Shape is not associated with the origin of pericolonic tumor deposits

Negative prognostic impact of tumor deposits in stage III colorectal cancer patients

BACKGROUND

The prognostic value of tumor deposits (TDs) in stage III colorectal cancer (CRC) patients is poorly described based on the current tumor node metastasis (TNM) stage system.

MATERIALS AND METHODS

Based on the data from the Surveillance, Epidemiology, and End Result (SEER) database between 2010 to 2020 and local hospital between 2006 to 2022, the clinicopathological features of stage III CRC patients with TDs were screened by Chi-square test. Kaplan-Meier curves were performed to describe the significant difference in overall survival (OS) among the different groups, and log-rank tests were used to compare the cumulative survival distributions.

RESULT

Patients with TDs exhibited more aggressive tumors, characterized by advanced T staging (T3&T4), N staging (N2), perineural invasion, and more advanced TNM stage. The presence of TDs was identified as a negative prognostic factor in stage III CRC patients, with the co-existence of TDs and lymph node metastasis associated the poorest prognosis. A pairwise comparison revealed no statistically significant difference between TD+N1a/b and N1c groups, while the OS of TD-LN+ (TD- N1a/b) patients was the most favorable within the N1 stage. Notably, patients with a single lymph node positive had a significantly better OS than those with a single TD positive.

CONCLUSION

The presence of tumor deposits was a negative prognostic factor in stage III colorectal cancer patients, and the significance of tumor deposits was underestimated in the current TNM staging system.

Micro-Computed Tomography Whole-Block Imaging Reveals Origin and Path of Rectal Cancer Tumor Deposits: A Pilot Study

In colorectal carcinoma (CRC), tumor deposits (TDs) are described as macroscopic/microscopic nests/nodules in the lymph drainage area discontinuous with the primary mass, without identifiable lymph node (LN) tissue, and not confined to vascular or perineural spaces. A TD is categorized as pN1C only when no bona fide LN metastasis exists. However, there has been an ongoing debate on whether TDs should be counted as LNs. The fact that the origin of TDs is not fully understood adds further uncertainty. This pilot study aims to evaluate whether whole-block imaging by micro-computed tomography (micro-CT WBI) that enables three-dimensional reconstruction of whole-mount (WM) blocks can serve as a tool to assess the origin and path of CRC TDs. We evaluated whole-slide imaging (WSI) and micro-CT WBI of 20 WM blocks from a rectal cancer resection that contained TDs. Each TD was tracked through the contiguous blocks to define their origin and path. Of eleven TDs identified on WSI, six were detected on WBI. Strikingly, six of six TDs trackable through the blocks on WBI revealed an origin from the main tumor. This pilot study provided evidence that micro-CT WBI can serve as an effective tool to evaluate the origin and path of CRC TDs.

Tumour deposits are independently associated with recurrence in colon cancer

AIM

Tumour deposits are focal aggregates of cancer cells in pericolic fat and mesentery, distinct from vessels, nerves and lymphatics. Their presence upstages lymph node negative patients but is ignored in lymph node positive patients. We investigated the clinicopathological factors associated with tumour deposits and their impact on recurrence in lymph node positive and negative patients.

METHOD

Clinicopathological variables were collected from the medical records of patients with Stage I-III colon cancer who underwent resection in 2017-2019. Pathology was reviewed by a gastrointestinal pathologist. Patients with rectal cancer, metastasis, and concurrent malignancy were excluded.

RESULTS

Tumour deposits were noted in 69 (9%) of 770 patients. They were associated with the presence of lymph node metastasis, advanced T category, poorly differentiated tumours, microsatellite stable subtype and lymphovascular and perineural invasion (p < 0.05). The presence of tumour deposits (hazard ratio 2.48, 95% CI 1.49-4.10) and of lymph node metastasis (hazard ratio 3.04, 95% CI 1.72-5.37) were independently associated with decreased time to recurrence. There was a weak correlation (0.27) between the number of tumour deposits and the number of positive lymph nodes.

CONCLUSION

Tumour deposits are associated with more advanced disease and high-risk pathological features. The presence of tumour deposits and lymph node metastasis were found to be independent risk factors for decreased time to recurrence. A patient with both lymph node metastasis and tumour deposits is more than twice as likely to have recurrence compared with a patient with only lymph node metastasis. Tumour deposits independently predict recurrence and should not be ignored in lymph node positive patients.

Clinical and Pathologic Predictors of Tumor Deposits in Colorectal Cancer

BACKGROUND

Tumor deposits (TDs) are a special metastatic pattern of colorectal cancer (CRC). This study aims to explore the pathological characteristics of TD and find out the risk factors of TD in CRC.

METHODS

TDs cases of CRC were selected and validated by HE staining. The correlation between TDs and T stages, N stages, and microsatellite instability was calculated by the chi-squared (χ2) test.

RESULTS

A total of 2553 patients with colorectal cancer undergoing intestinal resection were included in this study. Two hundred fifty-nine cases of TDs patients were included. The positive rate of TDs was 1.9% (2/105) in T1, 3.8% (10/266) in T2, 11% (231/2305) in T3, and 22.8% (16/77) in T4. T3 and T4 were more prone to TDs than T1 and T2, but there was no difference between T3 and T4. The positive rate of TDs was 7.2% (107/1491) in N0, 14.3% (152/1062) in N + , and N + was more prone to TDs than N0. The positive rate of TDs was 10.5% (256/2432) in MSS, 2.5% (3/121) in MSI, and MSS was more prone to TDs than MSI. Multivariate analysis showed lymph node invasion, T stage, and MSS were independent risk factors for TDs.

CONCLUSION

Lymph node invasion, T stage, and MSS were independent risk factors for TDs.

The Complexity of Shapes: How the Circularity of Tumor Nodules Affects Prognosis in Colorectal Cancer

The current stratification of tumor nodules in colorectal cancer (CRC) staging is subjective and leads to high interobserver variability. In this study, the objective assessment of the shape of lymph node metastases (LNMs), extranodal extension (ENE), and tumor deposits (TDs) was correlated with outcomes. A test cohort and a validation cohort were included from 2 different institutions. The test cohort consisted of 190 cases of stage III CRC. Slides with LNMs and TDs were annotated and processed using a segmentation algorithm to determine their shape. The complexity ratio was calculated for every shape and correlated with outcomes. A cohort of 160 stage III CRC cases was used to validate findings. TDs showed significantly more complex shapes than LNMs with ENE, which were more complex than LNMs without ENE (P < .001). In the test cohort, patients with the highest sum of complexity ratios had significantly lower disease-free survival (P < .01). When only the nodule with the highest complexity was considered, this effect was even stronger (P < .001). This maximum complexity ratio per patient was identified as an independent prognostic factor in the multivariate analysis (hazard ratio, 2.47; P < .05). The trends in the validation cohort confirmed the results. More complex nodules in stage III CRC were correlated with significantly worse disease-free survival, even if only based on the most complex nodule. These results suggest that more complex nodules reflect more invasive tumor biology. As most of the more complex nodules were diagnosed as TDs, we suggest providing a more prominent role for TDs in the nodal stage and include an objective complexity measure in their definition.

