Novel Criteria for Intratumoral Budding with Prognostic Relevance for Colon Cancer and Its Histological Subtypes

Prognostic Implications of Intratumoral Budding in Colorectal Cancer: Detailed Analysis Based on Tumor-Infiltrating Lymphocytes

BACKGROUND

This study aims to understand the clinical and pathological importance of intratumoral budding (ITB) in colorectal cancer (CRC) and its relationship with tumor-infiltrating lymphocytes (TILs). CRCs can be classified into hot (high immunoscore (IS)) and cold (low IS) tumors.

METHODS

We investigated the number of ITBs in a hotspot area and categorized them into high-ITB (≥5) and low-ITB (<5) groups. The clinicopathological significance of ITB in human CRCs was evaluated, and a detailed analysis based on tumor-infiltrating lymphocytes (TILs) was also performed.

RESULTS

High ITB was identified in 59 of 266 CRC cases (22.2%). High ITB significantly correlated with a poorly differentiated tumor, lympho-vascular invasion, perineural invasion, higher pT stage, lymph node metastasis, and higher metastatic lymph node ratio. High ITB was also significantly correlated with a low IS and low CD8-positive lymphocytic infiltrate. The number of ITBs was substantially higher in the low-IS group than in the high-IS group (3.28 ± 3.31 vs. 2.19 ± 2.59; p = 0.005). High ITB significantly correlated with worse overall survival (p = 0.004). In the low-IS group, CRCs with high ITB had a significantly worse prognosis than those with low ITB (p = 0.021). However, there was no significant difference in prognosis between the high- and low-ITB groups in the high-IS group (p = 0.498).

CONCLUSIONS

Taken together, high ITB was significantly correlated with aggressive tumor behaviors and worse survival in patients with CRCs. In addition, ITB can be useful for the prognostic stratification of CRCs with low IS.

Diagnostic and Therapeutic Management of Early Colorectal Cancer

Background

Early colorectal cancer (eCRC) is defined as cancer that does not cross the submucosal layer of the colon or rectum, including carcinoma in situ (pTis), pT1a, and pT1b. Early carcinomas differ in their prognosis depending on the risk profile. The differentiation between low and high risk is essential. The low-risk group includes R0-resected, well (G1) or moderately (G2) differentiated tumors without lymphatic vessel invasion (L0), without blood vessel invasion (V0) and a tumor size ≤3 cm. In this constellation, the estimated risk of lymph node metastasis is around 1% or below. The high-risk group includes tumors with incomplete resection (Rx), poor (G3) or undifferentiated (G4) carcinomas, and/or lymphatic and blood vessel invasion (L1) and size ≥3 cm. In a "high-risk" situation, there is a risk for lymph node metastasis of up to 23%.

Summary

The incidence of eCRC is rising with a rate of 10% in all endoscopically removed lesions during colonoscopy. For a correct histological evaluation, all suspected lesions should be completely resected. In case of a pT1 lesion in the rectum, pelvic magnetic resonance imaging should be performed to evaluate for suspicious lymph nodes. The therapeutic approach for eCRC is based on histological assessment and ranges from endoscopic resection to radical oncological surgery. The advantages, disadvantages, and associated risks of the individual treatment strategy need to be carefully discussed on a tumor board and with the patient.

Key Messages

Treatment options for early colorectal cancer depend on the histological assessment. Poorly differentiated carcinomas, a Kudo ≥ SM2 classified lesion, and a Haggitt level 4 always represent a "high-risk" situation. It should also be mentioned that in rectal cancer, local surgical tumor excision (full-wall excision) is also sufficient for pT1 carcinomas with a "low-risk" constellation (G1/G2; L0, size <3 cm) and an R0 resection.

