Clinical significance of pT sub-classification in surgical pathology of colorectal cancer

The impact of mismatch repair status and systemic inflammatory markers on radiological staging in colon cancer

OBJECTIVE

Mismatch repair (MMR) deficient (dMMR) colon cancer (CC) is distinct from MMR proficient (pMMR) CC, yet the impact of MMR status on radiological staging is unclear. The purpose of this study was to investigate how MMR status impacts CC CT staging.

METHODS

We retrospectively compared CT staging accuracy between dMMR and pMMR CC patients undergoing curative resection. Accuracy was assessed as individual tumour (T)/nodal (N) stages and as dichotomous "statuses" (T1/2 vs T3/4; N0 vs N1/2). Patient characteristics were analysed for factors to support staging.

RESULTS

There was no significant difference in overall staging accuracy between the dMMR (44 patients) and pMMR (57 patients) groups. dMMR tumours with incorrect N stage/"status" were more likely to be overstaged than pMMR tumours (90% vs 59%; p = 0.023 for "N status"). Platelet count, CRP and neutrophil count (AUC 0.76 (p = 0.0078), 0.75 (p = 0.034) and 0.70 (p = 0.044), respectively) were associated with "N status" in dMMR tumours.

CONCLUSION

Whilst overall staging accuracy was similar between groups, incorrectly N staged dMMR tumours were more likely to be overstaged than pMMR tumours, risking inappropriate surgical or neoadjuvant treatment. We describe novel relationships between several inflammatory markers and pathological "N status" in dMMR CC, which if integrated into routine practice may improve CT staging accuracy.

ADVANCES IN KNOWLEDGE

Compared to pMMR CC, dMMR CC is at significant risk of N overstaging. Platelet count, CRP and neutrophil count are higher in dMMR CC patients with nodal metastases than those without, and their role in refining clinical staging requires further investigation.

Prognostic Factors Among Colonic Adenocarcinomas Invading Into the Muscularis Propria

Depth of invasion through the intestinal wall, categorized as primary tumor stage (pT), is an important prognostic factor in colorectal cancer. However, additional variables that may affect clinical behavior among tumors involving the muscularis propria (pT2) have not been examined at length. We evaluated 109 patients with pT2 colonic adenocarcinomas (median age: 71 y, interquartile range: 59 to 79 y) along various clinicopathologic parameters, including invasion depth, regional lymph node involvement, and disease progression after resection. Tumors extending to the outer muscularis propria (termed pT2b) were associated in multivariate analysis with older patient age (P=0.04), larger tumor size (P<0.001), higher likelihood of lymphovascular invasion (LVI; P=0.03) and higher lymph node stage (pN; P=0.04), compared with tumors limited to the inner muscle layer (pT2a), and LVI was the single most important variable predicting regional lymph node metastasis at resection in these tumors (P=0.001). The Kaplan-Meier analysis during a median clinical follow-up of 59.7 months (interquartile range: 31.5 to 91.2) revealed that disease progression was more likely in pT2 tumors that exhibited, at the time of staging: size >2.5 cm (P=0.039), perineural invasion (PNI; P=0.047), high-grade tumor budding (P=0.036), higher pN stage (P=0.002), and distant metastasis (P<0.001). Proportional hazards (Cox) regression identified high-grade tumor budding (P=0.02) as independently predicting shorter progression-free survival in pT2 tumors. Finally, among cases that would not ordinarily be candidates for adjuvant treatment (ie, pT2N0M0), the presence of high-grade tumor budding was significantly associated with disease progression (P=0.04). These data suggest that, during the diagnosis of pT2 tumors, pathologists may wish to pay particular attention and ensure adequate reporting of certain variables such as tumor size, depth of invasion within the muscularis propria (ie, pT2a vs. pT2b), LVI, PNI, and, especially, tumor budding, as these may affect clinical treatment decisions and proper patient prognostication.

The percentage of mesorectal infiltration as a prognostic factor after curative surgery for pT3 rectal cancer

AIM

The aim of this study is to evaluate the prognostic value of a novel variable - the percentage of mesorectal infiltration (PMI) - in pT3 rectal cancer.

METHOD

A cohort of 241 patients with pT3 rectal adenocarcinoma, operated on between February 2002 and May 2019, was selected for the analysis. Data concerning patient, treatment and tumour characteristics were collected. The depth of mesorectal infiltration (DMI) and the distance between the deepest invasion and the circumferential resection margin (CRM) were measured. The PMI was calculated using a formula combining these parameters.

RESULTS

Neoadjuvant therapy was administered in 33.2% of cases. A complete mesorectal excision was achieved in 74% of patients. The CRM was affected in 24 patients (9.9%). The 5-year actuarial local recurrence (LR), overall recurrence (OR) and overall survival (OS) rates were 7.5%, 22.9% and 72.4%, respectively. The PMI was significantly associated with worse oncological outcomes regarding LR (p = 0.009), OR (p = 0.001) and OS (p = 0.016) rates. A cut-off value of PMI >60% had the highest specificity (80%) for LR (p = 0.026), OR (p = 0.04) and OS (p = 0.07).

