio (LNR) was strongly associated with survival in stage III colon cancer, independent of LNY and the number of positive nodes.

CONCLUSIONS

Higher LNY is significantly associated with reduced 5-year mortality rates in stage I-III colon cancer up to the 22-node mark. The strong correlation between LNR and mortality highlights its potential value for improving treatment planning in future clinical practice.

Enhanced Proteomic Coverage in Tissue Microenvironment by Immune Cell Subtype Library-Assisted DIA-MS

Immune cells that infiltrate the tumor microenvironment (TME) play crucial roles in shaping cancer development and influencing clinical outcomes and therapeutic responses. However, obtaining a comprehensive proteomic snapshot of tumor-infiltrating immunity in clinical specimens is often hindered by small sample amounts and a low proportion of immune infiltrating cells in the TME. To enable in-depth and highly sensitive profiling of microscale tissues, we established an immune cell-enriched library-assisted strategy for data-independent acquisition mass spectrometry (DIA-MS). Firstly, six immune cell subtype-specific spectral libraries were established from sorted cluster of differentiation markers, CD8+, CD4+ T lymphocytes, B lymphocytes, natural killer cells, dendritic cells, and macrophages in murine mesenteric lymph nodes (MLNs), covering 7815 protein groups with surface markers and immune cell-enriched proteins. The feasibility of microscale immune proteomic profiling was demonstrated on 1 μg tissue protein from the tumor of murine colorectal cancer (CRC) models using single-shot DIA; the immune cell-enriched library increased coverage to quantify 7419 proteins compared to directDIA analysis (6978 proteins). The enhancement enabled the mapping of 841 immune function-related proteins and exclusive identification of many low-abundance immune proteins, such as CD1D1, and CD244, demonstrating high sensitivity for immune landscape profiling. This approach was used to characterize the MLNs in CRC models, aiming to elucidate the mechanism underlying their involvement in cancer development within the TME. Even with a low percentage of immune cell infiltration (0.25-3%) in the tumor, our results illuminate downregulation in the adaptive immune signaling pathways (such as C-type lectin receptor signaling, and chemokine signaling), T cell receptor signaling, and Th1/Th2/Th17 cell differentiation, suggesting an immunosuppressive status in MLNs of CRC model. The DIA approach using the immune cell-enriched libraries showcased deep coverage and high sensitivity that can facilitate illumination of the immune proteomic landscape for microscale samples.

Prognostic and predictive value of examined lymph node count in stage III colorectal cancer: a population based study

BACKGROUND

The role of tumor-draining lymph nodes in the progression of malignant tumors, including stage III colorectal cancer (CRC), is critical. However, the prognostic and predictive value of the number of examined lymph nodes (ELNs) are not fully understood.

METHODS

This population-based study retrospectively analyzed data from 106,843 patients with stage III CRC who underwent surgical treatment and registered in three databases from 2004 to 2021. The Surveillance, Epidemiology, and End Results (SEER) cohort was divided using into training and test cohorts at a ratio of 3:2. We employed restricted cubic spline (RCS) curves to explore nonlinear relationships between overall survival (OS) and ELNs counts and performed Cox regression to evaluate hazard ratios across different ELNs count subtypes. Additional validation cohorts were utilized from the First Affiliated Hospital, Sun Yat-sen University and The Cancer Genome Atlas (TCGA) under the same criteria. Outcomes measured included OS, cancer-specific survival (CSS), and progression-free survival (PFS). Molecular analyses involved differential gene expression using the "limma" package and immune profiling through CIBERSORT. Tissue microarray slides and multiplex immunofluorescence (MIF) were used to assess protein expression and immune cell infiltration.

RESULTS

Patients with higher ELNs counts (≥ 17) demonstrated significantly better long-term survival outcomes across all cohorts. Enhanced OS, CSS, and PFS were notably evident in the LN-ELN group compared to those with fewer ELNs. Cox regression models underscored the prognostic value of higher ELNs counts across different patient subgroups by age, sex, tumor differentiation, and TNM stages. Subtype analysis based on ELNs count revealed a marked survival benefit in patients treated with adjuvant chemotherapy in the medium and large ELNs counts (≥ 12), whereas those with fewer ELNs showed negligible benefits. RNA sequencing and MIF indicated elevated immune activation in the LN-ELN group, characterized by increased CD3+, CD4+, and CD8 + T cells within the tumor microenvironment.

