The retroperitoneal surface in distal caecal and proximal ascending colon carcinoma: the Cinderella surgical margin?

Evaluation of colon cancer prognostic factors by CT and MRI: an up-to-date review

Colorectal cancer (CRC) is a significant global health concern. Prognostication of CRC traditionally relies on the Union for International Cancer Control (UICC) and American Joint Committee on Cancer (AJCC) TNM staging classifications, yet clinical outcomes often vary independently of stage. Despite similarities, rectal and colon cancers are distinct in their diagnostic methodologies and treatments, with MRI and CT scans primarily used for staging rectal and colon cancers, respectively. This paper examines the challenges in accurately assessing prognostic factors of colon cancer such as primary tumor extramural extension, retroperitoneal surgical margin (RSM) involvement, extramural vessel invasion (EMVI), and lymph node metastases through preoperative CT and MRI. It highlights the importance of these factors in risk stratification, treatment decisions, and surgical planning for colon cancer patients. Advancements in imaging techniques are crucial for improving clinical management and optimizing patient outcomes, underscoring the necessity for ongoing research to refine diagnostic methods and incorporate novel findings into practice.

Current Challenges and Controversies in Colorectal Carcinoma Pathologic Staging-A Practical Guide

The pathologic assessment of colorectal carcinoma specimens plays a crucial role in the therapeutic management of patients and disease prognostication. The TNM staging system is used globally and is a critical component of colorectal carcinoma pathology reporting. However, our experience informs us that there are significant variations in the assignment of the TNM stage, both between pathologists and between hospital centers. We identify several potential reasons for this, among them suboptimal gross and microscopic assessment of colorectal resection specimens and, later, nonuniformity in applying criteria set forth in pathologic TNM staging guidelines. In addition, some defining characteristics of the staging system remain poorly defined. We aim to enlist those issues with potential remedies to improve reproducibility and, therefore, multidisciplinary discussion.

Assessing the histopathology reports of colorectal carcinoma surgery: An audit of three years with emphasis on lymph node yield

Background

A comprehensive histopathology report of colorectal carcinoma surgery is important in cancer staging and planning adjuvant treatment. Our aim was to review histopathology reports of operated specimens of colorectal carcinoma in our institution between 2013 and 2015 to assess different histological parameters, including lymph node yield, and to evaluate compliance to minimum data sets.

Methods

After approval by the institutional review board (IRB), we analyzed 1230 histopathology reports of colorectal carcinoma between 2013 and 2015. Various gross and microscopic findings (along with age, sex) were noted, for example, specimen type, tumor site, resection margins including circumferential resection margin (CRM), lymphovascular invasion, perineural invasion, pTNM stage, lymph node yield, etc.

Results

Out of 1230 patients, 826 (67.15%) were men and 404 (32.85%) were women. The overall mean age was 52 (range: 18 - 90) years. There were 787 surgeries for rectal cancers. All reports commented on the type of specimen, tumor size (mean = 4.38 cm), proximal, and distal margins. Lymphovascular invasion (LVI) and the pT stage were mentioned in 98.06% and 99.84%, respectively. The overall mean lymph node yield was 18.38 (median = 15, range = 0-130 lymph nodes). A statistically significant difference in lymph node yield was detected between rectal and colonic cancer patients (14.79 and 27.26); post neoadjuvant therapy (NACT) cases, and NACT naive cases (13.51 and 25.11); and high tumor stage and low tumor stage disease (20.60 and 15.22). Not commenting on extramural vascular emboli, tumor budding, and CRM in non-rectal cancer cases were the lacunae.

Conclusion

Our compliance with minimal data sets is satisfactory. The overall mean lymph node yield was 18.38 (median = 15). Extramural vascular emboli, tumor budding need to be captured.

The impact of subdivisions of microscopically positive (R1) margins on patterns of relapse in stage III colorectal cancer - A retrospective cohort study

AIM

Microscopically positive (R1) margins are associated with poorer outcomes in patients with colorectal cancer. However, the impact of subdivisions of R1 margins, be they to the primary tumour (R1 tumour) or to lymph node metastases (R1LNM), on patterns of relapse is unknown.

METHODS

Patients treated for stage III colorectal cancer from 01 January 2016 to 31 December 2019 in four specialist centres were identified from the Danish national cancer registry. Patients were stratified into three groups according to margin status (R0 vs. R1 tumour vs. R1LNM). The primary outcomes were local recurrence-free survival (LRFS), distant metastases-free survival (DMFS) and disease-specific survival (DSS).

RESULTS

A total of 1,164 patients were included, with R1 margins found in 237 (20.4%). Irrespective of tumour location, R1 tumour and R1LNM margins were independent prognostic factors for systemic relapse (R1 tumour HR 1.84, CI: 1.17-2.88, p = 0.008; R1LNM HR 1.59, CI: 1.12-2.27, p = 0.009) and disease-related death (R1 tumour HR 2.08, CI: 1.12-3.85, p = 0.020; R1LNM HR 1.84, CI: 1.12-3.02, p = 0.016). Whereas R1 tumour margins were associated with poorer 3-year LRFS in both colon and rectum cancer, R1LNM margins only reduced LRFS in patients with rectal cancer. Patterns of relapse differed between R1 subdivisions, with R1 tumour margins more likely to affect multiple anatomical sites, with a predilection for extra-hepatic/pulmonary metastases.

