International study group on rectal cancer regression grading: interobserver variability with commonly used regression grading systems. Hum Pathol. 2012;43:1917-1923. [PMID: 22575264 DOI: 10.1016/j.humpath.2012.01.020]

Beta-2-microglobulin positive tumor cells and CD8 positive lymphocytes are associated with outcome in post-neoadjuvant colorectal cancer resections

Locally advanced colorectal cancers are treated with neoadjuvant therapy (NAT), which has been shown to alter the characteristics of the tumor including size, lymph node yield, and histologic grade. We seek to interrogate the effect of NAT on the immune microenvironment. We compared 190 patients with colorectal adenocarcinoma treated with NAT with those without NAT (n = 926). We evaluated clinicopathologic and molecular factors and performed immunohistochemistry and quantification on tissue microarrays for HLA class I/II proteins, beta-2-microglobulin (B2M), CD8, CD163, LAG3, PD-L1, and FoxP3. Patients in the NAT group were younger (60.9 vs 67.9, p < 0.001) and more often male (59.5 vs. 47.9, p = 0.004) than those in the non-NAT group. Tumors in the NAT group were smaller (3.5 vs 4.7 cm, p < 0.001), less often high grade (6.5% vs. 16.2%, p = 0.001), more frequently in the rectum (68.9% vs. 6.6%, p < 0.001) and associated with lower lymph node yields (p = 0.002); however, the incidence of extramural venous invasion, perineural invasion, and AJCC stage 3-4 disease were not different. Immune cells positive for CD8 (p = 0.011) were significantly lower in the NAT group. A high number of CD8+ cells and higher expression of B2M in tumor cells showed a significant survival benefit in both NAT and non-NAT group. NAT is associated with an immune-low tumor environment. CD8+ cells and tumor B2M expression may help identify a subset of immune high-tumors following NAT. This identification could aid in determining patients who may benefit from conservative management of colorectal carcinomas.

Improving individualised therapies in localised gastro-oesophageal adenocarcinoma

Despite our increased understanding of the biological and molecular aspects of gastro-oesophageal tumourigenesis, the identification of prognostic or predictive factors remains challenging. Patients with resectable gastric and oesophageal adenocarcinoma are often treated similarly after surgical resection, regardless of their tumour biology, clinical characteristics, and histological treatment response. Substantial progress has been made in the past 5 years in managing patients with gastric or oesophageal adenocarcinoma, including the use of immune checkpoint inhibitors and new targeted therapies, leading to substantial improvements in clinical outcomes. These advancements have primarily been established in advanced and metastatic disease, while the management framework for local and locoregional disease is just beginning to shift. We provide an overview of existing data on biomarkers and tumour-related and host-related factors that are relevant to stratify patients into low-risk and high-risk recurrence groups, both before and after surgery, paving the way for more personalised treatment approaches.

Relevance of shrinkage versus fragmented response patterns in rectal cancer

AIMS

Partial response to neoadjuvant chemoradiotherapy (CRT) presents with one of two main response patterns: shrinkage or fragmentation. This study investigated the relevance of these response patterns in rectal cancer, correlation with other response indicators, and outcome.

METHODS AND RESULTS

The study included a test (n = 197) and a validation cohort (n = 218) of post-CRT patients with rectal adenocarcinoma not otherwise specified and a partial response. Response patterns were scored by two independent observers using a previously developed three-step flowchart. Tumour regression grading (TRG) was established according to both the College of American Pathologists (CAP) and Dworak classifications. In both cohorts, the predominant response pattern was fragmentation (70% and 74%), and the scoring interobserver agreement was excellent (k = 0.85). Patients with a fragmented pattern presented with significantly higher pathological stage (ypTNM II-IV, 78% versus 35%; P < 0.001), less tumour regression with Dworak (P = 0.004), and CAP TRG (P = 0.005) compared to patients with a shrinkage pattern. As a predictor of prognosis, the shrinkage pattern outperformed the TRG classification and stratified patients better in overall (fragmented pattern, hazard ratio [HR] 2.04, 95% confidence interval [CI] 1.19-3.50, P = 0.008) and disease-free survival (DFS; fragmented pattern, HR 2.50, 95% CI 1.23-5.10, P = 0.011) in the combined cohorts. The multivariable regression analyses revealed pathological stage as the only independent predictor of DFS.

CONCLUSIONS

The heterogeneous nature of tumour response following CRT is reflected in fragmentation and shrinkage. In rectal cancer there is a predominance of the fragmented pattern, which is associated with advanced stage and less tumour regression. While not independently associated with survival, these reproducible patterns give insights into the biology of tumour response.

Word of caution: Rectal cancer without response to neoadjuvant treatment - Do not wait for surgery

BACKGROUND

We hypothesized that prolonging the interval to surgery in non-responders to neoadjuvant chemoradiation therapy (nCRT) could lead to worse oncologic outcomes.

METHODS

Rectal adenocarcinoma patients with poor tumor response to nCRT (AJCC tumor regression grade 3) were selected. Oncologic outcomes were evaluated according to the time interval between completion of nCRT and surgery.

RESULTS

Among 56 non-responders, 28 patients surgically treated ≥8 weeks after completion of nCRT had worse disease-free survival (31% vs. 49%, p ​= ​0.05) and worse overall survival (34% vs. 53%, p ​= ​0.02) compared to patients <8 weeks. Using the three different intervals (≥12 weeks, 6-12 weeks, and< 6 weeks), waiting longer was consistently associated with worse overall (23% vs. 48% vs. 63%, p ​= ​0.02) and worse cancer-specific survival (35% vs. 61% vs. 71%, p ​= ​0.04), respectively.

CONCLUSION

For rectal cancer patients who are non-responders to nCRT, delay of surgery may lead to worse oncologic outcomes.

Peritoneal regression grading score (PRGS): first evidence for independent predictive and prognostic significance

Objectives

The peritoneal regression grading score (PRGS) is a four-tied pathologic score measuring tumor regression in biopsies from patients with peritoneal metastasis (PM) receiving chemotherapy.

Methods

This retrospective analysis of a prospective registry (NCT03210298) analyses 97 patients with isolated PM under palliative chemotherapy. We examined the predictive value of the initial PRGS for overall survival (OS) and the prognostic value of PRGS in repeated peritoneal biopsies.

Results

The 36 (37.1 %) patients with an initial mean PRGS≤2 had a longer median OS (12.1 months, CI 95 % 7.8-16.4) vs. 8.0 months (CI 95 % 5.1-10.8 months) in 61 (62.9 %) patients with PRGS≥3 (p=0.02) After stratification, the initial PRGS was an independent predictor of OS (Cox-regression, p<0.05). Out of 62 patients receiving≥two chemotherapy cycles, 42 (67.7 %) had a histological response (defined as a lower or stable mean PRGS in successive therapy cycles), and 20 (32.3 %) progressed (defined as an increasing mean PRGS). PRGS response was associated with a longer median OS (14.6 months, CI 5-95 % 6.0-23.2) vs. 6.9 (CI 5-95 % 0.0-15.9) months. PRGS response was prognostic in the univariate analysis (p=0.017). Thus, PRGS had both a predictive and prognostic significance in patients with isolated PM receiving palliative chemotherapy in this patient cohort.

Conclusions

This is the first evidence for the independent predictive and prognostic significance of PRGS in PM. These encouraging results need validation in an adequately powered, prospective study.

Intratumoral heterogeneity affects tumor regression and Ki67 proliferation index in perioperatively treated gastric carcinoma

BACKGROUND

Intratumoral heterogeneity (ITH) is a major problem in gastric cancer (GC). We tested Ki67 and tumor regression for ITH after neoadjuvant/perioperative chemotherapy.

METHODS

429 paraffin blocks were obtained from 106 neoadjuvantly/perioperatively treated GCs (one to five blocks per case). Serial sections were stained with Masson's trichrome, antibodies directed against cytokeratin and Ki67, and finally digitalized. Tumor regression and three different Ki67 proliferation indices (PI), i.e., maximum PI (KiH), minimum PI (KiL), and the difference between KiH/KiL (KiD) were obtained per block. Statistics were performed in a block-wise (all blocks irrespective of their case-origin) and case-wise manner.

RESULTS

Ki67 and tumor regression showed extensive ITH in our series (maximum ITH within a case: 31% to 85% for KiH; 4.5% to 95.6% for tumor regression). In addition, Ki67 was significantly associated with tumor regression (p < 0.001). Responders (<10% residual tumor, p = 0.016) exhibited prolonged survival. However, there was no significant survival benefit after cut-off values were increased ≥20% residual tumor mass. Ki67 remained without prognostic value.

CONCLUSIONS

Digital image analysis in tumor regression evaluation might help overcome inter- and intraobserver variability and validate classification systems. Ki67 may serve as a sensitivity predictor for chemotherapy and an indicator of ITH.