Predictive value of lesion morphology in rectal cancer based on MRI before surgery

OBJECTIVE

To explore the relationship of MRI morphology of primary rectal cancer with extramural vascular invasion (EMVI), metastasis and local recurrence.

MATERIALS AND METHODS

This retrospective study included 153 patients with rectal cancer. Imaging factors and histopathological index including nodular projection (NP), cord sign (CS) at primary tumor margin, irregular nodules (IN) of mesorectum, MRI-detected peritoneal reflection invasion (PRI), range of rectal wall invasion (RRWI), patterns and length of tumor growth, maximal extramural depth (EMD), histologically confirmed local node involvement (hLN), MRI T stage, MRI N stage, MRI-detected extramural vascular invasion (mEMVI) and histologically confirmed extramural vascular invasion (hEMVI) were evaluated. Determining the relationship between imaging factors and hEMVI, synchronous metastasis and local recurrence by univariate analysis and multivariable logistic regression, and a nomogram validated internally via Bootstrap self-sampling was constructed based on the latter.

RESULTS

Thirty-eight cases of hEMVI, fourteen cases of synchronous metastasis and ten cases of local recurrence were observed among 52 NP cases. There were 50 cases of mEMVI with moderate consistency with hEMVI (Kappa = 0.614). NP, CS, EMD and mEMVI showed statistically significant differences in the negative and positive groups of hEMVI, synchronous metastasis, and local recurrence. Compared to patients with local mass growth, the rectal tumor with circular infiltration had been found to be at higher risk of synchronous metastasis and local recurrence (P < 0.05). NP and IN remained as significant predictors for hEMVI, and mEMVI was a predictor for synchronous metastasis, while PRI and mEMVI were predictors for local recurrences. The nomogram for predicting hEMVI demonstrated a C-index of 0.868, sensitivity of 86.0%, specificity of 79.6%, and accuracy of 81.7%.

CONCLUSION

NP, CS, IN, large EMD, mEMVI, and circular infiltration are significantly associated with several adverse prognostic indicators. The nomogram based on NP has good predictive performance for preoperative EMVI. mEMVI is a risk factor for synchronous metastasis. PRI and mEMVI are risk factors for local recurrence.

Predictive value of MRI-detected tumor deposits in locally advanced rectal cancer

Background

Although tumor deposits (TDs) are not the same as lymph nodes, the prognosis of patients with TDs is similar or worse than that of patients with metastatic lymph nodes. TDs are mostly assessed by the histology of samples after surgery, thus, not helpful for preoperative treatment strategies. The primary objective of this study was to detect TDs by MRI and evaluate its predictive value.

Materials and methods

A total of 114 patients with rectal cancer were retrospectively analyzed. Clinicopathological and MRI data mainly including MRI- detected TDs (mTDs), tumor border configuration (TBC) on MRI, MRI-detected extramural vascular invasion (mEMVI), MRI-detected lymph node metastasis (mLN), MRI T stage, MRI N stage, the range of rectal wall involved by the tumor, peritoneal reflection invasion, tumor length, tumor location, cord sign at the tumor edge, nodular protrusion at the tumor edge, maximal extramural depth and pathology-proven lymph node involvement (pLN) were evaluated. The correlation of MRI factors with postoperative distant metastasis (PDM) and pLN were analyzed by univariate analysis and multivariate logistic regression analysis, and nomograms were established based on the latter. The diagnostic efficiency was evaluated by the receiver operating characteristic curve (ROC) and area under the curve (AUC).

Results

A total of 38 cases of pLN, 13 of PDM and 17 of pathology-proven TDs (pTDs) were found. Ten cases of PDM and 22 cases of pLN in 30 mTDs cases were also found. Chi-square test showed that mTDs, mLN, TBC, mEMVI, MRI T stage, nodular protrusion, cord sign, maximal extramural depth and peritoneal reflection invasion were correlated with PDM and pLN (P<0.05). mTDs and peritoneal reflection invasion were independent risk factors for PDM (odds ratio: 10.15 and 8.77, P<0.05), mTDs and mLN were independent risk factors for pLN (odds ratio: 5.50 and 5.91, P<0.05), and Hosmer-Lemeshow test showed that the results of two models were not statistically significant, suggesting that the fit was good. On this basis, two nomograms for predicting PDM and pLN were confirmed by Bootstrap self-sampling, and the C-indices of the two nomograms were 0.837 and 0.817, respectively. The calibration curves and ROC curves of the two nomograms showed that the correlation between the predicted and the actual incidence of PDM and pLN was good. The DeLong test showed that the predictive efficiency of the nomogram in predicting pLN was better than that of mLN (P=0.0129).

Conclusion

mTDs are a risk factor for PDM and lymph node metastasis. The two nomograms based on mTDs showed a good performance in predicting PDM and lymph node metastasis, possessing a certain clinical value.

Tumor deposits are associated with a higher risk of peritoneal disease in non-metastatic colorectal cancer patients

BACKGROUND AND OBJECTIVES

Tumor deposit (TD) is a poor prognostic factor in colorectal cancer (CRC) patients. This study aimed to determine whether TD carry the same risk of peritoneal recurrence as known high-risk (HR) features in CRC patients.

METHODS

A retrospective cohort-study of stage I-III CRC patients from 2010 to 2015 was conducted. TD group was defined by the presence of TD on histopathology whereas HR group was defined by the presence of obstruction, perforation, or T4-stage.

RESULTS

A total of 151 patients with CRC were identified, of which 50 had TD and 101 had a HR feature. The overall risk of peritoneal recurrence was higher in the TD group versus HR group (36.0% vs. 19.8%, p = 0.03). The risk of peritoneum as the site of first recurrence was also higher in the TD group (22.0% vs. 12.9%, p = 0.03). Overall cancer recurrence at any site was also higher in the TD group (56.0% vs. 34.7%, p = 0.01). Median time to first recurrence was 1.2 (0.7-1.9) years in the TD group compared to 1.4 (0.8-2.1) years in the HR group (p = 0.31).

CONCLUSIONS

In non-metastatic CRC patients, TD might have a higher risk of tumor recurrence versus their HR counterparts. Alternative strategies for surveillance and treatment should be considered.

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.

Magnetic resonance imaging radiomics modeling predicts tumor deposits and prognosis in stage T3 lymph node positive rectal cancer

PURPOSE

To develop a magnetic resonance imaging radiomics model to predict tumor deposits (TDs) and prognosis in stage T3 lymph node positive (T3N+) rectal cancer (RC).

