Objective assessment of tumor regression in post-neoadjuvant therapy resections for pancreatic ductal adenocarcinoma: comparison of multiple tumor regression grading systems

Rethinking tumor viability as prognostic factor in soft tissue sarcoma

Background

Histopathologic assessment of tumor viability has emerged as a potential predictive factor of outcomes in various cancers. This study evaluates the prognostic significance of viability in high-grade soft tissue sarcoma while accounting for different adjuvant regimens and clinical variables.

Methods

A retrospective chart review was conducted on 147 patients surgically treated for high-grade soft tissue sarcoma between 2010 and 2021 at a single institution. Perioperative, clinical and surveillance data were collected. Tumor viability was determined through histopathologic analysis by a board-certified pathologist.

Results

No significant differences in clinical variables were observed between groups with ≤10 % and >10 % tumor viability. Neoadjuvant treatments, tumor grade, size, and depth did not independently affect tumor viability. There was no statistically decreased risk of local recurrence in the group with ≤10 % viability compared to the group with >10 % viability (HR = 1.19, 95 % CI [0.57,2.50]) (p = 0.64). Margin status was the only variable that significantly increases the risk of LR on multivariate analysis.

Conclusion

This cohort suggests that neoadjuvant radiotherapy, chemotherapy, or their combination did not influence tumor viability predictably. Notably, tumors without neoadjuvant treatment exhibited a high rate of necrosis, potentially confounding the interpretation of treatment effect. Other factors such as tumor type may play a more significant role in the cause of tumor necrosis than originally thought. Pathologic tissue response continues to offer value for the management of STS, but these findings underscore the need for further investigation into tumor viability in soft tissue sarcoma, targeting specific treatments analyzed in large collaborative studies.

HIF-1α expression is associated with the pathological response to neoadjuvant chemotherapy in pancreatic ductal adenocarcinoma patients and can be predicted using CECT features

Background

Hypoxia-inducible factor-1-alpha (HIF-1α) has the potential to predict the neoadjuvant chemotherapy (NAC) response in pancreatic ductal adenocarcinoma (PDAC). This study aimed to assess the relationship between the pathological response and intratumoral HIF-1α expression in patients with PDAC receiving NAC, and investigate the predictive value of contrast-enhanced computed tomography (CECT) features in HIF-1α expression.

Methods

A total of 58 patients from three centers with pathologically confirmed PDAC who underwent NAC followed by surgery were retrospectively enrolled in this study. Immunohistochemistry was performed to detect intratumoral HIF-1α expression. The Chi-square test was used to evaluate the differences in intratumoral HIF-1α expression in PDAC responders and non-responders after NAC. Binary logistic regression and receiver operating characteristic (ROC) curves were used to determine the optimal correlation factors of different pathological responses in PDAC patients after NAC and to predict these factors using CECT features.

Results

Among the PDAC patients, 27 (46.55%) responders and 31 (53.45%) non-responders were identified via histopathological examination. Nuclear and cytoplasmic HIF-1α expression was significantly higher in the responders than the non-responders (P<0.001, P=0.036). However, HIF-1α expression in the stroma was not statistically significant (P=0.864). The multivariate logistic regression revealed that the %Δ carbohydrate antigen 19-9 (CA19-9), tumor differentiation, and nuclear HIF-1α were independent predictors of different pathological responses [odds ratio (OR) =9.005, P=0.037; OR =0.005, P=0.044; OR =0.352, P=0.018, respectively]. The ROC curve showed that nuclear HIF-1α expression was the optimal associated predictor of the pathologic response (area under the curve =0.873, 95% confidence interval: 0.782-0.964). The multivariate logistic regression also showed that of the CECT characteristics, the (post-NAC - pre-NAC) arterial phase (AP) was an independent predictive indicator of nuclear HIF-1α expression (OR =1.012, P=0.020).

Conclusions

Nuclear HIF-1α was the best predictor of the pathological response in patients with PDAC after NAC, and it can be predicted using CT feature of the (post-NAC - pre-NAC) AP.