CONCLUSIONS

The number of ELNs independently predicts survival and the immunological landscape at the tumor site in stage III CRC, underscoring its dual prognostic and predictive value.

Identification of ROS and KEAP1-related genes and verified targets of α-hederin induce cell death for CRC

In this study, we analyzed and verified differentially expressed genes (DEGs) in ROS and KEAP1 crosstalk in oncogenic signatures using GEO data sets (GSE4107 and GSE41328). Multiple pathway enrichment analyses were finished based on DEGs. The genetic signature for colorectal adenocarcinoma (COAD) was identified by using the Cox regression analysis. Kaplan-Meier survival and receiver operating characteristic curve analysis were used to explore the prognosis value of specific genes in COAD. The potential immune signatures and drug sensitivity prediction were also analyzed. Promising small-molecule agents were identified and predicted targets of α-hederin in SuperPred were validated by molecular docking. Also, expression levels of genes and Western blot analysis were conducted. In total, 48 genes were identified as DEGs, and the hub genes such as COL1A1, CXCL12, COL1A2, FN1, CAV1, TIMP3, and IGFBP7 were identified. The ROS and KEAP1-associated gene signatures comprised of hub key genes were developed for predicting the prognosis and evaluating the immune cell responses and immune infiltration in COAD. α-hederin, a potential anti-colorectal cancer (CRC) agent, was found to enhance the sensitivity of HCT116 cells, regulate CAV1 and COL1A1, and decrease KEAP1, Nrf2, and HO-1 expression significantly. KEAP1-related genes could be an essential mediator of ROS in CRC, and KEAP1-associated genes were effective in predicting prognosis and evaluating individualized CRC treatment. Therefore, α-hederin may be an effective chemosensitizer for CRC treatments in clinical settings.

The genomics of sporadic and hereditary colorectal cancer

Colorectal cancer (CRC) is a leading cause of cancer deaths worldwide. Over the past three decades, extensive efforts have sought to elucidate the genomic landscape of CRC. These studies reveal that CRC is highly heterogeneous at the molecular level, with different subtypes characterised by distinct somatic mutational profiles, epigenetic aberrations and transcriptomic signatures. This review summarises our current understanding of the genomic and epigenomic alterations implicated in CRC development and progression. Particular focus is given to how characterisation of CRC genomes is leading to more personalised approaches to diagnosis and treatment.

Variation in Lymph Node Assessment for Colon Cancer at the Tumor, Surgeon, and Hospital Level

BACKGROUND

We hypothesized that tumor- and hospital-level factors, compared with surgeon characteristics, are associated with the majority of variation in the 12 or more lymph nodes (LNs) examined quality standard for resected colon cancer.

STUDY DESIGN

A dataset containing an anonymized surgeon identifier was obtained from the National Cancer Database for stage I to III colon cancers from 2010 to 2017. Multilevel logistic regression models were built to assign a proportion of variance in achievement of the 12 LNs standard among the following: (1) tumor factors (demographic and pathologic characteristics), (2) surgeon factors (volume, approach, and margin status), and (3) facility factors (volume and facility type).

RESULTS

There were 283,192 unique patient records with 15,358 unique surgeons across 1,258 facilities in our cohort. Achievement of the 12 LNs standard was high (90.3%). Achievement of the 12 LNs standard by surgeon volume was 88.1% and 90.7% in the lowest and highest quartiles, and 86.8% and 91.6% at the facility level for high and low annual volume quartiles, respectively. In multivariate analysis, the following tumor factors were associated with meeting the 12 LNs standard: age, sex, primary tumor site, tumor grade, T stage, and comorbidities (all p < 0.001). Tumor factors were responsible for 71% of the variation in 12 LNs yield, whereas surgeon and facility characteristics contributed 17% and 12%, respectively.

CONCLUSIONS

Twenty-nine percent of the variation in the 12 LNs standard is linked to modifiable factors. The majority of variation in this quality metric is associated with non-modifiable tumor-level factors.

