From Dukes through Jass: pathological prognostic indicators in rectal cancer

Impact of tissue sampling on detection of venous invasion in colorectal cancer: a prospective analysis

AIMS

Venous invasion (VI) is a powerful yet under-reported prognostic factor in colorectal cancer (CRC). Efforts to improve its detection have largely focused upon histological assessment, with less attention paid to tissue-sampling strategies. This study aimed to prospectively determine the number of tumour blocks required to optimise VI detection in CRC resections. In addition, the relationship between linear spiculation (LS) and extramural venous invasion (EMVI) was investigated.

METHODS AND RESULTS

A standardised tissue sampling protocol was developed and applied prospectively to 217 CRC resections [AJCC 8th edition, stage 1 (n = 32); stage 2 (n = 84); stage 3 (n = 87); stage 4 (n = 14); and post-neoadjuvant therapy (n = 46)]. Elastin stains were performed on all tumour blocks. VI was identified in 55% of cases (EMVI = 37%; IMVI alone = 18%). The sensitivity of VI detection increased with increasing numbers of tumour blocks submitted [one block (35%), three blocks (66%), five blocks (84%), six blocks (95%) and seven blocks (97%)]. Similar findings were observed for EMVI [one block (35%), three blocks (73%), five blocks (89%), six blocks (96%) and seven blocks (96%)]. LS was identified macroscopically in 22% of specimens. In cases where no neoadjuvant therapy had been given, EMVI was significantly associated with LS (71% in LS+ cases versus 29% in LS- cases; P < 0.001). In addition, tumour blocks targeting LS were associated with a fivefold higher rate of EMVI compared with blocks that did not (P < 0.001).

CONCLUSIONS

Our findings demonstrate the impact of tissue sampling and quality of gross examination on VI detection and may inform practices in future CRC protocols.

18F-Fluorodeoxyglucose Positron Emission Tomography/Magnetic Resonance Imaging-Defined Extramural Venous Invasion Predicts Distant Metastasis and Reflects Strong Tumor Invasiveness in Rectal Cancer

INTRODUCTION

Extramural vascular invasion in patients with rectal cancer is a poor prognostic factor associated with distant metastasis; thus, accurate preoperative diagnosis is important. However, the accurate detection of extramural vascular invasion using magnetic resonance imaging (MRI) is difficult, and an improved diagnostic modality is required. In addition, the factors involved in the formation of extramural venous invasion (EMVI) remain unclear. In this study, we aimed to examine the ability of 18F-fluorodeoxyglucose positron emission tomography/MRI ([18F] FDG PET/MRI) to detect EMVI and elucidate the factors involved in EMVI.

METHODS

Thirty-one patients with rectal cancer were enrolled in this study between 2017 and 2021. We preoperatively evaluated the pelvic [18F] FDG PET/MRI to detect extramural vascular invasion ([18F] FDG PET/MRI-defined EMVI: pmrEMVI). To investigate the factors related to pmrEMVI, we confirmed the desmoplastic reaction (DR) and TWIST expression in the primary lesions of rectal cancer and examined its relationship with pmrEMVI.

RESULTS

Six of the 31 patients were pmrEMVI positive. Four pmrEMVI-positive patients had distant metastases. The levels of immature DR and TWIST1 expression were significantly higher in cases with pmrEMVI positivity.

CONCLUSION

pmrEMVI is a useful biomarker for predicting distant metastasis. In addition, pmrEMVI was significantly correlated with factors related to tumor invasiveness.

Association of age with outcomes in locally advanced rectal cancer treated with neoadjuvant therapy followed by surgery

INTRODUCTION

We aimed to assess the association of age with outcomes in patients with Locally Advanced Rectal Cancer (LARC) who received neoadjuvant therapy followed by major surgery.

METHODS

Retrospective review of 328 patients with LARC, N = 99 < 70 years (younger) versus N = 229 ≥ 70 years (elderly) from 2004 to 2018.

RESULTS

Elderly patients had a higher American Society of Anesthesiologists (ASA) score, Charlson Comorbidity Index (CCI), length of stay and 30-day readmissions (p < 0.05). They also had worse overall survival (OS) & disease-free survival (DFS) (p < 0.001), but similar disease-specific survival (DSS) compared to younger group. Age was not associated with hazard of death (HR 1.01, 0.98-1.03). Rather, CCI (HR 1.29, 1.01-1.5), extramural vascular invasion (HR 4.98, 2.84-8.74), and adjuvant therapy (0.37, 0.21-0.64) were significantly associated with the hazard of death; when controlled for stage, tumor distance from anal verge, and neoadjuvant completion.

CONCLUSION

Comorbidities and lower rates of adjuvant therapy, and not chronologic age, are associated with poor OS of elderly patients with LARC treated with neoadjuvant therapy and major surgery.

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

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

Molecular Basis of Extramural Vascular Invasion (EMVI) in Colorectal Carcinoma

BACKGROUND

Extramural vascular invasion (EMVI) is a known poor prognostic factor in colorectal carcinoma; however, its molecular basis has not been defined. This study aimed to assess the expression of molecular markers in EMVI positive colorectal carcinoma to understand their tumor microenvironment.

METHODS

Immunohistochemistry was performed on tissue microarrays of surgically resected colorectal cancer specimens for immunological markers, and BRAFV600E mutation (and on the tissue blocks for mismatch repair proteins). Automated quantification was used for CD8, LAG3, FOXP3, PU1, and CD163, and manual quantification was used for PDL1, HLA I markers (beta-2 microglobulin, HC10), and HLA II. The Wilcoxon rank-sum test was used to compare EMVI positive and negative tumors. A logistic regression model was fitted to assess the predictive effect of biomarkers on EMVI.

RESULTS

There were 340 EMVI positive and 678 EMVI negative chemo naïve tumors. PDL1 was barely expressed on tumor cells (median 0) in the entire cohort. We found a significantly lower expression of CD8, LAG3, FOXP3, PU1 cells, PDL1 positive macrophages, and beta-2 microglobulin on tumor cells in the EMVI positive subset (p ≤ 0.001). There was no association of BRAFV600E or deficient mismatch repair proteins (dMMR) with EMVI. PU1 (OR 0.8, 0.7-0.9) and low PDL1 (OR 1.6, 1.1-2.3) independently predicted EMVI on multivariate logistic regression among all biomarkers examined.

CONCLUSION

There is a generalized blunting of immune response in EMVI positive colorectal carcinoma, which may contribute to a worse prognosis. Tumor-associated macrophages seem to play the most significant role in determining EMVI.

Quantitative Nodal Burden and Mortality Across Solid Cancers

BACKGROUND

Nodal staging systems vary substantially across solid tumors, implying heterogeneity in the behavior of nodal variables in various contexts. We hypothesized, in contradiction to this, that metastatic lymph node (LN) number is a universal and dominant predictor of outcome across solid tumors.

METHODS

We performed a retrospective cohort analysis of 1 304 498 patients in the National Cancer Database undergoing surgery between 2004 and 2015 across 16 solid cancer sites. Multivariable Cox regression analyses were constructed using restricted cubic splines to model the association between nodal number and mortality. Recursive partitioning analysis (RPA) was used to derive nodal classification systems for each solid cancer based on metastatic LN count. The reproducibility of these findings was assessed in 1 969 727 patients from the Surveillance, Epidemiology, and End Results registry. Two-sided tests were used for all statistical analyses.

RESULTS

Consistently across disease sites, mortality risk increased continuously with increasing number of metastatic LNs (P < .001 for all spline segments). Each RPA-derived nodal classification system produced multiple prognostic groups spanning a wide spectrum of mortality risk (P < .001). Multivariable models using these RPA-derived nodal classifications demonstrated improved concordance with mortality compared with models using American Joint Committee on Cancer staging in sites where nodal classification is not based on metastatic LN count. Each RPA-derived nodal classification system was reproducible in a large validation cohort for all-cause and cause-specific mortality (P < .001). High quantitative nodal burden was the single strongest tumor-intrinsic variable associated with mortality in 12 of 16 disease sites.