Histopathological Growth Pattern in Colorectal Liver Metastasis and The Tumor Immune Microenvironment

Almost half of all patients with colorectal cancer present with or eventually develop metastasis, most frequently in the liver. Understanding the histopathological growth patterns and tumor immune microenvironment of colorectal liver metastases may help determine treatment strategies and assess prognosis. A literature search was conducted to gather information on cancer biology, histopathological growth patterns, and the tumor immune microenvironment in colorectal liver metastases, including their mechanisms and their impact on clinical outcomes. A first consensus on histopathological growth patterns emerged in 2017, identifying five growth patterns. Later studies found benefits from a two-tier system, desmoplastic and non-desmoplastic, incorporated into the updated 2022 consensus. Furthermore, the tumor immune microenvironment shows additional characteristic features with relevance to cancer biology. This includes density of T-cells (CD8+), expression of claudin-2, presence of vessel co-option versus angiogenesis, as well as several other factors. The relation between histopathological growth patterns and the tumor immune microenvironment delineates distinct subtypes of cancer biology. The distinct subtypes are found to correlate with risk of metastasis or relapse, and hence to clinical outcome and long-term survival in each patient. In order to optimize personalized and precision therapy for patients with colorectal liver metastases, further investigation into the mechanisms of cancer biology and their translational aspects to novel treatment targets is warranted.

Peritoneal regression grading score (PRGS) in peritoneal metastasis: how many biopsies should be examined?

Objectives

The four-tied peritoneal regression grading score (PRGS) is increasingly used to evaluate the response of peritoneal metastases (PM) to chemotherapy. The minimal number of peritoneal biopsies needed for PRGS determination remains unclear.

Methods

A prospective cohort of 89 PM patients treated with 210 pressurized intraperitoneal aerosol chemotherapy (PIPAC) cycles was investigated. Four biopsies from every abdominal quadrant were recommended. Histological tumor response was defined as a stable or decreasing mean PRGS between therapy cycles, progression increasing. We compared the diagnostic uncertainty induced by missing biopsies to the histological response.

Results

A total of 49 patients had at least two PIPAC and were eligible for therapy response assessment. Mean PRGS decreased from 2.04 (CI 5-95% 1.85-2.27) to 1.79 (CI 5-95% 1.59-2.01), p=0.14, as a proof of therapy effectiveness. 35 (71.4%) patients had a stable or decreasing PRGS (therapy response), 14 (28.6%) a PRGS increase (disease progression). Histology showed agreement between four biopsies in 42/210 laparoscopies (20%), between ≥3 biopsies in 103 (49%), and between ≥2 biopsies in 169 laparoscopies (81%). Mean loss of information with one missing biopsy was 0.11 (95% CI=0.13) PRGS points, with two missing biopsies 0.18 (95% CI 0.21). In 9/49 patients (18.3%), the loss of information with one less biopsy exceeded the change in PRGS under therapy.

Conclusions

A minimum of three biopsies is needed to diagnose PM progression with an accuracy superior to 80%. Missing biopsies often result in a false diagnosis of tumor progression.

Development of a method for digital assessment of tumor regression grade in patients with rectal cancer following neoadjuvant therapy

Neoadjuvant chemo-radiotherapy (nCRT) followed by surgical resection is the standard treatment strategy in patients with locally advanced rectal cancer (RC). The pathological effect of nCRT is assessed by determining the tumor regression grade (TRG) of the resected tumor. Various methods exist for assessing TRG and all are performed manually by the pathologist with an accompanying risk of interobserver variation. Automated digital image analysis could be a more objective and reproducible approach to evaluate TRG. This study aimed at developing a digital method to assess TRG in RC following nCRT, and correlate the results to the currently used Mandard method. A deep learning-based semi-automatic Epithelium-Tumor area Percentage (ETP) algorithm enabling quantification of tumor regression by determining the percentage of residual tumor epithelium out of the total tumor area was developed. The ETP was quantified in 50 cases treated with nCRT and 25 cases with no prior nCRT served as controls. Median ETP was 39.25% in untreated compared with 6.64% in patients who received nCRT (P < .001). The ETP of the resected tumors treated with nCRT increased along with increasing Mandard grade (P < .001). As new treatment strategies in RC are emerging, performing an accurate and reproducible evaluation of TRG is important in the assessment of treatment response and prognosis. TRG is often used as an outcome point in clinical trials. The ETP algorithm is capable of performing a precise and objective value of tumor regression.

H3K27me3 Immunohistochemical Loss Predicts Lower Response to Neo-Adjuvant Chemo-Radiotherapy in Rectal Carcinoma

A watch-and-wait approach was suggested to avoid the possible complications related to surgery in patients with rectal carcinoma showing clinical complete response after neoadjuvant chemo-radiotherapy (CRT). Since clinical response may not correlate with pathological response, markers with higher accuracy are needed to identify patients who are likely responders and could be spared surgery. This study aims to assess whether H3K27me3 immunohistochemical expression in pre-treatment rectal carcinoma predicts response to neoadjuvant CRT or shows prognostic relevance. We assessed H3K27me3 immunostaining in 46 endoscopic biopsies of rectal carcinomas treated with neoadjuvant CRT and surgery. H3K27me3 immunostaining was lost in 20, retained in 19, and inconclusive (absent in neoplastic and non-neoplastic cells) in 7 cases. Retained H3K27me3 immuno-expression was significantly associated with ypTNM stage 0 (p = 0.0111) and high tumor regression, measured using either five-tiered (p = 0.0042) or two-tiered Dworak tumor regression grade (p = 0.0009). Poor differentiation, determined counting the number of poorly differentiated clusters (PDC grade) or tumor budding (TB) foci (TB grade), in the pre-treatment biopsy, was significantly associated with a shorter time to progression after surgery (p = 0.008; p = 0.0093). However, only PDC grade (p = 0.0023), together with radial margin involvement (p = 0.0001), retained prognostic significance in the multivariate analysis. The assessment of H3K27me3 immunostaining in pre-treatment endoscopic biopsy of rectal carcinoma could be useful to predict response to neo-adjuvant CRT and to identify patients who could safely undergo watch-and-wait approach. PDC and TB grade in the pre-treatment biopsy could provide additional prognostic information in patients with rectal carcinoma treated with neoadjuvant CRT and surgery.

MRI tumour regression grade in locally recurrent rectal cancer

BACKGROUND

This study aimed to investigate the agreement between magnetic resonance tumour regression grade (mrTRG) and pathological regression grade (pTRG) in patients with locally recurrent rectal cancer (LRRC). Also, the reproducibility of mrTRG was investigated.

METHODS

All patients with LRRC who underwent a resection between 2010 and 2018 after treatment with induction chemotherapy and neoadjuvant chemo(re)irradiation in whom a restaging MRI was available were retrospectively selected. All MRI scans were reassessed by two independent radiologists using the mrTRG, and the pTRG was reassessed by an independent pathologist. The interobserver agreement between the radiologists as well as between the radiologists and the pathologist was assessed with the weighted kappa test. A subanalysis was performed to evaluate the influence of the interval between imaging and surgery.

RESULTS

Out of 313 patients with LRRC treated during the study interval, 124 patients were selected. Interobserver agreement between the radiologists was fair (k = 0.28) using a two-tier grading system (mrTRG 1-2 versus mrTRG 3-5). For the lead radiologist, agreement with pTRG was moderate (k = 0.52; 95 per cent c.i. 0.36 to 0.68) when comparing good (mrTRG 1-2 and Mandard 1-2) and intermediate/poor responders (mrTRG 3-5 and Mandard 3-5), and the agreement was fair between the other abdominal radiologist and pTRG (k = 0.39; 95 per cent c.i. 0.22 to 0.56). A shorter interval (less than 7 weeks) between MRI and surgery resulted in an improved agreement (k = 0.69), compared with an interval more than 7 weeks (k = 0.340). For the lead radiologist, the positive predictive value for predicting good responders was 95 per cent (95 per cent c.i. 71 per cent to 99 per cent), whereas this was 56 per cent (95 per cent c.i. 44 per cent to 66 per cent) for the other radiologist.

CONCLUSION

This study showed that, in LRRC, the reproducibility of mrTRG among radiologists is limited and the agreement of mrTRG with pTRG is low. However, a shorter interval between MRI and surgery seems to improve this agreement and, if assessed by a dedicated radiologist, mrTRG could predict good responders.

Tumor regression grade combined with lymph node status in esophageal squamous cell carcinoma after neoadjuvant chemoradiotherapy

Introduction

We aimed to elucidate the prognostic value of tumor regression grade (TRG) combined with lymph node status compared with the 8th edition of the ypTNM staging system in patients with advanced esophageal squamous cell cancer (ESCC) after neoadjuvant chemoradiotherapy (nCRT).

Methods

We enrolled 325 patients with ESCC who underwent nCRT followed by complete resection. We adopted the modified Schneider TRG system, with high (ypT0N0), mid (ypT0N+ or ypT + N0), and low (ypT + N+). After developing a multivariable Cox model, the discrimination ability of the ypStage and TRG systems was evaluated using the Akaike Information Criterion (AIC) and R² measure.