CONCLUSION

The PMI has an adverse prognostic impact on the oncological results following surgery for pT3 rectal cancer. It allows prediction of the risk of both LR and distant recurrence with higher accuracy than the DMI or the distance to the CRM. A PMI >60% may be used as a cut off value while subclassifying pT3 rectal tumours. It may influence decision-making while establishing adjuvant treatment and the follow-up schedule.

The measured distance between tumor cells and the peritoneal surface predicts the risk of peritoneal metastases and offers an objective means to differentiate between pT3 and pT4a colon cancer

Substantial variability exists in what pathologists consider as pT4a in colorectal cancer when tumor cells are within 1 mm of the free peritoneal surface. This study aimed to determine if the measured sub-millimeter distance between tumor cells and the free peritoneal surface would offer an objective means of stratifying patients according to the risk of developing peritoneal metastases. Histological slides of patients included in the COLOPEC trial, with resectable primary c/pT4N0-2M0 colon cancer, were centrally reassessed. Specific tumor morphological variables were collected, including distance from tumor to free peritoneal surface, measured in micrometers (µm). The primary outcome, 3-year peritoneal metastasis rate, was compared between four groups of patients stratified for relation of tumor cells to the peritoneum: 1) Full peritoneal penetration with tumor cells on the peritoneal surface, 2) 0-99 µm distance to the peritoneum, 3) 100-999 µm to the peritoneum, and 4) ≥1000 µm to the peritoneum, by using Kaplan-Meier analysis. In total, 189 cases were included in the present analysis. Cases with full peritoneal penetration (n = 89), 0-99 µm distance to the peritoneal surface (n = 34), 100-999 µm distance (n = 33), and ≥1000 µm distance (n = 33), showed significantly different 3-year peritoneal metastases rates of 25% vs 29% vs 6% vs 12%, respectively (Log Rank, p = 0.044). N-category did not influence the risk of peritoneal metastases in patients with a tumor distance beyond 100 µm, while only the N2 category seemed to result in an additive risk in patients with a distance of 0-99 µm. The findings of this study suggest that the measured shortest distance between tumor cells and the free peritoneal surface is useful as an objective means of stratifying patients according to the risk of developing peritoneal metastases. This simple measurement is practical and may help in providing a precise definition of pT4a. Trial registration: NCT02231086 (Clinicaltrials.gov).

pT3 colorectal cancer revisited: a multicentric study on the histological depth of invasion in more than 1000 pT3 carcinomas-proposal for a new pT3a/pT3b subclassification

Background

Pathological TNM staging (pTNM) is the strongest prognosticator in colorectal carcinoma (CRC) and the foundation of its post-operative clinical management. Tumours that invade pericolic/perirectal adipose tissue generally fall into the pT3 category without further subdivision.

Methods

The histological depth of invasion into the pericolic/perirectal fat was digitally and conventionally measured in a training cohort of 950 CRCs (Munich). We biostatistically calculated the optimal cut-off to stratify pT3 CRCs into novel pT3a (≤3 mm)/pT3b (>3 mm) subgroups, which were then validated in two independent cohorts (447 CRCs, Bayreuth/542 CRCs, Mainz).

Results

Compared to pT3a tumours, pT3b CRCs showed significantly worse disease-specific survival, including in pN0 vs pN+ and colonic vs. rectal cancers (DSS: P < 0.001, respectively, pooled analysis of all cohorts). Furthermore, the pT3a/pT3b subclassification remained an independent predictor of survival in multivariate analyses (e.g. DSS: P < 0.001, hazard ratio: 4.41 for pT3b, pooled analysis of all cohorts). While pT2/pT3a CRCs showed similar survival characteristics, pT3b cancers remained a distinct subgroup with dismal survival.

Discussion

The delineation of pT3a/pT3b subcategories of CRC based on the histological depth of adipose tissue invasion adds valuable prognostic information to the current pT3 classification and implementation into current staging practices of CRC should be considered.

Prognostic significance of additional histologic features for subclassification of pathological T3 colon cancer

Background

Additional histologic features of T3 colon cancer, such as tumour depth invasion beyond muscularis propria and elastic lamina invasion (ELI), have taken interest for a more accurate staging.

Methods

Patients with pT3 and pT4a (control group) colon adenocarcinoma were retrospectively collected from our institutional database. The study group was divided according to depth of tumour invasion < 5 mm and ≥ 5 mm, and into ELI − and ELI + . Chi-square test was used to compare the clinicopathological characteristics. OS and DFS were estimated using Kaplan–Meier method and compared with the log-rank test. Univariable and multivariable Cox proportional hazard models were employed to assess the effect on OS and DFS.

Results

Out of 290 pT3 tumours, 168 (58%) had a depth of tumour invasion < 5 mm and 122 (42%) ≥ 5 mm. The 5-year OS and DFS were 85.2, 68.7 and 60.9%, and 81.4, 73.9 and 60.1% in pT3 < 5 mm, pT3 ≥ 5 mm, and pT4a respectively (p = 0.001, p = 0.072). Considering ELI − (n = 157, 54%) and ELI + (n = 133, 46%), the 5-year OS and DFS were 78.9, 76.7, and 60.9%, and 75.5, 81.5, and 60.1% in ELI  − , ELI + and pT4a respectively (p = 0.955, p = 0.462). At multivariable analysis, the depth of invasion was found to be an independent predictive factor for OS (HR 2.04, 95%CI 1.28–3.24, p = 0.003) and DFS (HR 1.98, 95%CI 1.24–3.18, p = 0.004), while ELI did not result a prognostic factor for OS nor DFS.