METHODS

This retrospective study included 163 patients with pathologically confirmed T3N + RC from December 2013 to December 2015. The patients were divided into two groups for training and testing. Extracting radiomic features from MR images and selecting features using principal component analysis (PCA), then radiomic scores (rad-scores) were obtained by logistic regression analysis. Finally, a combined TDs prediction model containing rad-scores and clinical features was developed. A receiver operating characteristic (ROC) curve was used to assess the prediction performance. The overall survival (OS) rate in patients with high-risk and low-risk TDs predicted by rad-scores was validated by Kaplan-Meier survival curves.

RESULTS

Of the 163 patients included, histological TDs was diagnosed in 45 patients. The area under the curve (AUC) of the final model was 0.833 (training) and 0.844 (testing). The patients with rad-scores predicted high-risk were associated with OS. In addition, postoperative adjuvant therapy improved the OS of the high-risk TDs group (P < 0.05).

CONCLUSION

MRI-based radiomics modeling helps in the preoperative prediction of patients with TDs+ in T3N + RC and provides risk stratification for neoadjuvant therapy. In addition, the rad-scores of TDs could suggest different survival benefits of postoperative adjuvant therapy for T3N + RC patients and guide clinical treatment.

Distinguishing mesorectal tumor deposits from metastatic lymph nodes by using diffusion-weighted and dynamic contrast-enhanced magnetic resonance imaging in rectal cancer

OBJECTIVES

This study aimed to identify whether apparent diffusion coefficient (ADC) values and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) parameters are helpful in distinguishing mesorectal tumor deposits (TD) from metastatic lymph nodes (MLN) in rectal cancer (RC).

METHODS

Thirty patients (59 lesions, including 30 TD and 29 MLN) with RC who underwent pretreatment-MRI between February 2016 and August 2018 were enrolled. The morphological features, ADC values, and semi-quantitative parameters of DCE-MRI, including relative enhancement (RE), maximum enhancement (ME), maximum relative enhancement (MRE), time to peak (TTP), wash-in rates (WIR), wash-out rates (WOR), brevity of enhancement (BRE), and area under the curve (AUC) were measured on lesions (TD or MLN) and RC. The parameters were compared between TD and MLN, tumor with and without TD group by using Fisher's exact test, independent-samples t-test, and Mann-Whitney U test. The ratio (lesion-to-tumor) of the parameters was compared between TD and MLN. Receiver operating characteristic curve analysis and binary logistic regression analysis were used to assess the diagnostic ability of single and combined metrics for distinguishing TD from MLN.

RESULTS

The morphological features, including size, shape, and border, were significantly different between TD and MLN. TD exhibited significantly lower RE, MRE, RE-ratio, MRE-ratio, ADC_min-ratio, and ADC_mean-ratio than MLN. RE-ratio showed the highest AUC (0.749) and accuracy (77.97%) among single parameters. The combination of DCE-MRI and DWI parameters together showed higher diagnostic efficiency (AUC = 0.825).

CONCLUSIONS

Morphological features, ADC values, and DCE-MRI parameters can preoperatively help distinguish TD from MLN in RC.

KEY POINTS

• DWI and DCE-MRI can facilitate early detection and distinguishing mesorectal TD (tumor deposits) from MLN (metastatic lymph nodes) in rectal cancer preoperatively. • TD has some specific morphological features, including relatively larger size, lower short- to long-axis ratio, irregular shape, and ill-defined border on T2-weighted MR images in rectal cancer. • The combination of ADC values and semi-quantitative parameters of DCE-MRI (RE, MRE) can help to improve the diagnostic efficiency of TD in rectal 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.

Radiomics for differentiating tumor deposits from lymph node metastasis in rectal cancer

BACKGROUND

Tumor deposits (TDs) are not equivalent to lymph node (LN) metastasis (LNM) but have become independent adverse prognostic factors in patients with rectal cancer (RC). Although preoperatively differentiating TDs and LNMs is helpful in designing individualized treatment strategies and achieving improved prognoses, it is a challenging task.

AIM

To establish a computed tomography (CT)-based radiomics model for preoperatively differentiating TDs from LNM in patients with RC.

METHODS

This study retrospectively enrolled 219 patients with RC [TDs⁺LNM^- (n = 89); LNM⁺ TDs^- (n = 115); TDs⁺LNM⁺ (n = 15)] from a single center between September 2016 and September 2021. Single-positive patients (i.e., TDs⁺LNM^- and LNM⁺TDs^-) were classified into the training (n = 163) and validation (n = 41) sets. We extracted numerous features from the enhanced CT (region 1: The main tumor; region 2: The largest peritumoral nodule). After deleting redundant features, three feature selection methods and three machine learning methods were used to select the best-performing classifier as the radiomics model (Rad-score). After validating Rad-score, its performance was further evaluated in the field of diagnosing double-positive patients (i.e., TDs⁺LNM⁺) by outlining all peritumoral nodules with diameter (short-axis) > 3 mm.

RESULTS

Rad-score 1 (radiomics signature of the main tumor) had an area under the curve (AUC) of 0.768 on the training dataset and 0.700 on the validation dataset. Rad-score 2 (radiomics signature of the largest peritumoral nodule) had a higher AUC (training set: 0.940; validation set: 0.918) than Rad-score 1. Clinical factors, including age, gender, location of RC, tumor markers, and radiological features of the largest peritumoral nodule, were excluded by logistic regression. Thus, the combined model was comprised of Rad-scores of 1 and 2. Considering that the combined model had similar AUCs with Rad-score 2 (P = 0.134 in the training set and 0.594 in the validation set), Rad-score 2 was used as the final model. For the diagnosis of double-positive patients in the mixed group [TDs⁺LNM⁺ (n = 15); single-positive (n = 15)], Rad-score 2 demonstrated moderate performance (sensitivity, 73.3%; specificity, 66.6%; and accuracy, 70.0%).

CONCLUSION

Radiomics analysis based on the largest peritumoral nodule can be helpful in preoperatively differentiating between TDs and LNM.

Predictive and Prognostic Assessment Models for Tumor Deposit in Colorectal Cancer Patients With No Distant Metastasis

Background

More and more evidence indicated that tumor deposit (TD) was significantly associated with local recurrence, distant metastasis (DM), and poor prognosis for patients with colorectal cancer (CRC). This study aims to explore the main clinical risk factors for the presence of TD in CRC patients with no DM (CRC-NDM) and the prognostic factors for TD-positive patients after surgery.

Methods

The data of patients with CRC-NDM between 2010 and 2017 were extracted from the Surveillance, Epidemiology, and End Results (SEER) database. A logistic regression model was used to identify risk factors for TD presence. Fine and Gray’s competing-risk model was performed to analyze prognostic factors for TD-positive CRC-NDM patients. A predictive nomogram was constructed using the multivariate logistic regression model. The concordance index (C-index), the area under the receiver operating characteristic (ROC) curve (AUC), and the calibration were used to evaluate the predictive nomogram. Also, a prognostic nomogram was built based on multivariate competing-risk regression. C-index, the calibration, and decision-curve analysis (DCA) were performed to validate the prognostic model.

