Serosal surfaces, mucin pools, and deposits, oh my: challenges in staging colorectal carcinoma

Acellular mucin in non-neoplastic inflammatory conditions of lower gastrointestinal tract

PURPOSE

In the context of neoplasia, acellular mucin in lower gastrointestinal (GI) tract implies occult mucin-producing tumor and warrants additional workup. The clinical significance of acellular mucin in benign conditions remains unclear.

METHODS

Lower GI tract surgical specimens with acellular mucin without documented neoplastic conditions (colonic diverticulitis (n = 16), appendicitis (n = 14), and others (n = 8)) were retrieved. Low grade appendiceal mucinous neoplasm (LAMN) (n = 24) and diverticulitis without acellular mucin (n = 28) were used as controls for appendicitis and diverticulitis cases, respectively. Clinical data, histological findings, and additional workups performed due to acellular mucin were collected.

RESULTS

Patients with appendicitis with acellular mucin frequently presented with signs and symptoms of acute appendicitis (p = 0.016) compared to LAMN. 71 % were interval appendectomy, and 57 % had diverticula. In colonic diverticulitis cohort, no differences were found in terms of the duration of symptoms, age, gender and the degree of inflammation between the groups with and without acellular mucin. Seven of 8 patients with other conditions with acellular mucin had a history of abdominal surgery or fistula. Additional workup included levels (n = 7), consults (n = 11), and stains (n = 4).

CONCLUSION

Acellular mucin can be seen in a variety of benign conditions but this phenomenon is probably under-recognized and leads to additional investigations. Acellular mucin is likely translocated from the lumen through diverticulum or mural defect. Considering clinical context is crucial in providing accurate diagnosis while preserving laboratory resources.

Accelerated T2W Imaging with Deep Learning Reconstruction in Staging Rectal Cancer: A Preliminary Study

Deep learning reconstruction (DLR) has exhibited potential in saving scan time. There is limited research on the evaluation of accelerated acquisition with DLR in staging rectal cancers. Our first objective was to explore the best DLR level in saving time through phantom experiments. Resolution and number of excitations (NEX) adjusted for different scan time, image quality of conventionally reconstructed T2W images were measured and compared with images reconstructed with different DLR level. The second objective was to explore the feasibility of accelerated T2W imaging with DLR in image quality and diagnostic performance for rectal cancer patients. 52 patients were prospectively enrolled to undergo accelerated acquisition reconstructed with highly-denoised DLR (DLR_H40sec) and conventional reconstruction (ConR2min). The image quality and diagnostic performance were evaluated by observers with varying experience and compared between protocols using κ statistics and area under the receiver operating characteristic curve (AUC). The phantom experiments demonstrated that DLR_H could achieve superior signal-to-noise ratio (SNR), detail conspicuity, sharpness, and less distortion within the least scan time. The DLR_H40sec images exhibited higher sharpness and SNR than ConR2min. The agreements with pathological TN-stages were improved using DLR_H40sec images compared to ConR2min (T: 0.846vs. 0.771, 0.825vs. 0.700, and 0.697vs. 0.512; N: 0.527vs. 0.521, 0.421vs. 0.348 and 0.517vs. 0.363 for junior, intermediate, and senior observes, respectively). Comparable AUCs to identify T3-4 and N1-2 tumors were achieved using DLR_H40sec and ConR2min images (P > 0.05). Consequently, with 2/3-time reduction, DLR_H40sec images showed improved image quality and comparable TN-staging performance to conventional T2W imaging for rectal cancer patients.

The clinical significance of elastic lamina invasion in patients with pStage II colorectal cancer: a notable prognostic indicator

BACKGROUND

Some colorectal cancers (CRCs) are clinically diagnosed as cT4a with　serosal invasion (SI). However, the cT4a is most often underdiagnosed pathologically as pT3 without SI by hematoxylin-eosin (H&E) staining alone. Using Elastica van Gieson (EVG) staining, some pT3 tumors invade the elastic lamina (EL), which extends just below the serosal layer. Recently, EL invasion (ELI) has been described as a poor prognostic factor for disease-free survival (DFS) and overall survival (OS) in patients with pStage II CRC. However, its clinicopathological significance remains unclear due to the limited number of studies and poor understanding of ELI.

OBJECTIVE

This study investigated the association between the ELI and patient prognosis.

METHODS

After 1982, pathological diagnosis was routinely performed using H&E and EVG staining methods, and long-term follow up was performed until 2016. All clinicopathological features including ELI were prospectively registered into our computer and 569 patients with pStage II CRC were collected from the database. Based on the ELI status, pT3 was divided into three pathological categories: pT3ELI - was defined as pT3a, pT3ELI + as pT3b and unidentified EL (pT3EL -) as pT3u.

RESULTS

Using H&E staining alone, gross cT4a was most often pathologically underdiagnosed as pT3 (93.8%) and very rarely as pT4a, resulting in a large diagnostic discrepancy. Using EVG staining, 60.7% of the cT4a tumors were diagnosed as pT3b. The 10-year DFS and OS rates were similar for pT3a and pT3u patients. However, the 10-year DFS and OS rates of pT3b patients were significantly lower than those of pT3a patients (75.6% vs. 95.6%, p < 0.0001 and 58.4% vs. 70.6%, p = 0.0024, respectively) but did not differ from those of pT4a patients (70.6%, p = 0.5799 and 52.0%, p = 0.1116, respectively). Multivariate analysis revealed that the ELI was the strongest independent risk factor for recurrence and CRC-specific death (p < 0.0001).

CONCLUSIONS

A better understanding of the ELI allows us to reconsider the diagnostic discrepancy of serosal invasion, i.e., pT3b should be considered pT4a. The ELI-based subclassification of pT3 is expected to be incorporated into the TNM staging system in the future. The ELI is a notable prognostic indicator in patients with pStage II CRC.

Prediction of pathological complete response and prognosis in locally advanced rectal cancer

BACKGROUND

Colorectal cancer is currently the third most common malignant tumor and the second leading cause of cancer-related death worldwide. Neoadjuvant chemoradiotherapy (nCRT) is standard for locally advanced rectal cancer (LARC). Except for pathological examination after resection, it is not known exactly whether LARC patients have achieved pathological complete response (pCR) before surgery. To date, there are no clear clinical indicators that can predict the efficacy of nCRT and patient outcomes.

AIM

To investigate the indicators that can predict pCR and long-term outcomes following nCRT in patients with LARC.

METHODS

Clinical data of 128 LARC patients admitted to our hospital between September 2013 and November 2022 were retrospectively analyzed. Patients were categorized into pCR and non-pCR groups. Univariate analysis (using the χ 2 test or Fisher's exact test) and logistic multivariate regression analysis were used to study clinical predictors affecting pCR. The 5-year disease-free survival (DFS) and overall survival (OS) rates were calculated using Kaplan-Meier analysis, and differences in survival curves were assessed with the log-rank test.

RESULTS

Univariate analysis showed that pretreatment carcinoembryonic antigen (CEA) level, lymphocyte-monocyte ratio (LMR), time interval between neoadjuvant therapy completion and total mesorectal excision, and tumor size were correlated with pCR. Multivariate results showed that CEA ≤ 5 ng/mL (P = 0.039), LMR > 2.73 (P = 0.023), and time interval > 10 wk (P = 0.039) were independent predictors for pCR. Survival analysis demonstrated that patients in the pCR group had significantly higher 5-year DFS rates (94.7% vs 59.7%, P = 0.002) and 5-year OS rates (95.8% vs 80.1%, P = 0.019) compared to the non-pCR group. Tumor deposits (TDs) were significantly correlated with shorter DFS (P = 0.002) and OS (P < 0.001).

CONCLUSION

Pretreatment CEA, LMR, and time interval contribute to predicting nCRT efficacy in LARC patients. Achieving pCR demonstrates longer DFS and OS. TDs correlate with poor prognosis.

Prediction of pathological complete response and prognosis in locally advanced rectal cancer

BACKGROUND

Colorectal cancer is currently the third most common malignant tumor and the second leading cause of cancer-related death worldwide. Neoadjuvant chemoradiotherapy (nCRT) is standard for locally advanced rectal cancer (LARC). Except for pathological examination after resection, it is not known exactly whether LARC patients have achieved pathological complete response (pCR) before surgery. To date, there are no clear clinical indicators that can predict the efficacy of nCRT and patient outcomes.