Results

The mean duration of follow‐up was 56.7 ± 43.3 months. The survival curves between the adjacent groups of TRG were significantly different for both overall survival (OS) and recurrence‐free survival (RFS). However, there were no significant differences between ypStages II and III for OS (p = 0.683) or RFS (p = 0.760). The TRG system also had a discrimination ability in patients with ypStage I (p < 0.001 for both OS and RFS) and ypStage III (p = 0.045 for OS and 0.042 for RFS). Compared with the ypTNM staging system, the modified TRG had a lower AIC value (1835.99 vs. 1852.02) and a higher R² (0.256 vs. 0.177), indicating better discrimination ability and prediction accuracy.

Conclusions

For patients with ESCC who underwent esophagectomy following nCRT, the modified Schneider TRG system may complement the ypStage and help clinicians select the most appropriate postoperative treatment and surveillance.

Can Gastric Cancer Patients with High Mandard Score Benefit from Neoadjuvant Chemotherapy?

A high Mandard score may indicate the tumor is insensitive to chemotherapy. We analyzed tumor regression and lymph node response under different Mandard scores to assess the impact of Mandard score on prognosis. Methods. Mandard scores and ypN stage of postoperative pathological reports were recorded. The results were reviewed by a professional pathologist. The radiologist compared the tumor regression before and after chemotherapy by computed tomography (CT). The survival of all patients was obtained by telephone follow-up. Multivariate Cox regression was used to assess the relationship between overall risk of death and Mandard score, imaging evaluation, and ypN stage. Results. In the Mandard score (4-5) group, the median survival time for PR and ypN0 patients was 68.5 and 76.7 months. While in the Mandard score (1-2) group, the median survival time for PD and ypN3a patients was 15.6 and 14.5 months. Imaging evaluation of tumor regression (PR 68.5 months, SD 27.8 months, and PD 10.2 months) and lymph node remission (ypN0 76.7 months, ypN1 61.6 months, ypN2 18.0 months, ypN3a 18.7 months, and ypN3b 18.3 months) showed improved survival. Mandard score, imaging evaluation, and ypN stage are important prognostic factors affecting prognosis. Conclusion. A high Mandard score does not mean neoadjuvant chemotherapy is ineffective in gastric cancer. Patients with imaging evaluation of tumor regression and ypN stage reduction may benefit from neoadjuvant chemotherapy.

Grading der Tumorregression gastrointestinaler Karzinome nach neoadjuvanter Therapie

Prä- oder perioperative Chemo- oder Radiochemotherapie und anschließende Resektion ist die Standardtherapie von lokal fortgeschrittenem Ösophagus‑, Magen- und Rektumkarzinom. Eine Tumorregressionsgraduierung (TRG, auch Tumorregressionsgrad) kategorisiert das Ausmaß der regressiven Veränderungen nach neoadjuvanter Behandlung. Für gastrointestinale Karzinome existieren mehrere TRG-Systeme, die sich entweder auf das Ausmaß der therapieinduzierten Fibrose im Verhältnis zum Resttumor oder den geschätzten Anteil des Resttumors im Bereich des ehemaligen Tumorareals beziehen. Ein ideales TRG-System zeigt eine signifikante Interobserverübereinstimmung und bietet relevante prognostische Informationen – in den meisten Fällen ist eine vollständige oder nahezu vollständige Regression nach neoadjuvanter Therapie mit verbesserter Prognose verbunden. In diesem Review werden die am häufigsten verwendeten TRG-Systeme für gastrointestinale Karzinome vorgestellt und diskutiert. Zudem werden aktuelle Punkte wie die Standardisierung der Angabe von TRGs und die Thematik der Regression bei Lymphknotenmetastasen im Kontext eines TRG-Systems behandelt.

Tumor-Infiltrating Lymphocytes as Biomarkers of Treatment Response and Long-Term Survival in Patients with Rectal Cancer: A Systematic Review and Meta-Analysis

Simple Summary

This study investigated tumor-infiltrating lymphocytes (TILs) in pretherapeutic biopsies as biomarkers of treatment response and long-term prognosis in patients with locally advanced rectal cancer undergoing neoadjuvant chemoradiotherapy. A systematic review and meta-analysis was performed in accordance with the PRISMA guidelines. The results indicate that it is possible to identify a sub-group of patients with improved treatment response and long-term prognosis by assessing the density of CD8⁺ TILs at the time of diagnosis.

Abstract

Neoadjuvant chemoradiotherapy (NCRT) is indicated in locally advanced rectal cancer (LARC) to downstage tumors before surgery. Watchful waiting may be a treatment option to avoid surgery in patients, obtaining a complete clinical response. However, biomarkers predictive of treatment response and long-term prognosis are lacking. Here we investigated tumor-infiltrating lymphocytes (TILs) in pretherapeutic biopsies as predictive and prognostic biomarkers. A systematic review and meta-analysis was performed in accordance with the PRISMA guidelines. In total, 429 articles were identified, of which 19 studies were included in the systematic review and 14 studies in the meta-analysis. Patients with high pretherapeutic CD8⁺ TILs density had an increased likelihood of achieving a pathological complete response (RR = 2.71; 95% CI: 1.58–4.66) or a complete or near-complete pathological treatment response (RR = 1.86; 95% CI: 1.50–2.29). Furthermore, high CD8⁺ TILs density was a favorable prognostic factor for disease-free survival (HR = 0.57; 95% CI: 0.38–0.86) and overall survival (HR = 0.43; 95% CI: 0.27–0.69). CD3⁺, CD4⁺, and FOXP3⁺ TILs were not identified as predictive or prognostic biomarkers. Thus, assessing pretherapeutic CD8⁺ TILs density may assist in identifying patients with increased sensitivity to NCRT and favorable long-term prognosis.

Role of MRI‑based radiomics in locally advanced rectal cancer (Review)

Colorectal cancer is the third most common type of cancer, with high morbidity and mortality rates. In particular, locally advanced rectal cancer (LARC) is difficult to treat and has a high recurrence rate. Neoadjuvant chemoradiotherapy (NCRT) is one of the standard treatment programs of LARC. If the response to treatment and prognosis in patients with LARC can be predicted, it will guide clinical decision‑making. Radiomics is characterized by the extraction of high‑dimensional quantitative features from medical imaging data, followed by data analysis and model construction, which can be used for tumor diagnosis, staging, prediction of treatment response and prognosis. In recent years, a number of studies have assessed the role of radiomics in NCRT for LARC. MRI‑based radiomics provides valuable data and is expected to become an imaging biomarker for predicting treatment response and prognosis. The potential of radiomics to guide personalized medicine is widely recognized; however, current limitations and challenges prevent its application to clinical decision‑making. The present review summarizes the applications, limitations and prospects of MRI‑based radiomics in LARC.

Can histologic features predict neoadjuvant therapy response in rectal adenocarcinoma?

Current standard therapy for locally advanced rectal cancer (LARC) is neoadjuvant therapy followed by surgical resection; however, treatment response is variable among patients. This study aimed to identify histologic features that predict tumor response. This retrospective study included 105 patients with LARC, all of whom underwent biopsy followed by neoadjuvant therapy and subsequent surgical resection. Each patient's initial biopsy was evaluated for tumor grade, tumor budding, intraepithelial lymphocytes, intraepithelial neutrophils, desmoplasia, apoptosis, adjacent stromal lymphocytes, signet ring cells, mucinous features, tumoral Paneth cells, dirty necrosis, microscopic ulceration, and prominent lymphoid aggregates. These histologic features, along with patient age at diagnosis and tumor microsatellite status, were compared to tumor regression grades from the respective resection specimens. No histologic factors in tumor biopsies predictive of treatment response in post-therapy resection specimens were identified. Histologic features in pre-therapy biopsy samples of LARC do not predict subsequent response to neoadjuvant therapy. Effective and reliable methods to predict response to neoadjuvant therapy in rectal cancer remain elusive.

High CD8+ tumour-infiltrating lymphocyte density associates with unfavourable prognosis in oesophageal adenocarcinoma following poor response to neoadjuvant chemoradiotherapy

AIMS

Determining prognosis following poor response to neoadjuvant chemoradiotherapy (nCRT) in oesophageal adenocarcinoma (OAC) remains challenging. An immunosuppressive tumour microenvironment (TME) as well as immune infiltrate density and composition are considered to play a critical role in the immune interaction between host and tumour and can predict therapy response and survival in many cancers, including gastrointestinal malignancies. The aim of this study was to establish the TME characteristics associated with survival following a poor response to nCRT.