Conclusion

In pT3 colon cancer, depth of tumour invasion ≥ 5 mm is an independent risk factor for OS and DFS, whereas ELI did not result a prognostic factor affecting OS nor DFS.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10147-022-02192-y.

Comparison of Long-Term Survival Outcomes of T4a and T4b Colorectal Cancer

Background

Although T4b is known to have worse oncologic outcomes, it is unclear whether it truly shows a worse prognosis. This study aims to compare the survival differences between T4a and T4b.

Methods

Patients who were pathologically diagnosed with T3 and T4 colorectal adenocarcinoma from 2010 to 2014 were included (T3, n = 1822; T4a, n = 424; T4b, n = 67). Overall survival (OS) and cancer-specific survival (CSS) were compared between T4a and T4b using the Kaplan-Meier method and log-rank test.

Results

In stage II, T4a had better OS and CSS than T4b (5-year OS, 89.5% vs. 72.6%; 5-year CSS, 94.4% vs. 81.7%, all p < 0.05), however, in stage III, there were no significant differences in survivals between groups (all p > 0.05). In multivariable analysis, T classification was not an independent risk factor for OS (p > 0.05). However, for CSS, when respectively compared to T3, T4b (HR 3.53, p < 0.001) showed a relatively higher hazard ratio than T4a (HR 2.27, p < 0.001).

Conclusions

T4a showed more favorable OS and CSS than T4b, especially in stage II. Our findings support the current AJCC guidelines, in which T4b is presented as a more advanced stage than T4a.

Evolutions in rectal cancer MRI staging and risk stratification in The Netherlands

Purpose

To analyze how the MRI reporting of rectal cancer has evolved (following guideline updates) in The Netherlands.

Methods

Retrospective analysis of 712 patients (2011–2018) from 8 teaching hospitals in The Netherlands with available original radiological staging reports that were re-evaluated by a dedicated MR expert using updated guideline criteria. Original reports were classified as “free-text,” “semi-structured,” or “template” and completeness of reporting was documented. Patients were categorized as low versus high risk, first based on the original reports (high risk = cT3-4, cN+, and/or cMRF+) and then based on the expert re-evaluations (high risk = cT3cd-4, cN+, MRF+, and/or EMVI+). Evolutions over time were studied by splitting the inclusion period in 3 equal time periods.

Results

A significant increase in template reporting was observed (from 1.6 to 17.6–29.6%; p < 0.001), along with a significant increase in the reporting of cT-substage, number of N+ and extramesorectal nodes, MRF invasion and tumor-MRF distance, EMVI, anal sphincter involvement, and tumor morphology and circumference. Expert re-evaluation changed the risk classification from high to low risk in 18.0% of cases and from low to high risk in 1.7% (total 19.7%). In the majority (17.9%) of these cases, the changed risk classification was likely (at least in part) related to use of updated guideline criteria, which mainly led to a reduction in high-risk cT-stage and nodal downstaging.

Conclusion

Updated concepts of risk stratification have increasingly been adopted, accompanied by an increase in template reporting and improved completeness of reporting. Use of updated guideline criteria resulted in considerable downstaging (of mainly high-risk cT-stage and nodal stage).

Graphic abstract

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.

Beyond the NCCN Risk Factors in Colon Cancer: An Evaluation in a Swedish Population-Based Cohort

Background

The purpose of this study was to investigate whether pT3–4 and pN-subclassifications, lymph-node ratio (LNR), tumour deposits, pre- and postoperative carcinoembryonic antigen (CEA), and C-reactive protein (CRP)—all parameters commonly collected in clinical management—add information about recurrence risk against a background of routine clinicopathological parameters as defined by the NCCN.

Methods

The prospective cohort consisted of all 416 patients diagnosed with colon cancer stage I–III in Uppsala County between 2010 and 2015. Cox proportional hazard models were used to calculate hazard ratios for time to recurrence and overall survival. The results were compared with the entire Swedish population concerning parameters recorded in the national quality registry, SCRCR, during the same time period.

Results

The Uppsala cohort was representative of the entire Swedish cohort. In unadjusted analyses, pT3-subclassification, pN-subclassification, LNR, tumour deposits, elevated postoperative CEA, and preoperative CRP correlated with recurrence. After adjusting for T-, N-stage, and NCCN risk factors, pN-subclassification, sidedness, and elevated postoperative CEA levels correlated with recurrence. Survival correlated with parameters associated with recurrence, LNR, and elevated postoperative CRP.

Conclusions

Additional information on recurrence risk is available from several routinely recorded parameters, but most of the risk is predicted by the commonly used clinicopathological parameters.

Electronic supplementary material

The online version of this article (10.1245/s10434-019-08148-3) contains supplementary material, which is available to authorized users.