CONCLUSION

Subdivisions of R1 margins have a distinct impact on the oncological outcomes and patterns of disease relapse in patients with stage III colorectal cancer.

Nonmicroradical Resection Margin as a Predictor of Recurrence in Patients With Stage III Colon Cancer Undergoing Complete Mesocolic Excision: A Prospective Cohort Study

BACKGROUND

The prognostic value of the present definition of microradicality in colon cancer is poorly understood, especially considering the vast influence it has in rectal cancer prognosis.

OBJECTIVE

This study aimed to investigate whether the risk of recurrence after complete mesocolic excision for stage III colon cancer is associated with the distance from tumor tissue to resection margin and whether the location of the involved margin is of any significance.

DESIGN

A prospective cohort of patients was stratified into 2 groups to distinguish between direct margin invasion (0-mm resection margin) and a ≤1-mm resection margin without direct invasion or 3 groups to distinguish between the location of margin involvement (lateral tumor resection margin, central vascular ligation margin, and nonperitonealized mesocolic resection margin). Patients with microradical resections were used as a control group.

SETTINGS

We included all patients undergoing elective complete mesocolic excision for International Union Against Cancer stage III colon cancer at Nordsjællands Hospital between January 1, 2008, and December 31, 2016.

PATIENTS

A total of 276 patients met all inclusion criteria and none of the exclusion criteria.

MAIN OUTCOME MEASURES

Primary outcome was risk of recurrence after 3.2 years.

RESULTS

A total of 41 patients (15%) had a nonmicroradical resection. The 3.2-year cumulative incidence of recurrence for a 0-mm margin was 43% and 24% for a ≤1-mm margin without direct invasion, corresponding with an HR of 4.3 (p = 0.0146) and 1.3 (p = 0.474). The location of the involved margin showed no significant differences.

LIMITATIONS

This was a single-center study containing a limited number of patients with a nonmicroradical resection with a risk of type II error.

CONCLUSIONS

We found no increased risk of recurrence for a ≤1-mm margin without direct invasion, indicating that the present classification of microradicality might not be justified if an intact posterior mesocolic fascia without invasion of tumor tissue is present. See Video Abstract at http://links.lww.com/DCR/B625.

MARGEN DE RESECCIN NO MICRORRADICAL COMO PREDICTOR DE RECURRENCIA EN PACIENTES CON CNCER DE COLON EN ESTADIO III SOMETIDOS A ESCISIN MESOCLICA COMPLETA UN ESTUDIO DE COHORTE PROSPECTIVO

ANTECEDENTES:El valor pronóstico de la definición actual de microrradicalidad en el cáncer de colon es poco conocido, especialmente considerando la gran influencia que tiene en el pronóstico del cáncer de recto.OBJETIVO:Este estudio tiene como objetivo investigar si el riesgo de recurrencia después de la escisión mesocólica completa (CME) para el cáncer de colon en estadio III está asociado con la distancia desde el tejido tumoral hasta el margen de resección y si la localización del margen afectado tiene alguna importancia.DISEÑO:Una cohorte prospectiva de pacientes se estratificó en dos grupos para distinguir entre la invasión del margen directo (margen de resección de 0 mm) y un margen de resección ≤1 mm sin invasión directa, o tres grupos para distinguir entre la localización de la afectación del margen (resección lateral del margen del tumor, margen de ligadura vascular central y margen de resección mesocólica no peritonizada). Los pacientes con resecciones microrradicales se utilizaron como grupo control.ENTORNO CLÍNICO:Incluimos a todos los pacientes sometidos a CME electiva por cáncer de colon en estadio III de la UICC en el Hospital Nordsjællands, Dinamarca, entre el 1 de enero de 2008 y el 31 de diciembre de 2016.PACIENTES:Un total de 276 pacientes cumplieron todos los criterios de inclusión y ninguno de los criterios de exclusión.PRINCIPALES MEDIDAS DE RESULTADO:El resultado primario fue el riesgo de recurrencia después de 3 · 2 años.RESULTADOS:Un total de 41 (15%) pacientes tuvieron una resección no microrradical. La incidencia acumulada de recurrencia a los 3,2 años para un margen de 0 mm fue del 43% y del 24% para un margen ≤1 mm sin invasión directa, lo que corresponde a un cociente de riesgo de 4,3 (p = 0,0146) y 1,3 (p = 0,474) respectivamente. La localización del margen afectado no mostró diferencias significativas.LIMITACIONES:Estudio unicéntrico con un número limitado de pacientes con resección no microrradical con riesgo de error tipo II.CONCLUSIONES:No encontramos un mayor riesgo de recurrencia para un margen ≤1 mm sin invasión directa, lo que indica que la clasificación actual de microrradicalidad podría no estar justificada si está presente una fascia mesocólica posterior intacta sin invasión del tejido tumoral. Consulte Video Resumen en http://links.lww.com/DCR/B625. (Traducción-Dr Yazmin Berrones-Medina).