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

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.

Complete mesocolic excision for colon cancer: current status and controversies

According to Hohenberger's original description, complete mesocolic excision for colon cancer involves precise dissection of the avascular embryonic plane between the parietal retroperitoneum and visceral peritoneum of the mesocolon. This ensures mesocolic integrity, access to high ligation of the supplying vessels at their origin and an associated extended lymphadenectomy. Results from centres which have adopted this approach routinely have demonstrated that oncological outcomes can be improved by the rigorous implementation of established principles of cancer surgery. Meticulous anatomical dissection along embryonic planes is a well-established principle of precision cancer surgery used routinely by the specialist colorectal surgeon. Therefore, the real question concerns the need for true central vascular ligation and associated extended (D3) lymphadenectomy or otherwise, particularly along the superior mesenteric vessels when performing a right colectomy. Whether this approach results in improved overall or disease-free survival remains unclear and its role remains controversial particularly given the potential for significant morbidity associated with a more extensive central vascular dissection. Current literature is limited by considerable bias, as well as inconsistent and variable terminology, and the results of established randomized trials are awaited. As a result of the current state of equipoise, various national guidelines have disparate recommendations as to when complete mesocolic excision should be performed if at all. This article aims to review the rationale for and technical aspects of complete mesocolic excision, summarize available short and long term outcome data and address current controversies.

Complete mesocolic excision for right colon cancer: Is D3 lymphadenectomy necessary?

AIM

Although complete mesocolic excision (CME) for colon cancer is oncologically sound, to date, there has been no consensus on the extent of lymphadenectomy in radical right colectomy. This study essentially compared the perioperative and survival outcomes of CME with two templates of lymphadenectomy for right colon cancer.

METHOD

This was a propensity matched, retrospective analysis of a single centre, prospectively maintained database of all patients undergoing elective right colectomy for nonmetastatic, biopsy-proven adenocarcinoma from November 2013 to October 2018. CME + D3 was adopted selectively, documented prospectively, and compared with patients undergoing CME + central vascular ligation (CVL). The only technical difference between the groups was the excision of the surgical trunk of Gillot in the CME + D3 group. Postoperative, long-term outcomes and patterns of recurrence were compared between the groups.

RESULTS

Of the 244 eligible patients, 88 (36.1%) and 156 (63.9%) underwent CME + D3 and CME + CVL, respectively. Matched groups (72 [CME + D3] vs. 108 [CME + CVL]) showed no difference in histology, tumour grade, postoperative complications, mortality, and hospital stay. CME + D3 was preferentially performed laparoscopically (35.2% vs. 9%), was associated with lower blood loss (215 mL vs. 297 mL, p = 0.001), higher nodal yield (31 vs. 25 nodes, p = 0.003) and a higher incidence of chyle leak (4 vs. 0, p = 0.013). At a median follow-up of more than 57 months, there was no significant difference in local recurrence, disease-free or overall survival.

CONCLUSION

In this retrospective study, lymphadenectomy along the superior mesenteric vein, as a component of CME for right colon cancer, offered a higher nodal yield with no improvement in oncological outcome. Dissection of the SMV, over and above a D2 dissection, could therefore be restricted to specialized colorectal units until further studies establish the incremental oncological benefit of this extended lymphadenectomy or define a patient group in whom it is beneficial.

Inadequate Lymph Node Yield: An Inadequate Indication for Adjuvant Chemotherapy in Stage II Colon Cancer

Background

Optimal therapy for stage II colon cancer remains unclear, and national guidelines recommend "consideration" of adjuvant chemotherapy (ACT) in the presence of high-risk features, including inadequate lymph node yield (LNY, <12 nodes). This study aims to determine whether the survival benefit of ACT in stage II disease varies based on the adequacy of LNY.

Methods

We used the National Cancer Database (NCDB) to identify adults who underwent resection for a single primary T3 or T4 colon cancer between 2006 and 2018. Multivariable logistic regression tested for associations between ACT and prespecified demographic and clinical characteristics, including the adequacy of LNY. We used Cox proportional hazards models to assess overall survival and restricted cubic splines to estimate the optimal LNY threshold to dichotomize patients based on overall survival.