METHODS AND RESULTS

The prognostic significance of OAC-associated CD3⁺ , CD4⁺ , CD8⁺ , forkhead box protein 3 (FoxP3⁺ ) and programmed cell death ligand 1 (PD-L1) expression was studied by immunohistochemistry and quantified by automated image analysis in 123 patients who underwent nCRT and curative resection. Results from good and poor responders were contrasted and immune infiltration was related to disease course in both groups. Subsequently a cohort of 57 patients with a moderate response to nCRT was analysed in a similar fashion. Tumour cell percentage positively correlated to immune infiltration markers. In good and moderate responders, none of the immune infiltrate parameters was associated with survival; in poor responders CD8⁺ was an independent negative predictor of OS in univariate analysis (P = 0.03) and high CD8⁺ infiltration was associated with worse OS (15 versus 32 months, P = 0.042).

CONCLUSION

A high CD8⁺ density is an independent biomarker of poor OS in poor responders to nCRT, but not in good and moderate responders. Our results suggest that patients with a poor response to nCRT but concomitant high CD8⁺ counts in the resection specimen require adjuvant therapy.

Vascular calcification and response to neoadjuvant therapy in locally advanced rectal cancer: an exploratory study

Purpose

Patients with locally advanced rectal cancer (LARC) may experience a clinical complete response (cCR) to neoadjuvant chemoradiotherapy (NACRT) and opt for non-operative management. Pathological factors that relate to NACRT response have been well described. Host factors associated with response, however, are poorly defined. Calcification of the aortoiliac (AC) vessels supplying the rectum may influence treatment response.

Methods

Patients with LARC having NACRT prior to curative surgery at Glasgow Royal Infirmary (GRI) and St Mark’s hospital (SMH) between 2008 and 2016 were identified. AC was scored on pre-treatment CT imaging. NACRT response was assessed using pathologic complete response (pCR) rates, tumour regression grades (TRGs), the NeoAdjuvant Rectal score and T-/N-downstaging. Associations were assessed using Chi-squared, Mantel–Haenszel and Fisher’s exact tests.

Results

Of 231 patients from GRI, 79 (34%) underwent NACRT for LARC. Most were male (58%), aged over 65 (51%) with mid- to upper rectal tumours (56%) and clinical T3/4 (95%), node-positive (77%) disease. pCR occurred in 10 patients (13%). Trends were noted between higher clinical T stage and poor response by Royal College of Pathologist’s TRG (p = 0.021) and tumour height > 5 cm and poor response by Mandard TRG (0.068). In the SMH cohort, 49 of 333 (15%) patients underwent NACRT; 8 (16%) developed a pCR. AC was not associated with NACRT response in either cohort.

Conclusions

AC was not associated with NACRT response in this cohort. Larger contemporary cohorts are required to better assess host determinants of NACRT response and develop predictive models to improve patient selection.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00432-021-03570-1.

Pressurized Intraperitoneal Aerosol Chemotherapy for Colorectal Peritoneal Metastases

BACKGROUND

The benefit of repetitive PIPAC specifically in CPM patients has yet to be demonstrated in terms of oncological and functional outcomes.

OBJECTIVE

The aim of this study was to evaluate the outcome of patients with non-resectable colorectal peritoneal metastases (CPM) treated with pressurized intraperitoneal aerosol chemotherapy (PIPAC).

METHODS

We conducted an analysis of a prospective single-center database of all CPM patients who underwent PIPAC with oxaliplatin 92 mg/m² body surface (PIPAC-Ox). The outcome criteria were adverse events (Common Terminology Criteria for Adverse Events version 4.0), Peritoneal Regression Grading Score (PRGS), and survival.

RESULTS

Overall, 102 patients with a median age of 64 years (33-88) were scheduled for PIPAC-Ox. Access to the abdominal cavity for the first application failed in 22/102 (21.6%) patients. A total of 185 PIPACs were performed, with 26/102 (25.5%), 20/102 (19.6%), 17/102 (16.7%), and 17/102 (16.7%) patients undergoing one, two, three, and four or more PIPACs, respectively. Perioperative overall morbidity/mortality Grade I-V occurred in 14 (7.6%), 29 (15.8%), 6 (3.2%), 1 (0.5%), and 1 (0.5%) patient without significant differences between each cycle. Of 27 patients who underwent three or more PIPACs, 20/102 (19.6%) had major/complete CPM regression (PRGS 1-2). In a multivariate analysis, independent predictive factors for > 12 months' survival following the first PIPAC-Ox administration were three or more PIPACs (odds ratio [OR] 4.5, 95% confidence interval [CI] 1.35-15.2; p = 0.014) and younger patient age (OR 1.058, 95% CI 1.00-1.12; p = 0.039).

CONCLUSIONS

Repetitive PIPAC-Ox for CPM patients, alone or combined with perioperative systemic chemotherapy, is feasible. Our data suggest that three or more consecutive PIPAC-Ox cycles for advanced CPM can improve survival.

Prognostic Value of Tumor Regression Grade on MR in Rectal Cancer: A Large-Scale, Single-Center Experience

Objective

To determine the prognostic value of MRI-based tumor regression grading (mrTRG) in rectal cancer compared with pathological tumor regression grading (pTRG), and to assess the effect of diffusion-weighted imaging (DWI) on interobserver agreement for evaluating mrTRG.

Materials and Methods

Between 2007 and 2016, we retrospectively enrolled 321 patients (male:female = 208:113; mean age, 60.2 years) with rectal cancer who underwent both pre-chemoradiotherapy (CRT) and post-CRT MRI. Two radiologists independently determined mrTRG using a 5-point grading system with and without DWI in a one-month interval. Two pathologists graded pTRG using a 5-point grading system in consensus. Kaplan-Meier estimation and Cox-proportional hazard models were used for survival analysis. Cohen's kappa analysis was used to determine interobserver agreement.

Results

According to mrTRG on MRI with DWI, there were 6 mrTRG 1, 48 mrTRG 2, 109 mrTRG 3, 152 mrTRG 4, and 6 mrTRG 5. By pTRG, there were 7 pTRG 1, 59 pTRG 2, 180 pTRG 3, 73 pTRG 4, and 2 pTRG 5. A 5-year overall survival (OS) was significantly different according to the 5-point grading mrTRG (p = 0.024) and pTRG (p = 0.038). The 5-year disease-free survival (DFS) was significantly different among the five mrTRG groups (p = 0.039), but not among the five pTRG groups (p = 0.072). OS and DFS were significantly different according to post-CRT MR variables: extramural venous invasion after CRT (hazard ratio = 2.259 for OS, hazard ratio = 5.011 for DFS) and extramesorectal lymph node (hazard ratio = 2.610 for DFS). For mrTRG, k value between the two radiologists was 0.309 (fair agreement) without DWI and slightly improved to 0.376 with DWI.

Conclusion

mrTRG may predict OS and DFS comparably or even better compared to pTRG. The addition of DWI on T2-weighted MRI may improve interobserver agreement on mrTRG.

Pathological assessment of tumour regression following neoadjuvant therapy in pancreatic carcinoma

Pancreatic carcinoma is a relatively common malignancy with an overall poor prognosis which is somewhat improved in those patients for whom resection and adjuvant therapy is feasible. In recent years there has been a trend to administering neoadjuvant therapy (combination chemotherapy and/or chemoradiotherapy), followed by resection in patients who remain surgical candidates at the completion of this treatment. Advantages of a neoadjuvant approach may include greater likelihood of achieving complete resection with negative surgical margins, reduced treatment toxicity and greater cost effectiveness, as well as potentially sparing patients with rapidly progressive disease from major surgery. To gauge the tumour's response to preoperative therapy, and to compare the efficacy of different regimens, there is a need for a robust and reproducible system of assessing tumour regression in resection specimens. Several such systems have been proposed, but there is generally a lack of consensus as to which system is the 'best'. This review describes the evolution of a number of tumour regression grading systems which have been proposed, and discusses the relative merits and shortfalls of several of the most frequently applied schemata. Some problems common to many of these include poorly defined criteria, low interobserver reproducibility and a reliance on fibrosis as a surrogate for tumour kill, which may not be valid. Despite that, recent evidence suggests that the Dworak grading system (first developed for rectal cancer) may be useful in terms of both interobserver concordance and correlation with survival.

Magnetic resonance imaging tumor response score (mrTRS) predicts therapeutic effect and prognosis of locally advanced rectal cancer after neoadjuvant chemoradiotherapy: A prospective, multi-center study

BACKGROUND AND PURPOSE

The MRI-assessed tumor regression grade (mrTRG) is limited due to its subjectivity and poor consistency on pathological tumor regression grade (pTRG). A new MRI criterion was established to predict the prognosis of locally advanced rectal cancer (LARC).

MATERIALS AND METHODS

The new MRI criterion magnetic resonance imaging tumor response score (mrTRS) was based on the retrospective sample of 214 LARC patients (unpublished data). Subsequently, 878 LARC patients were enrolled for a prospective, multicenter study. Baseline and postoperative MRI were obtained, and imaging features were measured by collecting the pathological, clinical and follow-up data. Kaplan-Meier method with log-rank estimate and multivariate cox regression model was used to determine the prognosis of mrTRS in LARC patients with neoadjuvant chemoradiotherapy (NACRT). The predictive capability of 3-year prognosis between mrTRS and mrTRG was determined by time-dependent ROC curves.