Dataset for Pathology Reporting of Colorectal Cancer: Recommendations From the International Collaboration on Cancer Reporting (ICCR)

OBJECTIVE

The aim of this study to describe a new international dataset for pathology reporting of colorectal cancer surgical specimens, produced under the auspices of the International Collaboration on Cancer Reporting (ICCR).

BACKGROUND

Quality of pathology reporting and mutual understanding between colorectal surgeon, pathologist and oncologist are vital to patient management. Some pathology parameters are prone to variable interpretation, resulting in differing positions adopted by existing national datasets.

METHODS

The ICCR, a global alliance of major pathology institutions with links to international cancer organizations, has developed and ratified a rigorous and efficient process for the development of evidence-based, structured datasets for pathology reporting of common cancers. Here we describe the production of a dataset for colorectal cancer resection specimens by a multidisciplinary panel of internationally recognized experts.

RESULTS

The agreed dataset comprises eighteen core (essential) and seven non-core (recommended) elements identified from a review of current evidence. Areas of contention are addressed, some highly relevant to surgical practice, with the aim of standardizing multidisciplinary discussion. The summation of all core elements is considered to be the minimum reporting standard for individual cases. Commentary is provided, explaining each element's clinical relevance, definitions to be applied where appropriate for the agreed list of value options and the rationale for considering the element as core or non-core.

CONCLUSIONS

This first internationally agreed dataset for colorectal cancer pathology reporting promotes standardization of pathology reporting and enhanced clinicopathological communication. Widespread adoption will facilitate international comparisons, multinational clinical trials and help to improve the management of colorectal cancer globally.

The significance of subdivisions of microscopically positive (R1) margins in colorectal cancer: A retrospective study of a national cancer registry

AIM

Microscopically positive (R1) margins are associated with poorer outcomes in patients with colorectal cancer. However, little is known of the differential impact of subdivisions of R1 margins, be they to the primary tumour (R1tumour) or to lymph node metastases/tumour deposits (R1LNM).

METHODS

Patients treated for Stage III colorectal cancer from 1 January 2016 to 31 December 2019 were identified from the Danish national cancer registry. Patients were stratified into three groups according to margin status (R0 vs. R1tumour vs. R1LNM). The primary outcome was overall survival.

RESULTS

In all, 4186 patients were included, comprising 3012 patients with colon cancer and 1174 patients with rectal cancer. The R1 resection rates were 16.5% and 18.2% in patients with colon and rectum cancer, respectively. In colon cancers, 3-year overall survival was reduced in patients with R1LNM (65.7%, 95% CI 62.8-68.6) or R1tumour margins (51.8%, 95% CI 47.3-56.3) compared with R0 resections (80.8%, 95% CI 79.9-81.6, P < 0.001). A similar impact on survival was seen in rectal cancers (R0, 84.2%, 95% CI 82.9-85.5; R1LNM, 72.2%, 95% CI 67.8-76.6; R1tumour, 56.6%, 95% CI 50.0-63.2, P < 0.001). Margin status was independently prognostic of survival in both colon (R1tumour, hazard ratio 2.08, 95% CI 1.50-2.89, P < 0.001; R1LNM, hazard ratio 1.48, 95% CI 1.11-1.97, P = 0.008) and rectal cancers (R1tumour, hazard ratio 2.35, 95% CI 1.42-3.90, P < 0.001; R1LNM, hazard ratio 1.54, 95% CI 0.95-2.48, P = 0.077).

CONCLUSION

R1 subdivisions have distinct impacts on survival in Stage III colorectal cancer. Further focused research in these patient subgroups is warranted.

Positive circumferential resection margins following locally advanced colon cancer surgery: Risk factors and survival impact

BACKGROUND

While the prognostic implications of positive circumferential resection margins (CRM) have been established for rectal cancer, its significance in colon cancer has not been well defined. The aim of the current study was to determine national rates for positive CRM in locally advanced colon cancer, associated factors, and survival impact.

METHODS

The National Cancer Database was queried to identify patients with stage II-III adenocarcinoma of the colon (2004-2015).

RESULTS

Positive CRM was identified in 9% of stage II and 12% of stage III patients. Factors associated with negative CRM included surgery in a high-volume facility, adequate lymph-node harvest, and negative distal/proximal margins. No difference in CRM rates was observed between surgical approaches, although having a positive CRM was significantly associated with higher conversion rates. Positive CRM was associated with significantly lower overall survival on both univariate and multivariable analysis.