Results

Unadjusted 5- and 10-year survival rates were 84% and 75%, respectively, among patients who received ACT and 70% and 50% among patients who did not (log-rank P < 0.01). Inadequate LNY was independently associated with both receipt of ACT (odds ratios, 1.50; P < 0.01) and decreased overall survival [hazard ratio (HR), 1.56; P < 0.01]. ACT was independently associated with improved survival (HR, 0.67; P < 0.01); this effect size did not change based on the adequacy of LNY (interaction P = 0.41). Results were robust to re-analysis with our cohort-optimized threshold of 18 lymph nodes.

Conclusions

Consistent with contemporary guidelines, patients with inadequate LNY are more likely to receive ACT. LNY adequacy is an independent prognostic factor but, in isolation, should not dictate whether patients receive ACT.

Surgical management strategies for colorectal malignancies of the splenic flexure - A systematic review and network meta-analysis

BACKGROUND

Extended right hemicolectomy (ERHC) or left hemicolectomy (LHC) are accepted as the standard-of-care for colonic tumours of the splenic flexure. Lymphatic drainage at this site is poorly defined and subject to significant heterogeneity. Nevertheless, emerging evidence demonstrates the potential oncological safety of segmental splenic flexure colectomy (SFC).

AIM

To perform a systematic review and network meta-analysis (NMA) to compare outcomes following ERHC, LHC and SFC for splenic flexure tumours (SFTs).

METHODS

A systematic review was performed as per PRISMA guidelines. NMA was performed using R Shiny and Netmeta packages.

RESULTS

A total of 13 studies, involving 6176 patients (ERHC n = 785; LHC n = 1527; SFC n = 3864) were included in the NMA. There was no difference in overall survival (OS) (SFC vs LHC Hazard Ratio [HR] 1.0, 95% Credible Interval [CrI] 0.76,1.34; SFC vs ERHC HR 1.18, 95% CrI 0.85,1.58) between the groups. SFC had a shorter operation time (Mean 176.37 min; Mean Difference [MD] SFC vs LHC 20.34 min 95% CrI 10.9, 29.97; SFC vs ERHC MD 22.19 95% CrI 11.09, 33.29) but also had a lower average lymph node yield (LNY) compared with ERHC (MD 7.15, 95% CrI 5.71, 8.60). ERHC had a significantly higher incidence of post-operative ileus (Odds Ratio [OR] 3.47, 95% CrI 1.11, 10.84). There was also no difference observed for minimally invasive approaches, anastomotic leak rate, perioperative mortality, reoperation rates or length of stay.

CONCLUSIONS

While SFC may allow for reduced operative duration and improved bowel function postoperatively. SFC, LHC, ERHC are all acceptable approaches for curative resection of cancers of the splenic flexure, with no difference in OS observed. Thus, surgeon preference and candidate-specific factors will likely determine the management of SFTs.

Preoperative contrast-enhanced CT imaging and clinicopathological characteristics analysis of mismatch repair-deficient colorectal cancer

BACKGROUND

Colorectal cancer (CRC) can develop through various pathogenetic pathways, and one of the primary pathways is high microsatellite instability (MSI-H)/deficient mismatch repair (dMMR). This study investigated the correlation between preoperative contrast-enhanced CT (CECT) and clinicopathologic characteristics of colorectal cancer (CRC) according to different mismatch repair (MMR) statuses.

METHODS

From April 2021 to July 2022, a total of 281 CRC patients with preoperative CECT and available MMR status were enrolled from a single centre for this retrospective study. Preoperative CECT features and clinicopathologic characteristics were analysed. Univariate and multivariate logistic regression analyses were used for statistical analysis. A nomogram was established based on the multivariate logistic regression results. Preoperative and postoperative dynamic nomogram prediction models were established. The C-index, a calibration plot, and clinical applicability of the two models were evaluated, and internal validation was performed using three methods.

