Outcomes of right-sided and left-sided colon cancer after curative resection

Dysbiosis promotes recurrence of adenomatous polyps in the distal colorectum

BACKGROUND

Colorectal polyps, which are characterized by a high recurrence rate, represent preneoplastic conditions of the intestine. Due to unclear mechanisms of pathogenesis, first-line therapies for non-hereditary recurrent colorectal polyps are limited to endoscopic resection. Although recent studies suggest a mechanistic link between intestinal dysbiosis and polyps, the exact compositions and roles of bacteria in the mucosa around the lesions, rather than feces, remain unsettled.

AIM

To clarify the composition and diversity of bacteria in the mucosa surrounding or 10 cm distal to recurrent intestinal polyps.

METHODS

Mucosal samples were collected from four patients consistently with adenomatous polyps (Ade), seven consistently with non-Ade (Pol), ten with current Pol but previous Ade, and six healthy individuals, and bacterial patterns were evaluated by 16S rDNA sequencing. Linear discriminant analysis and Student's t-tests were used to identify the genus-level bacteria differences between groups with different colorectal polyp phenotypes. Pearson's correlation coefficients were used to evaluate the correlation between intestinal bacteria at the genus level and clinical indicators.

RESULTS

The results confirmed a decreased level of probiotics and an enrichment of pathogenic bacteria in patients with all types of polyps compared to healthy individuals. These changes were not restricted to the mucosa within 0.5 cm adjacent to the polyps, but also existed in histologically normal tissue 10 cm distal from the lesions. Significant differences in bacterial diversity were observed in the mucosa from individuals with normal conditions, Pol, and Ade. Increased abundance of Gram-negative bacteria, including Klebsiella, Plesiomonas, and Cronobacter, was observed in Pol group and Ade group, suggesting that resistance to antibiotics may be one risk factor for bacterium-related harmful environment. Meanwhile, age and gender were linked to bacteria changes, indicating the potential involvement of sex hormones.

CONCLUSION

These preliminary results support intestinal dysbiosis as an important risk factor for recurrent polyps, especially adenoma. Targeting specific pathogenic bacteria may attenuate the recurrence of polyps.

Prognostic factors and survival disparities in right-sided versus left-sided colon cancer

Right-sided colon cancer (RCC) and left-sided colon cancer (LCC) differ in features and outcomes because of variations in embryology, epidemiology, pathology, and prognosis. This study sought to identify significant factors impacting patient survival through Bayesian modelling. Data was retrospectively analysed from a colorectal neoplasia database. Data on demographics, perioperative risks, treatment, mortality, and survival was analysed from patients who underwent colon cancer surgery from January 2010 to December 2021. This study involved 2475 patients, with 58.7% having RCC and 41.3% having LCC. RCC patients had a notably higher mortality rate, and their overall survival (OS) rates were slightly lower than those with LCC (P < 0.05). RCC stages I-IV consistently exhibited worse OS and relapse-free survival (RFS) than LCC (P < 0.05). Factors like age, BMI, ASA score, cancer stage, and comorbidities had significant associations with OS and RFS. Poor and moderate differentiation, lower lymph node yield, and organ resection were linked to lower survival while receiving chemotherapy; higher BMI levels and elective surgery were associated with better survival (all P < 0.05). Our study reveals key differences between RCC and LCC, emphasising the impact of age, BMI, ASA score, cancer stage, and comorbidities on patient survival. These findings could inform personalised treatment strategies for colon cancer patients.

Prognostic value of primary tumor location in colorectal cancer: an updated meta-analysis