CONCLUSIONS

Quantitative metastatic LN burden is a fundamental driver of mortality across solid cancers and should serve as a foundation for pathologic nodal staging across solid tumors.

Oncological impact of vascular invasion in colon cancer might differ depending on tumor sidedness

Purpose

Vascular invasion is a well-known independent prognostic factor in colon cancer and tumor sidedness is also being considered a prognostic factor. The aim of this study was to compare the oncological impact of vascular invasion depending on the tumor location in stages I to III colon cancer.

Methods

A retrospective analysis was performed using data from patients who underwent curative resection between 2004 and 2015. Patients were divided into right-sided colon cancer (RCC) and left-sided colon cancer (LCC) groups according to the tumor location. Disease-free survival (DFS) and overall survival (OS) were compared between the RCC and LCC groups, depending on the presence of vascular invasion.

Results

A total of 793 patients were included, of which 304 (38.3%) had RCC and 489 (61.7%) had LCC. DFS and OS did not differ significantly between the RCC and LCC groups. Vascular invasion was a poor prognostic factor for DFS in both RCC (hazard ratio [HR], 2.291; 95% confidence interval [CI], 1.186–4.425; p = 0.010) and LCC (HR, 1.848; 95% CI, 1.139–2.998; p = 0.011). Additionally, it was associated with significantly worse OS in the RCC (HR, 3.503; 95% CI, 1.681–7.300; p < 0.001), but not in the LCC group (HR, 1.676; 95% CI, 0.885–3.175; p = 0.109). Multivariate analysis revealed that vascular invasion was independently poor prognostic factor for OS in the RCC (HR, 3.186; 95% CI, 1.391–7.300; p = 0.006).

Conclusion

This study demonstrated that RCC with vascular invasion had worse OS than LCC with vascular invasion.

Lymph Nodes as Anti-Tumor Immunotherapeutic Tools: Intranodal-Tumor-Specific Antigen-Pulsed Dendritic Cell Vaccine Immunotherapy

Simple Summary

In the field of cancer therapy, lymph nodes are important not only as targets for metastases resection but also as prudent target organs for cancer immunotherapy. Lymph nodes comprise a complete structure for the accumulation of a large number of T cells and their distribution throughout the body after antigen presentation and activation of dendritic cells. This review highlights current topics on the importance of lymph node structure in antitumor immunotherapy and intranodal-antigen-presenting mature dendritic cell vaccine therapy. We also discuss the rationale behind intranodal injection methods and their applications in neoantigen vaccine therapy, a new cancer immunotherapy.

Abstract

Hundreds of lymph nodes (LNs) are scattered throughout the body. Although each LN is small, it represents a complete immune organ that contains almost all types of immunocompetent and stromal cells functioning as scaffolds. In this review, we highlight the importance of LNs in cancer immunotherapy. First, we review recent reports on structural and functional properties of LNs as sites for antitumor immunity and discuss their therapeutic utility in tumor immunotherapy. Second, we discuss the rationale and background of ultrasound (US)-guided intranodal injection methods. In addition, we review intranodal administration therapy of tumor-specific-antigen-pulsed matured dendritic cells (DCs), including neoantigen-pulsed vaccines.

Risk stratification for predicting postoperative recurrence/metastasis of colorectal cancer by grade of venous invasion coupled with histological subtype

Background

Colorectal cancer (CRC) consists of several histological subtypes that greatly affect prognosis. Venous invasion (VI) has been implicated in the postoperative recurrence of CRC, but the relationship between the VI grade and postoperative recurrence in each histological subtype has not been clarified thus far.

Methods

A total of 323 CRCs without distant metastasis at surgery (pathologic stage III or lower), including 152 well-to-moderately differentiated adenocarcinomas (WMDAs), 98 poorly differentiated adenocarcinomas (PDAs), and 64 mucinous adenocarcinomas (MUAs), were analyzed. They were routinely processed pathologically, and VI was graded as follows irrespective of location by elastica van Gieson staining: v0 (none), no venous invasion; v1 (mild), 1–3 invasions per glass slide; v2 (moderate), 4–6 invasions per glass slide; and v3 (severe), ≥ 7 invasions per glass slide. Filling-type invasion in veins with a minor axis of ≥ 1 mm increased the grade by 1. The association of VI grade with prognosis was statistically analyzed.

Results

All recurrences occurred as distant metastases. Recurrence increased with VI grade in WMDA (v0 11.8%, v1 15.8%, v2 73.9%, v3 75.0%) and MUA (v0 15.2%, v1 30.8%, v2 40.0%). The recurrence rate was relatively high in PDA even with v0 and increased with VI grade (v0 27.8%, v1 32.7%, v2 33.3%, v3 60.0%). VI grade was a significant predictor of recurrence in WMDA but not in PDA and MUA by multivariate analysis. In node-negative (stage II or lower) CRC, the recurrence-free survival (RFS) rate exceeded 90% in v0 and v1 WMDA until postoperative day (POD) 2100 and v0 MUA until POD 1600 but fell below 80% in the other settings by POD 1000. In node-positive (stage III) CRC, the RFS rate fell below 80% in all histological subtypes by POD 1000.

Conclusions

VI grade v1 had a similar recurrence rate and RFS as grade v0 and may not warrant adjuvant chemotherapy in node-negative (stage II or lower) WMDA. In addition to node-positive (stage III) CRC, adjuvant chemotherapy may be indicated for node-negative (stage II or lower) CRC when it is WMDA with VI grade v2 or v3, MUA with VI, or PDA.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-022-02163-7.

Routine Elastin Staining in Surgically Resected Colorectal Cancer: Impact on Venous Invasion Detection and its Association With Oncologic Outcomes

Venous invasion (VI) is a powerful yet underreported prognostic factor in colorectal cancer (CRC). Its detection can be improved with an elastin stain. We evaluated the impact of routine elastin staining on VI detection in resected CRC and its relationship with oncologic outcomes. Pathology reports from the year before (n=145) and the year following (n=128) the implementation of routine elastin staining at our institution were reviewed for established prognostic factors, including VI. A second review, using elastin stains, documented the presence/absence, location, number, and size of VI foci. The relationship between VI and oncologic outcomes was evaluated for original and review assessments. VI detection rates increased from 21% to 45% following implementation of routine elastin staining (odds ratio [OR]=3.1; 95% confidence interval [CI]: 1.8-5.3; P<0.0001). The second review revealed a lower VI miss rate postimplementation than preimplementation (22% vs. 48%, respectively; P=0.007); this difference was even greater for extramural VI-positive cases (9% vs. 38%, respectively; P=0.0003). Missed VI cases postimplementation had fewer VI foci per missed case (P=0.02) and a trend towards less extramural VI than those missed preimplementation. VI assessed with an elastin stain was significantly associated with recurrence-free survival (P=0.003), and cancer-specific survival (P=0.01) in contrast to VI assessed on hematoxylin and eosin alone (P=0.053 and 0.1, respectively). The association between VI and hematogenous metastasis was far stronger for elastin-detected VI (OR=11.5; 95% CI: 3.4-37.1; P<0.0001) than for hematoxylin and eosin-detected VI (OR=3.7; 95% CI: 1.4-9.9; P=0.01). Routine elastin staining enhances VI detection and its ability to stratify risk in CRC and should be considered for evaluation of CRC resection specimens.

Prognostic significance of pathological sub-classification of pT3 rectal cancer

PURPOSE

Patients with pT3 rectal cancer represent a heterogeneous prognostic group. A more accurate histological sub-classification of pT status has been suggested as an improvement of the TNM staging system. The aim of the study was to evaluate the prognostic implication of a histopathologic sub-classification of pT3 rectal cancer.

