Clinicopathologic and immunohistochemical study of small apparently "de novo" colorectal adenocarcinomas

Endoscopic and pathological characteristics of de novo colorectal cancer: Retrospective cohort study

BACKGROUND

Endoscopy has rapidly developed in recent years and has enabled further investigation into the origin and features of intestinal tumors. The small size and concealed position of these tumors make it difficult to distinguish them from nonneoplastic polyps and carcinoma in adenoma (CIA). The invasive depth and metastatic potential determine the operation regimen, which in turn affects the overall survival and distant prognosis. The previous studies have confirmed the malignant features and clinicopathological features of de novo colorectal cancer (CRC).

AIM

To provide assistance for diagnosis and treatment, but the lack of a summary of endoscopic features and assessment of risk factors that differ from the CIA prompted us to conduct this retrospective study.

METHODS

In total, 167 patients with small-sized CRCs diagnosed by endoscopy were reviewed. The patients diagnosed as advanced CRCs and other malignant cancers or chronic diseases that could affect distant outcomes were excluded. After screening, 63 cases were excluded, including 33 de novo and 30 CIA cases. Patient information, including their follow-up information, was obtained from an electronic His-system. The characteristics between two group and risk factors for invasion depth were analyzed with SPSS 25.0 software.

RESULTS

Nearly half of the de novo CRCs were smaller than 1 cm (n = 16, 48.5%) and the majority were located in the distal colon (n = 26, 78.8%). The IIc type was the most common macroscopic type of de novo CRC. In a Pearson analysis, the differential degree, Sano, JNET, and Kudo types, surrounding mucosa, and chicken skin mucosa (CSM) were correlated with the invasion depth (P < 0.001). CSM was a significant risk factor for deep invasion and disturbed judgment of endoscopic ultrasound. A high degree of tumor budding and tumor-infiltrating lymphocytes are accompanied by malignancy. Finally, de novo CRCs have worse outcomes than CIA CRCs.

CONCLUSION

This is the first comprehensive study to analyze the features of de novo CRCs to distinguish them from nonneoplastic polyps. It is also the first study paying attention to CSM invasive depth measurement. This study emphasizes the high metastatic potential of de novo CRCs and highlights the need for more research on this tumor type.

Histopathologic features and microsatellite instability of sporadic colorectal carcinoma: An analysis of 400 cases

AIM: To investigate the clinicopathologic features of sporadic colorectal carcinoma with high level of microsatellite instability (MSI-H), detect deficient expression of DNA mismatch repair protein, predict tumor microsatellite instability (MSI) status, and create a platform for diagnosis and screening of genetic colorectal carcinoma.

METHODS: Clinical data for 400 cases of sporadic colorectal carcinoma were analyzed. All cases underwent histological assessment. The deficiency expression of mismatch repair protein was detected by immunohistochemistry. The MSI status of carcinoma was predicted and then confirmed by PCR.

RESULTS: Male patients and left-side location predominated in the present series. Of 400 cases of sporadic colorectal carcinoma, 18 cases of MSI-H, 98 cases of MSI-L and 284 cases of MSS were detected by immunohistochemistry. Pathological features of MSI-H colorectal carcinoma included villous and papilloma structures, poor or good differentiation, mucinous type, signet-cell carcinoma or any mucinous differentiation, increased tumor-infiltrating lymphocytes (TIL cells), the presence of Crohn-like reaction, and the lack of necrosis. PCR analysis confirmed that there were 7 cases of MSI-H tumors, 1 case of MSI-L, 6 cases of MSS and 4 cases of allele of heterozygosity.

CONCLUSION: Sporadic MSI-H colorectal carcinoma has unique morphology, but shows no correlation with patient age, sex, and tumor size. Morphological assessment with immunohistochemistry can be used as a routine method for screening MSI-H and genetic colorectal carcinoma and guiding individualized treatment.