The clinical, histological, and molecular differences between right-sided colon cancer (RCC) and left-sided colon cancer (RCC) have received considerable attention. Over the past decade, many articles have been published concerning the association between primary tumor location (PTL) of colorectal cancer and survival outcomes. Therefore, there is a growing need for an updated meta-analysis integrating the outcomes of recent studies to determine the prognostic role of right vs left-sidedness of PTL in patients with colorectal cancer. We conducted a comprehensive database review using PubMed, SCOPUS, and Cochrane library databases from February 2016 to March 2023 for prospective or retrospective studies reporting data on overall survival (OS) and cancer-specific survival (CSS) of RCC compared with LCC. A total of 60 cohort studies comprising 1,494,445 patients were included in the meta-analysis. We demonstrated that RCC is associated with a significantly increased risk of death compared with LCC by 25% (hazard ratio (HR), 1.25; 95% confidence interval (CI), 1.19-1.31; I2 = 78.4%; Z = 43.68). Results showed that patients with RCC have a worse OS compared with LCC only in advanced stages (Stage III: HR, 1.275; 95% CI 1.16-1.4; P = 0.0002; I2 = 85.8%; Stage IV: HR, 1.34; 95% CI 1.25-1.44; P < 0.0001; I2 = 69.2%) but not in primary stages (Stage I/II: HR, 1.275; 95% CI 1.16-1.4; P = 0.0002; I2 = 85.8%). Moreover, a meta-analysis of 13 studies including 812,644 patients revealed that there is no significant difference in CSS between RCC and LCC (HR, 1.121; 95% CI 0.97-1.3; P = 0.112). Findings from the present meta-analysis highlight the importance of PTL in clinical decision-making for patients with CRC, especially in advanced stages. We provide further evidence supporting the hypothesis that RCC and LCC are distinct disease entities that should be managed differently.

Serum Cytokine and miRNA Levels Are Differently Expressed in Right- and Left-Sided Colon Cancer

The tumor location in colorectal cancer (right- or left-sided colon cancer) is a key factor in determining disease progression. Right- and left-sided colon tumors are different in their clinical and molecular characteristics. Dysregulation of serum levels of proinflammatory cytokines, such as Transforming Growth Factor β (TGF-β) and Tumor Necrosis Factor-α (TNF-α), and Peroxisome Proliferator Activated Receptor-γ (PPAR-γ), known to be a growth-limiting and differentiation-promoting factor, as well as changes in miRNAs expression, are the major signaling pathways involved in the pathogenesis of this neoplasia. In the serum from 60 colorectal cancer (CRC) patients, we compared the differences in the expression of the levels of TGF-β, TNF-α, and PPAR-γ and in the expression of the main human miRNAs between right and left CRC. A significant over-expression in the TGF-β and TNF-α levels was observed in the serum from right-sided colon cancer patients. For the PPAR-γ, the patients with CRC located on the right-side showed lower levels than those detected in the serum from left-sided CRC subjects. Furthermore, significant differences also existed in the expression of specific circulating miRNAs between right- and left-sided CRC. In particular, the right upregulated miRNAs were all involved in the cell growth and proliferation related pathways. These findings confirm that the analysis of circulating levels of TGF-β, TNF-α, and PPAR-γ, as well as the study of the specific miRNAs in the serum, are able to identify specific characteristics of CRC patients, useful for choosing a personalized treatment protocol.

Prediction values of tertiary lymphoid structures in the prognosis of patients with left- and right-sided colon cancer: a multicenter propensity score-matched study

BACKGROUND

Tertiary lymphoid structures (TLS) are the lymphocyte aggregates that play a key role in the vast majority of solid tumors including colon cancer, displaying an antitumor effect under most circumstances. The heterogeneity between left- and right-sided colon cancer (LCC and RCC) encompasses various aspects, such as clinical manifestations, pathological features, and immune responses. However, the function and prognostic significance of TLS within LCC and RCC have yet to be fully understood.

METHODS

A retrospective analysis was performed on 2612 patients who underwent radical resection for LCC or RCC without distant metastasis in multiple medical centers. Utilizing propensity score matching, 121 patients with LCC and 121 patients with RCC were selected for the training set. An external validation set including 64 patients with LCC and 64 patients with RCC were also employed. Hematoxylin-eosin and immunohistochemical staining were used to assess TLS and the proportion of various immune cells. Clinical characteristics and prognostic values of TLS in patients with LCC and RCC were analyzed. Nomograms were constructed for LCC and RCC to predict 3-year and 5-year overall survival (OS), respectively.

RESULTS

For LCC and RCC patients, TLS was located in the interstitial region or outside the tumor tissue and mainly consisted of B cells and T cells. The TLS quantity and density in RCC were higher than those of LCC. In multivariate Cox regression analysis, TLS density ( P =0.014), vascular invasion ( P =0.019), and AJCC stage ( P =0.026) were independent prognostic factors for 5-year OS of RCC. For LCC patients, AJCC stage ( P =0.024), tumor differentiation ( P =0.001), and tumor budding ( P =0.040) emerged as independent prognostic factors for 5-year OS. Similar results were obtained in the external verification set. Separate nomograms for RCC and LCC were developed, displaying improved prediction performance compared to the AJCC 8th edition TNM staging system.

