Conventional tumor grading systems based on the degree of tumor differentiation may not always be optimal because of difficulty in objective assessment and insufficient prognostic value for decision making in colorectal cancer (CRC) treatment. This study aimed to determine the importance of assessing the number of poorly differentiated clusters as the primary criterion for histologic grading of CRC. Five hundred consecutive patients with curatively resected stage II and III CRCs (2000 to 2005) were pathologically reviewed. Cancer clusters of ≥5 cancer cells and lacking a gland-like structure were counted under a ×20 objective lens in a field containing the highest number of clusters. Tumors with <5, 5 to 9, and ≥10 clusters were classified as grade (G)1, G2, and G3, respectively (n=156, 198, and 146 tumors, respectively). Five-year disease-free survival rates were 96%, 85%, and 59% for G1, G2, and G3, respectively (P<0.0001). Poorly differentiated clusters affected survival outcome independent of T and N stages and could help in more effective stratification of patients by survival outcome compared with tumor staging (Akaike information criterion, 1086.7 vs. 1117.0; Harrell concordance index, 0.73 vs. 0.67). The poorly differentiated cluster-based grading system showed a higher weighted κ coefficient for interobserver variability (5 observers) compared with conventional grading systems (mean, 0.66 vs. 0.52; range, 0.55 to 0.73 vs. 0.39 to 0.68). Our novel histologic grading system is expected to be less subjective and more informative for prognostic prediction compared with conventional tumor grading systems and TNM staging. It could be valuable in determining individualized postoperative CRC treatment.

The proposed histologic DR categorization directly reflects tumor behavior in a modulating stromal environment and could provide valuable prognostic information for CRC patients.

Although recent findings of cancer biology research indicate that prognostic power arises from genes expressed by stromal cells rather than epithelial cells, desmoplastic reaction (DR) has not been completely examined as a prognostic marker for colorectal cancer. A pathologic review of 821 stage II and III patients who underwent R0 resection for colorectal cancer at 4 independent institutions was conducted. DR was classified as mature, intermediate, or immature based on the existence of hyalinized keloid-like collagen and myxoid stroma at the extramural desmoplastic front. Totally, 325, 282, and 214 patients were classified as having mature, intermediate, and immature DR, respectively. DR significantly influenced the recurrence rate in the liver, lung, and peritoneum (P≤0.0001 to 0.01). Five-year relapse-free survival (RFS) rate was the highest in the mature group (85.7%), followed by the intermediate (77.3%) and immature (50.4%) groups. A significant adverse impact of immature stroma on RFS was observed in subset analyses of the 4 institutions. Multivariate analysis revealed that DR, along with T and N stages, is an independent prognostic factor. On the basis of Harrell's concordance index, the prognostic power of DR categorization (0.67) in stratifying RFS was greater than any other conventional prognostic factors, including TNM (0.64), N (0.62) and T stages (0.59), venous invasion (0.59), and tumor grade (0.54). Characterizing DR based on the histologic products of activated fibroblasts is valuable for evaluating prognostic outcomes. To our knowledge, this is the first study reporting a greater prognostic power of histology of the fibrotic stroma than that of tumor factors.

Advanced lower rectal cancer patients having LNI in the lateral pelvic area are likely to receive prognostic benefit from lymphadenectomy. The most efficient means of determining the effectiveness of lateral dissection preoperatively is to estimate the nodal diameter in the "vulnerable" lateral regions by diagnostic imaging.

Favorable anticancer immunity occurred after CRT for rectal cancer by altering TIL subsets. A high CD8/FOXP3 IEL ratio before CRT and a high CD8+ STL density after CRT were associated with a favorable clinical outcome.