Assessment of peritoneal elastic laminal invasion improves survival stratification of pT3 and pT4a colorectal cancer: a meta-analysis

Evaluating peritoneal elastic laminal invasion (ELI) has been proposed as an additional assessment for pT3 colorectal cancers (CRC). Its clinical significance has not yet been established. We performed a meta-analysis to investigate the prognostic impact of ELI assessment for subcategorisation of pT3 CRC. We performed a search in three electronic databases. HR and its 95% CI for overall survival (OS) and disease-free survival (DFS) were calculated using the random effects model weighted by the inverse variance method. We identified six studies that met inclusion criteria out of an original 703 studies found with our database search terms. Our meta-analysis included 1925 patients with pT3 and pT4a CRCs. The presence of ELI in pT3 CRC was associated with shortened OS compared with ELI negative pT3 CRC (HR=1.76; 95% CI 1.21 to 2.55); whereas the DFS was not statistically significant (HR=1.79; 95% CI 0.91 to 3.52). Furthermore, pT4a patients’ OS (HR=1.84; 95% CI 1.41 to 2.40) and DFS (HR=1.88; 95% CI 1.17 to 3.04) were even worse than the OS and DFS of pT3 ELI (+) patients. ELI is a useful marker for stratifying patients with pT3 or pT4a CRCs into three prognostically distinct groups. We recommend the subcategorisation of pT3 CRC by ELI for better prognostic assessment and treatment strategy of patients with CRC.

Recurrence Risk After Up-to-Date Colon Cancer Staging, Surgery, and Pathology: Analysis of the Entire Swedish Population

BACKGROUND

Developments in the quality of care of patients with colon cancer have improved surgical outcome and thus the need for adjuvant chemotherapy.

OBJECTIVE

To investigate the recurrence rate in a large population-based cohort after modern staging, surgery, and pathology have been implemented.

DESIGN

This was a retrospective registry study.

SETTINGS

Data from patients included in the Swedish Colorectal Cancer Registry covering 99% of all cases and undergoing surgery for colon cancer stages I to III between 2007 and 2012 were obtained.

PATIENTS

In total, 14,325 patients who did not receive any neoadjuvant treatment, underwent radical surgery, and were alive 30 days after surgery were included.

MAIN OUTCOME MEASURES

Tumor and node classification and National Comprehensive Cancer Network-defined risk factors for recurrence were used to assess overall and stage-specific 5-year recurrence rates.

RESULTS

The median follow-up of nonrecurrent cases was 77 months (range, 47-118 mo). The 5-year recurrence rate was 5% in stage I, 12% in stage II, and 33% in stage III patients. In patients classified as having pT3N0 cancer with no or 1 risk factor, the 5-year recurrence rates were 9% and 11%. Risk factors for shorter time to recurrence were male sex, more advanced pT and pN classification, vascular and perineural invasion, emergency surgery, lack of central ligature, short longitudinal resection margin, postoperative complications, and, in stage III, no adjuvant chemotherapy.

LIMITATIONS

The registry does not contain some recently identified factors of relevance for recurrence rates, and some late recurrences may be missing.

CONCLUSIONS

The recurrence rate is less than that previously observed in historical materials, but current, commonly used risk factors are still useful in evaluating recurrence risks. Stratification by pT and pN classification and the number of risk factors enables the identification of large patient groups characterized by such a low recurrence rate that it is questionable whether adjuvant treatment is motivated. See Video Abstract at http://links.lww.com/DCR/A663.

How Should Imaging Direct/Orient Management of Rectal Cancer?

Modern rectal cancer management is dependent on preoperative staging, and radiological assessment is a crucial part of this process. Imaging must provide sufficient information to guide preoperative decision-making that is reliable and reproducible. Different methods have been used for local staging; however, magnetic resonance imaging (MRI) has shown to be the most reliable tool for this purpose. MRI offers prognostic information about the patients and guides the decision between neoadjuvant treatment and total mesorectal excision alone. Also, not only the initial staging but also restaging by MRI can provide significant information regarding tumor response that is essential when considering alternative approaches.

The degree of extramural spread of T3 rectal cancer: an appeal to the American Joint Committee on Cancer