METHODS

In this retrospective single-center study, pT3 rectal cancer patients who underwent surgery from January 2000 to December 2018 were evaluated. The maximum depth of tumor invasion beyond the muscularis propria was recorded. A ROC curve identified the best prognostic cutoff value to classify patients in two prognostic groups. Survival curves were estimated by the Kaplan-Meier method, and univariate and multivariate analyses with the Cox regression model were used to find independent factors influencing survival.

RESULTS

Overall, 203 patients were included. Four millimeters was identified as the best cutoff value: 82 patients showed a depth of invasion < 4 mm (group A) and 121 ≥ 4 mm (group B). Both the estimated 5-year OS and DFS were statistically better in group A than in group B (OS: 83.9% vs 62.2%, p < 0.01; DFS: 78.3% vs 40.6%, p < 0.01). The depth of tumor invasion was an independent risk factor for OS (HR 2.25, 95% CI 1.26-3.99, p = 0.006) and DFS (HR 2.30, 95% CI 1.40-3.78, p = 0.001).

CONCLUSION

Our findings suggest that a sub-classification of pT3 rectal cancer, based on the depth of tumor invasion, should be considered to be introduced in the TNM staging system.

Prognostic Significance of EMVI in Rectal Cancer in a Tertiary Cancer Hospital in India

Background  Presence of extramural venous invasion (EMVI) is a poor prognostic factor for rectal cancer as per literature. However, India-specific data are lacking.

Aim  The aim of the study is to determine the prognostic significance of EMVI in locally advanced rectal cancer on baseline MRI.

Materials and Methods  We retrospectively reviewed 117 MRIs of operable non-metastatic locally advanced rectal cancers in a tertiary cancer institute. Three dedicated oncoradiologists determined presence or absence of EMVI, and its length and thickness, in consensus. These patients were treated as per standard institutional protocols and followed up for a median period of 37 months (range: 2–71 months). Kaplan-Meier curves (95% CI) were used to determine disease-free survival (DFS), distant-metastases free survival (DMFS), and overall survival (OS). Univariate analysis was performed by comparing groups with log-rank test.

Results  EMVI positive cases were 34/114 (29%). More EMVI-positive cases developed distant metastasis compared with EMVI-negative cases (14/34–41% vs. 22/83–26%). The difference, however, was not statistically significant ( p  = 0.146). After excluding signet-ring cell cancers ( n  = 14), EMVI showed significant correlation with DMFS ( p  = 0.046), but not with DFS or OS. The median thickness and length of EMVI was 6 and 14 mm, respectively in patients who developed distant metastasis, as compared with 5 and 11 mm in those who did not, although this difference was not statistically significant.

Conclusion  EMVI is a predictor of distant metastasis in locally advanced non-metastatic, non-signet ring cell rectal cancers. EMVI can be considered another high-risk feature to predict distant metastasis.

Feasibility and Performance of Elastin Trichrome as a Primary Stain in Colorectal Cancer Resection Specimens: Results of an Interobserver Variability Study

Venous invasion (VI) is a powerful prognostic factor in colorectal cancer (CRC) that is widely underreported. The ability of elastin stains to improve VI detection is now recognized in several international CRC pathology protocols. However, concerns related to the cost and time required to perform and evaluate these stains in addition to routine hematoxylin and eosin (H&E) stains remains a barrier to their wider use. We therefore sought to determine whether an elastin trichrome (ET) stain could be used as a "stand-alone" stain in CRC resections, by comparing the sensitivity, accuracy, and reproducibility of detection of CAP-mandated prognostic factors using ET and H&E stains. Representative H&E- and ET-stained slides from 50 CRC resections, including a representative mix of stages and prognostic factors, were used to generate 2 study sets. Each case was represented by H&E slides in 1 study set and by corresponding ET slides from the same blocks in the other study set. Ten observers (3 academic gastrointestinal [GI] pathologists, 4 community pathologists, 3 fellows) evaluated each study set for CAP-mandated prognostic factors. ET outperformed H&E in the assessment of VI with respect to detection rates (50% vs. 28.6%; P<0.0001), accuracy (82% vs. 59%, P<0.0001), and reproducibility (k=0.554 vs. 0.394). No significant differences between ET and H&E were observed for other features evaluated. In a poststudy survey, most observers considered the ease and speed of assessment at least equivalent for ET and H&E for most prognostic factors, and felt that ET would be feasible as a stand-alone stain in practice. If validated by others, our findings support the use of ET, rather than H&E, as the primary stain for the evaluation of CRC resections.

Multimodality Imaging of Abdominopelvic Tumors with Venous Invasion

A broad range of abdominal and pelvic tumors can manifest with or develop intraluminal venous invasion. Imaging features at cross-sectional modalities and contrast-enhanced US that allow differentiation of tumor extension within veins from bland thrombus include the expansile nature of tumor thrombus and attenuation and enhancement similar to those of the primary tumor. Venous invasion is a distinctive feature of hepatocellular carcinoma and renal cell carcinoma with known prognostic and treatment implications; however, this finding remains an underrecognized characteristic of multiple other malignancies-including cholangiocarcinoma, adrenocortical carcinoma, pancreatic neuroendocrine tumor, and primary venous leiomyosarcoma-and can be a feature of benign tumors such as renal angiomyolipoma and uterine leiomyomatosis. Recognition of tumor venous invasion at imaging has clinical significance and management implications for a range of abdominal and pelvic tumors. For example, portal vein invasion is a strong negative prognostic indicator in patients with hepatocellular carcinoma. In patients with rectal cancer, diagnosis of extramural venous invasion helps predict local and distant recurrence and is associated with worse survival. The authors present venous invasion by vascular distribution and organ of primary tumor origin with review of typical imaging features. Common pitfalls and mimics of neoplastic thrombus, including artifacts and anatomic variants, are described to help differentiate these findings from tumor in vein. By accurately diagnosing tumor venous invasion, especially in tumors where its presence may not be a typical feature, radiologists can help referring clinicians develop the best treatment strategies for their patients. ^©RSNA, 2020.

Clinical Outcome of Minor Salivary Gland Cancers in the Oral Cavity: A Comparative Analysis With Squamous Cell Carcinomas of the Oral Cavity

Purpose: Salivary gland cancer (SGC) in the oral cavity is not common and has been less studied in comparison with oral squamous cell carcinoma (SCC). This study aimed to identify the clinical characteristics and outcomes of SGC in the oral cavity compared with oral SCC.

Methods: The medical charts of the patients with SGC (N = 68) arising from minor salivary glands and SCC (N = 750) in the oral cavity between 1995 and 2017 were reviewed retrospectively. The clinical and pathological factors and treatment outcomes were compared to identify clinical differences between oral SGC and SCC in total cases and in tumor size and subsite (propensity score)-matched pairs (N = 68 in each group). In addition, pattern of local invasion was pathologically assessed in a subset of SGC and SCC tumors.

Results: Patients with SGC in the oral cavity showed >90% survival at 5 years. Most common pathologies of SGC were mucoepidermoid carcinoma (39.7%) and adenoid cystic carcinoma (35.3%), where high-grade tumors (including adenoid cystic carcinomas having solid components, grade 2 or 3) represented only 36.8%. Compared with oral SCC, surgery for SGC had narrow surgical safety margin. However, local control was very successful in SGC even with <5 mm or positive resection margin through surgery plus adjuvant radiation treatments or surgery alone for small low-grade tumors. Pathologic analysis revealed that the frequency of oral SGC with infiltrative tumor border was significantly lower than that of oral SCC (46.4 vs. 87.2%, P < 0.001).

Conclusions: SGC in the oral cavity represents relatively good prognosis and has a locally less aggressive pathology compared with oral SCC. Adjuvant radiation can be very effective to control minimal residual disease in oral SGC. Our study proposed that a different treatment strategy for oral SGC would be reasonable in comparison with oral SCC.