Clinicopathological Significances and Prognostic Role of Intratumoral Budding in Colorectal Cancers

Background: This study aims to evaluate the clinicopathological significance and prognostic implications of intratumoral budding (ITB) in colorectal cancers (CRCs) through a meta-analysis. Methods: We performed the meta-analysis using 13 eligible studies and investigated the rates of CRCs with high ITB. The correlation between ITB and clinicopathological characteristics, including disease-free survival, was evaluated. Results: The estimated rate of CRCs with high ITB was 0.233 (95% confidence interval (CI) 0.177–0.299) in overall CRCs. High ITB was significantly correlated with tumor grade, lymphatic invasion, perineural invasion, pT stage, and lymph node metastasis. In addition, ITBs were more frequently found in medullary and signet-ring cell carcinomas than in conventional adenocarcinomas and mucinous carcinomas. However, the high ITB rate was not correlated with tumor border, tumor-infiltrating lymphocytes, or microsatellite instability. CRCs with a good response after neoadjuvant therapy revealed a lower rate of high ITB than those with a poor response (hazard ratio (HR) 0.114, 95% CI 0.070–0.179 vs. 0.321, 95% CI 0.204–0.467). In addition, CRCs with high ITB had a worse disease-free survival than those with low ITB (HR 1.426, 95% CI 1.092–1.863). Conclusions: The ITB was significantly correlated with aggressive tumor behaviors and a worse prognosis in CRCs. The detection of ITB, as a histological parameter, can be useful for predicting clinicopathologic features and the prognosis of CRC.

Fast whole-slide cartography in colon cancer histology using superpixels and CNN classification

Purpose: Automatic outlining of different tissue types in digitized histological specimen provides a basis for follow-up analyses and can potentially guide subsequent medical decisions. The immense size of whole-slide-images (WSIs), however, poses a challenge in terms of computation time. In this regard, the analysis of nonoverlapping patches outperforms pixelwise segmentation approaches but still leaves room for optimization. Furthermore, the division into patches, regardless of the biological structures they contain, is a drawback due to the loss of local dependencies. Approach: We propose to subdivide the WSI into coherent regions prior to classification by grouping visually similar adjacent pixels into superpixels. Afterward, only a random subset of patches per superpixel is classified and patch labels are combined into a superpixel label. We propose a metric for identifying superpixels with an uncertain classification and evaluate two medical applications, namely tumor area and invasive margin estimation and tumor composition analysis. Results: The algorithm has been developed on 159 hand-annotated WSIs of colon resections and its performance is compared with an analysis without prior segmentation. The algorithm shows an average speed-up of 41% and an increase in accuracy from 93.8% to 95.7%. By assigning a rejection label to uncertain superpixels, we further increase the accuracy by 0.4%. While tumor area estimation shows high concordance to the annotated area, the analysis of tumor composition highlights limitations of our approach. Conclusion: By combining superpixel segmentation and patch classification, we designed a fast and accurate framework for whole-slide cartography that is AI-model agnostic and provides the basis for various medical endpoints.

The impact of body mass index on prognosis in patients with colon carcinoma

BACKGROUND

The impact of body mass index (BMI) on prognosis in patients with curatively resected stage I-III colon carcinoma was analyzed.

METHODS

The prospectively collected data of 694 patients who underwent complete mesocolic excision between 2003 and 2014 were analyzed. BMI was classified into four categories: underweight (BMI < 18.5 kg/m²; n = 13), normal weight (BMI 18.5 to 24.9 kg/m²; n = 221), overweight (BMI 25.0 to 29.9 kg/m²; n = 309), and obese (BMI ≥ 30.0 kg/m²; n = 151). Univariate and multivariate analyses for comparison of prognosis were performed.

RESULTS

The 5-year rate of locoregional recurrence in all 694 patients was 2.1%, and no differences were found with respect to BMI (p = 0.759). For distant metastasis, the 5-year rate for all patients was 13.4%, and BMI did not have a significant impact (p = 0.593). The 5-year rate of disease-free survival for all 694 patients was 72.4%. The differences with respect to BMI were not found to be significant in univariate analysis (p = 0.222). In multivariate Cox regression analysis, disease-free survival was significantly better in obese patients (HR 0.7; p = 0.034). Regarding overall survival, the 5-year rate for all patients was 78.1%. In univariate analyses, no significant differences were found for BMI (p = 0.094). In the Cox regression analysis, overweight and obese patients had significantly better survival (overweight: HR 0.7; p = 0.027; obese: HR 0.6; p = 0.019).

CONCLUSION

The better survival of overweight and obese patients in multivariate analyses must be interpreted with caution. It is influenced by several factors and seems to correspond to the phenomenon of the obesity paradox.