Results

The predictive nomogram to predict the presence of TD had a C-index of 0.785 and AUC of 0.787 and 0.782 in the training and validation sets, respectively. From the competing-risk analysis, chemotherapy (subdistribution hazard ratio (SHR) = 0.542, p < 0.001) can significantly reduce CRC-specific death (CCSD). The prognostic nomogram for the outcome prediction in postoperative CRC-NDM patients with TD had a C-index of 0.727. The 5-year survival of CCSD was 17.16%, 36.20%, and 63.19% in low-, medium-, and high-risk subgroups, respectively (Gray’s test, p < 0.001).

Conclusions

We constructed an easily predictive nomogram in identifying the high-risk TD-positive CRC-NDM patients. Besides, a prognostic nomogram was built to help clinicians identify poor-outcome individuals in postoperative CRC-NDM patients with TD. For the high-risk or medium-risk subgroup, additional chemotherapy may be more advantageous for the TD-positive patients rather than radiotherapy.

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.

Histopathological diagnosis of tumour deposits in colorectal cancer: a Delphi consensus study

AIMS

Tumour deposits (TDs) are an important prognostic marker in colorectal cancer. However, the classification, and inclusion in staging, of TDs has changed significantly in each tumour-node-metastasis (TNM) edition since their initial description in TNM-5, and terminology remains controversial. Expert consensus is needed to guide the future direction of precision staging.

METHODS AND RESULTS

A modified Delphi consensus process was used. Statements were formulated and sent to participants as an online survey. Participants were asked to rate their agreement with each statement on a five-point Likert scale and also to suggest additional statements for discussion. These responses were circulated together with anonymised comments, and statements were modified prior to carrying out a second online round. Consensus was set at 70%. Overall, 32 statements reached consensus. There were concerns that TDs were currently incorrectly placed in the TNM system and that their prognostic importance was being underestimated. There were concerns regarding interobserver variation and it was felt that a clearer, more reproducible definition of TDs was needed.

CONCLUSIONS

Our main recommendations are that the number of TDs should be recorded even if lymph node metastases (LNMs) are also present and that nodules with evidence of origin [extramural venous invasion (EMVI), perineural invasion (PNI), lymphatic invasion (LI)] should still be categorised as TDs and not excluded, as TNM-8 specifies. Whether TDs should continue to be included in the N category at all is controversial, and did not achieve consensus; however, participants agreed that TDs are prognostically worse than LNMs and the N1c category is suboptimal, as it does not reflect this.

The prognostic significance of tumor deposits in patients with head and neck squamous cell carcinomas

Background

A tumor deposit (TD) is a phenomenon that has not been well studied in head and neck squamous cell carcinoma (HNSCC) but might have prognostic significance. The present study was conducted to explore the presence and the prognostic significance of TDs in patients with HNSCCs.

Methods

Six hundred forty-two pathologically confirmed HNSCC patients with neck dissection samples were enrolled in this retrospective study. Patients were followed up and evaluated every 3 months in the first 3 years after surgery, and every 6 months thereafter by physical examination and computed tomography (CT)/magnetic resonance imaging (MRI) scans. The five-year overall survival (OS), disease-specific survival (DSS), and recurrence-free survival (RFS) were compared in the TD and non-TD groups using multivariable analyses and propensity score matching (PSM) methodology (1:1).

Results

The 5-year OS, DSS, and RFS rate of all patients was 77.3%, 80.6%, and 71.9%, respectively. In the multivariable analyses, poorer rates of OS (HR =2.345, P<0.001), DSS (HR =2.818, P<0.001), and RFS (HR =2.536, P<0.001) were observed in the TD versus the non-TD group. In the PSM cohort, eighty-one patients who had TDs were paired with 70 patients without TDs. Significantly diminished rates of DSS (P=0.040) and RFS (P=0.004) were found in the TD versus the non-TD group.

Conclusions

In response to sparse reports regarding TDs in HNSCCs, the present study proposes the TD as an independent poor prognostic factor meriting further research because of its association with diminished OS, DSS, and RFS rates.

Deep Convolutional Neural Network-Based Lymph Node Metastasis Prediction for Colon Cancer Using Histopathological Images

Background

Human evaluation of pathological slides cannot accurately predict lymph node metastasis (LNM), although accurate prediction is essential to determine treatment and follow-up strategies for colon cancer. We aimed to develop accurate histopathological features for LNM in colon cancer.

Methods

We developed a deep convolutional neural network model to distinguish the cancer tissue component of colon cancer using data from the tissue bank of the National Center for Tumor Diseases and the pathology archive at the University Medical Center Mannheim, Germany. This model was applied to whole-slide pathological images of colon cancer patients from The Cancer Genome Atlas (TCGA). The predictive value of the peri-tumoral stroma (PTS) score for LNM was assessed.

Results

A total of 164 patients with stages I, II, and III colon cancer from TCGA were analyzed. The mean PTS score was 0.380 (± SD = 0.285), and significantly higher PTS scores were observed in patients in the LNM-positive group than those in the LNM-negative group (P < 0.001). In the univariate analyses, the PTS scores for the LNM-positive group were significantly higher than those for the LNM-negative group (P < 0.001). Further, the PTS scores in lymphatic invasion and any one of perineural, lymphatic, or venous invasion were significantly increased in the LNM-positive group (P < 0.001 and P < 0.001).

Conclusion

We established the PTS score, a simplified reproducible parameter, for predicting LNM in colon cancer using computer-based analysis that could be used to guide treatment decisions. These findings warrant further confirmation through large-scale prospective clinical trials.

[Histomorphological and molecular-pathological prognostic factors in colorectal cancer]

Colorectal carcinomas are the second most common cancer and cause of cancer death in Germany for both men and women. Different aspects of morphological, immunohistochemical, and molecular pathological prognostic factors of colorectal carcinomas and their precursors were investigated. We demonstrated the prognostic relevance and importance of a precise classification of pericolonic tumor deposits (PTDs) in the pT category of the TNM classification. Furthermore, we demonstrated that patients with regional lymph node metastases after neoadjuvant chemoradiotherapy (nCRT) in rectal carcinomas with ypN0 status do not have a worse prognosis than patients without signs of preoperative lymph node metastases.Molecular pathological examinations of so-called serrated colorectal fibroblastic polyps as possible precursor lesions of colorectal carcinomas showed that their epithelial area represents a true neoplastic component and thus allows for their consideration in the context of a risk assessment for colorectal carcinomas.