How to measure tumour response in rectal cancer? An explanation of discrepancies and suggestions for improvement

Various methods categorize tumour response after neoadjuvant therapy, including down-staging and tumour regression grading. Response categories allow comparison of different treatments within clinical trials and predict outcome. A reproducible response categorization could identify subgroups with high or low risk for the most appropriate subsequent treatments, like watch and wait. Lack of standardization and interpretation difficulties currently limit the usability of these approaches. In this review we describe these difficulties for the evaluation of chemoradiation in rectal cancer. An alternative approach of tumour response is based on patterns of residual disease, including fragmentation. We summarise the evidence behind this alternative method of response categorisation, which explains a number of very relevant clinical discrepancies. These issues include differences between downstaging and tumour regression, high local regrowth in advanced tumours during watchful waiting procedures, the importance of resection margins, the limited value of post-treatment biopsies and the relatively poor outcome of patients with a near complete pathological response. Recognition of these patterns of response can allow meaningful development of novel biomarkers in the future.

Rectal Cancer: Staging

The imaging of rectal cancer has evolved noticeably over the past 2 decades, paralleling the advances in therapy. The methods for imaging rectal cancer are increasingly used in clinical practice with the purpose of helping to detect, characterize and stage rectal cancer. In this setting, MR imaging emerged as the most useful imaging method for primary staging of rectal cancer; the present review focuses on the role of MR imaging in this regard.

The Crohn's-Like Lymphoid Reaction to Colorectal Cancer-Tertiary Lymphoid Structures With Immunologic and Potentially Therapeutic Relevance in Colorectal Cancer

The Crohn's-like lymphoid reaction (CLR) to colorectal cancer (CRC), a CRC-specific ectopic lymphoid reaction, is thought to play an important role in the host response to CRC. CLR is characterized by peritumoral lymphocytic aggregates that are found at the advancing edge of the tumor. Spatial and molecular characterization of CLR within the tumor microenvironment (TME) have uncovered a spectrum of peritumoral lymphoid aggregates with varying levels of organization and maturation. In early stages of CLR development, CD4+ T-cells cluster predominantly with mature antigen presenting dendritic cells. As CLR matures, increasing numbers of B-cells, as well as follicular dendritic cells are recruited to create lymphoid follicles. When highly organized, CLR resembles functional tertiary lymphoid structures (TLS), allowing for lymphocyte recruitment to the TME and promoting a tumor-specific adaptive immune response. CLR has been consistently associated with favorable prognostic factors and improved survival among CRC patients, often providing more prognostic information than current clinical staging systems. However, consensus is lacking regarding CLR scoring and it is not clinically assessed or reported. Differences between CLR and other cancer-associated lymphoid structures exist both in primary and metastatic disease, underscoring the need to characterize organ-specific TLS. Further research is needed to explore the role of CLR in predicting response to immunotherapy and to leverage CLR to promote immunotherapeutic strategies in CRC.

Low- Versus High-Risk Rectal Cancer Based on MRI Features: Outcomes in Patients Treated Without Neoadjuvant Chemoradiotherapy

OBJECTIVE

The objective of this study was to compare the prognoses of patients with low- and high-risk rectal cancer detected by MRI who were treated without neoadjuvant chemoradiotherapy (NCRT) and to determine independent risk factors.

MATERIALS AND METHODS

This retrospective study included 185 patients with pathologically proven rectal adenocarcinoma who were treated without NCRT. Cancer was defined as high risk if one or more of the following factors were present: extramural depth of tumor invasion greater than 5 mm or stage T4a or T4b for tumor in the mid or high rectum; involvement of intersphincteric space, levators, or adjacent organs for tumor in the low rectum; extramural venous invasion (EMVI); or circumferential resection margin (CRM) involvement. Patients without any of those risk factors were placed in the low-risk group. The Kaplan-Meier method and Cox proportional hazards regression model were used to compare the survival outcomes between the two groups and to investigate the univariate and multivariate influences of the risk factors.

RESULTS

Cancer was deemed to be low risk in 65 (35.1%) patients and high risk in 120 (64.9%) patients. The two patient groups had statistically significant differences in 3-year actuarial overall survival (OS; 100% vs 88.3%, p = 0.0044), disease-free survival (DFS; 92.3% vs 60.0%, p < 0.0001), and local recurrence (LR; 1.5% vs 10.0%, p = 0.0297). CRM involvement was identified as an independent risk factor for OS (hazard ratio [HR], 4.78; 95% CI, 1.24-18.45), DFS (HR, 2.44; 95% CI, 1.24-4.81), and LR (HR, 3.92; 95% CI, 1.07-14.41). Moreover, EMVI was identified as an independent risk factor for DFS (HR, 2.46; 95% CI, 1.28-4.74).

CONCLUSION

The LR and long-term survival of patients in the low-risk group were more favorable than those of patients in the high-risk group. EMVI and CRM status were independent risk factors.

Diagnostic performance of 18F-FDG PET/CT using point spread function reconstruction on initial staging of rectal cancer: a comparison study with conventional PET/CT and pelvic MRI

Background

Accurate staging is crucial for treatment selection and prognosis prediction in patients with rectal cancer. Point spread function (PSF) reconstruction can improve spatial resolution and signal-to-noise ratio of PET imaging. The aim of this study was to evaluate the effectiveness of ¹⁸F-FDG PET/CT with PSF reconstruction for initial staging in rectal cancer compared with conventional PET/CT and pelvic MRI.

Methods

A total of 59 patients with rectal cancer underwent preoperative ¹⁸F-FDG PET/CT and pelvic MRI. The maximum standardized uptake value (SUVmax) and lesion to background (L/B) ratio of possible metastatic lymph nodes, and metabolic tumor volumes (MTVs) of primary tumors were calculated. For N and T (T1-2 vs T3-4) staging, sensitivities, specificities, positive predictive values, negative predictive values, and accuracies were compared between conventional PET/CT [reconstructed with ordered subset expectation maximization (OSEM)], PSF-PET/CT (reconstructed with OSEM+PSF), and pelvic MRI. Histopathologic analysis was the reference standard.

Results

For N staging, PSF-PET/CT provided higher sensitivity (78.6%) than conventional PET/CT (64.3%), and pelvic MRI (57.1%), and all techniques showed high specificity (PSF-PET: 95.4%, conventional PET: 96.7%, pelvic MRI: 93.5%). SUVmax and L/B ratio were significantly higher in PSF-PET/CT than conventional-PET/CT (p < 0.001). The accuracy for T staging in PSF-PET/CT (69.4%) was not significantly different to conventional PET/CT (73.5%) and pelvic MRI (73.5%). MTVs of PSF and conventional PET showed a significant difference among T stages (p < 0.001), with higher values in advanced stages. In M staging, both PSF and conventional PET/CT diagnosed all distant metastases correctly.

Conclusions

PSF-PET/CT produced images with higher lesion-to-background contrast than conventional PET/CT, which allowed improved detection of lymph node metastasis without compromising specificity, and showed comparable diagnostic value to MRI in local staging. PSF-PET/CT is likely to have a great value for initial staging in rectal cancer.

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.

Immunotherapy as a Potential Treatment for Chordoma: a Review

Chordoma is a locally aggressive primary malignancy of the axial skeleton. The gold standard for treatment is en bloc resection, with some centers now advocating for the use of radiation to help mitigate the risk of recurrence. Local recurrence is common, and salvaging local failures is quite difficult. Chemotherapy has been ineffective and small molecule targeted therapy has had only marginal benefits in small subsets of patients with rare tumor phenotypes or refractory disease. Recent successes utilizing immunotherapy in a variety of cancers has led to a resurgence of interest in modifying the host immune system to develop new ways to treat tumors. This review will discuss these studies and will highlight the early studies employing immune strategies for the treatment of chordoma.