AIM

To investigate the indicators that can predict pCR and long-term outcomes following nCRT in patients with LARC.

METHODS

Clinical data of 128 LARC patients admitted to our hospital between September 2013 and November 2022 were retrospectively analyzed. Patients were categorized into pCR and non-pCR groups. Univariate analysis (using the χ² test or Fisher’s exact test) and logistic multivariate regression analysis were used to study clinical predictors affecting pCR. The 5-year disease-free survival (DFS) and overall survival (OS) rates were calculated using Kaplan-Meier analysis, and differences in survival curves were assessed with the log-rank test.

RESULTS

Univariate analysis showed that pretreatment carcinoembryonic antigen (CEA) level, lymphocyte-monocyte ratio (LMR), time interval between neoadjuvant therapy completion and total mesorectal excision, and tumor size were correlated with pCR. Multivariate results showed that CEA ≤ 5 ng/mL (P = 0.039), LMR > 2.73 (P = 0.023), and time interval > 10 wk (P = 0.039) were independent predictors for pCR. Survival analysis demonstrated that patients in the pCR group had significantly higher 5-year DFS rates (94.7% vs 59.7%, P = 0.002) and 5-year OS rates (95.8% vs 80.1%, P = 0.019) compared to the non-pCR group. Tumor deposits (TDs) were significantly correlated with shorter DFS (P = 0.002) and OS (P < 0.001).

CONCLUSION

Pretreatment CEA, LMR, and time interval contribute to predicting nCRT efficacy in LARC patients. Achieving pCR demonstrates longer DFS and OS. TDs correlate with poor prognosis.

Polymeric nanotheranostics for solid tumor management: Recent developments and global regulatory landscape

Polymeric nanotheranostics have emerged as promising vehicles for diagnosis‐cum‐targeted therapy in solid tumors, offering precise delivery of therapeutic agents at the site of solid tumors and minimizing systemic side effects. This article summarizes the latest developments in using polymeric nanoparticles for specific treatment strategies in solid tumors. It explores the various methods these nanoparticles utilize for targeted medication delivery. This includes passive targeting through the amplified permeability and retention effect, active targeting via interactions between ligands and receptors, and stimuli‐responsive release mechanisms such as pH, temperature, and enzymatic triggers. Furthermore, we highlight recent developments in stimuli‐responsive polymeric nanoparticles, which enable controlled drug release in response to specific cues in the tumor microenvironment, thus enhancing therapeutic efficacy. Also, we focus on the theranostic polymeric nanoparticles, which are used for diagnosing and treating solid tumors. We discuss critical regulatory considerations and the regulatory bodies of different countries that regulate nanomedicines' safety, efficacy, quality, and manufacturing processes. Overall, this review provides insights into the latest innovations in polymeric nanoparticles for targeted therapy in solid tumors, elucidating their mechanisms of action, stimuli‐responsive properties, and regulatory pathways, which collectively contribute to developing effective and safe nanomedicines for cancer treatment.

Identification of an Objective Cut-Off Point to Define the Clinical Stage T4a in Colon Cancer

Introduction: The current state of pathology practice and the variability in diagnosing pT4a colon cancer have been underexplored in existing studies. Our objective was to establish a specific cutoff point to distinguish between the pathological stages of pT3 and pT4a in colon cancer. Methods: We conducted a cross-sectional study involving pT3 and pT4 (pN0-2, cM0) colon cancers, measuring the distance to the serosa. Patients were categorized and analyzed based on this distance and the peritoneal reaction, with the aim being to ascertain their prognostic implications. Results: A total of 384 patients were analyzed. Patients with a distance between the invading front of cancer and the serosa ≥ 1 mm without a peritoneal reaction exhibited a median survival of 118 months, contrasting the amount of 70 months for those with <1 mm plus peritoneal reaction. Only lengths <1 mm with peritoneal reaction showed a significant correlation with mortality (p < 0.001). Conclusion: Our study revealed that patients in whom neoplastic cells were less than 1 mm from the serosal surface, accompanied by a peritoneal reaction (hemorrhage, inflammation, neovascularization, fibrin), had significantly lower survival rates compared to those with more than 1 mm distance and without peritoneal response (70 vs. 118 months, p < 0.001). Hence, such cases should be considered within the pT4a stage.

The development and implementation of pathological parameters and molecular testing impact prognosis of colorectal adenocarcinoma

Objective

This study aims to analyze how changes in pathological diagnosis practice and molecular detection technology have affected clinical outcomes for colorectal cancer (CRC) patients in Fudan University Shanghai Cancer Center (FUSCC).

Methods

This retrospective cohort study analyzed 21,141 pathologically confirmed CRC cases diagnosed at FUSCC from 2008 to 2020. Patients were divided into five groups for different analytical purposes: (1) the before vs. since 2014 groups to analyze the influence of the changes in the classification criteria of pT3 and pT4 staging on the survival of patients; (2) the partial vs. total mesorectal excision (TME) groups to analyze whether evaluation of completeness of the mesorectum have impact on the survival of patients; (3) the tumor deposit (TD)(+)N0 vs. TD(+)N1c groups to analyze the influence of the changes in the pN staging on the survival of patients with positive TD and negative regional lymph node metastasis (LNM); (4) the before vs. since 2013 groups to analyze the influence of the changes in the testing process of deficient mismatch repair on the survival of patients; and (5) the groups with vs. without RAS/BRAF gene mutation testing to analyze the influence of these testing on the survival of patients. Patients' clinicopathological parameters, including age at diagnosis, sex, tumor size, location, differentiation, mucinous subtype, TD, lymphovascular invasion, perineural invasion, tumor depth, LNM and distant metastasis, and tumor-node-metastasis (TNM) stage, were compared between groups. Kaplan-Meier analysis with log rank method was performed for patients' overall survival (OS) and disease-free survival (DFS) analyses.

Results

In pathological reports, there were three parameter changes that impacted patient outcomes. Firstly, changes in the pT staging criteria led to a shift of the ratio of patients with stage pT3 to stage pT4 from 1: 110.9 to 1: 0.26. In comparison to patients admitted before 2014 (n = 4,754), a significant difference in prognosis between pT3 and pT4 stages was observed since 2014 (n = 9,965). Secondly, we began to evaluate the completeness of the mesorectum since 2016. As a result, 91.0% of patients with low rectal cancer underwent TME (n = 4,111) surgery, and patients with TME had significantly better OS compared with partial mesorectal excision (PME, n = 409). Thirdly, we began to stage TD (+) LNM (-) as N1c since 2017. The results showed that N1c (n = 127) but not N0 (n = 39) can improve the prognosis of patients without LNM and distal metastasis. In molecular testing, there have been three and five iterations of updates regarding mismatch repair (MMR)/microsatellite instability (MSI) status and RAS/BRAF gene mutation detection, respectively. The standardization of MMR status testing has sharply decreased the proportion of deficient MMR (dMMR) patients (from 32.5% to 7.4%) since 2013. The prognosis of patients underwent MMR status testing since 2013 (n = 867) were significantly better than patients before 2013 (n = 1,313). In addition, detection of RAS/BRAF gene mutation status (n = 5,041) resulted in better DFS but not OS, for patients with stage I-III disease (n = 16,557).

Conclusion

Over the past few decades, updates in elements in pathological reports, as well as the development of standardized tests for MMR/MSI status and RAS/BRAF gene mutations have significantly improved patient outcomes.

Small arteriole sign: an imaging feature for staging T4a colon cancer

OBJECTIVES

By analyzing the distribution of existing and newly proposed staging imaging features in pT1-3 and pT4a tumors, we searched for a salient feature and validated its diagnostic performance.

METHODS

Preoperative multiphase contrast-enhanced CT images of the training cohort were retrospectively collected at three centers from January 2016 to December 2017. We used the chi-square test to analyze the distribution of several stage-related imaging features in pT1-3 and pT4a tumors, including small arteriole sign (SAS), outer edge of the intestine, tumor invasion range, and peritumoral adipose tissue. Preoperative multiphase contrast-enhanced CT images of the validation cohort were retrospectively collected at Beijing Cancer Hospital from January 2018 to December 2018. The diagnostic performance of the selected imaging feature, including accuracy, sensitivity, and specificity, was validated and compared with the conventional clinical tumor stage (cT) by the McNemar test.

