A Novel Combined Tumor Budding-Poorly Differentiated Clusters Grading System Predicts Recurrence and Survival in Stage I-III Colorectal Cancer

Tumor Budding Assessment in Colorectal Carcinoma: Normalization Revisited

Tumor budding (TB) is a powerful prognostic factor in colorectal cancer (CRC). An internationally standardized method for its assessment (International Tumor Budding Consensus Conference [ITBCC] method) has been adopted by most CRC pathology protocols. This method requires that TB counts are reported by field area (0.785 mm 2 ) rather than objective lens and a normalization factor is applied for this purpose. However, the validity of this approach is yet to be tested. We sought to validate the ITBCC method with a particular emphasis on normalization as a tool for standardization. In a cohort of 365 stage I-III CRC, both normalized and non-normalized TB were significantly associated with disease-specific survival and recurrence-free survival ( P <0.0001). Examining both 0.95 and 0.785 mm 2 field areas in a subset of patients (n=200), we found that normalization markedly overcorrects TB counts: Counts obtained in a 0.95 mm 2 hotspot field were reduced by an average of 17.5% following normalization compared with only 3.8% when counts were performed in an actual 0.785 mm 2 field. This resulted in 45 (11.3%) cases being downgraded using ITBCC grading criteria following normalization, compared with only 5 cases (1.3%, P =0.0007) downgraded when a true 0.785 mm 2 field was examined. In summary, the prognostic value of TB was retained regardless of whether TB counts in a 0.95 mm 2 field were normalized. Normalization resulted in overcorrecting TB counts with consequent downgrading of most borderline cases. This has implications for risk stratification and adjuvant treatment decisions, and suggests the need to re-evaluate the role of normalization in TB assessment.

Prognostic impact of tumor budding in rectal cancer after neoadjuvant therapy: a systematic review and meta-analysis

BACKGROUND

Tumor budding (TB) is a negative prognostic factor in colorectal cancer; however, its prognostic impact following neoadjuvant therapy for patients with rectal cancer remains unclear. This study aims to assess the prognostic impact of TB and the correlation between TB and other pathological features in patients with rectal cancer after neoadjuvant therapy.

METHODS

A comprehensive search of PubMed, Embase, Cochrane, Scopus, CNKI, Wanfang, and ClinicalKey databases was conducted for studies on the prognosis of TB in rectal cancer after neoadjuvant therapy from the inception of the databases to January 2023, and the final literature included was determined using predefined criteria. Quality assessment of the studies included, extraction of general and prognostic information from them, and meta-analyses were carried out progressively.

RESULTS

A total of 11 studies were included, and the results of the meta-analysis showed that high-grade tumor budding (TB-1) increased the risk of poor 5-year disease-free survival (HR = 1.75, 95% CI 1.38-2.22, P < 0.00001), 5-year overall survival (HR = 1.77, 95% CI 1.21-2.59, P = 0.003), local recurrence (OR = 4.15, 95% CI 1.47-11.75, P = 0.007), and distant metastasis (OR = 5.36, 95% CI 2.51-11.44, P < 0.0001) in patients with rectal cancer after neoadjuvant therapy. TB-1 was significantly associated with poor differentiation and lymphatic, perineural, and venous invasion.

CONCLUSION

Tumor budding is significantly correlated with unfavorable prognosis and poor pathological characteristics following neoadjuvant therapy for rectal cancer. We anticipate more high-quality, prospective studies in the future to confirm our findings.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42022377564.

Effects of tumour budding on adjuvant chemotherapy in colorectal cancer

BACKGROUND

High tumour budding has been indicated as a risk factor of poor survival in colorectal cancer. This study aimed to investigate the impact of tumour budding grades and the use of adjuvant chemotherapy on prognosis in patients with colorectal cancer.

METHODS

This study included consecutive colorectal cancer patients who underwent radical surgery for primary colorectal adenocarcinoma at The Sixth Hospital of Sun Yat-sen University between 2009 and 2019. Tumour budding was assessed based on the recommendations of the International Tumor Budding Consensus Conference using haematoxylin and eosin (H&E)-stained slides with tumour samples. The primary outcome of interest was to correlate tumour budding with disease-free survival and overall survival; the secondary outcome was investigation of the impact of adjuvant therapy on different tumour budding grades. In addition, a subgroup analysis was performed for the effects of lymphocytic infiltration on adjuvant chemotherapy in patients with Bd3.

RESULTS

Of 709 eligible patients, 412 with colorectal cancer were included. According to the International Tumor Budding Consensus Conference, 210 (50.9 per cent), 127 (30.8 per cent) and 75 (18.2 per cent) were classified as low budding (Bd1), intermediate budding (Bd2) and high budding (Bd3) respectively. Patients with Bd1, Bd2 and Bd3 had 5-year disease-free survival rates of 82.9 per cent, 70.1 per cent and 49.3 per cent respectively, and 5-year overall survival rates of 90 per cent, 79.5 per cent and 62.7 per cent respectively (P <0.001). Adjuvant chemotherapy yielded a significant survival benefit in patients with Bd3 (5-year disease-free survival, 65 per cent versus 31.4 per cent, P <0.001; 5-year overall survival, 84.4 per cent versus 63.1 per cent, P <0.001), but not in those with Bd1 or Bd2. In patients with Bd3, the benefit of adjuvant chemotherapy was maintained in those with low, but not high lymphocytic infiltration.

CONCLUSION

High grade of tumour budding was strongly correlated with poorer survival outcomes in colorectal cancer. Patients with Bd3 benefited from adjuvant chemotherapy, with the exclusion of patients with high lymphocytic infiltration.

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.