Tumour Cell Seeding to Lymph Nodes from In Situ Colorectal Cancer

Is it time to acknowledge intramucosal colorectal carcinoma?

AIM

The term 'intramucosal carcinoma' in the colorectum is controversial when used as a synonym for high-grade dysplasia. However, setting clear definitions for this diagnosis (i.e. unequivocal infiltrative growth in the lamina propria, which might be most easily recognized in cases with overt poor differentiation or formation of signet ring cells or tumour budding) allow us to investigate its relevance.

METHODS AND RESULTS

We reviewed cases from our archive (1990-2024) and selected 14 true intramucosal carcinomas using our strict histological criteria, excluding high-grade dysplasia and invasive carcinomas. These occur primarily in conventional adenomas and are frequently associated with microsatellite instability (50%). Our study shows a low estimated incidence of intramucosal carcinoma (0.01%) in population screening and highlights the low lymph node risk and the good outcome of patients with intramucosal carcinoma.

CONCLUSION

The rare diagnosis of intramucosal colorectal carcinoma aids in identifying patients at increased colorectal cancer risk, notably those with hereditary syndromes. Standardizing this diagnosis is critical to prevent overdiagnosis and unnecessary treatment.

Structural changes in the organs of the lymphoid system in terms of induced carcinogenesis

Colorectal cancer is the third most common cancer in the world. Despite recent therapeutic advances, it causes more than 500,000 deaths each year. The immune system plays a crucial role in protecting the body from cancer. However, cancer cells are able to evade immune detection and destruction. For example, they can downregulate antigen expression, produce immunosuppressive molecules, or recruit immune cells that perform regulatory or inhibitory functions. Understanding the complex interactions between the immune system and carcinogenesis is crucial for developing effective cancer treatments. The study aimed to determine the morphological changes in the thymus, spleen, and lymph nodes under N,N-dimethylhydrazine-induced carcinogenesis. The study was performed on 77 male outbred albino rats weighing 190-230 g, kept in standard vivarium conditions. Colon adenocarcinoma was modeled by administration of N,N-dimethylhydrazine hydrochloride for 30 weeks. To study the peculiarities of morphological and functional changes in lymphoid organs in the dynamics of colon tumor lesions, animals were withdrawn from the experiment every 30 days. Paraffin sections of the thymus, spleen, and lymph nodes 5-6 μm thick were made on a rotary microtome and stained with hematoxylin and eosin. The experimental investigation unveiled the character and extent of histological alterations within the lymphoid system organs under conditions of N,N-dimethylhydrazine-induced colon adenocarcinomatosis. As the experiment progressed, there was a noticeable escalation in the severity of detrimental and degenerative modifications observed in the thymus, spleen, and lymph nodes. These modifications were evident in the disruption of blood circulation within the examined organs, leading to vascular wall impairment and hemorrhaging, the disarray of morphofunctional elements and the development of fibrosis. Given the significant role played by the thymus, spleen, and lymph nodes in regulating carcinogenesis and maintaining immune balance, it is extremely important to delve into understanding the changes in their structure and function. Obtained results indicate that carcinogenesis is accompanied by pronounced morphological changes in the structural components of the lymphoid system organs, the degree of which increases in direct proportion to the duration of exposure to the oncogenic factor.

Finding the minimum number of retrieved lymph nodes in node-negative colorectal cancer using Real-world Data and the SEER database

BACKGROUND

Current clinical guidelines recommend the removal of at least 12 lymph nodes (LNs) in resectable colorectal cancer (CRC). With advancements in lymphadenectomy technologies, the number of retrieved lymph nodes (rLNs) has markedly increased. This study aimed to investigate the lowest number of rLNs in node-negative patients.

MATERIALS AND METHODS

A total of 1103 N0 and 208 N1a stage patients were enrolled in our cohort, while 8503 N0 and 1276 N1a patients from the Surveillance, Epidemiology, and End Results CRC database were included. Propensity score matching and multivariate Cox regression analyses were performed to mitigate the influence of selection bias and control for potential confounding variables.

RESULTS

The median number of rLNs in N0 patients increased from 13.5 (interquartile range [IQR]: 9-18) in 2013 to 17 (IQR: 15-20) in 2019. The restrictive cubic spline illustrated a nonlinear relationship between rLNs and prognosis (nonlinearity, P =0.009), with a threshold ( N =16) influencing clinical outcomes. Patients at either N0 or N1a stage with sufficient rLNs (≥16) demonstrated superior prognoses to those with a limited rLNs (<16). After adjusting for clinical confounders, similar prognoses were observed in N0 limited and N1a adequate populations. Furthermore, Kaplan-Meier curves revealed that N0 limited patients who received chemotherapy exhibited better outcomes than those who did not.

CONCLUSIONS

Among patients with node-negative CRC, it is crucial to remove 16 or more LNs effectively. Fewer than 16 rLNs should be regarded as an independent risk factor, implying the need for adjuvant chemotherapy.

Lymph Node Molecular Analysis with OSNA Enables the Identification of pT1 CRC Patients at Risk of Recurrence: A Multicentre Study

Early-stage colorectal carcinoma (CRC)-pT1-is a therapeutic challenge and presents some histological features related to lymph node metastasis (LNM). A significant proportion of pT1 CRCs are treated surgically, resulting in a non-negligible surgical-associated mortality rate of 1.5-2%. Among these cases, approximately 6-16% exhibit LNM, but the impact on survival is unclear. Therefore, there is an unmet need to establish an objective and reliable lymph node (LN) staging method to optimise the therapeutic management of pT1 CRC patients and to avoid overtreating or undertreating them. In this multicentre study, 89 patients with pT1 CRC were included. All histological features associated with LNM were evaluated. LNs were assessed using two methods, One-Step Nucleic Acid Amplification (OSNA) and the conventional FFPE plus haematoxylin and eosin (H&E) staining. OSNA is an RT-PCR-based method for amplifying CK19 mRNA. Our aim was to assess the performance of OSNA and H&E in evaluating LNs to identify patients at risk of recurrence and to optimise their clinical management. We observed an 80.9% concordance in LN assessment using the two methods. In 9% of cases, LNs were found to be positive using H&E, and in 24.7% of cases, LNs were found to be positive using OSNA. The OSNA results are provided as the total tumour load (TTL), defined as the total tumour burden present in all the LNs of a surgical specimen. In CRC, a TTL ≥ 6000 CK19 m-RNA copies/µL is associated with poor prognosis. Three patients had TTL > 6000 copies/μL, which was associated with higher tumour budding. The discrepancies observed between the OSNA and H&E results were mostly attributed to tumour allocation bias. We concluded that LN assessment with OSNA enables the identification of pT1 CRC patients at some risk of recurrence and helps to optimise their clinical management.