The Role of Tumor Deposits in Predicting the Efficacy of Chemotherapy in Stage III Colon Cancer

Purpose

To evaluate the role of tumor deposits (TDs) in predicting the efficacy of chemotherapy in stage III colon cancer.

Methods

Using the SEER^∗Stat software Version 8.3.6, we started with a national cohort of colon cancer cases diagnosed between 2004 and 2016. We used the χ² (Chi-square) test to compare differences between different categorical variables according to the number of TDs. The Cox proportional hazards regression model was used to determine the independent association of different clinical and pathological variables with CSS, which were adjusted for other significant prognostic factors.

Results

We have identified 29,017 patients diagnosed with stage III colon cancer from the SEER database. The results of multivariate analyses showed that patients with the receipt of chemotherapy had 54.7% decreased risk of cancer-specific mortality compared with those not (HR = 0.453, 95% CI = 0.425-0.483, P < 0.0001) in the no-TD group; In the 1-2-TD group, patients with the receipt of chemotherapy had 56.8% decreased risk of cancer-specific mortality compared with those not (HR = 0.432, 95% CI = 0.364-0.512, P < 0.0001); In the ≥3-TD group, patients with the receipt of chemotherapy had 51.8% decreased risk of cancer-specific mortality compared with those not (HR = 0.482, 95% CI = 0.389-0.597, P < 0.0001).

Conclusions

Our study demonstrated that the presence of TDs was associated with a dismal prognosis and high number of TDs would also contribute to the worse survival of colon cancer. High number of TDs did not affect the survival benefit of chemotherapy in stage III colon cancer.

Tumor deposit indicates worse prognosis than metastatic lymph node in gastric cancer: a propensity score matching study

Background

The prognostic value of tumor deposit (TD) in gastric cancer is controversial. This study aims to investigate the prognostic value of TD.

Methods

The consecutive patients diagnosed with gastric cancer from October 2007 to October 2012 were selected. The patients were divided by whether they suffered TD into two groups. The basic data were comparable between the two groups after propensity score matching (PSM), then survival analysis [overall survival (OS) and cancer-specific survival (CSS)] was applied in two groups. After that, all the patients were divided by pN staging and survival analysis were applied in each subgroup. At last, all patients were divided into TD group, pN1 stage group, pN2 stage group, pN3a, and pN3b stage group, OS and CSS were compared between them. Multivariable competing risk analyses tested association of TD with OS and CSS, before and after PSM.

Results

Eight hundred and three patients were concluded. After PSM, 137 patients with TD and 274 patients without TD were selected, the 5-year OS and CSS rates of patients with TD were significantly worse than patients without TD (OS: 19.7% vs. 42.0%, P<0.001; CSS: 22.6% vs. 45.6%, P<0.001). In all patients' survival analysis, the 5-year OS and CSS rates of TD group were comparable with pN3a group (OS: 19.7% vs. 25.3%, P=0.221, CSS: 22.6% vs. 30.1%, P=0.092) and pN3b group (OS: 19.7% vs. 19.6% P=0.349, CSS: 22.6% vs. 23.5%, P=0.452). Meanwhile, on multivariable cox regression analyses, the presence of TD significantly reduces the OS and CSS of patients in gastric cancer.

Conclusions

TD has a marked impact on the prognosis of gastric cancer. Even patients with TD had the same prognosis with pN3 stage.

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.

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.

Tumor deposit is an independent prognostic indicator in patients who underwent radical resection for colorectal cancer

Background: Tumor deposits are one of the promising factors among the different edition of Tumor, Node, Metastasis classification. Despite improvement in the treatment of various types of metastatic disease the source and prognostic significance of tumor deposits in staging has not been deliberating the agreeable opinion. We investigated the possibility of tumor deposit as independent prognostic factor and evaluating its prognostic value in colorectal carcinoma patients. Methods: Author studied 313 colorectal cancer patients clinocopathological data and outcome who underwent radical resection. Data between 2011-2015 were retrospectively collected from Shanghai East Hospital, affiliated with Tongji University data information centre. The analysis was used to calculate 2 years disease free survival(DFS) and relation of tumor deposit with number of lymph node positive. Cox-regression analysis was performed to assess the prognostic factor. Results: Out of 313 colorectal patients included in the study, tumor deposits were detected in 17%. Tumor deposits (TDs) are relevantly associated with significant poor outcomes. The tumor deposit were significantly correlated with T-stage(P=<0.001), N-stage(P=<0.001), PLNC(P=<0.001), venous invasion(P=<0.001), TNM staging(P=<0.001), CEA(P=0.021) and CA19-9(P=0.042) of primary tumor. The Kaplan-Meier analysis revealed that disease-free survival of CRC patients with positive tumor deposit were significantly poorer that those with negative tumor deposit cohort(P=<0.001) And with multivariate analysis in different model, we found that positive tumor deposit were significantly associated with shorter DSF which is totally independent with lymph node status (P=0.001 and P=0.023 respectively). Subgroup analysis found that of 179 CRC patients with negative lymph node status, the DFS of patients with positive tumor deposit were significantly shorter that those with negative tumor deposit(P=,0.001). Of 134patients with positive lymph node status, the DFS of patients shows similar result. (P=<0.001). Conclusion: We have shown that TDs are not equal to lymph node metastasis with respect to biology and outcome. Tumor deposits are an independent adverse prognostic factor in CRC patient who have undergone radical resection.

Prognostic value and characteristics of N1c colorectal cancer

AIM

The presence of tumour deposits (TDs) in colorectal cancer (CRC) is associated with poor prognosis. The seventh edition of TNM subclassified a new nodal stage, N1c, characterized by the presence of TDs without any concurrent positive lymph node (LN). It is not clear if the N1c category is or is not equal to LN metastasis. We aimed to examine the prevalence, characteristics and prognostic significance of this new subcategory.

METHOD

Consecutive patients who underwent surgery for CRC in two centres (2011-2014) were analysed. N1 cM0 patients were matched against non-N1 cM0 (N0, N1a and N1b) patients for 3-year overall survival (OS) and disease-free survival (DFS).

RESULTS

We identified 1122 patients with 648 (57.8%) colonic cancers. In 57 patients (5.1%), N1c status was associated with rectal cancers [rectum = 33/57 (57.9%) vs colon = 24/57 (42.1%); P = 0.029], a higher pathological tumour stage [pT3-T4 N1c = 55/843 (6.5% vspT3-T4 non-N1c = 2/279 (0.7%); P < 0.0001] and vascular emboli [n = 35 (61.4%) vs n = 552 (51.8%); P = 0.0305]. Synchronous metastasis was observed in 23 cases (40%). After a mean follow-up of 31 months, 3-year OS for M0 patients, was 89.4%, 89.1%, 86.6% and 81.8% for N0, N1a, N1b and N1c tumours, respectively. DFS was significantly worse for N1c than for N0 (P = 0.0169), with N1c status having a significant effect on DFS in colonic cancers (P = 0.014). The presence of more than one TD was associated with a significantly worse DFS (P = 0.021).