Background:The crosstalk between cancer cells and stroma is involved in the acquired capability for metastasis through the induction of epithelial–mesenchymal transition (EMT). We aimed to clarify the prognostic value of the histological category of EMT in colorectal cancer (CRC).Methods:Tumour EMT was graded into one of three histological categories on the basis of integrated assessment of poorly differentiated clusters and pro-EMT desmoplasia at the leading edge of the primary tumour (HistologyEMT). Stage II and III CRC patients (cohort 1, N=500) and stage IV patients (cohort 2, N=196) were retrospectively analysed.Results:In cohort 1, patients were stratified into three groups with widely different disease-free survival rates (95%, 83% and 39%) on the basis of HistologyEMT (P<0.0001). In cohort 2, HistologyEMT significantly stratified overall survival of patients irrespective of metasectomy. Multivariate analyses indicated that HistologyEMT had a strong prognostic impact independent of staging factors. Statistically, HistologyEMT had a better prognostic stratification power than T and N stages; however, in cohort 2, the power of M substage was superior.Conclusions:A histological model to categorise EMT by integrated assessment of dedifferentiation and desmoplastic environment is a potent prognostic index independent of staging factors.

Background: Efficacy of adjuvant chemotherapy in patients with stage II colon cancer is still controversial. The SACURA trial is a randomised-controlled study evaluating the superiority of 1-year adjuvant treatment with oral tegafureuracil (UFT) to surgery alone for stage II colon cancer. Methods: Patients were randomly assigned to the surgery-alone group or UFT group (UFT at 500e600 mg/day for 5 days, followed by 2-day rest, for 1 year). The primary end-point was disease-free survival (DFS). Target sample size was 2000, determined with one-sided alpha of 0.05, power of 0.9 and assumed hazard ratio (HR) 0.729. Results: A total of 1982 patients (997 in the surgery-alone group and 985 in the UFT group) were analysed. Median follow-up was 69.5 months, median age was 66 years and for stage IIA/ IIB/IIC, the distribution was 84%/13%/3%. The 5-year DFS rate was 78.4% in the surgery-alone group and 80.2% in the UFT group. The HR for DFS was 0.91 (95% confidence interval [CI], 0.75e1.10; p Z 0.31); superiority of UFT was not demonstrated. Approximately 9% of patients experienced second cancers, which consist 40.7% of the DFS events. The 5-year relapse-free and overall survival rates of the surgeryalone and UFT group were 84.6% and 87.2% (HR, 0.82; 95% CI, 0.65e1.04) and 94.3% and 94.5% (HR, 0.93; 95% CI, 0.66e1.31), respectively. Subgroup analysis failed to disclose superiority in prognosis of adding UFT to the patients with risk factors for recurrence. Conclusions: Superiority of 1-year adjuvant UFT over surgery alone was not demonstrated in stage II colon cancer. Patients with risk factors for recurrence did not benefit from UFT. Trial registration: ClinicalTrials. Gov. #NCT00392899.

Highly accurate risk assessment of recurrence may improve adjuvant treatment practice in stage II colorectal cancer (CRC), which lacks definite prognostic factors. Recent studies indicate the importance of stroma in determining cancer behavior, although there are few histopathologic criteria for its evaluation. A pathology review of 679 stage II CRC patients (1980-2005) was conducted at an institution. Desmoplastic reaction (DR) results were classified as mature, intermediate, or immature depending on the presence of hyalinized collagen bundles and myxoid stroma observed at the extramural desmoplastic front on hematoxylin–eosin-stained slides. Pathologically, 430, 180, and 69 tumors were classified into the mature, intermediate, and immature groups, respectively. On the basis of the DR results, 5-year recurrence rate was found to have a wide range of 9.1% to 30.7%; 5-year relapse-free survival (RFS) rates were highest in the mature group (85.2%), followed by the intermediate (77.1%), and immature (60.9%) groups. Multivariate analyses revealed an independent effect of DR pattern on RFS. In addition, 446 patients treated at 4 independent institutions (2007-2008) were examined as a second cohort for result validation, revealing an adverse prognostic impact of unfavorable DR and identifying DR categorization as an independent prognostic factor. In both cohorts, Harrell’s concordance index for RFS was higher than the other conventional factors in the DR including T stage. Categorizing DR pattern based on the histologic products of fibroblasts at the desmoplastic front help elucidate their important biological role in cancer development, thus providing clinically useful prognostic information regarding stage II CRC.