The PD-1 expressing immune phenotype of T cell exhaustion is prominent in the 'immunoreactive' microenvironment of colorectal carcinoma

AIMS

This study was designed to test programmed cell death 1 (PD-1) expression of T cells, the hallmark of T cell exhaustion, in different 'immune-classes' of colorectal carcinoma microenvironments as delineated by unsupervised hierarchical cluster analysis.

METHODS AND RESULTS

A tissue microarray was made with punches from the invasive margins of 40 microsatellite-unstable and 34 microsatellite-stable colorectal carcinomas. Immune cells were phenotyped by CD8, granzyme B, CD4, FoxP3, CD68, S-100, PD-1 and programmed cell death ligand 1 (PD-L1) immunohistochemistry; tumour area per tissue spot was quantified by cytokeratin (CK)18 immunohistochemistry. For each tissue spot, intra-epithelial immune cells were counted and densities of the various immune cells were calculated. Unsupervised hierarchical cluster analysis with these data yielded a group of 'anergic/immune-naive' microenvironments (47.3%), a group of 'intermediates' (27.0%) and a group of 'immunoreactives' (25.7%) in which PD-1 expressing T cells were prominent. Sixteen of 19 tissue spots representing immunoreactive microenvironments derived from microsatellite-unstable tumours and three were from microsatellite-stable tumours. Further phenotyping of intra-epithelial T cells by sequential immunohistochemistry showed frequent granzyme B/CD8 co-expression, whereas PD-1/CD8 co-expression was more variable. Using receiver operating curve (ROC) analysis, assignment to immune classes was seen to be feasible with good sensitivity and specificity by CD8 counts only.

CONCLUSION

A subset of colorectal carcinoma microenvironments is distinguished from the rest by an immune cell composition suggestive of active host anti-tumour immune defence, but this appears to be antagonized by a brisk undercurrent of T cell exhaustion. This observation may have implications for selecting colorectal carcinoma patients for immune checkpoint therapy.

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

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

Dual-Energy CT of Rectal Cancer Specimens: A CT-based Method for Mesorectal Lymph Node Characterization

BACKGROUND

An accurate method to assess malignant lymph nodes in the mesorectum is needed. Dual-energy CT scans simultaneously with 2 levels of energy and thereby provides information about tissue composition based on the known effective Z value of different tissues. Each point investigated is represented by a certain effective Z value, which allows for information on its composition.

OBJECTIVE

We wanted to standardize a method for dual-energy scanning of rectal specimens to evaluate the sensitivity and specificity of benign versus malignant lymph node differentiation. Histopathological evaluation of the nodes was our reference.

DESIGN

This was a descriptive and prospective study.

SETTINGS

Seventeen rectal specimens were examined in 2 series. The first series was conducted with 3 specimens from patients who were not given perioperative contrast; 3 had iodine-based contrast and 3 had gadolinium-based contrast. We concluded that iodine was the contrast agent of choice and therefore included 8 more patients in a second series, given iodine-based contrast, for further analysis.

PATIENTS

Quantitative imaging data were collected from 197 individual lymph nodes from 17 specimens, from patients with rectal cancer.

MAIN OUTCOME MEASURES

We measured accuracy of differentiating benign from malignant lymph nodes by investigating the following: 1) gadolinium, iodine, and water concentrations in lymph nodes; 2) dual-energy ratio; 3) dual-energy index; and 4) effective Z value.

RESULTS

Optimal discriminations between benign and malignant lymph nodes were obtained using the following cutoff values: 1) effective Z at 7.58 (sensitivity, 100%; specificity, 90%; and accuracy, 93%), 2) dual-energy ratio at 1.0 × 10 (sensitivity, 96%; specificity, 87%; and accuracy, 90%), 3) dual-energy index at 0.03 (sensitivity, 97%; specificity, 88%; and accuracy, 91%), and 4) iodine concentration at 2.58 μg/mL (sensitivity, 86%; specificity, 92%; and accuracy, 89%).

LIMITATIONS

The investigation is conducted on isolated surgical specimens from rectal cancer operations.

CONCLUSIONS

Dual-energy CT can be performed on rectal specimens. The discrimination between benign and malignant nodes seems promising when using iodine as contrast.

Imaging Advances in Colorectal Cancer

The optimal management of rectal cancer is achieved through a shared multidisciplinary decision making process with accurate staging by imaging being critical for treatment planning. Good quality, high-resolution MRI has become the imaging gold standard as it allows consistent staging and stratification of patients into distinct prognostic groups according to MR-findings. Imaging features other than T and N have been proven to influence patient outcomes, and increasingly these features are taken into consideration when determining treatment options: distance of tumour to the potential circumferential margin (CRM), presence of tumour within the extramural rectal vessels (EMVI), discontinuous tumour deposits (N1c), relationship to the intersphincteric plane in low rectal tumours and to pelvic compartments in advanced disease. The presence or absence of proven adverse MR features should be included in the MRI report and shared with the patient when treatment choices are offered. MRI enables the identification of high risk tumours where the use of neoadjuvant therapy is justified and is a robust method of identifying patients with a strong likelihood of complete response after preoperative treatment.

MRI Detection of Extramural Venous Invasion in Rectal Cancer: Correlation With Histopathology Using Elastin Stain

OBJECTIVE

The purpose of this article is to evaluate the diagnostic performance of MRI for detection of extramural venous invasion (EMVI) compared with histopathologic analysis using elastin stain.

MATERIALS AND METHODS

Forty-nine patients with rectal cancer who had undergone surgical resection with preoperative MRI were identified. Thirty-seven patients had received preoperative chemoradiation therapy (CRT). Sixty-nine MRI studies were independently reviewed by two blinded radiologists for EMVI using a score of 0-4. Comparison was made with histopathologic results obtained by two pathologists reviewing the elastin-stained slides in consensus. EMVI status was also correlated with other tumoral and prognostic features on imaging and pathologic analysis. Statistical analysis was performed using Fisher exact and McNemar tests.

RESULTS

EMVI was present in 31% of the pathology specimens. An MRI EMVI score of 3-4 was 54% sensitive and 96% specific in detecting EMVI in veins 3 mm in diameter or larger. Inclusion of a score of 2 as positive for EMVI increased the sensitivity to 79% but decreased the specificity to 74%, with poor positive predictive value. Preoperative CRT had no significant effect on the diagnostic performance of MRI. Contrast-enhanced MRI increased reader confidence for diagnosis or exclusion of EMVI compared with T2-weighted imaging. EMVI status correlated with depth of extramural invasion and proximity to mesorectal fascia.

CONCLUSION

Despite an anticipated increase in sensitivity for EMVI detection by histopathologic analysis using elastin compared with H and E staining, MRI maintains a high specificity and moderate sensitivity for the detection of EMVI.

Venous Invasion in Colorectal Cancer: Impact of Morphologic Findings on Detection Rate

PURPOSE

Venous invasion (VI) is widely accepted as a poor prognostic factor in colorectal cancer (CRC), and is indicated as a high-risk factor determining the use of adjuvant chemotherapy in CRC. However, there is marked interobserver and intraobserver variability in VI identification and marked variability in the real prevalence of VI in CRC.

MATERIALS AND METHODS

We investigated the detection rate of VI in 93 consecutive cases of T3 or T4 CRC based on the following: original pathology report, review of hematoxylin and eosin (H&E) slides with attention to the "protruding tongue" and "orphan arteriole" signs, and elastic stain as the gold standard.

RESULTS

Overall, the detection rate of VI was significantly increased as follows: 14/93 (15.1%) in the original pathology report, 38/93 (40.9%) in review of H&E slides with attention to the "protruding tongue" and "orphan arteriole" signs, and 45/93 (48.4%) using elastic stain. VI detection based on morphologic features showed 77.8% sensitivity and 91.1% specificity and showed a linear correlation (Spearman correlation coefficient, 0.727; p < 0.001) with VI detected by elastic stain. In addition, improved agreement between detection methods (detection on the basis of morphologic features, κ=0.719 vs. original pathology report, κ=0.318) was observed using kappa statistics.