Clinicopathological differences of colorectal cancers according to tumor origin: Identification of possibly de novo lesions

Colorectal cancer (CRC) is considered to develop through the conventional adenoma-carcinoma sequence. However, the existence of de novo carcinogenesis, without any intervening precursor lesions, has been suggested for certain morphologically different tumors lacking polypoid characteristics. The presence of such tumors, along with their correlation with cardinal clinicopathological parameters, such as stage, grade and site, was retrospectively investigated in a series of 119 surgically treated CRC cases. The absence of particular polypoid characteristics (adenomatous remnants or coexisting polyps in the tumor vicinity) in combination with an infiltrative (or ulceroinfiltrative) growth pattern, were the criteria defining the nonpolypoid origin. The recorded frequencies of remnants, coexisting polyps and infiltrative tumors were 7, 5, 9 and 32%, respectively. The incidence of cases meeting the above-mentioned criteria was 28.5%. These nonpolypoid lesions exhibited a predilection for proximal anatomical site (P=0.04), probably associated with their infiltrative pattern. Most importantly, de novo lesions (unlike polypoid) were rarely found among cases with indolent tumor characteristics (stage I or grade I, P=0.008), showing a considerably different overall pattern of distribution by stage and grade as compared to that of polypoid tumors (P=0.03). The fact that nonpolypoid CRCs appeared to be clinicopathologically different from their polypoid counterparts is supportive of possible de novo origin and suggestive of a likely worse clinical behavior. The impact of these findings should be investigated to determine potential applications in the diagnosis, treatment and surveillance of these lesions.

The water method significantly enhances detection of diminutive lesions (adenoma and hyperplastic polyp combined) in the proximal colon in screening colonoscopy - data derived from two RCT in US veterans

PURPOSE: Emerging data indicate a colonoscopist-controlled method is needed to avoid missing proximal colon pre-malignant lesions. Screening colonoscopy does not prevent all proximal colon cancers. Even diminutive lesions in the proximal colon harbor dysplasia. In addition to adenomas (presumptive cancer precursors), recent proposals to reevaluate proximal colon hyperplastic polyps as serrated polyps which could be pre-malignant or harbingers of interval neoplasia dramatize the importance of attending to these lesions. The finding that the water method increased yield of proximal diminutive adenomas prompted assessment of the hypothesis that the water method increases yield of all proximal diminutive lesions (adenoma and hyperplastic polyp) in screening cases. METHODS: Two RCT assessed the water method with primary outcome of completion of unsedated colonoscopy when the option of scheduled, unsedated or sedation on demand was used. Diminutive (<10 mm) lesions proximal to the splenic flexure were tracked. RESULTS: In screening cases, 31% and 6% of the water and air group had at least one proximal diminutive lesion (p=0.0012). Regression analysis revealed withdrawal time, method and volume of water used were significant predictors of proximal diminutive lesions. Effect of the water method on detection of proximal diminutive lesions was independent of age, body mass index, endoscopist, sedation, cecal intubation rate, bowel cleanliness score on withdrawal and total procedure time. LIMITATION: Male subject predominance, analysis of secondary outcomes of pooled RCT data. CONCLUSION: The hypothesis that the water method effectively enhances proximal diminutive lesion detection in screening colonoscopy in diverse clinical settings should be tested.

The water method significantly enhances proximal diminutive adenoma detection rate in unsedated patients

BACKGROUND: Colonoscopy has been reported to fail to prevent some post screening colonoscopy incident cancers or minimize cancer mortality in the proximal colon. These reports question the effectiveness of colonoscopy in detecting all proximal adenomas. Diminutive ones which can be obscured by residual feces are particularly at risk. The water method provides salvage cleansing of sub-optimal preparations. OBJECTIVE: To test the hypothesis that the water method enhances proximal diminutive adenoma detection rate (ADR). DESIGN: The data bases of two parallel RCT were combined and analyzed. SETTING: Two Veterans Affairs endoscopy units. PATIENT AND METHODS: The water and air methods were compared in these two parallel RCT examining unsedated patients. MAIN OUTCOME MEASUREMENTS: The combined data on diminutive and overall ADR in the proximal colon, overall ADR, cecal intubation rate, withdrawal time and global bowel cleanliness score. RESULTS: Data in the water (n=92) and the air (n=90) groups were assessed. The water method yielded a significantly higher proximal diminutive ADR, 28.3% vs. 14.4% (p=0.0298); cecal intubation rate, 99% vs. 90% (p=0.0091); mean withdrawal time 19 (10) vs. 15 (8) min (p=0.0065) and mean global bowel cleanliness score during withdrawal, 2.6 (0.7) vs. 2.3 (0.6) (p=0.0032). Increase in proximal overall ADR in the water group approached significance, 29.3% vs. 16.7% (p=0.0592). LIMITATION: Small number of predominantly male veterans. CONCLUSION: The significantly higher cecal intubation rate, longer mean withdrawal time and better mean global bowel cleanliness score favor the outcome of significantly enhanced proximal diminutive ADR in the water group.