RESULTS

In total, 249 patients were enrolled in the proficient mismatch repair (pMMR) group and 32 patients in the deficient mismatch repair (dMMR) group. In multivariate analysis, tumour location (right-hemi colon vs. left-hemi colon, odds ratio (OR) = 2.90, p = .036), the hypoattenuation-within-tumour ratio (HR) (HR > 2/3 vs. HR < 1/3, OR = 36.7, p < .001; HR 1/3-2/3 vs. HR < 1/3, OR = 6.05, p = .031), the number of lymph nodes with long diameter ≥ 8 mm on CECT (OR = 1.32, p = .01), CEA status (CEA positive vs. CEA negative, OR = 0.07, p = .002) and lymph node metastasis (OR = 0.45, p = .008) were independent risk factors for dMMR. Pre- and postoperative C-statistic were 0.861 and 0.908, respectively.

CONCLUSION

The combination of pre-operative CECT and clinicopathological characteristics of CRC correlates with MMR status, providing possible non-invasive MMR prediction. Particularly for dMMR CRC, tumour-draining lymph node status should be prudently evaluated by CECT.

Clinical Effectiveness of Fluorescence Lymph Node Mapping Using ICG for Laparoscopic Right Hemicolectomy: A Prospective Case-Control Study

BACKGROUND

The distinction between D3 lymph nodes and actual lymphatic pathways in primary tumors can be difficult during surgery, making it challenging to confirm the completeness of D3 lymph node dissection. Fluorescence lymph node mapping (FLNM) is a promising method for lymph node visualization.

PURPOSE

This study aimed to assess whether FLNM enhances the effectiveness of D3 lymph node dissection in patients with right-sided colon cancer.

METHODS

Endoscopic submucosal indocyanine green injection were performed on the distal margin of the colon cancer. In an FLNM group, the lymphatic drainage pathway and distribution of D3 lymph nodes were explored. Pathological evaluations were conducted for the fluorescent D3 and non-fluorescent D3 lymph nodes.

RESULTS

The FLNM group showed a significantly higher number of harvested lymph nodes in the D3 area. In stage III patients, the proportion of D3 lymph node metastasis was significantly higher in the FLNM group. The harvested D3 lymph node count showed a proportional correlation with a metastatic lymph node count of up to 15.

CONCLUSION

FLNM could be considered a promising new strategy to potentially increase harvested D3 lymph node counts in colon cancer surgery.

Immune microenvironment and lymph node yield in colorectal cancer

BACKGROUND

Lymph node (LN) harvesting is associated with outcomes in colonic cancer. We sought to interrogate whether a distinctive immune milieu of the primary tumour is associated with LN yield.

METHODS

A total of 926 treatment-naive patients with colorectal adenocarcinoma with more than 12 LNs (LN-high) were compared with patients with 12 or fewer LNs (LN-low). We performed immunohistochemistry and quantification on tissue microarrays for HLA class I/II proteins, beta-2-microglobulin (B2MG), CD8, CD163, LAG3, PD-L1, FoxP3, and BRAF V600E.

RESULTS

The LN-high group was comprised of younger patients, longer resections, larger tumours, right-sided location, and tumours with deficient mismatch repair (dMMR). The tumour microenvironment showed higher CD8+ cells infiltration and B2MG expression on tumour cells in the LN-high group compared to the LN-low group. The estimated mean disease-specific survival was higher in the LN-high group than LN-low group. On multivariate analysis for prognosis, LN yield, CD8+ cells, extramural venous invasion, perineural invasion, and AJCC stage were independent prognostic factors.

CONCLUSION

Our findings corroborate that higher LN yield is associated with a survival benefit. LN yield is associated with an immune high microenvironment, suggesting that tumour immune milieu influences the LN yield.

The Impact of Age in the Treatment of Non-comorbid Patients with Rectal Cancer: Survival Outcomes from the National Cancer Database

BACKGROUND

Multimodal therapy has improved survival outcomes for rectal cancer (RC) significantly with an exemption for older patients. We sought to assess whether older non-comorbid patients receive substandard oncological treatment for localized RC referring to the National Comprehensive Cancer Network (NCCN) guidelines and whether it affects survival outcomes.

METHODS

This is a retrospective study using patient data from the National Cancer Data Base (NCDB) for histologically confirmed RC from 2002 to 2014. Non-comorbid patients between ≥50 and ≤85 years and defined treatment for localized RC were included and assigned to a younger (<75 years) and an older group (≥75 years). Treatment approaches and their impact on relative survival (RS) were analyzed using loess regression models and compared between both groups. Furthermore, mediation analysis was performed to measure the independent relative effect on age and other variables on RS. Data were assessed using the Strengthening the Reporting of Observational studies in Epidemiology (STROBE) checklist.