CONCLUSION

Slide review with special attention to the "protruding tongue" and "orphan arteriole" signs could be used for better identification of VI in CRC in routine surgical practice.

Systematic review of prognostic importance of extramural venous invasion in rectal cancer

AIM: To systematically review the survival outcomes relating to extramural venous invasion in rectal cancer.

METHODS: A systematic review was conducted using PRISMA guidelines. An electronic search was carried out using MEDLINE, EMBASE, CINAHL, Cochrane library databases, Google scholar and PubMed until October 2014. Search terms were used in combination to yield articles on extramural venous invasion in rectal cancer. Outcome measures included prevalence and 5-year survival rates. These were graphically displayed using Forest plots. Statistical analysis of the data was carried out.

RESULTS: Fourteen studies reported the prevalence of extramural venous invasion (EMVI) positive patients. Prevalence ranged from 9%-61%. The pooled prevalence of EMVI positivity was 26% [Random effects: Event rate 0.26 (0.18, 0.36)]. Most studies showed that EMVI related to worse oncological outcomes. The pooled overall survival was 39.5% [Random effects: Event rate 0.395 (0.29, 0.51)].

CONCLUSION: Historically, there has been huge variation in the prevalence of EMVI through inconsistent reporting. However the presence of EMVI clearly leads to worse survival outcomes. As detection rates become more consistent, EMVI may be considered as part of risk-stratification in rectal cancer. Standardised histopathological definitions and the use of magnetic resonance imaging to identify EMVI will improve detection rates in the future.

Lack of Association between Membrane-Type 1 Matrix Metalloproteinase Expression and Clinically Relevant Molecular or Morphologic Tumor Characteristics at the Leading Edge of Invasive Colorectal Carcinoma

Colorectal cancer (CRC) is one of the leading causes of death from cancer in the western world, but tumor biology and clinical course show great interindividual variation. Molecular and morphologic tumor characteristics, such as KRAS/BRAF mutation status, mismatch repair (MMR) protein expression, tumor growth pattern, and tumor cell budding, have been shown to be of key therapeutic and/or prognostic relevance in CRC. Membrane-type 1 matrix metalloproteinase (MT1-MMP) is a membrane-anchored zinc-binding endopeptidase that is expressed at the leading edge of various invasive carcinomas and promotes tumor cell invasion through degradation of the extracellular matrix. The aim of this study was to investigate possible associations between MT1-MMP expression and molecular tumor characteristics as well as morphologic features of tumor aggressiveness in a consecutive series of 79 CRC tissue samples. However, although MT1-MMP was expressed in 41/79 samples (52%), there was no significant association between MT1-MMP expression and KRAS/BRAF mutation status, MMR protein expression, presence of lymphovascular invasion, tumor growth pattern, tumor-infiltrating lymphocytes, or tumor cell budding in our sample cohort (P > 0.05). Thus, we conclude that although MT1-MMP may play a role in CRC invasion, it is not of key relevance to the current models of CRC invasion and aggressiveness.

The prognostic significance of postchemoradiotherapy high-resolution MRI and histopathology detected extramural venous invasion in rectal cancer

OBJECTIVE

This study aimed to determine the prognostic significance of extramural venous invasion (EMVI) after chemoradiotherapy (CRT) by both magnetic resonance imaging (MRI) (ymrEMVI) and histopathology (ypEMVI).

BACKGROUND

EMVI is a prognostic factor in rectal cancer but whether this remains so after CRT preoperative is unknown. Histopathological definitions of EMVI are variable and lead to underreporting particularly after CRT.

METHODS

All consecutive patients staged on initial MRI as EMVI-positive undergoing preoperative CRT and curative surgery between Jan 2006 and Jan 2012 were included. Posttreatment EMVI status (yEMVI) was reevaluated for both MRI and pathology. The primary endpoint of disease-free survival (DFS) for ymrEMVI and ypEMVI was calculated using the Kaplan-Meier product limit and compared with a Mantel-Cox log-rank test. A P < 0.05 was considered significant. Hazard ratios (HRs) for disease recurrence were generated using Cox proportional hazard regression for MRI and histopathology tumor characteristics.

RESULTS

A total of 188 patients who had evidence of EMVI on initial baseline MRI staging were included. MRI detected significantly more patients with persistent EMVI than histopathology (53% vs 19%) but both were prognostic for worse survival-ymrEMVI (HR 1.97) and ypEMVI (HR 2.39). Patients with persistent ymrEMVI-positivity had significantly worse DFS at 3 years (42.7%) compared with ymrEMVI-negative tumors (79.8%); DFS for was 36.9% versus 65.9% positive and negative ypEMVI, respectively.

CONCLUSIONS

Detection of EMVI post-CRT is prognostically significant whether detected by MRI or histopathology. EMVI status after treatment may be used to counsel patients regarding ongoing risks of metastatic disease, implications for surveillance, and systemic chemotherapy.

Local massive venous invasion in colorectal cancer: CT-pathological correlation and its clinical implication

OBJECTIVE

To identify CT findings of massive venous invasion (MVI) in colorectal cancer, compare them to pathological findings and evaluate its clinical implications.

METHODS

Among 423 patients who received surgical resection of colorectal cancer, pre-operative CT of 26 patients (15 males, 11 females; mean age, 63.0 ± 12.1 years) with histopathologially proven MVI and 26 patients (14 males, 12 females; mean age, 71.1 ± 9.6 years) with histopathologically proven lymph node (LN) metastases were reviewed and compared with histopathological findings. We evaluated CT detectability of MVI and the morphologic differences between MVI and LN metastasis. All cases were followed up for at least 6 months after surgery.

RESULTS

Pre-operative CT correctly diagnosed only one case as tumour thrombus. 9 lesions were not detected on CT, and others were misdiagnosed pre-operatively as regional LN metastasis (14 cases) and juxtatumoural abscess (2 cases). After reviewing these cases, MVIs were identifiable in 20 of 26 cases. MVI was depicted on CT as nodules (oval, lobulated), abscess-like or intravenous tumour thrombus. MVI was significantly larger than LN metastasis (p < 0.05), while contrast enhancement was significantly lower (p < 0.05), and MVI often had an enhanced rim. Ten patients had synchronous metastases, and six patients had metachronous distant metastases within 5 years.

CONCLUSION

Many cases of MVI were distinguishable from LN metastases on pre-operative CT of colorectal cancer, but their appearances were varied, reflecting their histopathological behaviours. The distant metastatic rate was much higher in cases with MVI.

ADVANCES IN KNOWLEDGE

Radiologists should be aware of CT findings of MVI in colorectal cancer as a sentinel sign of distant metastasis.

MRI-detected extramural vascular invasion is an independent prognostic factor for synchronous metastasis in patients with rectal cancer

OBJECTIVES

To determine whether magnetic resonance imaging (MRI)-detected extramural vascular invasion (EMVI) could predict synchronous distant metastases in rectal cancer.

METHODS

Patients who underwent rectal MRI between July 2011 and December 2012 were screened. This study included 447 patients with pathologically confirmed rectal adenocarcinoma who had undergone MRI without previous treatment. Distant metastases were recorded at the initial work-up and over a 6-month follow-up. Univariate/multivariate logistic regression models were used to determine the risk of metastasis. The diagnostic performance was calculated using pathologic lymphovascular invasion (LVI) as a gold standard.

RESULTS

Among 447 patients, 79 patients (17.7 %) were confirmed to have distant metastases. Three MRI features are significantly associated with a high risk of distant metastasis: positive EMVI (odds ratio 3.02), high T stage (odds ratio 2.10) and positive regional lymph node metastasis (odds ratio 6.01). EMVI in a large vessel (≥3 mm) had a higher risk for metastasis than EMVI in a small vessel (<3 mm). Sensitivity, specificity and accuracy of MRI-detected EMVI were 28.2 %, 94.0 % and 80.3 %, respectively.