The T3 category of the TNM classification includes over 60% of all rectal tumours and encompasses the greatest variance in cancer-specific end-points than any other T category. The most recent edition of the cancer staging handbook of the American Joint Committee on Cancer (AJCC) dated 2010 does not divide T3 tumours into subgroups which reflect cancer-specific outcome more sensitively. The original aim of the present study was to review the literature to assess the influence of the degree of extramural extent of T3 rectal cancer on local recurrence and survival. An article written by the authors was accepted for publication but was withdrawn immediately after they became aware of the publication of the 4th edition of the TNM Supplement by the Union for International Cancer Control dated 2012, which was not accessible by the search system used. This article dealt with the subdivision of the T3 category although this was not included in the most up-to-date AJCC guidelines and was stated to be 'entirely optional'. Medline, PubMed and Cochrane Library searches were performed to identify all studies that investigated the degree of extramural spread and its relationship to survival and local recurrence. Twenty-two studies were identified of which 12 assessed the degree of histopathological extramural spread measured in millimetres. In 18 of the 22 studies the degree of extramural spread was a statistically significant prognostic factor for survival and local recurrence. Analysis of the studies indicated that the subdivision of category T3 rectal cancer into two subgroups of extramural spread ≤ 5 mm or more than 5 mm resulted in markedly different survival and local recurrence rates. The data were insufficient to allow validation of any greater subdivision. Measurement of the extent of extramural spread by MRI before any treatment agreed with the histopathological measurement in the surgical specimen to within 1 mm. The extent of extramural spread in T3 rectal cancer measured in millimetres is a powerful prognostic factor. A subdivision of T3 into T3a and T3b of less than or equal to or more than 5 mm appears to give the greatest discrimination of local recurrence and survival. Preoperative T3 subdivision by MRI has the same sensitivity as histopathological examination of the resected specimen. Given the clinical need for the pretreatment classification of the T3 category for oncological management planning, the evidence strongly indicates that the subdivision of the T3 category by MRI should be formally considered as part of the TNM staging system for rectal cancer.

Complete Pathological Response After Neoadjuvant Long-Course Chemoradiotherapy for Rectal Cancer and Its Relationship to the Degree of T3 Mesorectal Invasion

BACKGROUND

Many studies have shown significantly improved outcomes (reduced local recurrence and improved overall survival) for patients achieving a complete pathological response from neoadjuvant chemoradiotherapy.

OBJECTIVE

This study aimed to document the complete pathological response rate and outcomes in patients receiving preoperative long-course chemoradiotherapy stratified for the extent of T3 mesorectal invasion measured on preoperative imaging.

DESIGN

This is a retrospective study of prospectively collected data, of patients with rectal cancer in the Cabrini Monash University Department of Surgery colorectal neoplasia database, incorporating data from Cabrini Hospital and The Alfred Hospital, identifying patients entered between January 2010 and June 2014.

PATIENTS AND SETTINGS

One hundred eighteen patients with T3 rectal cancer met the selection criteria for the study; 26 achieved complete pathological response (22%).

MAIN OUTCOME MEASURES

Outcomes in terms of complete pathological response and oncological outcomes such as disease-free and overall survival were analyzed.

RESULTS

Patients with complete pathological response had significantly less preoperative invasion than those with no complete pathological response (p < 0.001). Depth of invasion was the only variable associated with complete pathological response (p < 0.002), and the likelihood of complete pathological response decreased by 35% for every millimeter of invasion. Complete pathological response was associated with increased disease-free survival (p = 0.018) and a lower risk of cancer progression (p = 0.046). Depth of invasion was associated with an increased risk of death after surgery; HR increased by 1.07 (95% CI, 1.00-1.15) for each 1-mm increase in invasion.

LIMITATIONS

This was a retrospective study with the usual limitations, although these were minimized through the use of a clinician-driven prospective database.

CONCLUSIONS

The smaller the degree of T3 invasion, the higher the chance of achieving complete pathological response (up to 35%), which is associated with improved disease-free and overall survival. A higher complete pathological response rate is observed in early T3 disease in comparison with more extensive T3 invasion.

Current concepts of colorectal cancer resection pathology

The discussion of pathology results is one of the important items in the multidisciplinary meeting. These results describe not only the adequacy of earlier treatments (neoadjuvant therapy, surgery), but guide subsequent treatment decisions by providing staging information and additional prognostic and predictive factors. In the era of next-generation sequencing, every so often the emphasis is put on the molecular background of tumours, but the information that can be retrieved from the resection specimen remains essential for optimal patient care. In the current review the different surgical approaches will be described, together with the relevant macroscopic evaluations. Microscopic features will be addressed, giving an overview that is aimed at optimal information exchange in the multidisciplinary meeting. Finally, special requirements for reporting local excisions and specimen after neoadjuvant therapy will be discussed.

Grading lymph node metastasis: a feasible approach for prognostication of patients with stage III colorectal cancer

This study aimed to assess the clinicopathological significance of tumour differentiation of metastatic lymph node tissue in patients with American Joint Committee on Cancer (AJCC)/Union for International Cancer Control (UICC) stage III colorectal cancer. In a cohort of 145 patients, lymph node grades were G1 in 77 (53.1%), G2 in 41 (28.3%) and G3 in 27 (18.6%) cases, respectively. Despite differences in 77 (53.1%) cases, primary tumour and lymph node grade correlated significantly (Somer's D=0.639; p<0.001). Lymph node grade was significantly associated with N classification (p=0.009), tumour size (p=0.024) and lymphovascular invasion (p=0.004). Patients with lymph node grade G1 had better progression-free survival (p=0.031) and cancer-specific survival (p=0.008). Multivariable analysis identified lymph node grade as independent predictor of cancer-specific survival in this cohort. In conclusion, lymph node grade emerged as a promising novel prognostic variable for patients with AJCC/UICC stage III disease. Additional studies are warranted to validate this new finding.

Clinical impact of elastic laminal invasion in colon cancer: elastic laminal invasion-positive stage II colon cancer is a high-risk equivalent to stage III

BACKGROUND

Elastic laminal invasion is defined as tumor invasion beyond the peritoneal elastic lamina. It is one of the factors affecting the prognosis of patients with colon cancer.