CONCLUSIONS

Positive CRM rates exceeded 10% nationally and have an adverse impact on survival. While several tumor characteristics were identified as independent risk factors, oncologic resections and surgery at high-volume centers were associated with lower rates of positive CRM. These findings emphasize the need for process improvement initiatives targeting modifiable factors, including adoption of appropriate oncologic techniques, standardized pathology reporting, and potential neoadjuvant strategies.

Comparison of the eighth version of the American Joint Committee on Cancer manual to the seventh version for colorectal cancer: A retrospective review of our data

AIM

To analyze the survival trends in colorectal cancer (CRC) based on the different classifications recommended by the seventh and eighth editions of the American Joint Committee on Cancer staging system (AJCC-7^th and AJCC-8^th).

METHODS

The database from our institution was queried to identify patients with pathologically confirmed stage 0-IV CRC diagnosed between 2006 and 2012. Data from 2080 cases were collected and 1090 cases were evaluated through standardized inclusion and exclusion criteria. CRC was staged by AJCC-7^th and then restaged by AJCC-8^th. Five-year disease-free survival (DFS) and overall survival (OS) were compared. SPSS 21.0 software was used for all data. DFS and OS were compared and analyzed by Kaplan-Meier and Log-rank test.

RESULTS

Linear regression and automatic linear regression showed lymph node positive functional equations by tumor-node-metastasis staging from AJCC-7^th and tumor-node-metastasis staging from AJCC-8^th. Neurological invasion, venous infiltration, lymphatic infiltration, and tumor deposition put forward stricter requirements for pathological examination in AJCC-8^th compared to AJCC-7^th. After re-analyzing our cohort with AJCC-8^th, the percentage of stage IVB cases decreased from 2.8% to 0.8%. As a result 2% of the cases were classified under the new IVC staging. DFS and OS was significantly shorter (P = 0.012) in stage IVC patients compared to stage IVB patients.

CONCLUSION

The addition of stage IVC in AJCC-8^th has shown that peritoneal metastasis has a worse prognosis than distant organ metastasis in our institution’s CRC cohort. Additional datasets should be analyzed to confirm these findings.

Competing risks analysis of the effect of local residual tumour on recurrence and cancer-specific death after resection of colorectal cancer: implications for staging

The pTNM staging system for colorectal cancer (CRC) is not entirely effective in discriminating between potentially curative and non-curative resections because it does not account for local residual tumour in patients with stages I, II or III. This study aimed to evaluate the prognostic importance of histologically verified tumour in any line of resection of the bowel resection specimen (TLR) in relation to pTNM stages and to demonstrate how TLR may be integrated into pTNM staging. Information on patients in the period 1995 to 2010 with complete follow-up to the end of 2015 was extracted from a prospective database of CRC resections. The outcome variables were the competing risks incidence of CRC recurrence and CRC-specific death. After exclusions, 2220 patients remained. In 1930 patients with pTNM stages I-III tumour, recurrence was markedly higher in those with TLR than in those without (HR 6.0, 95% CI 4.2-8.5, p < 0.001) and this persisted after adjustment for covariates associated with recurrence. CRC-specific death was markedly higher in the presence of TLR (HR 7.7, CI 5.3-11.2, p < 0.001), which persisted after adjustment for relevant covariates. These results justify removing patients with TLR from pTNM stages I to III and placing them in stage IV, thereby allowing the categorisation of all patients with any known residual tumour into three prognostically distinct groups. This study demonstrates how TLR may be integrated into pTNM staging, thus improving the definition of the three stages which are considered potentially curable (I, II and III).

The role of multidetector CT in local staging and evaluation of retroperitoneal surgical margin involvement in colon cancer

PURPOSE

We aimed to evaluate preoperative T and N staging and retroperitoneal surgical margin (RSM) involvement in colon cancer using multidetector computed tomography (MDCT).

METHODS

In this retrospective study, preoperative MDCTs of 141 patients with colon adenocarcinoma were evaluated in terms of T and N staging and retroperitoneal surgical margin involvement by two observers. Results were compared with histopathology.

RESULTS

In determining extramural invasion, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of MDCT were 81%, 50%, 95%, 26%, and 81% for observer 1 and 87%, 75%, 97%, 27%, and 84% for observer 2, respectively. Moderate interobserver agreement was observed (ĸ=0.425). In determining T stage of the tumor, accuracy of MDCT was 55% for observer 1 and 51% for observer 2. In the detection of lymph node metastasis, sensitivity, specificity, PPV, NPV, and accuracy of MDCT were 84%, 46%, 60%, 74% and 64% for observer 1 and 84%, 56%, 65%, 78%, and 70% for observer 2, respectively. Interobserver agreement was substantial (ĸ=0.650). RSM was involved in six cases (4.7%). When only retroperitoneal colon segments were considered, 1.6% of subjects demonstrated RSM involvement. Four of the six RSM-positive tumors were located on sigmoid colon and one tumor was on transverse colon and caecum. Considering all colon tumors, in the detection of RSM involvement, sensitivity and specificity of MDCT were 33% and 81% for observer 1 and 50% and 80% for observer 2. Interobserver agreement was moderate (ĸ=0.518).