RESULTS

In the training cohort, a total of 268 patients were enrolled, and only SAS was significantly different between pT1-3 and pT4a tumors. The accuracy, sensitivity, and specificity of the SAS and conventional cT in differentiating T1-3 and T4a tumors were 94.4%, 81.6%, and 97.3% and 53.7%, 32.7%, and 58.4%, respectively (all p < 0.001). In the validation cohort, a total of 135 patients were collected. The accuracy, sensitivity, and specificity of the SAS and the conventional cT were 93.3%, 76.2%, and 96.5% and 62.2%, 38.1%, and 66.7%, respectively (p < 0.001, p = 0.021, p < 0.001).

CONCLUSION

Small arteriole sign positivity, an indirect imaging feature of serosa invasion, may improve the accuracy of identifying T4a colon cancer.

CLINICAL RELEVANCE STATEMENT

Small arteriole sign helps to distinguish T1-3 and T4a colon cancer and further improves the accuracy of preoperative CT staging of colon cancer.

KEY POINTS

• The accuracy of preoperative CT staging of colon cancer is not ideal, especially for T4a tumors. • Small arteriole sign (SAS) is a newly defined imaging feature that shows the appearance of tumor-supplying arterioles at the site where they penetrate the intestine wall. • SAS is an indirect imaging marker of tumor invasion into the serosa with a great value in distinguishing between T1-3 and T4a colon cancer.

Presence of tumor deposits is a strong indicator of poor outcome in patients with stage III colorectal cancers undergoing radical surgery

BACKGROUND

Tumor deposits (TDs) are emerging as an adverse prognostic factor in colorectal cancers (CRCs). However, TDs are somewhat neglected in the current staging system. It has been proposed either to add the TD count to the number of metastatic lymph nodes or to consider TDs as distant metastases; however, the scientific basis for these proposals seems questionable. This study aimed to investigate a new staging system.

METHODS

A total of 243 consecutive patients with stage III CRC who were undergoing curative resection and adjuvant chemotherapy were included. Each substage of stage III TNM was split according to the absence or presence of TDs. Receiver operating characteristic (ROC) curves and bootstrap methods were used to compare the current vs the new competing staging system in terms of oncologic outcome prediction.

RESULTS

A high rate of TDs was recorded (124 cases [51%]). TDs were correlated with other adverse prognostic indicators, particularly vascular and perineural invasions, and showed a negative correlation with the number of removed lymph nodes, suggesting a possible multimodal origin. In addition, TDs were confirmed to have a negative impact on oncologic outcome, regardless of their counts. Compared with the current staging system, the new classification displayed higher values at survival ROC analysis, a significantly better stratification of patients, and effective identification of patients at high risk of recurrence.

CONCLUSIONS

TDs negatively affect the prognosis in CRCs. A revision of the staging system could be useful to optimize treatments. The proposed new classification is easy to implement and more accurate than the current one. This study was registered online on the ClinicalTrials.gov website under the following identifier: NCT05923450.

Assessment of Elastic Laminal Invasion Contributes to an Objective pT3 Subclassification in Colon Cancer

The extent of tumor spread influences on the clinical outcome, and which determine T stage of colorectal cancer. However, pathologic discrimination between pT3 and pT4a in the eighth edition of the American Joint Committee on Cancer (AJCC)-TNM stage is subjective, and more objective discrimination method for deeply invasive advanced colon cancer is mandatory for standardized patient management. Peritoneal elastic laminal invasion (ELI) detected using elastic staining may increase the objective discrimination of deeply invasive advanced colon cancer. In this study, we constructed ELI study group to investigate feasibility, objectivity, and prognostic utility of ELI. Furthermore, pT classification using ELI was investigated based on these data. At first, concordance study investigated objectivity using 60 pT3 and pT4a colon cancers. Simultaneously, a multi-institutional retrospective study was performed to assess ELI's prognostic utility in 1202 colon cancer cases from 6 institutions. In the concordance study, objectivity, represented by κ, was higher in the ELI assessment than in pT classification. In the multi-institutional retrospective study, elastic staining revealed that ELI was a strong prognostic factor. The clinical outcome of pT3 cases with ELI was significantly and consistently worse than that of those without ELI. pT classification into pT3 without ELI, pT3 with ELI, and pT4a was an independent prognostic factor. In this study, we revealed that ELI is an objective method for discriminating deeply invasive advanced colon cancer. Based on its feasibility, objectivity, and prognostic utility, ELI can subdivide pT3 lesions into pT3a (without ELI) and pT3b (with ELI).

Recent advances of pathomics in colorectal cancer diagnosis and prognosis

Colorectal cancer (CRC) is one of the most common malignancies, with the third highest incidence and the second highest mortality in the world. To improve the therapeutic outcome, the risk stratification and prognosis predictions would help guide clinical treatment decisions. Achieving these goals have been facilitated by the fast development of artificial intelligence (AI) -based algorithms using radiological and pathological data, in combination with genomic information. Among them, features extracted from pathological images, termed pathomics, are able to reflect sub-visual characteristics linking to better stratification and prediction of therapeutic responses. In this paper, we review recent advances in pathological image-based algorithms in CRC, focusing on diagnosis of benign and malignant lesions, micro-satellite instability, as well as prediction of neoadjuvant chemoradiotherapy and the prognosis of CRC patients.

Tumor deposits in colorectal cancer: Refining their definition in the TNM system

Tumor deposits (TDs) are discontinuous tumor spread in the mesocolon/mesorectum which is found in approximately 20% of colorectal cancer (CRC) and negatively affects survival. We have a history of repeated revisions on TD definition and categorization in the tumor-node-metastasis (TNM) system leading to stage migration. Since 1997, TDs have been categorized as T or N factors depending on their size (TNM5) or contour (TNM6). In 2009, TNM7 provided the category of N1c for TDs in a case without positive lymph nodes (LNs), which is also used in TNM8. However, increasing evidence suggests that these revisions are suboptimal and only "partially" successful. Specifically, the N1c rule is certainly useful for oncologists who are having difficulty with TDs in a case with no positive LNs. However, it has failed to maximize the value of the TNM system because of the underused prognostic information of individual TDs. Recently, the potential value of an alternative staging method has been highlighted in several studies using the "counting method." For this method, all nodular type TDs are individually counted together with positive LNs to derive the final pN, yielding a prognostic and diagnostic value that is superior to existing TNM systems. The TNM system has long stuck to the origin of TDs in providing its categorization, but it is time to make way for alternative options and initiate an international discussion on optimal treatment of TDs in tumor staging; otherwise, a proportion of patients end up missing an opportunity to receive the optimal adjuvant treatment.

Tumor budding as a predictor for prognosis and therapeutic response in gastric cancer: A mini review

In recent years, the role of tumor budding in gastric cancer has received increased attention across a number of disciplines. Several studies have found associations between tumor budding and the prediction of lymph node metastasis in early gastric cancer, prognosis of advanced gastric cancer, predictors of therapeutic response to immune checkpoint inhibitors, such as microsatellite instability (MSI), and therapeutic targets of molecular targeted therapy, such as human epidermal growth factor receptor 2 (HER-2). Therefore, tumor budding is a major element in the formulation of risk stratification and precision medicine strategies for patients with gastric cancer.

Prognostic impact of tumor deposits on overall survival in colorectal cancer: Based on Surveillance, Epidemiology, and End Results database

BACKGROUND

In colorectal cancer, tumor deposits (TDs) are considered to be a prognostic factor in the current staging system, and are only considered in the absence of lymph node metastases (LNMs). However, this definition and the subsequent prognostic value based on it is controversial, with various hypotheses. TDs may play an independent role when it comes to survival and addition of TDs to LNM count may predict the prognosis of patients more accurately.

AIM

To assess the prognostic impact of TDs and evaluate the effect of their addition to the LNM count.

METHODS

The patients are derived from the Surveillance, Epidemiology, and End Results database. A prognostic analysis regarding impact of TDs on overall survival (OS) was performed using Cox regression model, and other covariates associating with OS were adjusted. The effect of addition of TDs to LNM count on N restaging was also evaluated. The subgroup analysis was performed to explore the different profile of risk factors between patients with and without TDs.