OBJECTIVE

This study aimed to investigate the clinical impact of elastic laminal invasion in colon cancer and the magnitude of the worse prognosis of elastic laminal invasion-positive, node-negative patients.

DESIGN

This was a retrospective cohort study.

SETTINGS

This study reviewed data from a tertiary care cancer center in Japan.

PATIENTS

The records of 436 patients with pT3 or pT4a colon cancer who underwent curative resection between January 1996 and December 2006 were reviewed.

MAIN OUTCOME MEASURES

The primary outcome measure was recurrence-free survival. Cox regression analyses established the factors associated with recurrence-free survival. Six groups formed by combining the factors were compared.

RESULTS

Of the patients with pT3 disease, those who were positive for elastic laminal invasion had a 5-year recurrence-free survival rate of 73.8% compared with a rate of 85.0% in those who were negative for elastic laminal invasion and 53.5% in patients with pT4 disease. Three unfavorable prognostic factors were identified, including lymph node metastasis, positive elastic laminal invasion, and a lack of adjuvant chemotherapy. Log-rank analysis revealed statistically significant differences in recurrence-free survival between group 1 (node negative, elastic laminal invasion negative, and no adjuvant chemotherapy) and group 3 (node negative, elastic laminal invasion positive, and no adjuvant chemotherapy). The HR for group 1 compared with group 3 was 0.49 (95% CI, 0.27-0.90). Furthermore, the HRs for group 2 (node positive, elastic laminal invasion negative, and received adjuvant chemotherapy) and group 4 (node positive, elastic laminal invasion positive, and received adjuvant chemotherapy) vs group 3 were 0.77 (95% CI, 0.35-1.69) and 1.36 (95% CI, 0.62-2.98).

LIMITATIONS

Our study has limited prediction accuracy of our prognostic stratification, and an analysis of small subgroups may not have been capable of detecting significant differences. In addition, a wide range of hematoxylin and eosin- and elastica-stained slides were examined per case.

CONCLUSIONS

Elastic laminal invasion adversely influences prognosis in pT3 and pT4a colon cancer. Although elastic laminal invasion positivity does not affect prognosis in node-positive patients receiving adjuvant chemotherapy, node-negative patients with elastic laminal invasion have a similar risk of recurrence as node-positive patients.

Prognostic subdivision of ypT3 rectal tumours according to extension beyond the muscularis propria

Background

The subdivision of T3 in rectal carcinoma according to the depth of invasion into perirectal fat has been recommended in the TNM Supplement since 1993. This study assessed the prognostic impact of this pathological staging in tumours removed after neoadjuvant chemoradiotherapy (ypT3).

Methods

Data from patients with ypT3 rectal carcinoma (less than 12 cm from the anal verge) treated with neoadjuvant chemoradiation and total mesorectal excision were analysed. Tumour category ypT3 was subdivided into ypT3a (5 mm or less) and ypT3b (more than 5 mm), based on histological measurements of maximal tumour invasion beyond the outer border of the muscularis propria.

Results

Important differences between ypT3a (81 patients) and ypT3b (43) were found in 5-year rates of locoregional recurrence (7 versus 18 per cent; P = 0·049), distant metastasis (20 versus 41 per cent; P = 0·002), disease-free survival (73 versus 47 per cent; P = 0·001), overall survival (79 versus 74 per cent; P = 0·036) and cancer-related survival (81 versus 74 per cent; P = 0·007). In Cox regression analyses, the ypT3 subclassification was identified as an independent prognostic factor for disease-free (ypT3b: hazard ratio (HR) 2·13, 95 per cent confidence interval 1·16 to 3·89; P = 0·014), observed (ypT3b: HR 2·02, 1·05 to 3·87; P = 0·035) and cancer-related (ypT3b: HR 2·46, 1·20 to 5·04; P = 0·014) survival. Extramural venous invasion was found to be an additional prognostic factor, but the pathological node category after chemoradiotherapy (ypN) did not influence survival.

Conclusion

In ypT3 rectal carcinomas, the proposed subclassification is superior to ypN in predicting prognosis.

The depth of post-treatment perirectal tissue invasion is a predictor of outcome in patients with clinical T3N1M0 rectal cancer treated with neoadjuvant chemoradiation followed by surgical resection

BACKGROUND

To determine if patients with clinical stage III rectal cancer treated with neoadjuvant chemoradiotherapy (CRT) and surgery have an improved survival when the response to treatment results in a pathologic T3 tumor with a microscopic focus (≤5 mm) compared with a larger (>5 mm) invasion of the perirectal tissue.

METHODS

A retrospective review was conducted of 56 consecutive patients clinically diagnosed as T3N1M0 rectal cancer before treatment, who completed neoadjuvant CRT followed by surgical resection. Those with residual pathologic T3 disease (n = 28) were analyzed separately. Clinicopathologic data including T stage, lymph node status, k-ras status, and differentiation were reviewed.