Locally Advanced Pancreas Cancer, Is There a Role for Surgery?

Locally advanced pancreatic cancer (LAPC) represents a unique clinical scenario in which the tumor is considered localized but unresectable due to anatomic factors. Despite a consensus against upfront surgery, no standard approach to induction therapy exists for patients with LAPC. Extended systemic therapy has shown promise in establishing tumor response and remains the standard of care. While associated with improved local control, the timing and role of radiation therapy remain in question. Following adequate response to induction chemotherapy, a safe attempt at margin-negative resection can be considered. Special attention should be given to required vascular skeletonization and/or resection with reconstruction.

Feasibility of major hepatectomy following preoperative chemotherapy for advanced perihilar cholangiocarcinoma

BACKGROUND

The safety of major hepatectomy following preoperative chemotherapy for perihilar cholangiocarcinoma (PHCC) is underexplored. This study evaluates the impact of preoperative chemotherapy on surgical outcomes and assesses chemotherapy-induced liver injury in patients with advanced PHCC.

METHODS

This retrospective study included 62 PHCC patients who underwent surgery between January 2019 and January 2024. Patients were divided into an upfront surgery group (UFS, n = 31) and a preoperative chemotherapy group (POC, n = 31). Preoperative chemotherapy was indicated when R0/R1 resection was unachievable, complex surgery was needed, or future liver reserve was insufficient. Baseline characteristics, surgical procedures, postoperative complications, and pathological findings were compared.

RESULTS

Postoperative complications were comparable between groups, with Clavien-Dindo grade ≥3a rates of 30.7 % in the POC group and 24.3 % in the UFS group. Despite longer operative times and hospital stays in the POC group, no significant differences in hepatotoxicity or pathological findings, including Kleiner and Rubbia-Brandt scores, were observed. Notably, a pathological complete response was achieved in 12.9 % of the POC group.

CONCLUSION

Major hepatectomy following preoperative chemotherapy for PHCC is safe and does not increase the risk of postoperative complications or hepatotoxicity. Further studies are warranted to refine resectability criteria and optimize patient selection.

Maintenance Therapy for Pancreatic Cancer, a New Approach Based on the Synergy between the Novel Agent GP-2250 (Misetionamide) and Gemcitabine

The novel Oxathiazinane derivative GP-2250 (Misetionamide) displays antineoplastic activity in vitro and in vivo, as previously shown in pancreatic cancer cells and in patient-derived mouse xenografts (PDX). Currently, GP 2250 is under phase I clinical trial in pancreatic ductal adenocarcinoma (PDAC). GP-2250 in combination with Gemcitabine displays a high synergistic capacity in various primary and established pancreatic cancer cell lines. Additionally, in the eight PDX models tested, the drug combination was superior in reducing tumor volume with an aggregate tumor regression (ATR) of 74% compared to Gemcitabine alone (ATR: 10%). Similarly, in a PDX maintenance setting following two weeks of treatment with nab-Paclitaxel plus Gemcitabine, the combination of GP-2250 plus Gemcitabine resulted in outstanding tumor control (ATR: 79%) compared to treatment with Gemcitabine alone (ATR: 19%). Furthermore, GP-2250 reduced the ratio of tumor-initiating CD133+ markers on the surface of PDAC cells in spheroid cultures, indicating a possible mechanism for the synergistic effect of both substances. Considering the high tolerability of GP 2250, these results may open up a new approach to maintenance therapy with GP-2250/Gemcitabine combination following nab-Paclitaxel plus Gemcitabine as first-line treatment.

The benefit of adjuvant chemotherapy following pancreaticoduodenectomy for pancreatic adenocarcinoma depends on response to neoadjuvant therapy

BACKGROUND

The benefit of adjuvant therapy (AT) remains unclear in pancreatic ductal adenocarcinoma (PDAC) after neoadjuvant therapy (NAT) and surgical resection.