CONCLUSIONS

MRI-detected EMVI is an independent risk factor for synchronous metastasis in rectal cancer. EMVI in large vessels is a stronger risk factor for distant metastasis than EMVI in small vessels.

KEY POINTS

• EMVI, LN metastasis and T staging on MRI are risk factors for metastasis. • EMVI in large vessels has greater risk for metastasis than in small vessels. • Regional LN metastasis on MRI has highest risk for predicting metastasis. • MR findings could be helpful for selecting patients at high risk for metastasis.

The evolution in the detection of extramural venous invasion in rectal cancer: implications for modern-day practice

SUMMARY 

Venous invasion has been considered a poor prognostic factor in rectal cancer for over half a century. This term has evolved in recent years and now applies specifically to tumor invasion into extramural veins – extramural venous invasion. This distinction from intramural venous invasion is important as it is more clinically relevant. Extramural venous invasion can be identified by histopathology and MRI but until recently there has been a lack of consistency in definitions and detection techniques. This paper reviews the historical evidence for the prognostic importance and detection of venous invasion in rectal cancer.

Correlation of rectal tumor volumes with oncological outcomes for low rectal cancers: does tumor size matter?

PURPOSES

Several reports have described a relationship between tumor volume and oncological outcomes for certain cancers. There is paucity of similar data for rectal cancer. We conducted this study to establish whether tumor volume, mesorectal volume, and the tumor volume to mesorectal volume ratio (TV/MRV), evaluated by magnetic resonance imaging (MRI), affect the oncological outcomes of patients with rectal cancer.

METHODS

We performed volumetric analysis of rectal tumors from magnetic resonance imaging (MRI) images and assessed their correlation with oncological outcomes, using clinical and radiological databases.

RESULTS

The subjects of this study were 25 of 35 patients who underwent rectal cancer surgery after staging with MRI, after the exclusion of 7 patients for whom MRI images could not be retrieved and 3 patients who had metastases identified at diagnosis. Tumor volume (TV) was a significant predictor of overall survival hazard ratio (95% CI); 5.8 (1.2-29), (P = 0.03). Mesorectal volume (MRV) and TV/MRV did not correlate with oncological outcomes.

CONCLUSIONS

We found a direct relationship between tumor volume and overall survival, which may be used to stratify rectal tumors for neoadjuvant therapy. A larger prospective study is required to confirm this correlation.

Expression and DNA methylation of TNF, IFNG and FOXP3 in colorectal cancer and their prognostic significance

BACKGROUND

Colorectal cancer (CRC) progression is associated with suppression of host cell-mediated immunity and local immune escape mechanisms. Our aim was to assess the immune function in terms of expression of TNF, IFNG and FOXP3 in CRC.

METHODS

Sixty patients with CRC and 15 matched controls were recruited. TaqMan quantitative PCR and methylation-specific PCR was performed for expression and DNA methylation analysis of TNF, IFNG and FOXP3. Survival analysis was performed over a median follow-up of 48 months.

RESULTS

TNF was suppressed in tumour and IFNG was suppressed in peripheral blood mononuclear cells (PBMCs) of patients with CRC. Tumours showed enhanced expression of FOXP3 and was significantly higher when tumour size was >38 mm (median tumour size; P=0.006, Mann-Whitney U-test). Peripheral blood mononuclear cell IFNG was suppressed in recurrent CRC (P=0.01). Methylated TNFpromoter (P=0.003) and TNFexon1 (P=0.001) were associated with significant suppression of TNF in tumours. Methylated FOXP3cpg was associated with significant suppression of FOXP3 in both PBMC (P=0.018) and tumours (P=0.010). Reduced PBMC FOXP3 expression was associated with significantly worse overall survival (HR=8.319, P=0.019).

CONCLUSIONS

We have detected changes in the expression of immunomodulatory genes that could act as biomarkers for prognosis and future immunotherapeutic strategies.

Site-specific tumor grading system in colorectal cancer: multicenter pathologic review of the value of quantifying poorly differentiated clusters

The study aimed to determine the value of a novel site-specific grading system based on quantifying poorly differentiated clusters (PDC; Grade(PDC)) in colorectal cancer (CRC). A multicenter pathologic review involving 12 institutions was performed on 3243 CRC cases (stage I, 583; II, 1331; III, 1329). Cancer clusters of ≥5 cancer cells and lacking a gland-like structure (PDCs) were counted under a ×20 objective lens in a field containing the maximum clusters. Tumors with <5, 5 to 9, and ≥10 PDCs were classified as grades G1, G2, and G3, respectively. According to Grade(PDC), 1594, 1005, and 644 tumors were classified as G1, G2, and G3 and had 5-year recurrence-free survival rates of 91.6%, 75.4%, and 59.6%, respectively (P<0.0001). Multivariate analysis showed that Grade exerted an influence on prognostic outcome independently of TNM staging; approximately 20% and 46% of stage I and II patients, respectively, were selected by Grade(PDC) as a population whose survival estimate was comparable to or even worse than that of stage III patients. Grade(PDC) surpassed TNM staging in the ability to stratify patients by recurrence-free survival (Akaike information criterion, 2915.6 vs. 2994.0) and had a higher prognostic value than American Joint Committee on Cancer (AJCC) grading (Grade(AJCC)) at all stages. Regarding judgment reproducibility of grading tumors, weighted κ among the 12 institutions was 0.40 for Grade(AJCC) and 0.52 for Grade(PDC). Grade(PDC) has a robust prognostic power and promises to be of sufficient clinical value to merit implementation as a site-specific grading system in CRC.

Characteristics and significance of colorectal cancer associated lymphoid reaction

A subset of colorectal cancers (CRCs) exhibits so-called Crohn's like lymphoid reaction (CLR), an inflammatory reaction pattern that consists of numerous transmural lymphoid aggregates. However, the composition of these aggregates, their biological mechanisms and their prognostic significance are not well-defined. We analyzed two CRC cohorts (418 and 149 patients) and determined clinicopathological features including survival. A new method for evaluating CLR based on counting the areal density of the lymphoid follicles (CLR density) was adopted. Immune cell densities at intratumoral and peritumoral regions, as well as the composition of the lymphoid follicles, were studied by immunohistochemistry. We found that CLR comprised of lymphoid aggregates with no evidence of granuloma formation. High CLR density associated with lower tumor stage, lack of preoperative radiotherapy or chemoradiotherapy and deficient mismatch repair enzyme expression. CLR density had positive correlations with peritumoral and intratumoral densities of CD83(+) mature dendritic cells and T cells. High CLR density associated with better survival and had prognostic value that was independent of stage, Klintrup-Mäkinen score for peritumoral inflammation and the numbers of tumor infiltrating T cells. CLR density evaluation had excellent intraobserver and interobserver agreement. In conclusion, the results suggest that CLR contributes to the adaptive antitumor immunity. Quantitative evaluation of CLR density is a relevant prognostic indicator in CRC.

Tumor growth pattern as predictor of colorectal liver metastasis recurrence

BACKGROUND

Surgical resection is the gold standard therapy for the treatment of colorectal liver metastases (CRM). The aim of this study was to investigate the impact of tumor growth patterns on disease recurrence.

METHODS

We enrolled 91 patients who underwent CRM resection. Pathological specimens were prospectively evaluated, with particular attention given to tumor growth patterns (infiltrative vs pushing).

RESULTS

Tumor recurrence was observed in 65 patients (71.4%). According to multivariate analysis, 3 or more lesions (P = .05) and the infiltrative tumor margin type (P = .05) were unique independent risk factors for recurrence. Patients with infiltrative margins had a 5-year disease-free survival rate significantly inferior to patients with pushing margins (20.2% vs 40.5%, P = .05).