CONCLUSION

Our results indicate that N1c CRC patients should be included among high-risk patients for whom it is widely accepted that adjuvant chemotherapy should be considered.

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.

Mesenteric Tumor Deposits in Midgut Small Intestinal Neuroendocrine Tumors Are a Stronger Indicator Than Lymph Node Metastasis for Liver Metastasis and Poor Prognosis

Mesenteric tumor deposits (MTDs) are not included in the American Joint Committee on Cancer (AJCC) staging system for midgut small intestinal neuroendocrine tumors (NETs). We examined the prognostic significance of MTDs associated with midgut NETs. Hematoxylin and eosin slides from 132 resected jejunal/ileal NETs were reviewed for AJCC tumor stage, lymph node (LN) metastasis, MTDs, and hepatic metastases. MTDs were defined as discrete irregular mesenteric tumor nodules discontinuous from the primary tumor. Clinical or pathologic evidence of metastases and survival data were abstracted from electronic medical records. The cohort included 72 male and 60 female patients with a median age of 60 years. LN metastasis, MTDs, and liver metastasis were present in 80%, 68%, and 58% of patients, respectively. Female sex and presence of MTDs were independent predictors of liver metastasis. The odds ratio for hepatic metastasis in the presence of MTDs was 16.68 (95% confidence interval [CI], 4.66-59.73) and 0.81 (95% CI, 0.20-3.26) for LN metastasis. Age, MTDs, and hepatic metastasis were associated with disease-specific survival (DSS) in univariate analysis. Primary tumor histologic grade, pT3/T4 stage, and LN metastasis were not associated with DSS. Multivariate analysis of liver metastasis-free survival stratified by tumor grade showed that MTDs were associated with adverse outcomes. The hazard ratio for MTDs was 4.58 (95% CI, 1.89-11.11), compared with 0.98 (95% CI, 0.47-2.05) for LN metastasis. MTDs, but not LN metastasis, in midgut NETs are a strong predictor for hepatic metastasis and are associated with poor DSS.

Tumor Deposits in Colorectal Cancer: Improving the Value of Modern Staging-A Systematic Review and Meta-Analysis

Purpose Colorectal cancer (CRC) treatment is largely determined by tumor stage. Despite improvements made in the treatment of various types of metastatic disease, staging has not been refined. The role of tumor deposits (TDs) in staging remains debated. We have assessed the relation of TDs with metastatic pattern to evaluate whether TDs might add significant new information to staging. Methods We performed a systematic literature search that was focused on the role of TDs in CRC. Studies with neoadjuvant-treated patients were excluded. Data on stage, histologic factors, and outcome were extracted. Data from four large cohorts were analyzed for the relevance of the presence of TDs, lymph node metastases (LNMs), and extramural vascular invasion (EMVI) on the pattern of metastases and outcomes. Results Of 10,106 included patients with CRC, 22% presented with TDs. TDs are invariably associated with poor outcome. Presence of TDs was associated with presence of LNMs and EMVI. In a pairwise comparison, effects of TD were stronger than those of both LNMs and EMVI. In the logistic regression model, TDs in combination with LNMs is the strongest predictor for liver (odds ratio [OR], 5.5), lung (OR, 4.3) and peritoneal metastases (OR, 7.0). Presence of EMVI adds information for liver and lung metastases, but not for peritoneal metastases. Conclusion We have shown that TDs are not equal to LNMs or EMVI with respect to biology and outcome. We lose valuable prognostic information by allocating TDs into nodal category N1c and only considering TDs in the absence of LNMs. Therefore, we propose that the number of TDs should be added to the number of LNMs to derive a final N stage.

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 significance of classified extramural tumor deposits and extracapsular lymph node invasion in T3-4 colorectal cancer: a retrospective single-center study

Background

Extramural tumor deposits (TDs) and extracapsular lymph node involvement (ECLNI) are considered to be poor prognostic factors in patients with T3–4, N0–2, M0 colorectal cancer (CRC). Although TDs are known to have multiple origins and pleomorphic features, the prognostic significances of the different type of TDs have not yet been established.

Methods

We performed a retrospective review of 385 consecutive patients with T3–4, N0–2, M0 CRC who received curative resection at our institution between 2006 and 2012. We classified the TDs into two groups: invasive-type TD (iTD), which is characterized by the presence of lymphatic invasion, vascular invasion, perineural invasion, or undefined cancer cell clusters and nodular-type TD (nTD), which is characterized by a smooth or irregular-shaped tumor nodule other than an iTD. ECLNI was defined as invasion of cancer cells into capsular collagen tissues or adipose tissues beyond the capsular collagen. Multivariate analyses were used to assess the prognostic significance of iTD, ND, and ECLNI for relapse-free survival (RFS), disease-specific survival (DSS), and sites of recurrence.

Results

In patients without lymph node (LN) metastasis, the incidences of iTD and nTD were both in the range of 2–3 %. Conversely, in patients with LN metastasis, the incidences of iTD, nTD, and ECLNI were 31, 22, and 34 %, respectively. iTD, nTD, and ECLNI were all significant independent adverse factors for RFS in rectal cancer, and were all associated with pT, pN, and LN ratio. iTD was a significant independent adverse prognostic factor for DSS in rectal cancer, metastasis to the liver in colorectal cancer, and distant LN metastasis in colon cancer. ECLNI was a significant independent prognostic factor for RFS in colon cancer.

Conclusions

Classifying TDs and assessing ECLNI may help establish significant prognostic factors for patients with T3–4, N0–2, M0 CRC.

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

Colorectal carcinoma is the third most common cancer in the United States. Proper and standardized pathologic staging is vital for prognostic assessment and impacts therapeutic decisions. The Tumor Node Metastasis (TNM) staging system was developed by the American Joint Committee on Cancer (AJCC) to be a data-driven, evidence-based staging system providing an accurate prediction of outcome. The AJCC 7th edition (2010) included several changes clarifying some issues and leading to new controversies. We aim to address selected challenging issues in tumor T staging, neoadjuvant treatment effects in rectal cancer, and definition of lymph node vs tumor deposit. Serosal involvement in colorectal cancer is staged as T4, which is associated with decreased survival and may impact additional therapy decisions. Although careful sampling and sectioning are helpful, challenges remain in interpretation of tumor within 1 mm of serosal surface with a reaction. Elastic stain as a surrogate marker for serosal invasion has been studied, but its usefulness remains unclear. Some unique issues in rectal cancer include the presence of serosa in proximal but not in distal tumors and post-neoadjuvant effects. Tumor should be staged based on tumor cells rather than acellular mucin pools. Additionally, tumor response should be graded only in primary tumor but not in lymph nodes or metastatic sites. The distinction between tumor deposits and lymph nodes has been modified in AJCC TNM from using size in the 5th edition, to the round contour in the 6th edition, to only features of residual lymph node architecture in the 7th edition. Interobserver variability remains but tumor deposits should be documented when present. The number of deposits should not be added to the total number of positive lymph nodes, and the N1c designation should only be used in cases without any positive lymph nodes. Future clarification will likely evolve as more data become available.