CONCLUSION

MDCT is a promising technique with moderate interobserver agreement in detection of extramural invasion, lymph node metastases, and RSM involvement in colon carcinomas.

Significance of R1 resection margin in colon cancer resections in the modern era

AIM

Circumferential resection margin involvement (R1) in rectal cancer is a predictive factor for poor prognosis. The aim of this study was to confirm the prognostic significance of R1 in colon cancer resection and to establish whether the introduction of laparoscopic colorectal surgery influenced this.

METHOD

Prospectively collected data on a patient pathway data manager for sequential patients with colon cancer treated at our specialist unit from January 2005 to December 2010 were analysed. There were 1110 colonic resections (elective 865; emergency 245). A circumferential resection margin involvement of < 1 mm was considered positive.

RESULTS

The total R1 rate was 13.3% (elective 10.4%; emergency 23.6%; P < 0.001). Other statistically significant risk factors for an R1 resection included tumour perforation (P < 0.001), poorly differentiated carcinoma (P < 0.001), T4 tumour (P < 0.001), vascular invasion (P < 0.001), lymph node metastasis (P < 0.001), distant metastasis (P < 0.001) and palliative resection (P < 0.001). Over half of the elective resections were undertaken laparoscopically (486/865; 56.2%). When compared with elective open resection (379/865; 43.8%), the R1 rate was similar (P = 0.491) with similar disease-free survival (DFS) and overall survival (OS). The overall relapse rate was 18.9% in R0 and 55.5% in R1 resections (P < 0.001). Kaplan-Meier survival analysis showed significant improvements in DFS and OS in R0 over R1 patients.

CONCLUSION

The R1 margin in colon cancer resection is an important marker for advanced disease and a prognostic factor for DFS and OS. The introduction of laparoscopic surgery has not influenced the outcome in our unit despite a complex case mix.

AJCC Cancer Staging Manual 7th edition criteria for colon cancer: do the complex modifications improve prognostic assessment?

BACKGROUND

The 7th edition of the AJCC Cancer Staging Manual (AJCC-7) includes substantial changes for colon cancer (CC), which are particularly complex in patients with stage II and III disease. We used a national cancer database to determine if these changes improved prediction of survival.

STUDY DESIGN

The database of the Surveillance, Epidemiology and End Results Program was queried to identify patients with pathologically confirmed stage I to III CC diagnosed between 1988 and 2008. Colon cancer was staged by the 6(th) edition of the AJCC Cancer Staging Manual (AJCC-6) and then restaged by AJCC-7. Five-year disease-specific survival and overall survival were compared.

RESULTS

After all exclusion criteria were applied, AJCC-6 and AJCC-7 staging was possible in 157,588 patients (68.9%). Bowker's test of symmetry showed that the number of patients per substage was different for AJCC-6 and AJCC-7 (p < 0.001). The Akaike information criteria comparison showed superior fit with the AJCC-7 model (p < 0.001). However, although AJCC-7 staging yielded a progressive decrease in disease-specific survival and overall survival of patients with stage IIA (86.3% and 72.4%, respectively), IIB (79.4% and 63.2%, respectively), and IIC (64.9% and 54.6%, respectively) CC, disease-specific survival and overall survival of patients with stage IIIA disease increased (89% and 79%, respectively). Subset analysis of patients with >12 lymph nodes examined did not affect this observation.

CONCLUSIONS

The AJCC-7 staging of CC does not address all survival discrepancies, regardless of the number of lymph nodes examined. Consideration of other prognostic factors is critical for decisions about therapy, particularly for patients with stage II CC.

Surgeons' Evaluation of Colorectal Cancer Resections Against Standard HPE Protocol-Auditing the Surgeons

The survival of Colorectal Cancer patients is very much dependent on complete tumor resection and multimodality adjuvant treatment. However, the main determinants for management plan of these patients rely heavily on accurate staging through histopathological examination (HPE). A reliable standard HPE protocol will be a significant impact in determining best surgical outcome. We evaluate surgeons' intra-operative judgment and the quality of resected specimens in the treatment of colorectal cancers. To quantify the quality of surgery by applying standard HPE protocol in colorectal cancer specimens and to assess the use of new format for pathological reporting in Colorectal Cancer using a formulated standard proforma. We perform a prospective observation of all colorectal cancer patients who underwent surgical resection over 8 month duration. Surgeons are required to make self-assessment about completion of tumor excision and possible lymph nodes or adjacent organ involvement while all pathologists followed standard reporting protocol for examination of the specimens. We evaluate the accuracy of surgeons judgment against HPE. The study involved 44 colorectal cancers comprising of 23 male and 21 female patients. The majority of these patients were Malay (50%) followed by Chinese (43%) and Indian (7%). The main presenting symptoms were bleeding (32%), intestinal obstruction (29%) and perforation (7%). Sixteen (36%) patients underwent emergency surgery.Rectal tumor was the commonest (53%) followed by sigmoid colon (22.7%). Neoadjuvant Chemoradiation were given to 8 patients and complete pathological response was observed in 1 (12.5%) of these. The final TNM classification for staging were; stage I (22.7%), stage IIa (18.2%), stage IIb (11.4%), stage IIIa (2.3%), stage IIIb (25%), stage IIIc (13.6%) and stage IV (6.8%).The commonest surgery performed was anterior resection with mesorectal excision (43.2%). Ten patients (22.7%) had laparoscopic surgery with 3 (30%) patients converted to open surgery. The surgeons claimed to have performed a curative resection with complete excision and clear margin in 40 (90%) patients. Of these, only 1 (2.5%) patient had a positive resection margin. Meanwhile, the surgeons reported involvement of resection margins in 4 cases but this was disputed by the HPE in all 4 cases. Lymph nodes involvement was detected intra-operatively in 13 (29.5%) of the cases and all were proven positive for metastases through HPE. On the other hand, of the remaining 31 patients who were reported as no obvious lymphadenopathy by the surgeons, lymph nodes positvity was found in 7 (22.5%) cases. Using standard HPE reporting protocol brings suitable evaluation of surgery in colorectal cancer treatment. Although surgeons' judgment is fairly accurate in predicting margin clearance and complete specimen excision, complete mesocolic and mesorectal excision is of utmost importance since lymph nodes metastatic involvement may not be obvious at surgery.