RESULTS

The results demonstrated that mrTRS acted as an independent predictor of survival outcomes. mrTRS stratified by good and moderate responders showed significantly lower risk of death (HR = 0.04, 95%CI 0.01-0.31; HR = 0.35, 95%CI 0.23-0.52), distant metastasis (HR = 0.25, 95%CI 0.13-0.52; HR = 0.42, 95%CI 0.30-0.58), and local recurrence when compared with poor responders(HR = 0.01 95%CI 0.23-0.52;HR = 0.38, 95%CI 0.16-0.90). In contrast, no significant difference was observed among mrTRG stratified groups. Excellent and substantial interobserver agreement for mrTRS and mrTRG evaluation was observed (κ = 0.92 and 0.62), respectively.

CONCLUSION

mrTRS can serve as an effective predictor for assessing tumor regression grade in LARC patients with NACRT.

Connection and distinction of tumor regression grading systems of gastrointestinal cancer

OBJECTIVES

As the neoadjuvant therapy has been successfully introduced in the treatment of gastrointestinal malignancies, the evaluation of therapeutic effectiveness is becoming increasingly important. Tumor-node-metastasis system has been widely applied. However, this system is mainly based on the location of residual tumor, but does not consider the amount of residual tumor. Tumor regression grading system, a quantitative method to assess the reaction of tumor to neoadjuvant treatment, could be used as a supplement to tumor-node-metastasis system and provide additional information on prognosis. To date, numerous gastrointestinal grading systems have been used in esophageal/esophagogastric junction carcinoma, gastric adenocarcinoma, colorectal cancer, and most of them were considered to associate with clinical outcomes.

MATERIALS AND METHODS

In this review, firstly, we expounded the importance of tumor regression grading systems, and summarized the histopathological changes after neoadjuvant therapy. Secondly, we introduced some commonly used gastrointestinal systems, as well as the relationships and nuance. Finally, we discussed pivotal issues about these systems. In this part, we explained the calculation methods based on grid points and square measures, discussed several factors leading to observer bias, containing the slice number and the grading tier number, and analyzed the factors that might affect clinical significance, covering anatomical location, the selection of survival index, and the tumor type.

RESULTS

Tumor regression grade systems could be divided into two main classifications, the relative amount of fibrosis and residual tumor, and the proportion of residual tumor in the tumor bed. However, the definitions of these systems were still need to be improved.

CONCLUSIONS

The tumor regression grading system is useful in evaluating tumor response to neoadjuvant therapy, but more work is needed to refine and unify the system.

Pathological Complete Response Following Different Neoadjuvant Treatment Strategies for Locally Advanced Rectal Cancer: A Systematic Review and Meta-analysis

Background

Pathological complete response (pCR) following neoadjuvant treatment for locally advanced rectal cancer (LARC) is associated with better survival, less local recurrence, and less distant failure. Furthermore, pCR indicates that the rectum may have been preserved. This meta-analysis gives an overview of available neoadjuvant treatment strategies for LARC and analyzes how these perform in achieving pCR as compared with the standard of care.

Methods

Pubmed, Embase, and Cochrane Central bibliographic databases were searched. Randomized controlled trials in which patients received neoadjuvant treatment for MRI-staged nonmetastatic resectable LARC were included. The primary outcome was pCR, defined as ypT0N0. A meta-analysis of studies comparing an intervention with standard fluoropyrimidine-based chemoradiation (CRT) was performed.

Results

Of the 17 articles included in the systematic review, 11 were used for the meta-analysis. Addition of oxaliplatin to fluoropyrimidine-based CRT resulted in significantly more pCR compared with fluoropyrimidine-based CRT only (OR 1.46), but at the expense of more ≥ grade 3 toxicity. Other treatment strategies, including consolidation/induction chemotherapy and short-course radiotherapy (SCRT), did not improve pCR rates. None of the included trials reported a benefit in local control or OS. Five-year DFS was significantly worse after SCRT-delay compared with CRT (59% vs. 75.1%, HR 1.93).

Conclusions

All included trials fail to deliver high-level evidence to show an improvement in pCR compared with standard fluoropyrimidine-based CRT. The addition of oxaliplatin might result in more pCR but at the expense of more toxicity. Furthermore, this benefit does not translate into less local recurrence or improved survival.

Electronic supplementary material

The online version of this article (10.1245/s10434-020-08615-2) contains supplementary material, which is available to authorized users.

Varying practices in tumor regression grading of gastrointestinal carcinomas after neoadjuvant therapy: results of an international survey

Tumor regression grading is routinely performed on neoadjuvantly treated gastrointestinal cancer resections. Challenges in tumor regression grading include grossing standards, multiple grading systems, and difficulty interpreting therapy-induced changes. We surveyed gastrointestinal pathologists around the world for their practices in handling neoadjuvantly treated gastrointestinal cancer specimens and reporting tumor regression using a 23-question online survey. Topics addressed grossing, histologic work-up, tumor regression grading systems, and degree of difficulty identifying and estimating residual cancer within treatment effect. Two-hundred three responses were received, including 173 participants who completed the entire questionnaire. Fifty percent of the participants were from Europe, 29% from North America, 10% from Australia, and 11% from other continents. Ninety-five percent routinely report a tumor regression grade and 92% have standardized grossing and histologic work-up: 27% always completely embed the entire tumor bed, 54% embed the complete tumor site if not a grossly apparent, large mass. Fifty-nine percent use hematoxylin & eosin alone for assessment; the remaining use additional stains. In North America and Australia, the American Joint Committee on Cancer (AJCC)/College of American Pathologists (CAP)/Ryan system is routinely used for gastroesophageal (71%) and rectal carcinomas (77%). In Europe, the Mandard system is common (36%) for gastroesophageal tumors, followed by AJCC/CAP/Ryan (22%), and Becker (10%); for rectal CA, the Dworak system (30%) is followed by AJCC/CAP/Ryan (24%) and Mandard (14%). This regional differences were significant (p < 0.001 each). Fifty-one percent prefer a four-tiered system. Sixty-six percent think that regressive changes in lymph nodes should be part of a regression grade. Sixty-nine percent consider identifying residual tumor straight-forward, but estimating therapy-induced fibrosis difficult (57%). Free comments raised issues of costs for work-up and clinical relevance. In conclusion, this multinational survey provides a comprehensive overview of grossing and histologic work-up with regards to tumor regression grading in gastrointestinal cancers with partly significant regional differences particularly between North America and Europe.

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.

The Effect of Lymph Nodes' Histologic Response on Survival Outcomes in Moroccan Patients with Rectal Cancer

Prognosis for patients with locally advanced rectal cancer remains controversial. The purpose of this study was to elucidate possible association between therapeutic effect on lymph nodes (LNs) and patient prognosis. Overall, 149 patients with rectal cancer received preoperative radiotherapy in concomitance with chemotherapy or exclusive radiotherapy before rectal excision. Microscopic examination of formalin-fixed lymph nodes was assessed for therapeutic effect. The establishment of groups combined reaction tissue types of fibrosis, colloid, and necrosis after neoadjuvant treatment was assigned. The average age was 56.38 years, ranged between 22 and 88 years, 53% were female, and 47% were men, with a sex ratio of 1 : 12. In the present study, we noticed that after a median follow-up time of 40.67 months (0-83; SD: 21.1), overall survival was statistically significant depending on age groups. Kaplan-Meier analysis showed significant differences in the rate of patients with an age under 65 years (70.64%) versus those with an age over 85 years (36.5%) (p < 0.001). Also, the OS was statistically significant depending on therapeutic effect groups composed of 0TE (No Therapeutic effect), C+ (presence of only colloidal effect), F+ (presence of only fibrosis tissue), and ME+ (mixture of 2 or 3 types of therapeutic effect) group. Indeed, we observed a significantly higher OS rate in the ME + group (86%) compared with the OS rate of LNs group with no therapeutic effect (57%) (p=0.028). Additionally, there was a significant association between the presence of fibrosis on LNs and an extended delay of more than 8 weeks to neoadjuvant treatment completion and surgery. Our study indicates that the best patient prognosis could be predicted based on tumor presenting a best pathologic effect on lymph nodes, and that delaying surgery for more than 8 weeks to neoadjuvant treatment completion improves therapeutic response on LNs.

High expression of microRNA-199a-5p is associated with superior clinical outcomes in patients with locally advanced rectal cancer

PURPOSE

We aimed to identify biomarkers of response to preoperative CRT in patients with LARC using comprehensive miRNA analysis.

METHODS

This study included 65 rectal cancer specimens and 89 serum samples from patients diagnosed with LARC and treated with preoperative. All specimens were collected before CRT for evaluation of biologic differences between the good and poor CRT response groups (ypStage 0/I versus II/III/IV). For specific miRNA discovery, 800 miRNAs in 20 rectal cancer specimens were analyzed with a NanoString assay. For validation, a total of 65 tissue and 89 serum samples were tested with reverse transcription-polymerase chain reaction (RT-PCR).