Accuracy of TNM staging in colorectal cancer: a review of current culprits, the modern role of morphology and stepping-stones for improvements in the molecular era

Colorectal cancer (CRC) is the third most common cancer worldwide. Survival is largely stage-dependant, guided by the tumor-node-metastases (TNM) system for TNM assessment. Histopathological evaluation, including assessment of lymph node status, is important for correct TNM staging. However, recent updates in the TNM system have resulted in controversy. A continued debate on definitions resulting in potential up- and downstaging of patients, which may obscure survival data, has led the investigators to investigate other or alternative staging tools. Consequently, additional prognostic factors have been searched for using the regular light microscopy. Among the factors evaluated by histopathology include the evaluation of tumor budding and stromal environment, angiogenesis, as well as involvement of the immune system (including the 'Immunoscore'). We review the current role of histopathology, controversies in TNM-staging and suggested alternatives to better predict outcome for CRC patients in the era of genomic medicine.

Controversies in the pathological assessment of colorectal cancer

Pathologic assessment of colorectal cancer specimens plays an essential role in patient management, informing prognosis and contributing to therapeutic decision making. The tumor-node-metastasis (TNM) staging system is a key component of the colorectal cancer pathology report and provides important prognostic information. However there is significant variation in outcome of patients within the same tumor stage. Many other histological features such as tumor budding, vascular invasion, perineural invasion, tumor grade and rectal tumor regression grade that may be of prognostic value are not part of TNM staging. Assessment of extramural tumor deposits and peritoneal involvement contributes to TNM staging but there are some difficulties with the definition of both of these features. Controversies in colorectal cancer pathology reporting include the subjective nature of some of the elements assessed, poor reporting rates and reproducibility and the need for standardized examination protocols and reporting. Molecular pathology is becoming increasingly important in prognostication and prediction of response to targeted therapies but accurate morphology still has a key role to play in colorectal cancer pathology reporting.

Tumor deposit is a poor prognostic indicator for patients who have stage II and III colorectal cancer with fewer than 4 lymph node metastases but not for those with 4 or more

BACKGROUND

Extranodal tumor deposits are involved in TNM classification. However, it is uncertain whether a tumor deposit is a regular lymph node metastasis, and its prognostic significance in patients with stage II or III colorectal cancer remains to be established.

OBJECTIVE

This study aimed to determine the prognostic significance of tumor deposits for stage II and III colorectal cancer.

DESIGN

This study is a retrospective review of clinicopathological data.

SETTING

This study was conducted at a tertiary care hospital/referral center in Japan.

PATIENTS

We reviewed the clinical course of 171 stage II and 173 stage III consecutive patients between January 1999 and December 2006.

MAIN OUTCOME MEASURES

We examined the clinicopathological features of colorectal cancers with tumor deposits and calculated overall survival and recurrence-free survival of the patients according to the status of tumor deposits. The primary outcome was the impact of tumor deposits on patient survival.

RESULTS

Thirty-five (10.2%) patients with colorectal cancers had tumor deposits in the pericolic and/or mesocolic region. Survival rates among the patients with tumor deposits were significantly lower than those without (5-year overall survival: 58.4% vs 81.0%, p < 0.0001; 5-year recurrence-free survival: 47.1% vs 73.4%, p < 0.0001). Tumor deposit was an independent prognostic factor for patients with colorectal cancer in multivariate analysis (overall survival: HR, 2.30; 95% CI, 1.26-4.04; p = 0.04; recurrence-free survival: HR, 2.42; 95% CI, 1.04-4.90; p = 0.04). Tumor deposit was an independent prognostic factor in N0 and N1 colorectal cancer, whereas N2 cancer had poor survival outcome regardless of tumor deposit.

LIMITATIONS

Our study was a single-institution retrospective study, and the numbers of patients were relatively small to draw firm conclusions.

CONCLUSION

Tumor deposit may be an independent adverse prognostic factor for stage II and III N1 colorectal cancer.

Effect of tumor deposits on overall survival in colorectal cancer patients with regional lymph node metastases

Objectives: The staging system of the International Union Against Cancer considers tumor deposits to be N1c in patients with no regional lymph node metastasis, but the significance of tumor deposits in patients with regional lymph node metastases is unclear. We investigated the effect of tumor deposits on overall survival in colorectal cancer patients with regional lymph node metastases.

Patients and Methods: From 2000 to 2008, 551 patients underwent resections for colorectal cancer at our medical center. We excluded 87 patients who had distant metastases or had received neoadjuvant chemotherapy or radiotherapy from our study and statistically analyzed the remaining 464 patients.

Results: Stepwise multivariate Cox proportional hazards analysis in patients with regional lymph node metastases showed only tumor deposits to be significant for overall survival (hazard ratio: 2.813; P = 0.0002). Recurrence was seen in 49.2% of patients with tumor deposits (30/61) compared with 14.4% of patients without them (58/403; P < 0.0001). Tumor deposits did not show the same effect on overall survival as lymph node metastases.

Conclusions: Tumor deposits were significantly associated with poorer overall survival in colorectal cancer patients with regional lymph node metastases. The effect of tumor deposits on overall survival was between that of lymph node metastasis and distant metastasis.

Perigastric tumor deposits in primary gastric cancer: implications for patient prognosis and staging

BACKGROUND

Metastatic nodules in perigastric adipose tissue without evidence of lymph node tissue have been reported in gastric cancers. However, the morphological features and clinical significance of perigastric tumor deposits (TD) have not been clarified in gastric cancers.

METHODS

To demonstrate the clinical implication of perigastric TD, 653 consecutive gastric cancer patients were enrolled and all of their slides were reviewed. Separate tumor nodules in the perigastric fat were classified as perigastric TD and correlated with clinicopathologic features and patient survival.

RESULTS

Perigastric TD were observed in 156 (23.9 %) of 653 patients. Perigastric TD were associated with synchronous distant metastasis (p < 0.001), independently of depth and venous invasion. There was a significant difference between the overall survival of those with and without TD by univariate (p < 0.001) and multivariate (p = 0.001) survival analyses. However, distant metastasis or patient prognosis could not be predicted by the morphologic patterns of the TD (p > 0.05). When TD without lymph node tissue and lymph node metastasis were recorded separately, TD were observed in 13 node-negative patients. The overall survival of node-negative patients with TD was significantly worse than that of node-negative patients without TD (p < 0.001).