Perspectives on current tumor-node-metastasis (TNM) staging of cancers of the colon and rectum

Improvements in classifications of cancers based on discovery and validation of important histopathological parameters and new molecular markers continue unabated. Though still not perfect, recent updates of classification schemes in gastrointestinal oncology by the American Joint Commission on Cancer (tumor-node-metastasis [TNM] staging) and the World Health Organization further stratify patients and guide optimization of treatment strategies and better predict patient outcomes. These updates recognize the heterogeneity of patient populations with significant subgrouping of each tumor stage and use of tumor deposits to significantly "up-stage" some cancers; change staging parameters for subsets of IIIB and IIIC cancers; and introduce of several new subtypes of colon carcinomas. By the nature of the process, recent discoveries that are important to improving even routine standards of patient care, especially new advances in molecular medicine, are not incorporated into these systems. Nonetheless, these classifications significantly advance clinical standards and are welcome enhancements to our current methods of cancer reporting.

Review of histopathological and molecular prognostic features in colorectal cancer

Prediction of prognosis in colorectal cancer is vital for the choice of therapeutic options. Histopathological factors remain paramount in this respect. Factors such as tumor size, histological type and subtype, presence of signet ring morphology and the degree of differentiation as well as the presence of lymphovascular invasion and lymph node involvement are well known factors that influence outcome. Our understanding of these factors has improved in the past few years with factors such as tumor budding, lymphocytic infiltration being recognized as important. Likewise the prognostic significance of resection margins, particularly circumferential margins has been appreciated in the last two decades. A number of molecular and genetic markers such as KRAS, BRAF and microsatellite instability are also important and correlate with histological features in some patients. This review summarizes our current understanding of the main histopathological factors that affect prognosis of colorectal cancer.

Expression of p53, Ki-67 and c-Myc proteins is predictive of the surgical molecular margin in colorectal carcinoma

Surgical resection is the mainstay of treatment for colorectal carcinoma, however, the overall survival is modest due to frequent local recurrence from residual cancer cells after "curative" resection. Therefore, the status of surgical margin (tumor free or positive) has a significant influence on patient's survival. The difference in molecular profile between mucosa neighboring tumor lesions and remote area (surgical margin) may aid in evaluating resection status. 44 colorectal tumor tissues with corresponding adjacent non-neoplastic mucosa (within 3 cm from tumor tissues), and 110 tumor tissues with corresponding surgical margin mucosa (5 cm from tumor tissues) were randomly collected, fixed in 10% formalin and followed by embedding in paraffin. And the expression of p53, Ki-67 and c-Myc were investigated by tissue microarray (TMA) and immunohistochmistry. The expression of p53, Ki-67 and c-Myc were decreased in both adjacent non-neoplastic mucosa and mucosa of surgical margin, comparing to their expression in corresponding cancer cells. Furthermore, the expression of these proteins in mucosa of remote area (surgical margin) was significantly lower than those adjacent to tumor lesions. The expression of p53, Ki-67 and c-Myc in mucosa can be used as molecular marker for assessing surgical margin status in colorectal carcinoma.

TNM staging system of colorectal carcinoma: a critical appraisal of challenging issues

CONTEXT

Colorectal cancer is the leading cause of morbidity and death among gastrointestinal tumors and ranks fourth after lung, breast, and ovarian cancers. Despite a continuous refinement of the T (tumor), N (node), and M (metastasis) staging system to express disease extent and define prognosis, and eventually to guide treatment, the outcome of patients with colorectal cancer may vary considerably even within the same tumor stage. Therefore, the need for new factors, either morphologic or molecular, that could more precisely stratify patients into different risk categories is clearly warranted.