RESULTS

Among all 56 patients, there was no identified predictor of survival following neoadjuvant CRT and surgery. Among those with residual T3 disease, tumors extending >5 mm invasion into the perirectal tissue were associated with a higher risk of recurrence (50% vs 17%) and worse overall survival (4.3 vs 6.8 years, P = .015) when compared to tumors with ≤5 mm invasion into the perirectal tissue.

CONCLUSION

The depth of residual T3 tumor invasion into the perirectal tissue correlates with recurrence and overall survival in patients who underwent neoadjuvant therapy followed by surgical resection for clinically staged T3N1M0 rectal cancer.

Do t3 rectal cancers always need radiochemotherapy?

The limitation of the traditional method of stratifying patients with rectal cancer for prognosis using magnetic resonance imaging (MRI) and computerised tomography (CT)-TNM staging-is that cT3 tumors comprise the vast majority of rectal cancers. There is a wide variability in outcomes for cT3. Despite this observation, many still advocate routine short course preoperative radiotherapy (SCPRT) or chemoradiation (CRT) for all patients staged as cT3N0 regardless of tumour location, proximity to other structures or extent, despite the fact that advances in imaging with MRI now offer the ability to predict potential outcomes in terms of the risk of local and metastatic recurrence for the individual. Preoperative CRT is designed to reduce local recurrence. The majority of local recurrences historically reflected inadequate quality of the mesorectal resection. Currently, optimal quality-controlled surgery in terms of total mesorectal excision (TME) in the trial setting can be associated with much lower local recurrence rates of less than 10 % whether patients receive radiotherapy or not. Because of the high risk of metastatic disease in selected patients, integrating more active chemotherapy is now attractive. Chemoradiotherapy (CRT) achieves shrinkage and sometimes eradication of tumour-i.e. a pathological complete response (pCR), and reduces local recurrence, but has no impact on overall survival. CRT also increases surgical morbidity and impacts on anorectal, urinary and sexual function with an increased risk of second malignancies. Hence, the predominant aims of CRT have been to shrink/downstage a tumour to allow an R0 resection to be performed, or to increase the chances of performing sphincter-sparing surgery. However, it remains unclear why shrinkage/downstaging is meaningful to a patient unless the tumour is initially borderline resectable or unresectable (i.e. the CRM is threatened) or the aim is to perform a lesser operation (i.e. sphincter-sparing or local excision) or for organ-sparing, i.e. to avoid surgery altogether. If it is important to shrink the cancer-ie there is a predicted threat to the CRM, then CRT is currently the treatment of choice. If the cancer is resectable and the aim is simply to lower the risk of local recurrence and preoperative CRT does not impact on survival, can CRT be omitted in selected cases? The answer is yes-with the proviso that we are using good quality MRI and the surgeon is performing good quality TME surgery within the mesorectal plane.

Extramural extension as indicator for postoperative adjuvant chemotherapy in Stage IIA (pT3N0) colon cancer

The usefulness of adjuvant chemotherapy (CMT) in patients with Stage IIA colon cancer remains unclear. The present study aimed to investigate extramural extension as an indicator for adjuvant CMT. Data were reviewed from 202 consecutive patients with Stage IIA colon cancer that underwent curative surgery between 1995 and 2007. The distance of the extramural extension (DEE) was measured histologically. The optimal prognostic cut-off point of the DEE for oncologic outcomes was statistically determined. The eligible surviving patients had been followed for a median period of 75 months (range: 2-210 months). Patients were subdivided into two groups according to the optimal cut-off point; DEE ≤5 mm (pT3a) and DEE >5 mm (pT3b). The pT3b was the most powerful independent risk factor for postoperative recurrence (P = 0.0324, HR: 3.04, 95% CI: 1.098-8.408), and was significantly correlated with distant metastasis (P = 0.0161 HR: 5.19, 95% CI: 1.765-15.239). The recurrence-free and cancer-specific 5-year survival rates in patients with pT3b were significantly lower than in patients with pT3a (81.5% vs. 95.4%, P = 0.0003 and 85.9% vs. 97.4%, P = 0.0007, respectively). pT3b could be an important risk factor for distant metastasis in Stage IIA colon cancer. Postoperative adjuvant CMT may be indicated for patients with pT3b.

Benefit of the measurement of mesorectal extension in patients with pT3N1-2 rectal cancer without pre-operative chemoradiotherapy: Post-operative treatment strategy

A treatment strategy based on the distance of mesorectal extension (DME) for pT3N1-2 rectal cancer patients without pre-operative chemoradiotherapy has not yet been defined. The present study aimed to describe the benefit of the measurement of mesorectal extension in stratifying treatment for pT3N1-2 rectal cancer patients. Data from 512 patients with pT3N1-2 rectal cancer undergoing curative surgery at 28 institutes were analyzed in this study. DME was measured histologically, and the optimal prognostic cut-off point of the DME was determined using Cox regression analyses. Survival was calculated using the Kaplan-Meier method. The patients were subdivided into two groups based on the optimal prognostic cut-off point: DME ≤4 mm and DME >4 mm. The DME was found to be a powerful independent risk factor for predicting distant and local recurrences. The recurrence-free 5-year survival rates of patients with DME >4 mm were significantly poorer for Stages IIIB (53.3%; p=0.0015; HR, 1.76; 95% CI, 1.233–2.501) and IIIC (32.9%; p=0.0095; HR, 1.64; 95% CI, 1.119–2.407) than for patients with DME ≤4 mm (69.7 and 50.4%, respectively). The cancer-specific survival rates of patients with DME >4 mm were also significantly worse than those with DME ≤4 mm. A value of 4 mm provides the best cut-off point for subdividing the mesorectal extension to predict oncologic outcomes. Measurement of mesorectal extension appears to be of benefit in stratifying patients for post-operative adjuvant treatments.