CONCLUSIONS

Perigastric TD significantly correlated with distant metastasis and satisfactorily predicted patient outcomes independently of invasion depth, lymph node metastasis, and other clinicopathologic factors. Our findings suggest that perigastric TD should be included in the staging of patients with gastric cancer.

Optimal colorectal cancer staging criteria in TNM classification

PURPOSE

Histologic components of the TNM classification system have been repeatedly revised since the fifth edition (TNM5). TNM classification revisions provide different criteria for categorizing tumor nodules without residual lymph node structure (ND). However, there are few systematic evaluations regarding the effectiveness of these revisions.

PATIENTS AND METHODS

A multicenter pathologic review for ND in colorectal cancer (CRC) was performed. Tumor staging defined by TNM5, sixth edition (TNM6), and seventh edition (TNM7) were compared on the basis of Akaike information criterion (AIC) and Harrell's concordance index (c-index). Moreover, TNM7's prognostic value was compared between the original ND and modified criteria, which considered all regional NDs as lymph node metastasis (LNM) irrespective of the original structure.

RESULTS

In 1,716 treated patients with CRC (1994 to 1998), tumor stages (I/II/III) exhibited better prognoses in TNM7 (AIC, 3055.1; c-index, 0.7215) than in TNM6 (AIC, 3063.7; c-index, 0.7149), but not better than in TNM5 (AIC, 3051.6; c-index, 0.7240). Comparing the original TNM7 and modified criteria, 4.2% of patients were classified in different N stages (N0/N1/N2a/N2b); both AIC and the c-index were superior in the modified criteria (AIC, 3029.40; c-index, 0.7271) compared with the original criteria (AIC, 3040.58; c-index, 0.7230). Modified criteria were also associated with improved prognostic power of tumor stages (I/IIA/IIB/IIC/IIIA/IIIB/IIIC). These results were similar in another cohort of 2,242 treated patients with CRC (1999 to 2003).

CONCLUSION

The prognostic value of TNM7 is better than that of TNM6; however, improvement over TNM5 is insignificant. By considering all regional NDs as LNM irrespective of their morphology, TNM classification can be simplified and its prognostic value improved.

Has the new TNM classification for colorectal cancer improved care?

In 2009, the Union for International Cancer Control issued the seventh edition of the well-used T (tumor), N (node), and M (metastasis) classification guidelines. There has been a continual refinement of the staging for colorectal cancer since this system for assessing tumor stage was initially adopted and it has been used to guide treatment decisions for over 50 years. However, the outcome after therapy for patients with colorectal cancer is very variable, even when patients are assigned to the same TNM category. This article assesses the changes that have been made since the sixth edition and discusses whether they are, in fact, informative improvements for a practicing clinician.

Actual Status of Distribution and Prognostic Impact of Extramural Discontinuous Cancer Spread in Colorectal Cancer

Purpose

To clarify the prognostic impact of tumor nodules without residual lymph node (LN) structure (ND) in colorectal cancer and to determine optimal categorization of ND in tumor staging.

Patients and Methods

A multicenter, retrospective pathologic review was performed for 1,716 patients with stages I to III curatively resected colorectal cancer treated at 11 institutions between 1994 and 1998. An additional 2,242 patients from nine institutions were enrolled between 1999 and 2003 as a second cohort to validate the results.

Results

LN metastasis (LNM) and ND were observed in 33.7% and 16.0% (smooth-contour nodule [S-ND], 8.2%; irregular-contour nodule [I-ND], 10.7%) of patients in the first cohort. S-ND and I-ND were similarly distributed in the regional area. There was no considerable difference in the impact on survival between S-ND (hazard ratio [HR], 2.7; 95% CI, 1.9 to 3.8) and I-ND (HR, 4.3; 95% CI, 3.3 to 5.8) or between LNM (HR, 4.5; 95% CI, 3.4 to 6.0) and ND (HR, 4.0; 95% CI, 3.1 to 5.3). LNM and ND were similarly associated with the mode of recurrence. Tumor nodules ≥ 5 mm growing with venous/perineural invasion (ND [v/pni+]), judged with 0.61 κ value among 11 observers, had an independent prognostic value for 5-year survival of 42%; similar results were observed in the second cohort.

Conclusion

These results do not support the TNM system in which S-ND is treated differently from I-ND in tumor staging; LNM and ND should be considered together in the same category. The presence of ND (v/pni+) has a considerable adverse prognostic effect.

Incorporation of extranodal metastasis of gastric carcinoma into the 7th edition UICC TNM staging system

Background

To assess the clinical significance and prognostic impact of extranodal metastasis (EM) in gastric carcinoma and establish an optimal classification in the staging system.

Methodology/Principal Findings

A total of 1343 patients with gastric carcinoma who underwent surgical resection were recruited to determine the frequency and prognostic significance of EMs. EMs were divided into two groups (EM1 and EM2) and then incorporated into the 7^th edition UICC TNM staging system. EMs was detected in 179 (13.3%) of 1343 patients who underwent radical resection. Multivariate analysis identified EMs as an independent prognostic factor (HR = 1.412, 95%CI = 1.151–1.731, P<0.001). After curative operation, the overall survival rate were worse in patients with ≥3 cases of EM (EM2) than those with the number of 1 and 2 cases (EM1) (P<0.001). Survival of patients with EM1 was found almost comparable to that of N3 stage (P = 0.437). Survival of patients with EM2 showed similar to that of stage IV patients (P = 0.896). By using the linear trend X², likelihood ratio X², and Akaike information criterion (AIC) test, EM1 treated as N3 stage and EM2 treated as M1 stage performed higher linear trend X² scores, likelihood ratio X² scores, and lower AIC value than the 7^th edition UICC TNM staging system, which represented the optimum prognostic stratification, together with better homogeneity, discriminatory ability, and monotonicity of gradients.

Conclusions/Significance

EMs might be classified based on their number and prognostic information and should incorporate into the TNM staging system.

Evidence-based medicine: the time has come to set standards for staging

For international communication in cancer, staging systems such as TNM are essential; however, the principles and processes used to decide about changes in every new edition of TNM need to be subject to debate. Changes with major impact for patient treatment are introduced without evidence. We think that TNM should be a continual reactive process, rather than a proactive process. Changes should only occur after extensive discussion within the community, and before the introduction of any changes these should be tested for reproducibility and compared to the currently used gold standard. TNM should not be used to test hypotheses. It should introduce established facts that are beneficial to predicting patient prognosis. TNM should thus be restructured on a basis equivalent to evidence-based guidelines. The strength of the evidence should be explicitly stated and the evidence base given. It is time for the principles of staging to be widely debated and new principles and processes to be introduced to ensure that we are not in the same situation in the future. The disparity between therapeutic decision making and TNM staging is marked and we would appeal for the radical overhaul of TNM staging to make it fit for the twenty-first century. TNM is central to the management of cancer patients and we must protect and enhance its reputation.