RESULTS

Of 59,769 included patients, 48,389 (81.0%) were assigned to the younger group (<75 years). Oncologic resection was performed in 79.6% of the younger patients compared to 67.2% of the older patients (p < 0.001). Chemotherapy (74.3% vs. 56.1%) and radiotherapy (72.0% vs. 58.1%) were provided less often in older patients, respectively (p < 0.001). Increasing age was associated with enhanced 30- and 90-day mortality with 0.6% and 1.1% in the younger and 2.0% and 4.1% in the elderly group (p < 0.001) and worse RS rates [multivariable adjusted HR: 1.93 (95% CI 1.87-2.00), p < 0.001]. Adherence to standard oncological therapy resulted in a significant increase in 5-year RS (multivariable adjusted HR: 0.80 (95% CI 0.74-0.86), p < 0.001). Mediation analysis revealed that RS was mainly affected by age itself (84%) rather than the choice of therapy.

CONCLUSIONS

The likelihood to receive substandard oncological therapy increases in the older population and negatively affects RS. Since age itself has a major impact on RS, better patient selection should be performed to identify those that are potentially eligible for standard oncological care regardless of their age.

Comparing minimally invasive surgical and open approaches to pelvic exenteration for locally advanced or recurrent pelvic malignancies - Systematic review and meta-analysis

INTRODUCTION

Pelvic exenteration (PE) is a complex multivisceral surgical procedure indicated for locally advanced or recurrent pelvic malignancies. It poses significant technical challenges which account for the high risk of morbidity and mortality associated with the procedure. Developments in minimally invasive surgical (MIS) approaches and enhanced peri-operative care have facilitated improved long term outcomes. However, the optimum approach to PE remains controversial.

METHODS

A systematic literature search was conducted in accordance with PRISMA guidelines to identify studies comparing MIS (robotic or laparoscopic) approaches for PE versus the open approach for patients with locally advanced or recurrent pelvic malignancies. The methodological quality of the included studies was assessed systematically and a meta-analysis was conducted.

RESULTS

11 studies were identified, including 2009 patients, of whom 264 (13.1%) underwent MIS PE approaches. The MIS group displayed comparable R0 resections (Risk Ratio [RR] 1.02, 95% Confidence Interval [95% CI] 0.98, 1.07, p = 0.35)) and Lymph node yield (Weighted Mean Difference [WMD] 1.42, 95% CI -0.58, 3.43, p = 0.16), and although MIS had a trend towards improved towards improved survival and recurrence outcomes, this did not reach statistical significance. MIS was associated with prolonged operating times (WMD 67.93, 95% CI 4.43, 131.42, p < 0.00001) however, this correlated with less intra-operative blood loss, and a shorter length of post-operative stay (WMD -3.89, 955 CI -6.53, -1.25, p < 0.00001). Readmission rates were higher with MIS (RR 2.11, 95% CI 1.11, 4.02, p = 0.02), however, rates of pelvic abscess/sepsis were decreased (RR 0.45, 95% CI 0.21, 0.95, p = 0.04), and there was no difference in overall, major, or specific morbidity and mortality.

CONCLUSION

MIS approaches are a safe and feasible option for PE, with no differences in survival or recurrence outcomes compared to the open approach. MIS also reduced the length of post-operative stay and decreased blood loss, offset by increased operating time.

The effect of preoperative endoscopic tattooing using India ink on lymph node yield in laparoscopic colectomy for stage I right-sided colon cancer

PURPOSE

The purpose of this study is to evaluate the effect of preoperative endoscopic tattooing using India ink (ETI) on the number of retrieved lymph nodes (LNs) dissected during laparoscopic surgery for stage I right-sided colon cancer (RCC).

METHODS

This single-center, retrospective study included stage I RCC patients who underwent laparoscopic surgery between January 2010 and December 2021. The clinicopathological background and number of LNs retrieved were compared between patients managed with and without ETI. A multiple linear regression analysis was used to examine the effect of independent variables on the LN yield.