RESULTS

In the discovery set, 16 target miRNAs were detected. In the validation set, higher expression of three miRNAs (miR-199a/b-3p, miR-199a-5p, and miR-199b-5p) was significantly associated with better response to CRT. In the univariate survival analysis, upregulation of these three miRNAs was associated with superior relapse-free survival (RFS) and overall survival (OS). Meanwhile, only a higher level of tissue miR-199a-5p was associated with superior RFS [hazard ratio (HR), 0.0.91; 95% confidence interval (CI) 0.035-0.580; p = 0.002] and OS (HR, 0.272; 95% CI 0.023-0.658; p < 0.001) in the multivariate survival analysis. Also, a higher level of exosomal miR-199b-5p correlated with better response to CRT (p = 0.0397).

CONCLUSION

High expression of tissue miR-199a/b-3p, miR-199a-5p, and miR-199b-5p was significantly associated with response to CRT, and a high level of tissue miR-199a-5p was associated with superior survival outcomes. Also, upregulated exosomal miR-199b-5p correlated with CRT response, reflecting its promise as a circulating biomarker of CRT response in patients with LARC.

Pathological Tumor Regression Grade Classifications in Gastrointestinal Cancers: Role on Patients' Prognosis

Preoperative chemotherapy or combined radiotherapy and chemotherapy (CRT), followed by surgery, represents the standard approach for locally advanced esophageal, gastric, and rectal carcinomas. To adequately evaluate the effects of neoadjuvant CRT in the resection specimens, several histopathologic tumor regression grade (TRG) scoring systems have been introduced into clinical practice. The primary goal of these TRG systems relies on a correct prognostic stratification of patients in the attempt to help clinical decision-making and influence surgical strategies, postoperative adjuvant therapies, and surveillance intensity. However, most TRG systems suffer from poor reproducibility and low interobserver concordance rates. Many efforts have been made in the identification of alternative, robust, simple, and universally accepted TRG scoring systems, which would help in the comparison of different treatment strategies and in the standardization of multimodal therapies. The aim of this review is to analyze the most commonly used TRG systems in gastrointestinal cancers highlighting their pitfalls and usefulness, depending on the tumor type.

Area of residual tumor (ART) can predict prognosis after post neoadjuvant therapy resection for pancreatic ductal adenocarcinoma

An increasing number of patients with pancreatic ductal adenocarcinoma (PDAC) have undergone resection after neoadjuvant therapy (NAT). We have reported Area of Residual Tumor (ART) as a useful pathological assessment method to predict patient outcomes after post NAT resection in various cancer types. The aim of this study was to assess the prognostic performance of ART in PDAC resected after NAT. Sixty-three patients with PDAC after post NAT resection were analyzed. The viable residual tumor area was outlined and the measurement of ART was performed using morphometric software. The results were compared with those of the College of American Pathologist (CAP) regression grading. Of 63 cases, 39 (62%) patients received chemoradiation therapy and 24 (38%) received chemotherapy only. The median value of ART was 163 mm2. Large ART with 220 mm2 as the cut-off was significantly associated with lymphatic invasion, vascular invasion and perineural invasion, while CAP regression grading was not associated with any clinicopathological features. By multivariate analysis, large ART (≥220 mm2) was an independent predictor of shorter relapse free survival. Together with our previous reports, an ART-based pathological assessment may become a useful method to predict patient outcomes after post NAT resection across various cancer types.

Predicting pathological complete response by comparing MRI-based radiomics pre- and postneoadjuvant radiotherapy for locally advanced rectal cancer

BACKGROUND

Total mesorectal excision following neoadjuvant chemoradiotherapy (nCRT) is recommended in the latest treatment of locally advanced rectal cancer (LARC).

OBJECTIVE

To predict whether patients with LARC can achieve pathologic complete response (pCR), comparing MRI-based radiomics between before and after neoadjuvant radiotherapy (nRT) was performed.

METHODS

One hundred and sixty-five MRI-based radiomics features in axial T2-weighted images were obtained quantitatively from Imaging Biomarker Explorer Software. The specific features of conventional and developing radiomics were selected with the analysis of least absolute shrinkage and selection operator logistic regression, of which the predictive performance was analyzed with receiver operating curve and calibration curve, and applied to an independent cohort.

RESULTS

One hundred and thirty-one target patients were enrolled in the present study. A radiomics signature founded on seven radiomics features was generated in the primary cohort. A remarkable difference about Rad-score between pCR and non-pCR group occurred in both of primary (P < .001) or validation cohorts (P < .001). The value of area under the curves was 0.92 (95% CI, 0.86-0.99) and 0.87 (95% CI, 0.74-1.00) in the primary and validation cohorts, respectively. The Rad-score (OR = 23.581; P < .001) from multivariate logistic regression analysis was significant as an independent factor of pCR.

CONCLUSION

Our predictive model based on radiomics features was an independent predictor for pCR in LARC and could be a candidate in clinical practice.

Histopathological growth patterns of colorectal liver metastasis exhibit little heterogeneity and can be determined with a high diagnostic accuracy

Colorectal liver metastases (CRLM) exhibit distinct histopathological growth patterns (HGPs) that are indicative of prognosis following surgical treatment. This study aims to assess the reliability and replicability of this histological biomarker. Within and between metastasis HGP concordance was analysed in patients who underwent surgery for CRLM. An independent cohort was used for external validation. Within metastasis concordance was assessed in CRLM with ≥ 2 tissue blocks. Similarly, concordance amongst multiple metastases was determined in patients with ≥ 2 resected CRLM. Diagnostic accuracy [expressed in area under the curve (AUC)] was compared by number of blocks and number of metastases scored. Interobserver agreement (Cohen’s k) compared to the gold standard was determined for a pathologist and a PhD candidate without experience in HGP assessment after one and two training sessions. Both the within (95%, n = 825) and the between metastasis (90%, n = 363) HGP concordance was high. These results could be replicated in the external validation cohort with a within and between metastasis concordance of 97% and 94%, respectively. Diagnostic accuracy improved when scoring 2 versus 1 blocks(s) or CRLM (AUC = 95.9 vs. 97.7 [p = 0.039] and AUC = 96.5 vs. 93.3 [p = 0.026], respectively), but not when scoring 3 versus 2 blocks or CRLM (both p > 0.2). After two training sessions the interobserver agreement for both the pathologist and the PhD candidate were excellent (k = 0.953 and k = 0.951, respectively). The histopathological growth patterns of colorectal liver metastasis exhibit little heterogeneity and can be determined with a high diagnostic accuracy, making them a reliable and replicable histological biomarker.

Is the Pathologic Response of T3 Rectal Cancer to High-Dose-Rate Endorectal Brachytherapy Comparable to External Beam Radiotherapy?

BACKGROUND

Endorectal brachytherapy is an attractive option in the neoadjuvant setting for locally advanced rectal cancer, but it is not considered standard of care.

OBJECTIVE

This study aimed to compare pathologic outcomes of patients with clinical T3 rectal cancer who underwent high-dose-rate endorectal brachytherapy with those who underwent conventional external beam radiotherapy.

DESIGN

This study is a retrospective chart review.

SETTINGS

This study was conducted in a single large tertiary academic colorectal surgery practice in Canada.

PATIENTS

Adult patients with MRI-staged T3 rectal adenocarcinoma treated with neoadjuvant radiotherapy followed by total mesorectal excision from 2007 to 2016 were included.

INTERVENTIONS

Neoadjuvant radiotherapy was delivered by high-dose-rate endorectal brachytherapy or conventional external beam radiotherapy.

MAIN OUTCOME MEASURES

Primary outcome was pathologic complete response, defined as ypT0N0. Secondary outcomes included tumor (T stage) and lymph node (N stage) downstaging and tumor regression grade.

RESULTS

Ninety-nine patients were identified as having clinical T3 rectal cancer based on blinded pretreatment MRI review. Mean age was 66.2 years (± 6.2) and 59 patients (59.6%) were male. Thirty-three patients were clinically node negative (33.3%), 45 had c-N1 disease (45.5%), and 21 had c-N2 disease (21.2%). Sixty-four patients (64.6%) underwent high-dose-rate endorectal brachytherapy and 35 (35.4%) underwent external beam radiotherapy. The high-dose-rate endorectal brachytherapy group had a lower median mesorectal depth of invasion (4 mm vs 5 mm, p = 0.010); all other preoperative tumor characteristics were similar in both groups. Eighteen patients (18.2%) achieved pathologic complete response: 12 in the high-dose-rate endorectal brachytherapy group and 6 in the conventional external beam radiotherapy group (18.8% vs 17.1%, p = 0.84). High-dose-rate endorectal brachytherapy was superior to conventional radiotherapy for tumor (T stage) downstaging (59.4% vs 28.6%, p = 0.0030) but not for lymph node (N stage) downstaging (35.9% vs 51.4%, p = 0.14).