RESULTS

Overall, 103755 patients were enrolled with 14131 (13.6%) TD-positive and 89624 (86.4%) TD-negative tumors. TD-positive patients had worse prognosis compared with TD-negative patients, with 3-year OS rates of 47.3% (95%CI, 46.5%-48.1%) and 77.5% (95%CI, 77.2%-77.8%, P < 0.0001), respectively. On multivariable analysis, TDs were associated poorer OS (hazard ratio, 1.35; 95%CI, 1.31-1.38; P < 0.0001). Among TD-positive patients, the number of TDs had a linear negative effect on disease-free survival and OS. After reclassifying patients by adding TDs to the LNM count, 885 of 19 965 (4.4%) N1 patients were restaged as pN2, with worse outcomes than patients restaged as pN1 (3-year OS rate: 78.5%, 95%CI, 77.9%-79.1% vs 63.2%, 95%CI, 60.1%-66.5%, respectively; P < 0.0001).

CONCLUSION

TDs are an independent prognostic factor for OS in colorectal cancer. The addition of TDs to LNM count improved the prognostic accuracy of tumor, node and metastasis staging.

Advances in the management of peritoneal malignancies

Peritoneal surface malignancies (PSMs) are usually associated with a poor prognosis. Nonetheless, in line with advances in the management of most abdominopelvic metastatic diseases, considerable progress has been made over the past decade. An improved understanding of disease biology has led to the more accurate prediction of neoplasia aggressiveness and the treatment response and has been reflected in the proposal of new classification systems. Achieving complete cytoreductive surgery remains the cornerstone of curative-intent treatment of PSMs. Alongside centralization in expert centres, enabling the delivery of multimodal and multidisciplinary strategies, preoperative management is a crucial step in order to select patients who are most likely to benefit from surgery. Depending on the specific PSM, the role of intraperitoneal chemotherapy and of perioperative systemic chemotherapy, in particular, in the neoadjuvant setting, is established in certain scenarios but questioned in several others, although more prospective data are required. In this Review, we describe advances in all aspects of the management of PSMs including disease biology, assessment and improvement of disease resectability, perioperative management, systemic therapy and pre-emptive management, and we speculate on future research directions.

Risk factors for metachronous peritoneal carcinomatosis after radical resection for patients with nonmetastatic pT3-4 colon cancer

BACKGROUND

Patients with nonmetastatic pT3-4 colon cancers are prone to develop metachronous peritoneal carcinomatosis (mPC). Risk factors for mPC and the influence of mutant kirsten rat sarcoma viral oncogene (KRAS)/neuroblastoma rat sarcoma (NRAS)/v-raf murine sarcoma viral oncogene homolog B1 (BRAF) and DNA mismatch repair (MMR) status on mPC remain to be described in these patients.

METHOD

All enrolled patients were identified from the prospectively collected colorectal cancer database of a tertiary referral hospital between 2013 and 2018. Multivariate analysis was used to identify risk factors associated with mPC.

RESULTS

Of the 1689 patients with nonmetastatic pT3-4 colon carcinoma, 8.4% (142/1689) progressed to mPC. Endoscopic obstruction (HR = 3.044, p < 0.001), elevated CA125 (HR = 1.795, p = 0.009), pT (T4a vs. T3, HR = 2.745, p < 0.001; T4b vs. T3, HR = 3.167, p = 0.001), pN (N1 vs. N0, HR = 2.592, p < 0.001; N2 vs. N0, HR = 4.049, p < 0.001), less than 12 lymph nodes harvested (HR = 2.588, p < 0.001), mucinous or signet ring cell carcinoma (HR = 1.648, p = 0.038), perineural invasion (HR = 1.984, p < 0.001), and adjuvant chemotherapy (HR = 1.522, p = 0.039) were strongly related to mPC but that mutant KRAS/NRAS/BRAF and MMR status was not associated with mPC.

CONCLUSION

This study identified the high-risk factors for mPC in patients with nonmetastatic pT3-4 colon carcinoma, and these factors should be considered in selective preventive therapy and close follow-up for patients subsequently deemed to have high risk for mPC.

Prognostic Value of Tumor Deposit Counts in Patients with Stage III Colorectal Cancer: A Population-Based Study

OBJECTIVE

To investigate the prognostic value of tumor deposits (TDs) counts in stage III colorectal cancer (CRC) patients and develop a prognostic nomogram.

METHODS

Data on stage III CRC patients from 2010 to 2015 were collected from the Surveillance, Epidemiology, and End Results (SEER) database. The Kaplan-Meier analysis was used to assess differences in survival outcomes among patients. The Cox regression analysis was performed to establish the independent prognostic factors for cancer-specific survival and to establish a nomogram. The nomograms' performance was evaluated by calibration plots and concordance index (C-index). Decision curve analysis (DCA) was used to assess the clinical utility of the prediction model.

RESULTS

A total of 23,345 CRC patients were included in this study, and 3,578 (15.3%) had TDs. Cox multivariate regression analyses revealed that age, race, histological tumor grade, the administered chemotherapy, pathological type, T-stage, CEA, N-stage, peripheral nerve invasion, and TDs were independent prognostic factors. Patients with many TDs (=0/1-4, HR: 1.325,/≥5 HR: 2.223) had poorer cancer-specific survival. The prognostic value of the number of TDs was comparable to that of lymph node metastasis. The C-indices of the nomogram were superior to TNM staging in training (0.730 vs 0.646) and validation (0.714 vs 0.636) groups. DCA revealed that the nomogram had a higher clinical net benefit compared to TNM staging.

CONCLUSIONS

TDs count is an adverse prognostic factor for stage III CRC patients. Furthermore, the TDs-based nomogram can accurately predict the prognostic outcomes for stage III CRC.

How Best to Play the Role of Tumor Deposits in Stage III Colon Cancer?

Background

The purpose of this study is to comprehensively evaluate the prognostic role of tumor deposits (TD) in stage III colon cancer.

Methods

24,600 CC patients with III stage colon cancer were collected from the Surveillance, Epidemiology, and End Result (SEER) database and 618 CC patients from the Second Affiliated Hospital of Harbin Medical University. All patients were divided into development, internal, and external validation cohorts. The combination of positive lymph nodes (PLN) and the status or number of TD was defined as modified pN (mpN) and novel pN (npN). The Cox proportional hazard regression model was used to analyze the relationship between cancer-specific survival (CSS) and mpN or npN. CSS stratified by pN, mpN, and npN was analyzed by the Kaplan–Meier curves. The area under the receiver operating characteristic curve (AUC) was used to demonstrate the predictive abilities of the pN, mpN, and npN stages. The validation cohorts were used to validate the results.

Results

The Cox proportional hazard regression model showed that mpN and npN were an independent prognostic factor for CSS. AUC showed that the predictive accuracy of mpN was better than that of the pN stage for 5-year CSS in the development (0.621 vs. 0.609, p < 0.001) and internal validation cohorts (0.618 vs. 0.612, p = 0.016) and the npN was also better than the pN stage for 5-year CSS in the development (0.623 vs. 0.609, p < 0.001) and internal validation cohorts (0.620 vs. 0.612, p = 0.001). However, there was no significant difference between the AUCs of mpN and npN. Moreover, the pN stage for 5-year CSS in the external validation cohort is 0.606 vs. 0.563, p = 0.045.

Conclusions

In stage III CC, mpN and npN may be superior to the pN stage in assessing prognosis, suggesting that the TD information should be included in the pN stage.

Prognostic and staging value of tumor deposits in patients with rectal cancer after neoadjuvant chemoradiotherapy

Background

The presence of tumor deposits (TDs) is only considered in the absence of lymph node metastases (LNMs) in the current TNM staging system. However, the prognostic value of TDs when concomitant with LNM for rectal cancer after neoadjuvant chemoradiotherapy (NCRT) remains unclear. This study aimed to evaluate the prognostic value of TDs and when concomitant with LNMs in rectal cancer after NCRT.