CONCLUSIONS

CRM patients with pushing margins presented superior disease-free survival rates compared with patients with infiltrative margins. Thus, the adoption of the margin pattern can represent a tool for improved selection of patients for adjuvant treatment.

Rectal cancer staging: focus on the prognostic significance of the findings described by high-resolution magnetic resonance imaging

High-resolution (HR) magnetic resonance imaging (MRI) has become an indispensable tool for multidisciplinary teams (MDTs) addressing rectal cancer. It provides anatomic information for surgical planning and allows patients to be stratified into different groups according to the risk of local and distant recurrence. One of the objectives of the MDT is the preoperative identification of high-risk patients who will benefit from neoadjuvant treatment. For this reason, the correct evaluation of the circumferential resection margin (CRM), the depth of tumor spread beyond the muscularis propria, extramural vascular invasion and nodal status is of the utmost importance. Low rectal tumors represent a special challenge for the MDT, because decisions seek a balance between oncologic safety, in the pursuit of free resection margins, and the patient's quality of life, in order to preserve sphincter function. At present, the exchange of information between the different specialties involved in dealing with patients with rectal cancer can rank the contribution of colleagues, auditing their work and incorporating knowledge that will lead to a better understanding of the pathology. Thus, beyond the anatomic description of the images, the radiologist's role in the MDT makes it necessary to know the prognostic value of the findings that we describe, in terms of recurrence and survival, because these findings affect decision making and, therefore, the patients' life. In this review, the usefulness of HR MRI in the initial staging of rectal cancer and in the evaluation of neoadjuvant treatment, with a focus on the prognostic value of the findings, is described as well as the contribution of HR MRI in assessing patients with suspected or confirmed recurrence of rectal cancer.

From the immune contexture to the Immunoscore: the role of prognostic and predictive immune markers in cancer

The inherent complexity of multifactorial diseases such as cancer renders the process of patient prognosis and prediction of response to therapy extremely difficult. Many markers, signatures, and methods have been described to evaluate the prognosis of cancer patients, yet very few translate into the clinic. Systems biology approaches have facilitated analysis of the complex interaction between tumors and the host-immune response, and allowed the definition of the immune contexture. Here we review the potential of the immune contexture, quantified by the Immunoscore, to provide a statistically strong parameter for prognosis. Finally we introduce the concept that the host-immune reaction could be the critical element in determining response to therapy. The effect on the immune response could be the underlying factor behind many of the predictive markers.

Objective criteria for crohn-like lymphoid reaction in colorectal cancer

We aimed to determine semiquantitative evaluation criteria for Crohn-like lymphoid reaction (CLR). We reviewed 1,032 patients with colorectal cancer and evaluated CLR by counting all peritumoral lymphoid aggregates (LAs) and by measuring the maximum diameter of the largest LA. The maximum diameter of the largest LA, rather than the number, had a significant impact on survival. Active CLR determined by the 1-mm rule was significantly associated with MLH1/MSH2 immunohistochemical staining deficiency. The group with LAs 1 mm or larger had lower recurrence (P = .0008) and a higher survival rate (P < .0001) than that without LAs 1 mm or larger. These results were similarly observed in another cohort of 500 patients with colorectal cancer. The k values for CLR evaluation among 8 observers were 0.67 for the 1-mm rule and 0.50 for Graham's criteria. The size of the largest LA best reflects the specific characteristics of CLR, and the 1-mm rule is expected to improve assessment reproducibility.

Resectable rectal cancer: which patient does not need preoperative radiotherapy?

It is well known that some patients with resectable rectal cancer benefit from preoperative radiotherapy in combination with or without chemotherapy. In order to reduce local recurrence and improve long-term survival, current guidelines advocate such neoadjuvant treatment in UICC (Union for International Cancer Control) stage II and III patients. However, the vast majority of patients may be adequately treated by rectal resection with total mesorectal excision (TME) alone. Recent evidence suggests an overtreatment of patients leading to unnecessary exposure to acute and long-term toxicity of radiation therapy. The question which consequently arises is which patient does not need preoperative radiotherapy. Improvements in MRI combined with better understanding of prognostic indicators suggest that patients with UICC stage I tumors, with tumors more than 12 cm proximal the anal verge can and patients with a circumferential resection margin ≥ 2 mm as assessed by preoperative MRI might be managed by radical surgery with adequate TME alone.

Changes in specialized blood vessels in lymph nodes and their role in cancer metastasis

Background

High endothelial venules (HEV) have been recognized to play a role in metastasis by its changes seen in the cancer microenvironment of lymph nodes (LN) and solid cancers. Squamous cell carcinoma (SCC) of the tongue is a prevalent tumor of the head and neck region with high propensity for LN metastasis. The extent of LN metastasis is the most reliable adverse prognostic factor. Primary tumors can induce vasculature reorganization within sentinel LN before the arrival of tumor cells and HEV represents these remodelled vessels. This study aims to evaluate the cancer induced vascular changes in regional lymph nodes (LN) of patients by studying the morphological and functional alterations of HEV and its correlation with clinical outcome and pathological features.

Methods

This study was based on 65 patients with SCC tongue who underwent primary surgical treatment including neck dissection. The patients were categorized into 2 groups based on the presence of malignancy in their cervical lymph nodes. A review of the patients' pathological and clinical data was performed from a prospective database. Immunohistochemical staining of the tissue blocks for HEV and high-power-field image analysis were performed and analyzed with correlation to the patients' clinical and pathological features.

Results

The total number of HEV was found to be significantly associated to disease-free interval. There was a similar association comparing the HEV parameters to overall survival. The density of abnormal HEV was significantly higher in patients with established metastases in their lymph nodes and HEV was shown to be a better prognosis factor than conventional tumor staging. The HEV morphological metamorphosis demonstrates a spectrum that correlates well with disease progression and clinical outcome.

Conclusions

The results suggest that the HEV displays a spectrum of morphological changes in the presence of cancer and LN metastasis, and that HEV is possibly involved in the process of cancer metastasis. We revealed the relationship of HEV and their metamorphosis in pre-metastatic and metastatic environments in regional lymph nodes of tongue cancer patients in relation to clinical outcomes. The significant observation of modified dilated HEV containing red blood cells in lymph nodal basin of a cancer suggests the shifting of its function from one primarily of immune response to that of a blood carrying vessel. It also demonstrated potential prognostic value. More studies are needed to elucidate its potential role in cancer immunotherapy and as a potential novel therapeutic approach to preventing metastasis by manipulating the remodelling processes of HEV.

Analysis of colorectal cancer morphology in relation to sex, age, location, and family history

BACKGROUND

Studies of colorectal cancer (CRC) have suggested different mechanisms of carcinogenesis in men and women, young and old patients, right- and left sided tumors, and sporadic and familial tumors. These differences might be reflected in morphology.

METHODS

CRCs from 1613 patients operated on in 2004-2006 in Sweden were histologically reviewed. Morphology was examined in relation to sex, age groups, location, and family history.

RESULTS

Tumors in the right colon were larger, of higher stage, more often poorly differentiated, more mucin-producing, more often had a peritumoral lymphocytic infiltrate and a high level of tumor-infiltrating lymphocytes (TILs), and more seldom had an infiltrating margin than tumors in the left colon and rectum (p < 0.0001 for most features). Young patients (<60 years) more seldom had multiple tumors but more often had perineural invasion, an infiltrative tumor margin, and high-stage tumors. Three features, TILs, medullary tumors, and invasive tumor margin, were related to sex. Only vascular invasion was related to familiality.

CONCLUSION

Location is the factor that has the most influence on tumor morphology. The results support the idea that different carcinogenic mechanisms may be involved in the right and left colon. Age is the most important determinant for the presence of multiple tumors and is a crucial factor for the aggressiveness of the disease.