RESULTS

A total of 169 patients were enrolled. Of these, 89 patients (52.7%) were classified into the ETI group, and 80 (47.3%) were classified into the no-ETI group. There were no significant differences in age, sex, body mass index, or tumor progression between the two groups. A univariate analysis showed that the number of LNs retrieved was significantly higher in female (26 vs. 24, p = 0.026), with tumor localization in the ascending or transverse colon (20 in the cecum, 26 in the ascending colon, 27 in the transverse colon, p < 0.001), and with preoperative ETI (28 vs. 21, p < 0.001). In a multivariate linear regression analysis, female sex (p = 0.0011), D3 lymphadenectomy (p = 0.046), and preoperative ETI (p = 0.012) were independently associated with the LN yield.

CONCLUSION

In laparoscopic surgery for stage I RCC, preoperative ETI increased the number of LNs retrieved and allowed for appropriate staging.

Do differences in surgical quality account for the higher rate of R1 margins to lymph node metastases in right- versus left-sided Stage III colon cancer: A retrospective cohort study

AIM

Microscopically positive (R1) margins to lymph node metastases (R1LNM) are associated with poorer oncological outcomes in patients with Stage III colon cancer. R1LNM margins are more common in right-sided cancer, although the cause of this phenomenon is unknown. We sought to investigate whether differences in surgical quality account for the higher rate of R1LNM in right-sided cancers.

METHOD

Patients treated for Stage III colon cancer from 1 January 2016 to 31 December 2018 were identified using the Danish national cancer registry. Indicators of surgical quality (mesocolic resection grade, median lymph node yield, and length to the distal colonic margin) were compared according to tumour site and margin status.

RESULTS

In all, 1765 patients were included, 981 (55.6%) with right-sided cancers. R1LNM margins were more common in right-sided cancers (14.4% vs. 6.1%, P < 0.001). All three surgical quality indicators were higher in patients with right-sided cancers (mesocolic resection planes 81.7% vs. 69.5%, P < 0.001; median lymph node yield 28 vs. 25, P < 0.001; ≥5 cm to the distal colon margin 81.2% vs. 53.6%, P < 0.001). When stratified according to margin status, no differences in mesocolic resection planes or resectate length were noted, whilst median lymph node yield was higher in patients with R1LNM margins (29 vs. 27, P = 0.009).

CONCLUSION

Surgical quality does not appear to be poorer in patients undergoing surgery for right-sided versus left-sided colon cancers in Denmark. Suboptimal surgery does not appear to be responsible for R1LNM margins, implying that these margins may be a surrogate for more aggressive biology.

Assessment of Updated Commission on Cancer Guidelines for Intraoperative Lymph Node Sampling in Early Stage NSCLC

INTRODUCTION

The American College of Surgeons Commission on Cancer recently updated its sampling recommendations for early stage NSCLC from at least 10 lymph nodes to at least one N1 (hilar) and three N2 (mediastinal) lymph node stations. Nevertheless, intraoperative lymph node sampling minimums remain subject to debate. We sought to evaluate these guidelines in patients with early stage NSCLC.

METHODS

We performed a cohort study using a uniquely compiled data set from the Veterans Health Administration. We manually abstracted data from operative notes and pathology reports of patients with clinical stage I NSCLC receiving surgery (2006-2016). Adequacy of lymph node sampling was defined using count-based (≥10 lymph nodes) and station-based (≥three N2 and one N1 nodal stations) minimums. Our primary outcome was recurrence-free survival. Secondary outcomes were overall survival and pathologic upstaging.

RESULTS

The study included 9749 patients. Count-based and station-based sampling guidelines were achieved in 3302 (33.9%) and 2559 patients (26.3%), respectively, with adherence to either sampling guideline increasing over time from 35.6% (2006) to 49.1% (2016). Adherence to station-based sampling was associated with improved recurrence-free survival (multivariable-adjusted hazard ratio = 0.815, 95% confidence interval: 0.667-0.994, p = 0.04), whereas adherence to count-based sampling was not (adjusted hazard ratio = 0.904, 95% confidence interval: 0.757-1.078, p = 0.26). Adherence to either station-based or count-based guidelines was associated with improved overall survival and higher likelihood of pathologic upstaging.