OBJECTIVES

To present the state of the art with regard to the colorectal cancer staging system and to discuss confusing and/or challenging issues, including the assessment of peritoneal membrane involvement, vascular invasion, tumor deposits, and pathologic tumor response to neoadjuvant chemoradiotherapy.

DATA SOURCES

Literature review of relevant articles indexed in PubMed (US National Library of Medicine) and primary material from the authors' institutions.

CONCLUSIONS

Two emerging needs exist for the TNM system, namely, further stratification of patients with the same tumor stage and incorporation of nonanatomic factors, the latter including molecular and treatment factors. The identification and classification of morphologic features encountered in the pathologic examination of colorectal cancer specimens may be difficult and a source of subjective variability. Enhanced pathologic analysis, agreed-upon standard protocols, and standardization should improve the completeness and accuracy of pathology reports.

Practical and molecular evaluation of colorectal cancer: new roles for the pathologist in the era of targeted therapy

CONTEXT

Colorectal cancer is the third most common cancer and the fourth most common cause of cancer death worldwide. Patient cases are discussed in multidisciplinary meetings to decide on the best management on an individual basis. Until recently, the main task of the pathologist in such teams was to provide clinically useful reports comprising staging of colorectal cancer in surgical specimens. The advent of total mesorectal excision and the application of anti-epidermal growth factor receptor (EGFR)-targeted therapies for selected patients with metastasized colorectal cancer have changed the role of the pathologist.

OBJECTIVES

To present the traditional role of the pathologist in the multidisciplinary team treating patients with colorectal cancer, to address the technique of total mesorectal excision and its implications for the evaluation of surgical specimens, to offer background information on the various EGFR-targeted therapies, and to review the currently investigated tissue biomarkers assumed to be predictive for efficacy of such therapies, with a focus on the role of the pathologist in determining the status of such biomarkers in individual tumors.

DATA SOURCES

This article is based on selected articles pertaining to biopsy evaluation of colorectal carcinoma and reviews of EGFR-targeted therapies for this cancer. All references are accessible via the PubMed database (US National Library of Medicine and the National Institutes of Health).

CONCLUSIONS

Pathologists play an increasingly important role in the diagnosis and management of colorectal cancer because of the advent of new surgical techniques and of targeted therapies. It is expected that this role will increase further in the near future.

Retroperitoneal margin involvement by adenocarcinoma of the caecum and ascending colon: what does it mean?

OBJECTIVE

Circumferential margin involvement (CRM) is a powerful predictor of local recurrence, distant metastasis and patient survival in rectal cancer. In this study, we aimed to determine the frequency of retroperitoneal margin involvement in right colon cancer and describe its relationship to tumour stage and outcome of surgical treatment.

METHOD

Two hundred and twenty-eight consecutive resections for adenocarcinoma of the ascending colon and caecum were identified between 1998 and 2006. Tumour involvement of the posterior retroperitoneal surgical resection margin (RSRM) was recorded and correlated with tumour stage, grade and clinical outcome. RSRM positive patients were compared with CRM positive rectal tumours resected in the same surgical unit.

RESULTS

Nineteen of 228 right hemicolectomies (8.4%) showed tumour involvement of the RSRM (defined as < or = 1 mm). Approximately half of the RSRM positive patients underwent palliative resections because of synchronous distant metastases. Out of nine 'potentially curative' resections where the RSRM was involved, five patients subsequently developed metastatic recurrence and two isolated local recurrence. RSRM positivity was associated with advanced tumour stage and more extensive extramural spread than CRM positive rectal cancers.

CONCLUSION

Retroperitoneal surgical resection margin involvement by caecal and ascending colon carcinoma is a marker of advanced tumour stage and associated with a high incidence of synchronous and metachronous distant metastasis. More aggressive surgery to obtain a clear margin or postoperative radiotherapy to the tumour bed is likely to benefit only a minority of patients.

Optimal pathologic staging: defining stage II disease

Tumor stage remains the most important determinant of prognosis in colorectal cancer and is the basis of all authoritative patient management guidelines. The pathologic assessment of stage II disease is especially critical because it may help to identify patients at additional risk for whom surgery alone may not be curative. Accurate analysis of regional lymph nodes, extent of tumor penetration, and circumferential resection margins constitute the most crucial issues. For assignment of pN0, adequacy of the surgical resection and thoroughness of the lymph node harvest from the resection specimen are both essential. The minimum number of lymph nodes has been variably determined to be between 12 and 18 for assignment of pN0, but the confidence level increases with increasing numbers of nodes examined. The ability of exhaustive analysis of sentinel lymph nodes using special techniques to substitute for an exhaustive lymph node harvest and standard node examination has not been definitively shown. Although special techniques may facilitate the identification of minute amounts of tumor (i.e., isolated tumor cells) in regional lymph nodes, the prognostic significance of such findings remains unclear. Additional stage-independent pathologic features that have been validated as adverse prognostic factors include involvement by tumor of mural lymphovascular channels, venous vessels, or the surgical resection margin of the operative specimen and high tumor grade. The presence of these features may help to identify patients for whom surgery alone will not be curative and adjuvant therapies may be appropriate.