Methods

Patients with rectal cancer who had received NCRT between 2010 and 2016 were obtained from the Surveillance, Epidemiology and End Results (SEER) 18 (year range, 1975–2016) database. Data were extracted on the following: age, sex, race, TNM stage, total LNs harvested, positive LNs, histologic type, perineural invasion, grade, carcinoma embryonic antigen status, TD number, and cancer-specific survival (CSS) rates. The primary objective was to determine the prognostic impact of TDs on CSS. The effect of the addition of TD to the LNM count for a novel N stage was also evaluated. Univariate and multivariate analyses were performed using the Kaplan-Meier method and Cox models.

Results

Of 9,620 patients, 865 (9.0%) had TDs. TD-positive patients showed a worse prognosis than TD-negative patients (HR =2.39, 95% CI: 2.04–2.80, P<0.001), and multivariate analysis showed that the presence of TDs was an independent poor prognostic factor (HR =1.41, 95% CI: 1.19–1.67, P<0.001). Regarding the LN status, TDs were associated with a higher risk of cancer-specific death in the LNM- group (HR =2.43, 95% CI: 1.86–3.18, P<0.001), M1 group (HR =1.51, 95% CI: 1.08–2.10, P<0.001), and ypN1 group (HR =2.08, 95% CI: 1.61–2.70, P<0.001), but not in the ypN2 group (HR =0.97, 95% CI: 0.69–1.36, P=0.84). Patients with concomitant TDs and LNM showed significantly worse survival than those with TDs or LNM alone (5-year CSS: 48.2%, 72.2%, and 67.8%, respectively). The 5-year CSS rates were 86.2%, 77.4%, 65.1%, 53.8%, and 46.5% for the novel N0, N1a, N1b, N2a, and N2b groups, respectively (P<0.05 across all groups). Time dependent receiver operating characteristic curve analysis and decision curve analysis showed that the novel N stage was superior to the current ypN stage.

Conclusions

The presence of TDs is an independent poor prognostic factor for LARC patients after NCRT. The concomitant presence of TDs and LNM indicates a significantly worse survival, and the addition of TD to LNM may help to better prompt appropriate risk stratification.

Prognostic value of tumor deposits for long-term oncologic outcomes in patients with stage III colorectal cancer: a systematic review and meta-analysis

PURPOSE

The presence of tumor deposits (TDs) in colorectal cancer is associated with a poor prognosis. In patients with the concomitant presence of both TDs and lymph nodes (LNs), there is no staging option except for the number of positive LNs alone. Therefore, to determine the prognostic value of TDs in patients with stage III colorectal cancer, meta-analyses of survival outcomes of patients with TDs were performed comparing different subgroups based on the lymph node status.

METHODS

PubMed, EMBASE, and the Cochrane Library were searched. Data were pooled, and overall effect size was calculated using random-effect models. Outcome measures were 5-year overall survival (OS) and 5-year disease-free survival (DFS).

RESULTS

We included in the analysis 18 nonrandomized studies and 1 prospective study that examined 90,455 patients. N1c patients (TD + LN-) had worse 5-year DFS than TDs-negative stage III patients (TD-LN +) with a RR of 1.30 (95% CI 1.06-1.61, I² = 47%). In subgroup analysis, N1c patients had worse 5-year DFS (RR = 1.60, 95% CI = 1.25-2.05, I² = 40%) compared with TDs-negative N1 patients (TD-N1) whereas N1c patients had better 5-year OS (RR = 0.72, 95% CI = 0.62-0.83, I² = 0%) and 5-year DFS (RR = 0.75, 95% CI = 0.57-0.99, I² = 0%) compared with TDs-negative N2 patients (TD-N2).

CONCLUSIONS

These results may suggest that current nodal staging for colorectal cancer needs modification. The presence of TDs may have more adverse oncologic outcomes than TDs-negative N1 patients. More studies are warranted to further verify these results.

Pathology and Prognosis of Colonic Adenocarcinomas With Intermediate Primary Tumor Stage Between pT2 and pT3

CONTEXT.—

Primary tumor stage (pT) is an important prognostic indicator in colonic adenocarcinomas; however, cases that have no muscle fibers beyond the advancing tumor edge but also show no extension beyond the apparent outer border of muscularis propria (termed pT2int), have not been previously studied.

OBJECTIVE.—

To address the clinicopathologic characteristics and prognosis of pT2int tumors.

DESIGN.—

We recharacterized 168 colon carcinomas and compared pT2int cases to bona fide pT2 and pT3 tumors.

RESULTS.—

In side-by-side analysis, 21 pT2int cases diverged from 29 pT2 tumors only in terms of larger size (P = .03), but they were less likely to show high-grade (P = .03), lymphovascular (P < .001), and extramural venous invasion (P = .04); discontinuous tumor deposits (P = .02); lymph node involvement (P = .001); and advanced stage (P = .001), compared with 118 pT3 tumors. Combining pT2int with pT2 cases (versus pT3) was a better independent predictor of negative lymph nodes in multivariate analysis (P = .04; odds ratio [OR], 3.96; CI, 1.09-14.42) and absent distant metastasis in univariate analysis (P = .04), compared with sorting pT2int with pT3 cases (versus pT2). Proportional hazards regression showed that pT2 and pT2int cases together were associated with better disease-free survival compared with pT3 tumors (P = .04; OR, 3.65; CI, 1.05-12.70). Kaplan-Meier analysis demonstrated that when pT2int were grouped with pT2 tumors, they were significantly less likely to show disease progression compared with pT3 (P = .002; log-rank test) and showed a trend toward better disease-specific survival (P = .06), during a mean patient follow-up of 44.9 months.

CONCLUSIONS.—

These data support the conclusion that pT2int carcinomas have clinicopathologic characteristics and are associated with patient outcomes more closely aligned with pT2 rather than pT3 tumors.

Smooth muscular layer: A new helpful criterion to reclassify tumor deposits into metastatic lymph nodes in patients with colo-rectal adenocarcinoma

CONTEXT

The origin of tumor deposit in colorectal cancer is still unknown, and currently there is no single morphological feature to distinguish a metastatic lymph node from a tumor deposit. Histologically, the normal lymph node capsule and trabeculae contain a smooth muscular layer, which when present in extramural deposits would strongly suggest their lymph node origin.

OBJECTIVE

We analyze the value of the smooth muscular layer criterion in reclassifying tumor deposit into metastatic lymph node.

DESIGN

A total of 458 colo-rectal carcinomas surgical specimens treated or not by neoadjuvant (radio)chemotherapy were retrospectively included. Harvested tumor deposits were analyzed by Hematoxylin and Eosin and elastin staining on 10 consecutive serial sections and by α- smooth muscle actin immunostaining.

RESULTS

A total of 129 tumor deposits were identified. 77 (60%) tumor deposits were reclassified into metastatic lymph node, of which 63 (49%) presented a smooth muscular layer on the initial Hematein Eosin staining and/or after serial tissue sections, confirmed by positive α-smooth muscle actin immunostaining in 43 out of 45 cases (90%). Fourteen (18%) additional tumor deposits were reclassified into metastatic lymph node by the appearance of lymphoid tissue after serial sections.

CONCLUSIONS

The presence of a smooth muscular layer in a presumable tumor deposit is helpful in pointing out its lymph node origin in patients with colo-rectal carcinomas. This criterion could improve the inter-observer agreement of tumor deposit identification, allowing accurate nodal staging and better assessment of patient's prognosis.

Prognostic value of tumor deposits in locally advanced rectal cancer: a retrospective study with propensity score matching

BACKGROUND

The actual risks posed by tumor deposits (TDs) in colorectal cancer are still incompletely assessed. We explored the prognostic value of TDs in locally advanced rectal cancer (LARC) patients using propensity score matching (PSM) method.

METHODS

Consecutive LARC patients in Peking University First Hospital between 2011 and 2015 were retrospectively analyzed. Kaplan-Meier methods and Cox proportional hazard regression analysis were conducted to explore prognostic values of TDs. PSM method was conducted to minimize selection bias. The correlation between TDs number and prognosis was explored.