CONCLUSIONS

Our study supports station-based sampling minimums (≥three N2 and one N1 nodal stations) for early stage NSCLC; however, the marginal benefit compared with count-based guidelines is minimal. Further efforts to promote widespread adherence to intraoperative lymph node sampling minimums are critical for improving patient outcomes after curative-intent lung cancer resection.

Comparing 5-Year Survival Rates Before and After Re-stratification of Stage I-III Right-Sided Colon Cancer Patients by Establishing the Presence/Absence of Occult Tumor Cells and Lymph Node Metastases in the Different Levels of Surgical Dissection

BACKGROUND

To establish the impact of re-stratification on the outcomes of patients (stage I-III right-sided colon cancer) based on the presence/absence of occult tumor cells (OTC) and/or metastatic lymph nodes in the different levels of surgical dissection.

METHODS

Consecutive patients were drawn from a multicenter prospective trial. After surgery, the surgical specimen was divided into the D1/D2 and D3 volumes before being further analyzed separately. All lymph nodes were examined with cytokeratin CAM 5.2 immunohistochemically. Lymph nodes containing metastases and OTC (micrometastases; isolated tumor cells) were identified. Re-stratification was as follows: RS1, stages I/II, no OTC in D1/D2 and D3 volumes; RS2, stages I/II, OTC in D1/D2 and/or D3; RS3, stage III, lymph node metastases in D1/D2, with/without OTC in D3; RS4, stage III, lymph node metastases in D3, with/without OTC in D3.

RESULTS

Eighty-seven patients (39 men, 68.4 + 9.9 years) were included. The standard stratified (SS) group contained the following: stages I/II (SS1) 57 patients; stage III (SS2) 30 patients. Re-stratified (RS) contained RS1 (38), RS2 (19), RS3 (24), and RS4 (6) patients. Lymph node ratio (OTC) RS2: 0.157 D1/D2; 0.035 D3 and 0.092 complete specimens. Lymph node ratio RS3: 0.113 D1/D2; complete specimen 0.056. Overall survival and disease-free survival were p = 0.875 and p = 0.049 for SS and p = 0.144 and p = 0.001 for RS groups, respectively.

CONCLUSION

This re-stratification identifies a patient group with poor prognosis (RS4). Removing this group from SS2 eliminates all the differences in survival between RS2 and RS3 groups. The level of dissection of the affected nodes may have an impact on survival.

CLINICAL TRIAL

"Safe Radical D3 Right Hemicolectomy for Cancer through Preoperative Biphasic Multi-Detector Computed Tomography (MDCT) Angiography" registered at http://clinicaltrials.gov/ct2/show/NCT01351714.

Circulating Lymphocytes Reflect the Local Immune Response in Patients with Colorectal Carcinoma

Tumor-infiltrating lymphocytes (TILs) correlate with the number and size of the surrounding lymph nodes in patients with colorectal carcinoma (CRC) and reflect the quality of the antitumor immune response. In this prospective study, we analyzed whether this response correlated with the circulating lymphocytes in peripheral blood (PB). In 47 patients with newly diagnosed CRC, flow cytometry was performed to analyze the B cells, T cells, NK cells, and a variety of their subsets in PB. The results were correlated with TILs in the resected tumor and with the number and size of the surrounding lymph nodes in nodal negative (N- patients (LN5: number of lymph nodes measuring ≥5 mm) and the metastasis-to-lymph node size ratio (MSR) in nodal positive patients (N+). Differences between the number of TILs could be seen between N+ and N- patients, dependent on the LN5 and MSR categories, with higher values in N- cases and in patients with a higher LN5 category or a lower MSR. Additionally, higher values of various circulating lymphocyte subgroups were observed in these patients. For the total PB lymphocytes, CD8 cells, and some of their subgroups, a positive correlation with the TILs was found. This study shows that circulating lymphocytes—in particular, cytotoxic T cells—correlate with the local antitumor immune response displayed by TILs and lymph node activation. Our findings indicate that local and generalized antitumor immune responses are concordant with their different components.