LIMITATIONS

This study was limited by its retrospective nature and modest sample size.

CONCLUSIONS

Neoadjuvant treatment of T3 rectal cancer with high-dose-rate endorectal brachytherapy appears to achieve equivalent rates of pathologic complete response and superior T-stage downstaging compared with conventional external beam radiotherapy. See Video Abstract at http://links.lww.com/DCR/A905.

Neoadjuvant chemoradiation and rectal cancer

Neoadjuvant chemoradiation (NACR) is now standard of care in stage II and III rectal cancer. The advent of this modality of treatment has impacted on the way the pathological evaluation of resection specimens that have been subjected to preoperative chemoradiation is conducted. The gross description, sectioning and microscopic examination have had to be adapted to accommodate the changes induced by NACR. Attempts at introducing a uniform approach to the gross triaging and reporting of these specimens have been met with muted response. There still exists much variation in approach. The purpose of this overview is to highlight some of the newer developments and issues around NACR-treated rectal cancers from a pathological point of view. The NACR-treated resection specimens should be handled in a consistent manner, at least within individual institutions, if not universally. There should be generous sampling with multiple sections taken as tumour is often sequestered deep in the bowel wall. Microscopic examination should be extra vigilant as residual cancer can be present as single cells or small clusters, often deep in the muscularis propria or serosa. Acellular pools of mucin or non-viable tumour cells in mucin within the bowel wall or lymph nodes are not regarded as positive and do not upstage the tumour. The issue of grading of regression has been the subject of much debate, and several approaches have been published. It is recommended that a system that has clinical meaning and use to oncologists be used. Lymph node counts will be reduced after NACR, but reasonable attempts to accrue 12 nodes should be made.

Tumor regression grade as a clinically useful outcome predictor in patients with rectal cancer after preoperative chemoradiotherapy

BACKGROUND

The prognostic role of tumor regression grade is not clear. This study evaluated the prognostic significance of tumor regression grade in patients with rectal cancer after preoperative chemoradiotherapy.

METHODS

A total of 639 patients with confirmed rectal cancer who had undergone preoperative chemoradiotherapy and radical resection during the period October 2002 through December 2011 were included in this study. The tumor regression grade was graded: TRG0 (complete response), TRG1 (moderate), TRG2 (minimal), and TRG3 (poor). The prognostic significance of tumor regression grade was evaluated.

RESULTS

With a median follow-up of 56.7 months, the rates of 5-year overall survival, disease-free survival, and local recurrence-free survival among the TRG groups differed significantly (all P < .001). For patients with TRG0, TRG1, and TRG2-3, disease-free survivals were different between the ypStage (P < .001, P < .001, and P = .043). Multivariate analysis revealed findings to substantiate that the tumor regression grade represents a valuable and independent prognostic factor for long-term, disease-free survival (P = .041). Independent predictors of TRG2-3 consisted of lymphovascular invasion, tumor budding, and the pretreatment serum level of carcinoembryonic antigen in multivariate regression analysis. Clinical risk grouping, using 3 predictors for TRG2-3 was different (P < .001).

CONCLUSION

The tumor regression grade may represent a useful prognostic variable to better individualize the prognosis and potentially further therapy for each rectal cancer patient who underwent chemoradiotherapy.

Impact of Tumor Regression Grade as a Major Prognostic Factor in Locally Advanced Rectal Cancer after Neoadjuvant Chemoradiotherapy: A Proposal for a Modified Staging System

There is ongoing debate regarding the significance of complete or near-complete response after neoadjuvant chemoradiotherapy (CRT) for rectal cancer. This study assessed the prognostic value of the Dworak tumor regression grade (TRG) following neoadjuvant CRT and surgery primarily in patients with pathological stage (ypStage) II and III rectal cancer. The records of 331 patients who underwent neoadjuvant CRT followed by total mesorectal excision between 2004 and 2015 were retrospectively reviewed. Patients were categorized as having a good response (GR, TRG 3/4, n = 122) or a poor response (PR, TRG 1/2, n = 209). At a median follow-up of 65 months, five-year disease-free survival (DFS) was higher in the GR group than in the PR group (91.3% vs. 66.6%, p < 0.001). Patients with a GR and ypStage II disease had a five-year DFS that was indistinguishable from that of patients with ypStage 0–I disease (92.3% vs. 90.7%, p = 0.885). Likewise, patients with a GR and ypStage III disease had a five-year DFS similar to those with ypStage II disease (76.0% vs. 75.9%, p = 0.789). A new modified staging system that incorporates grouped TRG (GR vs. PR) was developed. The prognostic performance of this modified stage and the ypStage was compared with the Harrell C statistic. C statistic of the modified stage was higher than that of the ypStage (0.784 vs. 0.757, p = 0.012). The results remained robust after multivariate Cox regression analyses. In conclusion, a GR to neoadjuvant CRT is an independent predictor of good DFS and overall survival and further stratifies patients so as to estimate the risk of recurrence and survival among patients with ypStage II and III rectal cancer.

Pathology assessment of pancreatic cancer following neoadjuvant treatment: Time to move on

Neoadjuvant treatment has increasingly become an integral part of the multimodal management of patients with pancreatic cancer. In patients who are able to undergo surgery following preoperative therapy, tumour regression grading remains the diagnostic gold standard for the histomorphological assessment of the effect of neoadjuvant treatment. In recent years, however, there has been growing concern about inherent flaws of tumour regression grading systems as well as their imprecise and impractical criteria that result in divergence of practice and lack of interobserver agreement. Furthermore, existing tumour regression systems differ in their defining criteria and thresholds, leading to incomparability of data. In this review, the principles and limitations of the main existing tumour regression systems are discussed, and potential alternative assessment approaches and novel markers are presented.

Pathologic assessment of gastrointestinal tract and pancreatic carcinoma after neoadjuvant therapy

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

Comparison between MRI and pathology in the assessment of tumour regression grade in rectal cancer

Background:

Limited data exist regarding the correlation between MRI tumour regression grade (mrTRG) and pathological TRG (pTRG) in rectal cancer.

Methods:

mrTRG and pTRG were compared in rectal cancer patients from two phase II trials (EXPERT and EXPERT-C). The agreement between radiologist and pathologist was assessed with the weighted κ test while the Kaplan–Meier method was used to estimate survival outcomes.

Results:

One hundred ninety-one patients were included. Median time from completion of neoadjuvant treatment to pre-operative MRI and surgery was 4.1 weeks (interquartile range (IQR): 3.7–4.7) and 6.6 weeks (IQR: 5.9–7.6), respectively. Fair agreement was found between mrTRG and pTRG when regression was classified according to standard five-tier systems (κ=0.24) or modified three-tier systems (κ=0.25). Sensitivity and specificity of mrTRG 1–2 (complete/good radiological regression) for the prediction of pathological complete response was 74.4% (95% CI: 58.8–86.5) and 62.8% (95% CI: 54.5–70.6), respectively. Survival outcomes of patients with intermediate pathological regression (pTRG 2) were numerically better if complete/good regression was also observed on imaging (mrTRG 1–2) compared to poor regression (mrTRG 3–5) (5-year recurrence-free survival 76.9% vs 65.9%, P=0.18; 5-year overall survival 80.6% vs 68.8%, P=0.22).

Conclusions:

The agreement between mrTRG and pTRG is low and mrTRG cannot be used as a surrogate of pTRG. Further studies are warranted to assess the ability of mrTRG to identify pathological complete responders for the adoption of non-operative management strategies and to provide complementary prognostic information to pTRG for better risk-stratification after surgery.

Tumor regression grading of gastrointestinal cancers after neoadjuvant therapy

Neoadjuvant therapy has been successfully introduced in the treatment of locally advanced gastrointestinal malignancies, particularly esophageal, gastric, and rectal cancers. The effects of preoperative chemo- or radiochemotherapy can be determined by histopathological investigation of the resection specimen following this treatment. Frequent histological findings after neoadjuvant therapy include various amounts of residual tumor, inflammation, resorptive changes with infiltrates of foamy histiocytes, foreign body reactions, and scarry fibrosis. Several tumor regression grading (TRG) systems, which aim to categorize the amount of regressive changes after cytotoxic treatment in primary tumor sites, have been proposed for gastroesophageal and rectal carcinomas. These systems primarily refer to the amount of therapy-induced fibrosis in relation to the residual tumor (e.g., the Mandard, Dworak, or AJCC systems) or the estimated percentage of residual tumor in relation to the previous tumor site (e.g., the Becker, Rödel, or Rectal Cancer Regression Grading systems). TRGs provide valuable prognostic information, as in most cases, complete or subtotal tumor regression after neoadjuvant treatment is associated with better patient outcomes. This review describes the typical histopathological findings after neoadjuvant treatment, discusses the most commonly used TRG systems for gastroesophageal and rectal carcinomas, addresses the limitations and critical issues of tumor regression grading in these tumors, and describes the clinical impact of TRG.