CONCLUSIONS

Differences in TLS quantity and density were observed between LCC and RCC, suggesting that a nomogram based on TLS density could more effectively predict survival for RCC patients. Furthermore, a nomogram based on tumor budding was recommended for better prediction of LCC patient survival. Taken together, these results suggested that the immune and clinical characteristics of colon cancer at left and right side were substantially different, which may lead to the use of different prediction model and the development of individual treatment strategy.

Bach Mai Procedure for complete mesocolic excision, central vascular ligation, and D3 lymphadenectomy in total laparoscopic right hemicolectomy: a prospective study

PURPOSE

Total laparoscopic right hemicolectomy with complete mesocolic excision (CME), central vascular ligation (CVL), and D3 lymphadenectomy is still the most challenging colon procedures for gastrointestinal surgeons. We herein report the technical details and our preliminary experience of Bach Mai Procedure - a novel-combining (cranial, medial to lateral, and caudal) approach with early resection of the terminal ileum.

METHODS

The dissection stage was central vascular isolation and ligation by a combined multiple approaches in the following four steps: cranial approach, dissecting along the inferior aspect of pancreatic isthmus to reveal the middle colic vessels and the anterior aspect of the superior mesentery vein and then exposed the right gastroepiploic vein and the trunk of Henle; medial-to-lateral approach, exposing the surgical axis - the superior mesenteric vascular axis and then early resection of the terminal ileum to open the dissection from the bottom up; and caudal approach, radical ligation of the ileocecal artery and right colic artery (central vascular ligation), lymph node dissection (D3 lymphadenectomy), and resecting the Toldt fascia of the colon to release the entire right colon from the abdominal wall.

RESULTS

In 12 months, there were 32 cases of primary right-sided colon malignancies that have undergone tLRH_{D3, CME/CVL} based on the Bach Mai Procedure. In 3 cases (9.4%), the tumor site was hepatic flexure. The median of lymph node number (LNN) was 38, with the maximum number which was 101. No serious postoperative complications (grade 3 or higher) neither inhospital mortality was detected.

CONCLUSION

This Bach Mai procedure, a novel-combining approach with early resection of the terminal ileum, is technically feasible and safe for tLRH_{D3, CME/CVL}. Further investigations and follow-up must be proceeded to evaluate the long-term outcomes of our technique.

Associations of advanced age with comorbidity, stage and primary subsite as contributors to mortality from colorectal cancer

Background

Although survival from colorectal cancer (CRC) has improved substantially in recent decades, people with advanced age still have a high likelihood of mortality from this disease. Nonetheless, few studies have investigated how cancer stage, subsite and comorbidities contribute collectively to poor prognosis of older people with CRC. Here, we decided to explore the association of age with mortality measures and how other variables influenced this association.

Methods

Using linkage of several administrative datasets, we investigated the risk of death among CRC cases during 2003–2014. Different models were used to explore the association of age with mortality measures and how other variables influenced this association.

Results

Our results indicated that people diagnosed at a young age and with lower comorbidity had a lower likelihood of all-cause and CRC-specific mortality. Aging had a greater association with mortality in early-stage CRC, and in rectal cancer, compared that seen with advanced-stage CRC and right colon cancer, respectively. Meanwhile, people with different levels of comorbidity were not significantly different in terms of their increased likelihood of mortality with advanced age. We also found that while most comorbidities were associated with all-cause mortality, only dementia [SHR = 1.43 (1.24–1.64)], Peptic ulcer disease [SHR = 1.12 (1.02–1.24)], kidney disease [SHR = 1.11 (1.04–1.20)] and liver disease [SHR = 1.65 (1.38–1.98)] were risk factors for CRC-specific mortality.

Conclusion

This study showed that the positive association of advanced age with mortality in CRC depended on stage and subsite of the disease. We also found only a limited number of comorbidities to be associated with CRC-specific mortality. These novel findings implicate the need for more attention on factors that cause poor prognosis in older people.