Accuracy of CT prediction of poor prognostic features in colonic cancer

Whilst imaging of poor prognostic features in rectal cancers has assisted pre-operative treatment stratification, such features have yet to be evaluated in colonic cancers. This study aims to develop criteria for identifying poor prognostic features in colonic tumours and assess the accuracy of CT prediction against histopathology. Criteria were developed for predicting T-stage and N-stage, the presence of extramural vascular invasion and involvement of the retroperitoneal surgical margin (RSM). These criteria were tested on 33 patients with colonic cancer who underwent pre-operative high-resolution CT of their tumour. Two radiologists (Obs 1 and Obs 2) identified independently these poor prognostic features and the results were compared with the final histopathological results. Histological agreement and interobserver variation were calculated using the kappa test. Accuracy of CT prediction of tumour extension beyond muscularis propria was 82% (Obs 1) and 70% (Obs 2). Correct prediction of RSM involvement was 76% (95% confidence interval (CI): 57.8-88.9%) and 79% (95%CI: 61.1-91%) for Obs1 and Obs 2, respectively, with significant agreement between observers (kappa = 0.455, p = 0.050). Prognosis was correctly predicted using CT in 82% (95%CI: 61.5-81.2%) (Obs1) and 85% (95%CI: 68.1-94.9%) (Obs2) with moderate agreement (kappa = 0.459, kappa = 0.527, respectively) with histology. In conclusion, CT has potential as the imaging modality of choice in the pre-operative prediction of poor prognostic features in colonic cancers and could play a role in future treatment stratification.

Reporting colorectal cancer

The management of colorectal cancer is a team process. High-quality reporting of colorectal cancer is very important as the whole team relies upon the skill of the pathologist. Failure to report key features can lead to undertreatment of this disease. The use of a proforma has been demonstrated to be beneficial and we recommend staying with TNM5 due to scientific and reproducibility issues with TNM6. Important features in stage II/Dukes' B cases are extramural vascular invasion, peritoneal involvement, extent of extramural spread, incomplete resection and perforation. All of these may lead to adjuvant therapy being administered. The surgically created circumferential resection margin (CRM) and the mode of its creation are important features and the CRM retains its value after preoperative therapy. Regression grading should be applied only to fully resected tumours and the dissection and sampling must be standardized to allow comparison of results between trials and centres. When reporting local resections of early-stage cancers we need to look for features that predict spread to local lymph nodes to allow a full resection to be considered.

Microarray-based molecular margin methylation pattern analysis in colorectal carcinoma

The positive surgical margins are associated with postsurgical recurrence in colorectal carcinoma patients, and molecular margin analysis is considered to be more sensitive in detecting preneoplastic lesions than is conventional histological margin examination. Here, we developed a microarray and established six calibration curves for hMLH1 gene methylation patterns analysis in 20 colorectal resected margin specimens and corresponding tumor tissue specimens as well as four normal tissue specimens. The results indicated that a moderate methylation level (8-42%) was found in 20 surgical margin tissues, extensive methylation (25-58%) was detected in 20 tumor tissues, and little or no methylation was observed in normal tissues. Of the six paired probes, the average methylation levels in 20 tumor tissues were 60, 35, 43, 53, 38, and 27%, whereas the average methylation levels of the six paired probes in 20 surgical margin tissues were 43, 16, 24, 28, 21, and 11%. Thus, this study demonstrated the feasibility of this assay for molecular assessment use. In addition, it will contribute significant information to our understanding of CpG island methylation for cancer diagnosis and postoperative recurrence.

Serosal involvement in gastrointestinal cancer: its assessment and significance

There is an increasing burden upon diagnostic histopathologists to identify accurately factors of prognostic and therapeutic implication in gastrointestinal cancer. It is perhaps partly because of the use of rigid sequential staging systems, such as the Dukes' classification, that some factors, perhaps most notably involvement of surgical margins (especially in rectal cancer) and serosal involvement (particularly in oesophageal, colonic and rectal cancer), have been relatively neglected until more recently. This is surprising and concerning because both of these pathologically derived parameters strongly correlate with subsequent locoregional recurrence and, ultimately, with prognosis. Whilst the occurrence and significance of serosal involvement have been well recognized in gastric cancer for many years, relatively little attention has been paid to the phenomenon in oesophageal cancer and yet both pleural and peritoneal involvement may be comparatively commonly identified in oesophageal cancer. Serosal involvement and transperitoneal spread are also of considerable prognostic importance in primary appendiceal carcinoma. Only more recently has the significance of serosal involvement been appreciated in colonic and rectal cancer. In the colon, the phenomenon is now recognized to be one of the most important factors in predicting transperitoneal spread and overall prognosis. Furthermore, there is increasing interest in alternative novel strategies, including intraperitoneal chemotherapy and radical peritoneal surgery, as legitimate therapeutic options in many gastrointestinal cancers.