Depth of mesorectal extension has prognostic significance in patients with T3 rectal cancer

BACKGROUND

More than half of all rectal cancers are T3 lesions, but they are classified as a single-stage category.

OBJECTIVE

The aim of this study was to validate prognostic significance of mesorectal extension depth in T3 rectal cancer.

DESIGN

This study is a retrospective analysis of oncologic outcomes of patients with T3 rectal cancer grouped by mesorectal extension depth (T3a, <1 mm; T3b, 1-5 mm; T3c, 5-15 mm; T3d, >15 mm).

SETTINGS

This study was conducted at a tertiary referral cancer hospital.

PATIENTS

From 2003 to 2009, 291 patients who underwent a curative surgery were included.

MAIN OUTCOME MEASURES

Oncologic outcomes in terms of disease-free survival were analyzed.

RESULTS

The 5-year disease-free survival rate according to T3 subclassification was 86.5% for T3a, 74.2% for T3b, 58.3% for T3c, and 29.0% for T3d. It was significantly higher in T3a,b tumors than that in T3c,d tumors (77.6% vs 55.2%, p < 0.001). On univariate and multivariate analysis, prognostic factors affecting recurrence were preoperative CEA level ≥ 5 ng/mL (HR 2.617, 95% CI 1.620-4.226), lymph node metastasis (HR 3.347, 95% CI 1.834-6.566), and mesorectal extension depth >5 mm (HR 1.661, 95% CI 1.013-2.725). In subgroup analysis, independent prognostic factors were preoperative CEA level and mesorectal extension depth >5 mm for 200 patients with ypT3 rectal cancer and preoperative CEA level and lymph node metastasis for 91 patients with pT3 rectal cancer.

LIMITATIONS

This study lacks quality of surgery plane evaluation because of its retrospective nature. Moreover, pathologic examination was not done with a whole-mount section.

CONCLUSIONS

Depth of mesorectal extension >5 mm is a significant prognostic factor in patients with T3 rectal cancer. Depth of mesorectal extension especially may be more important than the nodal status in predicting the oncologic outcome for patients who had received preoperative chemoradiotherapy.

Validation of the seventh edition of the American Joint Committee on cancer tumor node-staging system in patients with colorectal carcinoma in comparison with sixth classification

BACKGROUND

The aim of this study was to compare survival rates assessed by the seventh-staging system with those by the sixth classification.

METHODS

This was a retrospective study of 3,377 patients who underwent surgery for colorectal adenocarcinoma from three university hospitals. The overall survival (OS) and cancer-specific survival (CSS) rates were compared between patients whose stages according to the seventh-staging system remained the same and patients whose stages migrated, and between subgroups within each new stage (homogeneity analysis).

RESULTS

In seventh edition, the 5-year OS and CSS rates of patients with T3n2 tumor were significantly greater in the downstaged patients (T3N2a) than in other patients (T3N2b) (OS, P = 0.010; CSS, P = 0.009). The 5-year survival rates for patients with T4a and T4b sub-classifications according to the seventh edition did not differ from those in patients with T4N0-1. Homogeneity analysis of subgroups classified using the new system showed that some subgroups of stage IIIB (T3N2a/T4aN1) had poorer survival rates compared with patients in other sub-categories in the same stage IIIB (P < 0.001).

CONCLUSION

Overall, the seventh edition provides a more detailed classification of the prognosis than the old system. However, further study would be warranted to evaluate the validity of sub-classification in seventh TNM-staging system, especially for T4a-b and T3N2a tumors.

Surgery for colorectal peritoneal carcinomatosis

Peritoneal carcinomatosis occurs in patients with advanced gastrointestinal and gynecological malignancies and also in patients who experience recurrence after treatment failure of the primary tumor. Malignant disease in the peritoneal cavity is a morbid and significant predictor of a diminished survival in a cancer patient. Systemic chemotherapy alone will not be adequate to palliate or treat patients with peritoneal carcinomatosis. Cytoreductive surgery is a new surgical technique that is performed using peritonectomy procedures to allow total eradication of peritoneal tumors. Intraperitoneal chemotherapy regimens such as intraoperative hyperthermic intraperitoneal chemotherapy (HIPEC) and early postoperative intraperitoneal chemotherapy (EPIC) are effective adjuvant treatment to treat the minimal residual disease after cytoreductive surgery to reduce the risk of locoregional recurrence. A substantial body of evidence available in the current literature has documented the survival benefits of combining cytoreductive surgery and intraperitoneal chemotherapy to treat a previously fatal phase of malignancy. This review provides a summary of the developments in the understanding and treatment of peritoneal surface malignancy from colorectal cancer.

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.