RESULTS

Four hundred and fifty-one LARC patients were recruited, and 78 (17.3%) patients were with TDs. Multivariate Cox analysis identified that the presence of TDs was an independent prognostic risk factor for overall survival (OS) (P = 0.044). PSM identified 76 matched pairs of LARC patients, and Kaplan-Meier curves revealed that patients with TDs experienced worse  OS (log-rank P = 0.0220) and relapse-free survival (RFS) (log-rank P = 0.0117). Subgroup analysis of 50 pairs extracted by PSM from 246 LARC patients with lymph node metastasis (LNM) further proved that TDs were significantly associated with worse OS (log-rank P = 0.0415), and the association was barely significant for RFS (log-rank P = 0.0527). There were non-significant tendencies towards higher mortality in TDs ≥ 2 than TD = 1 group (log-rank P = 0.348 for OS, log-rank P = 0.087 for RFS).

CONCLUSION

Our study manifested that the presence of TDs was an independent risk factor for LARC patients. The prognostic value of TDs for LARC patients with LNM should not be ignored.

T3 versus T4a staging challenges in deeply invasive colonic adenocarcinomas and correlation with clinical outcomes

Despite the latest 8th edition American Joint Committee on Cancer Staging Manual guidelines, disagreement still exists among pathologists regarding staging deeply invasive colonic adenocarcinomas ≤1 mm to the serosal surface. In this retrospective study, 151 untreated colonic adenocarcinomas staged initially as either pT3 or pT4a and with available 5-year follow-up data were retrieved and re-categorized: Group 1 (38 cases): pT4a with tumor at the serosa; Group 2 (49 cases): tumor ≤1 mm from the serosa, with intervening reactive fibrosis (40/49) or inflammation (9/49); Group 3 (64 cases): pT3 tumor >1 mm from the serosa. Clinical outcomes were analyzed. Groups 1 and 2 tumors showed significantly lower 5-year recurrence-free survival and lower overall survival rates (log-rank p < 0.001 for both), when compared with Group 3 tumors. Even after adjusting for adjuvant therapy and nodal metastases, the proportional hazards ratios for the risk of death (p < 0.001) and risk of recurrence (p = 0.005) showed significantly higher risk in Groups 1 and 2 compared with Group 3. The synchronous nodal (p = 0.012) and metachronous distant metastases (p = 0.004) were also significantly more in Groups 1 and 2 versus Group 3. Colonic adenocarcinomas ≤1 mm from the serosal surface behaved more akin to "bona fide" pT4a tumors at the serosal surface in our study with regards to clinical outcomes. We recommend these tumors be staged as pT4a rather than pT3, as supported by outcome data in our study. We hope this will also ensure reproducibility and consistency in staging these tumors across institutions.

A Modified Pathological N Stage Including Status of Tumor Deposits in Colorectal Cancer With Nodal Metastasis

Background

The American Joint Committee on Cancer 8th classification states that colorectal cancer (CRC) is classified as N1c stage when regional lymph nodes (LNs) are negative and tumor deposits (TDs) are positive. However, how to classify TDs when regional LNs are positive remains unclear. The current study aimed to investigate the possibility of combining positive LNs and positive TDs to develop a modified pathological N (mpN) stage for CRC.

Methods

We retrospectively analyzed 9,198 patients with stage III CRC from the Surveillance, Epidemiology, and End Results program who underwent surgery (6,440 in the training cohort and 2,758 the validation cohort). The combination of positive LNs and TD status was defined as mpN stage. Overall survival (OS) according to mpN and pathological N (pN) stages was analyzed by the Kaplan–Meier method. The area under the curves (AUCs) and Akaike’s information criterion (AIC) were applied to assess the predictive discrimination abilities and goodness-of-fit of the model. The clinical benefits were measured using decision curve analyses. The validation cohort was used to validate the results.

Results

AUC analysis showed that the prognostic discrimination of mpN stage (AUC = 0.628, 95% confidence interval (CI), 0.616–0.640) was better than that of pN stage (AUC = 0.618, 95% CI, 0.606–0.630, p = 0.006) for OS. The AIC demonstrated that mpN stage (AIC = 30,217) also showed superior model-fitting compared with pN stage (AIC = 30,257) and decision curve analyses revealed that mpN stage had better clinical benefits than pN stage. Similar results were found in the validation cohort.

Conclusions

Among patients with CRC and LN metastasis, mpN stage might be superior to pN stage for assessing prognosis and survival, suggesting that TD status should be included in the pN stage.

Reproducibility of AJCC Criteria for Classifying Deeply Invasive Colon Cancers Is Suboptimal for Consistent Cancer Staging

The eighth edition of the American Joint Committee on Cancer (AJCC) Staging Manual attempts to address ambiguity in the pT category assignment for colon cancer from prior editions. Despite modifications, the distinction between the pT3 and pT4a categories continues to be a source of diagnostic confusion. In this study, we assessed interobserver agreement among pathologists from different institutions in the application of AJCC eighth edition criteria for categorizing deeply invasive colonic adenocarcinomas. We identified morphologic patterns that produce diagnostic confusion. We assessed 47 colon cancers that closely approached the serosal surface. Six pathologists with interest in gastrointestinal pathology and 4 focused in other subspecialties classified each case as pT3 or pT4a, based on examination of low-magnification and high-magnification images of the most deeply invasive area. Interobserver agreement was assessed using Fleiss' κ. Cases displayed 3 morphologic patterns at the advancing tumor edge, namely, (1) continuous invasion through an inflammatory focus, (2) pushing border, and (3) infiltrative glands and cell clusters with serosal reaction. Gastrointestinal pathologists achieved slight (κ=0.21) or moderate (κ=0.46) and (κ=0.51) agreement in each category, whereas agreement among nongastrointestinal pathologist was fair (0.31) and (0.39), or moderate (0.57) for each category, respectively. In 10 (21%) cases, the distinction between pT3 and pT4a would have changed the overall clinical stage. We conclude that histologic criteria for serosal penetration is a persistent source of diagnostic ambiguity for gastrointestinal and general pathologists in the pT categorization of colon cancers. Clarification of these criteria will help ensure uniform reporting of pathologic and clinical stage.

Interobserver, intraobserver, and interlaboratory variability in reporting pT4a colon cancer

Clinical significance of the pT4 category in colon cancer is increasing with several therapeutic implications. The aim of this study was to evaluate variability in diagnosing pT4a colon cancer. Twelve pathologists classified 66 preselected scanned Hematoxylin/Eosin-stained slides with tumor cells at a distance of 25-1500 μm (n = 22), 0-25 μm (n = 22), or on (n = 22) the peritoneal surface. Inter- and intraobserver variability were calculated using Kappa statistics. For interlaboratory variability, pathology reports of pT3 and pT4a colon cancer were extracted from the Dutch Pathology Registry between 2012 and 2015. The proportion of pT4a (pT4a/(pT3+pT4a)) was compared between 33 laboratories. Potential risk of understaging was assessed by determining the average number of blocks taken from pT3 and pT4a N0-2M0 tumors with metachronous peritoneal metastasis. Interobserver variability among 12 pathologists was 0.50 (95%CI 0.41-0.60; moderate agreement). Intraobserver variability (8 pathologists) was 0.71 (substantial agreement). A total of 7745 reports with pT3 or pT4aN0-2M0 colon cancer from 33 laboratories were included for interlaboratory analysis. Median percentage of pT4a was 15.5% (range 3.2-24.6%). After adjustment for case mix, 8 labs diagnosed pT4a significantly less or more frequently than the median lab. Metachronous peritoneal metastases were histologically verified in 170 of 6629 pT3 and in 129 of 1116 pT4a tumors, with a mean number of blocks of 4.03(SD 1.51) and 4.78 (SD 1.76) taken from the primary tumors, respectively (p < 0.001). A substantial variability in diagnosing pT4a colon cancer exists, both at pathologist and laboratory level. Diagnosis of pT4a stage appears to be challenging and there is a need for standardizing assessment of this pathological entity.