Tumor Regression Grade After Neoadjuvant Chemoradiation and Surgery for Low Rectal Cancer Evaluated by Multiple Correspondence Analysis: Ten Years as Minimum Follow-up

BACKGROUND

The role of Mandard's tumor regression grade (TRG) classification is still controversial in defining the prognostic role of patients who have undergone neoadjuvant chemoradiation (CRT) and total mesorectal excision. The present study evaluated multiple correspondence analysis (MCA) as a tool to better cluster variables, including TRG, for a homogeneous prognosis.

PATIENTS AND METHODS

A total of 174 patients with a minimum follow-up period of 10 years were stratified into 2 groups: group A (TRG 1-3) and group B (TRG 4-5) using Mandard's classification. Overall survival and disease-free survival were analyzed using univariate and multivariate analysis. Subsequently, MCA was used to analyze TRG plus the other prognostic variables.

RESULTS

The overall response to CRT was 55.7%, including 13.2% with a pathologic complete response. TRG group A correlated strictly with pN status (P = .0001) and had better overall and disease-free survival than group B (85.1% and 75.6% vs. 71.1% and 67.3%; P = .06 and P = .04, respectively). The TRG 3 subset (about one third of our series) showed prognostically heterogeneous behavior. In addition to multivariate analysis, MCA separated TRG 1 and TRG 2 versus TRG 4 and TRG 5 well and also allocated TRG 3 patients close to the unfavorable prognostic variables.

CONCLUSION

TRG classification should be used in all pathologic reports after neoadjuvant CRT and radical surgery to enrich the prognostic profile of patients with an intermediate risk of relapse and to identify patients eligible for more conservative treatment. Thus, MCA could provide added value.

Applicability of American Joint Committee on Cancer and College of American Pathologists Regression Grading System in Rectal Cancer

BACKGROUND

Different tumor grading systems have been proposed to predict the association between tumor response and clinical outcome after preoperative chemoradiotherapy in patients with rectal cancer. The American Joint Committee on Cancer and College of American Pathologists regression grading system was recommended as the standard tumor regression grading system for rectal adenocarcinoma.

OBJECTIVE

This study evaluated the clinical applicability of the American Joint Committee on Cancer and College of American Pathologists regression grading system in neoadjuvant-treated patients with rectal cancer.

DESIGN

This is a retrospective cohort study based on clinical data from a prospectively maintained colorectal cancer database.

SETTINGS

This study was performed at a single tertiary referral center.

PATIENTS

A total of 144 patients with primary locally advanced mid-to-low rectal adenocarcinoma who underwent preoperative long-course chemoradiotherapy and total mesorectal excision between 2003 and 2012 were included.

MAIN OUTCOMES MEASURES

The primary outcome measures were the 5-year overall survival rate, the relapse-free survival rate, the cancer-specific survival rate, and cumulative recurrence rates.

RESULTS

Of the 144 patients, 16 (11%) were diagnosed as American Joint Committee on Cancer and College of American Pathologists regression grade 0, 43 patients (30%) as grade 1, 61 patients (42%) as grade 2, and 25 patients (17%) as grade 3.After a median follow-up time of 83 months (range, 3 to 147 mo), 5-year survival estimates for grades 0, 1, 2, and 3, were 93%, 77%, 81%, and 54% for overall survival (p = 0.006); 93%, 82%, 75%, and 55% for relapse-free survival (p = 0.03); and 100%, 86%, 89%, and 63% for cancer-specific survival (p = 0.006). The multivariate Cox regression analyses confirmed the American Joint Committee on Cancer and College of American Pathologists regression grading system as a prognostic factor for overall (p = 0.04), relapse-free (p = 0.02), and cancer-specific survival (p = 0.04).

LIMITATIONS

This was a retrospective study.

CONCLUSIONS

Our study findings confirm the clinical relevance and applicability of the American Joint Committee on Cancer and College of American Pathologists regression grade system as a predictive factor for patients with rectal cancer. See Video Abstract at http://links.lww.com/DCR/A320.

Delayed versus immediate surgery following short-course neoadjuvant radiotherapy in resectable (T3N0/N+) rectal cancer

PURPOSE

Preoperative short-course radiotherapy (SCRT) followed by surgery has shown advantage over surgery alone in patients with resectable rectal carcinoma (RC); however, the importance of the timing of surgery after SCRT has not been well defined. This study aimed to investigate the effect of this duration on treatment outcomes.

METHODS

Patients who underwent surgery after SCRT (25 Gy/500 cGy/daily/5fr, monday-friday) for resectable and infraperitoneal rectal adenocarcinoma (T3N0/(+)) were included into the study. Patients were divided into two groups in terms of the timing of surgery: delayed surgery (>4 weeks) or immediate surgery (<4 weeks).

RESULTS

A hundred and thirty-six patients were included in the study. Median time between RT and surgery was 4 ± 5.7 (1-58) weeks, where 68% (n = 93) patients underwent delayed surgery (≥4 weeks). The two groups did not differ in terms of surgical margin positivity, pathological tumor regression, N downstaging, or T downstaging (p > 0.05 for all). However, the number of positive lymph nodes was higher in the immediate surgery group [median 3 (0-18) vs. 1 (0-17), p = 0.009]. Median follow-up time was 36 ± 9 (6-93) months. Delayed surgery group had significantly longer mean overall survival (p = 0.038); however, the two groups did not differ in terms of local recurrence, mean time to local recurrence, or mean disease-free survival.

CONCLUSIONS

Our findings seem to support the benefit of a longer time interval between radiotherapy and surgery after short-course neoadjuvant radiotherapy in resectable rectal cancer in terms of overall survival. However, there is a need to better define patient characteristics that might benefit from delayed surgery.

External validation of chemotherapy response score system for histopathological assessment of tumor regression after neoadjuvant chemotherapy in tubo-ovarian high-grade serous carcinoma

Objective

The chemotherapy response score (CRS) system based on histopathological examination has been recently proposed for tubo-ovarian high-grade serous carcinoma (HGSC) to assess response to neoadjuvant chemotherapy (NAC). This study was aimed at validating the CRS system in an external cohort of tubo-ovarian HGSC patients.

Methods

This study included 110 tubo-ovarian HGSC patients who underwent NAC followed by interval debulking surgery. The 3-tiered CRS of the omental and adnexal tissue sections was determined by 3 independent pathologists. Differences in patient outcomes according to CRS were analyzed.

Results

The CRS system was highly reproducible among the 3 pathologists. Fleiss' kappa value and Kendall's coefficient of concordance for the omental CRS were 0.656 and 0.669, respectively. The omental CRS significantly predicted progression-free survival (PFS). The median PFS of patients whose tumors exhibited the omental CRS 1–2 (15 months) was significantly shorter than that of patients with an omental CRS of 3 (19 months; p=0.016). In addition, after adjusting for age, stage, and debulking status, the omental CRS was an independent prognostic factor for PFS of tubo-ovarian HGSC patients who were treated with NAC (adjusted hazard ratio [HR]=1.74; 95% confidence interval [CI]=1.05–2.87).

Conclusion

The CRS system for assessing NAC response was a reproducible prognostic tool in our cohort. The application of the CRS system after NAC can improve survival estimation in HGSC patients.

Do pathological variables have prognostic significance in rectal adenocarcinoma treated with neoadjuvant chemoradiotherapy and surgery?

AIM

To clarify which factors may influence pathological tumor response and affect clinical outcomes in patients with locally advanced rectal carcinoma treated with neo-adjuvant chemoradiotherapy and surgery.

METHODS

Tumor regression grade (TRG) according to the Dworak system and yTNM stage were assessed and correlated with pre-treatment clinico-pathological variables in 215 clinically locally advanced (cTNM stage II and III) rectal carcinomas. Prognostic value of all pathological and clinical factors on disease free survival (DFS) and cancer specific survival (CSS) was analyzed by Kaplan Meier and Cox-regression analyses.

RESULTS

cN+ status, mucinous histotype or poor differentiation in the pre-treatment biopsy were significantly associated with lower pathological response (low Dworak grade and TNM remaining unchanged/upstaging). Cases showing acellular mucin pools in surgical specimens all had unremarkable clinical courses with no deaths or recurrences during follow-up. Dworak grade had prognostic significance for DFS and CSS. However, compared to the 5-tiered system, a simplified two-tiered grading system, in which grades 0, 1 and 2 were grouped as absent/partial regression and grades 3 and 4 were grouped as total/subtotal regression, was more reproducible and prognostically informative. The two-tiered Dworak system, yN stage, craniocaudal extension of the tumor and radial margin status were significant independent prognostic variables.

CONCLUSION

Our data suggest that caution should be applied in using a conservative approach in rectal carcinomas with cN+ status, extensive/lower involvement of the rectum and mucinous histotype or poor differentiation. Although Dworak TRG is prognostically significant, a simplified two-tiered system could be preferable. Finally, cases with acellular mucin pools should be carefully evaluated to definitely exclude residual mucinous carcinoma.