Challenges with colorectal cancer staging: results of an international study

Challenges exist with standardized colorectal cancer reporting despite adoption of the American Joint Committee on Cancer-Staging Manual 8th edition. We performed this study to gauge current practice patterns among a diverse group of surgical pathologists. A web-based questionnaire depicting problematic issues and images related to colorectal carcinoma staging was circulated among 118 surgical pathologists and their responses were correlated with their geographic location (North America vs. Europe vs. others), nature of practice (academic vs. community), the sign-out model (gastrointestinal subspecialty vs. general surgical pathology), and years of professional experience. We found that a substantial number of practicing pathologists ignore recommended-staging criteria in specific settings, particularly with respect to assessment of advanced T stage. Tumors that communicated with the serosa through inflammatory foci were staged as pT3 (49%) or pT4a (51%) by nearly equal numbers of pathologists regardless of level of experience, the sign-out model, or geographic location. Only 65% assigned T stage and margin status based on extent of viable tumor in the neoadjuvant setting. One-third of pathologists, particularly those in Europe (p = 0.015), classified acellular mucin deposits as N1 disease when detected in treatment-naive cases. Nearly 50% of pathologists classified isolated tumor cells (i.e., deposits <0.2 mm) in lymph nodes as metastatic disease (i.e., pN1, p = 0.02). Our results suggest that pathologists ignore recommendations that are based on insufficient data and apply individualized criteria when faced with situations that are not addressed in the American Joint Committee on Cancer Staging Manual 8th edition. These variations in practice limit the ability to compare outcome data across different institutions and draw attention to areas that require further study.

The unique prognostic characteristics of tumor deposits in colorectal cancer patients

Background

Both AJCC 7th and 8th TNM systems have included tumor deposits (TDs) in nodal staging when lymph nodes metastases (LNMs) are negative in colorectal cancer (CRC). However, the prognostic role of TDs has not been determined in the presence of positive LNMs.

Methods

Two independent large-scale cohorts of CRC patients from the Surveillance Epidemiology and End Results (SEER) database (n=69,178) [2010-2013] and Fudan University Shanghai Cancer Center (FUSCC) (n=3,137) [2010-2014] were retrospectively analyzed. Kaplan-Meier method was used to estimate survival curves and univariate and multivariate analyses were performed by Cox proportional hazard model.

Results

TDs were observed in 12.3% (n=8,480) and 14.8% (n=463) of patients in the SEER and FUSCC cohorts, respectively. Multivariate analysis suggested TDs were an independent adverse prognostic factors for overall survival (OS) (P<0.001). Remarkably, both cohorts showed the presence of TDs was significantly associated with OS, but not was the number of TDs (P=0.982 and P=0.252 for the SEER and FUSCC cohorts, respectively). In the presence of LNMs, positive TDs were associated with a shorter OS [hazard ratio (HR): 2.69, 95.0% confidence interval (CI): 2.597-2.778; P<0.001]. Further analysis combining TDs with LNMs demonstrated that the prognosis of patients with N1TD (N1 with positive TDs) was same as the N2 patients, and N2TD (N2 with positive TDs) patients had much worse prognosis than N2 (P<0.001).

Conclusions

Our results have shown the unique features of TDs in patients with CRC, different from LNMs. In the presence of LNMs, TDs should also be considered in TMN system.

Mucin Pools Following Neoadjuvant Chemoradiotherapy for Rectal Cancer: A Marker of Response or Epiphenomenon?

Neoadjuvant chemoradiotherapy (CRT) is the standard of care for locally advanced rectal cancer. Morphologic changes such as fibrosis, inflammatory infiltrates, and the formation of extracellular mucin pools can be identified in the resection specimen after neoadjuvant CRT. The association of mucin pool formation with clinicopathologic variables and outcomes is unclear. The aim of this study was to meta-analyze all available evidence with regard to mucin pool formation and clinicopathologic outcomes following neoadjuvant CRT for rectal cancer. A comprehensive search for published studies analyzing outcomes between patients who formed mucin pools and patients who did not following neoadjuvant CRT for rectal cancer was performed. A random-effects model was used to combine the data. This study adhered to the recommendations of the MOOSE (Meta-analyses of Observational Studies in Epidemiology) guidelines. Data from 11 studies describing 1947 patients were included. Mucin pool formation was not associated with sex, T stage, N stage, tumor regression, pathologic complete response rate, lymphovascular invasion, perineural invasion, differentiation, margin status, local or distant recurrence, and disease-free or overall survival. Mucin pool formation is not associated with tumor response or downstaging; furthermore, on the basis of these data, it is not associated with local or systemic recurrence rate or survival.

Prognostic value of N1c in colorectal cancer: a large population-based study using propensity score matching

PURPOSE

We conducted this large population-based study to investigate the prognostic significance of N1c.

METHODS

Patients diagnosed with colorectal cancer from the surveillance, epidemiology, and end results (SEER) database between January 1, 2010, and December 31, 2010, were included in the sample. The primary outcome of interest used in our study was cause-specific survival (CSS). Cox proportional hazards models and Kaplan-Meier methods were used to evaluate the prognostic value of N1c. Propensity score matching (PSM) was implemented to reduce the possibility of selection bias using a logistic regression model.

RESULTS

A total of 19,991 patients diagnosed with colorectal cancer were identified from the SEER database. The median follow-up time of the whole cohort was 60 months (0-71 months). Multivariate Cox analysis showed that N1c was associated with significantly higher risk of colorectal cancer-specific mortality compared with N0 (HR = 1.962, 95%CI = 1.642 to 2.343, P < 0.001) and N1a (HR = 0.818, 95%CI = 0.678 to 0.987, P = 0.036); N1c was associated with significantly lower risk of colorectal cancer-specific mortality compared with N2a (HR = 1.296, 95%CI = 1.081 to 1.554, P = 0.005) and N2b (HR = 1.663, 95%CI = 1.391 to 1.989, P < 0.001). Yet the CSS difference between N1b and N1c did not achieve statistical difference (HR = 1.089, 95%CI = 0.909 to 1.304, P = 0.354).

CONCLUSIONS

The large population-based and propensity score-matched study with long follow-up time provides the first evidence that CSS difference between N1b and N1c does not achieve a statistical difference.

Detailed pathological analysis of the advancing edge of the tumour can effectively stratify clinical T4b colorectal cancer patients

AIMS

Pathological staging of colorectal cancers (CRCs) that involve adhesion to adjacent organs (clinical stages T4b, cT4b) is sometimes difficult because the morphology of the invasive front varies. To resolve this issue, we reviewed 492 surgically resected CRC samples, comprising 96 cT4b tumours and, for comparison, 335 typical pathological stages (p) T3 and 61 pT4a tumours.

METHODS AND RESULTS

Cases were subdivided into four groups according to the presence or absence of microscopic tumour invasion into the muscular wall of the adjacent organs and peritumoral abscess along invasive front. Those that directly invaded the wall of the adjacent organs without peritumoral abscess were associated with a significantly worse overall (OS) and recurrence-free survival (RFS) than the other three types of cT4b tumours. Those with peritumoral abscess showed similar prognosis to typical pT3 tumours, even when the advancing edge of the tumour invaded the wall of adjacent organs (staged as pT4b). Tumours showing fibrous adhesions without tumour cell invasion into the muscular wall of the adjacent organs showed a similar prognosis to typical pT3 tumours and showed a better prognosis than pT4a tumours.

CONCLUSION

Only CRCs with tumour cell invasion into the muscular wall of the adjacent organs should be classified as pT4b, and it might be better to avoid 'the presence of tumour cells in fibrous adhesion' to define pathological T4b CRCs. In addition, the presence of a peritumoral abscess should be recorded as a predictor of better prognosis.

A Review of Current Challenges in Colorectal Cancer Reporting

Context.—

Pathologic assessment of colorectal cancer resection specimens plays an important role in postsurgical management and prognostication in patients with colorectal cancer. Challenges exist in the evaluation and reporting of these specimens, either because of difficulties in applying existing guidelines or related to newer concepts.

Objective.—

To address challenging areas in colorectal cancer pathology and to provide an overview of the literature, current guidelines, and expert recommendations for the handling of colorectal cancer resection specimens in everyday practice.

Data Sources.—

PubMed (US National Library of Medicine, Bethesda, Maryland) literature review; reporting protocols of the College of American Pathologists, the Royal College of Pathologists of the United Kingdom, and the Japanese Society for Cancer of the Colon and Rectum; and classification manuals of the American Joint Committee on Cancer and the Union for International Cancer Control.

Conclusions.—

This review has addressed issues and challenges affecting quality of colorectal cancer pathology reporting. High-quality pathology reporting is essential for prognostication and management of patients with colorectal cancer.

Beyond T, N and M: The impact of tumor deposits on the staging and treatment of colorectal and gastric carcinoma

This review aims to describe the results of the most recent studies on the prognostic value of TDs and highlight the impact of TDs on the staging and treatment of colorectal and gastric carcinoma. For colorectal carcinoma TDs have an adverse prognostic effect that is at least similar to that of positive regional lymph nodes. However, support is growing in favor of including of TDs in the M category, rather than the N or T categories of the TNM classification. Moreover, TDs seem to have an adverse effect on outcomes not only in patients without lymph node involvement but also in patients with nodal involvement. Although the prognostic impact of TDs in gastric cancer appears to be undeniable, the actual prognostic determinants of TDs, particularly in relation to the number, size and histological types, remain to be established. Although the 7th and 8th Edition of the TNM classification of colorectal and gastric carcinoma includes TDs in the N category, no current procedures or methods to assess preoperative or intraoperative N-status allow TD detection. After neoadjuvant treatment for advanced rectal carcinoma, the presence of TDs may indicate incomplete eradication of the main tumor and not discontinuous tumor foci. TDs have an undeniable prognostic impact but no algorithm of staging and strategy of treatment has been conformed to this prognostic factor to overcome the classical T,N, and M prognostic categories. Staging and treatment of colorectal and gastric cancers should be reconsidered in light of the emerging prognostic value of TDs.

Pathologic assessment of gastrointestinal tract and pancreatic carcinoma after neoadjuvant therapy

Neoadjuvant therapy is increasingly used to treat patients with a wide variety of malignancies. Histologic evaluation of treated specimens provides important prognostic information and may guide subsequent chemotherapy. Neoadjuvant therapy is commonly employed in the treatment of locally advanced rectal adenocarcinoma, hepatic colorectal metastases, esophageal/esophagogastric junction carcinoma, and pancreatic ductal adenocarcinoma. Numerous tumor regression schemes have been used in these tumors and standardized approaches to evaluate these specimens are needed. In this review, the various tumor regression scoring systems that have been used in these organs are described and their associations with clinical outcomes are discussed. Recommendations regarding how to handle and report the histologic findings in these resections specimens are provided.

Lymph Node Metastasis in Colorectal Cancer

Pathologic examination of lymph nodes in patients with cancer remains crucial for postoperative treatment and prognosis prediction. In this article, the authors aim to review several important and challenging issues regarding lymph node metastasis in colorectal cancer using the AJCC staging manual, College of American Pathologists cancer protocol, as well as the literature. These topics include lymph node staging, the definition and controversies in tumor deposits, isolated tumor cells in lymph node and micrometastasis, lymph node ratio as a prognostic stratification factor, and neoadjuvant treatment effect in rectal cancer. Updates from the most recent AJCC 8th edition are included.

Extramural vascular invasion detected by contrast-enhanced multiple-row detectors computed tomography (ceMDCT) as a predictor of synchronous metastases in colon cancer

Background

Extramural Vascular Invasion (EMVI) is histologically defined as the presence of tumor cells beyond the muscularis propria in vessels resulting in disease metastases.

Objective

To determine whether EMVI, detected by contrast-enhanced multiple-row detectors computed tomography (MDCT), has closely association with synchronous metastases in colon cancer.

Methods

Patients with pathology proven colon cancer were included in this retrospective study. Preoperative imaging status, including Extramural tumor depth, Lymph nodes, tumor location, and ctEMVI status, were defined on MDCT. Postoperative pathological tumor stage, lymph node stage, and tumor differentiation, were defined in accordance with the American Joint Committee on Cancer (AJCC) 7^th Edition. Synchronous metastases were detected on follow-up MDCT 3 months after initial diagnosis or by surgery, if available. Associations between ctEMVI and other preoperative and postoperative factors were analyzed using Chi-squared tests. Logistic regression analyses were performed to analyze the preoperative and postoperative factors of synchronous metastases in colon cancer.

Results

ctEMVI was observed in 96 patients (96/241, 39.8%). The presence of ctEMVI varied significantly depending on ctEMD (χ2 = 66.557, P<0.001), lymph nodes status on MDCT (χ2 =24.533, P=0.001), pathological tumor status (χ2 = 36.267, P <0.001) and pathological lymph nodes status analyses (χ2 =32.103, P <0.001). Synchronous metastases were seen in 36 patients (36/96, 37.5%) with ctEMVI and 11 (11/145, 7.6%) patients without ctEMVI. The incidence of synchronous metastases was significantly higher in the cohort of positive ctEMVI with odds ratio (OR) of 7.309 (95% CI 3.485∼15.330, P<0.001). Positive ctEMVI (Odds ratio 4.654, 95%CI: 1.987∼10.898, P <0.001) and ctEMD larger than 5 mm (Odds ratio 2.654, 95%CI: 1.116∼6.309, P =0.027) were demonstrated to be significant preoperative factors in predicting synchronous metastases.

Conclusion

MDCT-detected EMVI could be used as a preoperative factor to predict synchronous metastases in colon cancer.

Assessment of lymph node involvement in colorectal cancer

Lymph node metastasis informs prognosis and is a key factor in deciding further management, particularly adjuvant chemotherapy. It is core to all contemporary staging systems, including the widely used tumor node metastasis staging system. Patients with node-negative disease have 5-year survival rates of 70%-80%, implying a significant minority of patients with occult lymph node metastases will succumb to disease recurrence. Enhanced staging techniques may help to identify this subset of patients, who might benefit from further treatment. Obtaining adequate numbers of lymph nodes is essential for accurate staging. Lymph node yields are affected by numerous factors, many inherent to the patient and the tumour, but others related to surgical and histopathological practice. Good lymph node recovery relies on close collaboration between surgeon and pathologist. The optimal extent of surgical resection remains a subject of debate. Extended lymphadenectomy, extra-mesenteric lymph node dissection, high arterial ligation and complete mesocolic excision are amongst the surgical techniques with plausible oncological bases, but which are not supported by the highest levels of evidence. With further development and refinement, intra-operative lymphatic mapping and sentinel lymph node biopsy may provide a guide to the optimum extent of lymphadenectomy, but in its present form, it is beset by false negatives, skip lesions and failures to identify a sentinel node. Once resected, histopathological assessment of the surgical specimen can be improved by thorough dissection techniques, step-sectioning of tissue blocks and immunohistochemistry. More recently, molecular methods have been employed. In this review, we consider the numerous factors that affect lymph node yields, including the impact of the surgical and histopathological techniques. Potential future strategies, including the use of evolving technologies, are also discussed.

Prognostic value of tumour deposit and perineural invasion status in colorectal cancer patients: a SEER-based population study

AIMS

The definition of tumour deposit (TD) in colorectal cancer (CRC) was changed recently in the American Joint Commission on Cancer (AJCC) Staging Manual, 7th edition. We aimed to examine the prognostic values of the newly defined TD and perineural invasion (PNI) in this population study.

METHODS AND RESULTS

We identified the incidental CRC cases with known TD or PNI status in the Surveillance, Epidemiology, and End Results (SEER) programme diagnosed in 2010 and 2011. Kaplan-Meier survival analysis and multivariable Cox proportional hazards models were used to estimate overall survivals (OS) and cancer-specific survival (CSS). We found that 6.71% (2774 of 41 323) of the CRC cases were positive for TD and 9.61% (3970 of 41 215) positive for PNI. In multivariable models, TD- and PNI-positive statuses correlated independently with worse 3-year OS [hazard ratio (HR): 1.68, 95% confidence interval (CI): 1.58-1.80 and HR: 1.24, 95%: CI: 1.16-1.32, respectively] and 3-year CSS (HR: 1.79, 95% CI: 1.65-1.94 and HR: 1.28, 95% CI: 1.18-1.38, respectively, P < 0.001 for all). Other independent prognostic factors included age, T category, N category, tumour location and tumour grade, but not gender. TD and PNI correlated with worse OS in all N categories (P < 0.001 for all). TD-associated HR for 3-year OS increases as the N category becomes lower (1.73 in N2, 2.32 in N1 and 3.24 in N0), while rare (1.4%) TD-positive CRC in N0 category should have been assigned to N1c.

CONCLUSIONS

Tumour deposit and PNI correlate independently with worse 3-year OS and CSS. TD appears prognostically more important in the CRC of lower N categories.