METHODS

The 2019 National Cancer Database was queried for patients with non-metastatic PDAC who received NAT followed by pancreaticoduodenectomy. Only patients with data regarding receipt of AT were included. Patients were classified if they had nodal down-staging specifically, or any downstaging (Tumor, Nodal, or overall). Propensity score matching (PSM) adjusted for pretreatment covariate imbalance between groups. The weighted Kaplan-Meier method and log-rank test were used to estimate the cumulative survival.

RESULTS

After exclusion criteria and PSM, a total of 2784 patients remained; 1689 (60.7%) received AT and 1095 (39.3%) did not receive AT. Among all, those with additional AT had a significantly improved overall survival (OS) (p < 0.001). Upon evaluation of patients without downstaging after NAT, those who received AT had improved OS (no nodal downstaging or any downstaging; p = 0.002; p = 0.001). When evaluating patients with downstaging after NAT, those receiving AT did not have improved OS (nodal downstaging or any downstaging: p = 0.352; p = 0.99).

CONCLUSION

Response to NAT appears to correlate with the benefit of AT following pancreaticoduodenectomy; patients who have a favorable response to NAT may not benefit from AT.

Identification of tumour regression in neoadjuvantly treated pancreatic cancer is based on divergent and nonspecific criteria

AIMS

Following the increased use of neoadjuvant therapy for pancreatic cancer, grading of tumour regression (TR) has become part of routine diagnostics. However, it suffers from marked interobserver variation, which is mainly ascribed to the subjectivity of the defining criteria of the categories in TR grading systems. We hypothesized that a further cause for the interobserver variation is the use of divergent and nonspecific morphological criteria to identify tumour regression.

METHODS AND RESULTS

Twenty treatment-naïve pancreatic cancers and 20 pancreatic cancers treated with neoadjuvant chemotherapy were reviewed by three experienced pancreatic pathologists who, blinded for treatment status, categorized each tumour as treatment-naïve or neoadjuvantly treated, and annotated all tissue areas they considered showing tumour regression. Only 50%-65% of the cases were categorized correctly, and the annotated tissue areas were highly discrepant (only 3%-41% overlap). When the prevalence of various morphological features deemed to indicate TR was compared between treatment-naïve and neoadjuvantly treated tumours, only one pattern, characterized by reduced cancer cell density and prominent stroma affecting a large area of the tumour bed, occurred significantly more frequently, but not exclusively, in the neoadjuvantly treated group. Finally, stromal features, both morphological and biological, were investigated as possible markers for tumour regression, but failed to distinguish TR from native tumour stroma.

CONCLUSION

There is considerable divergence in opinion between pathologists when it comes to the identification of tumour regression. Reliable identification of TR is only possible if it is extensive, while lesser degrees of treatment effect cannot be recognized with certainty.

Microscopic tumor mapping of post-neoadjuvant therapy pancreatic cancer specimens to predict post-surgical recurrence: A prospective cohort study

BACKGROUND

Although various pathological grading systems are available for evaluating the response of pancreatic ductal adenocarcinoma (PDAC) to neoadjuvant therapy (NAT), their prognostic value has not been thoroughly validated. This study examined whether microscopic tumor mapping of post-NAT specimens could predict tumor recurrence.

METHODS

This prospective study enrolled 52 patients who underwent pancreaticoduodenectomy after NAT for PDAC between 2019 and 2021. Microscopic mapping was performed to identify residual tumor loci within the tumor bed using 4 mm2 pixels. Patients were divided into small extent (SE; n = 26) and large extent (LE; n = 26) groups using a cutoff value of 226 mm2. The diagnostic performance for predicting tumor recurrence was evaluated using receiver operating characteristic (ROC) curves.

RESULTS

Carbohydrate antigen 19-9 levels were normalised after NAT in more patients in the SE group (SE 21 [80.8%] vs. LE 13 [50.0%]; P = 0.041). Tumor size (P < 0.001), T stage (P < 0.001), positive lymph node yield (P = 0.024), and perineural invasion rate (P = 0.018) were significantly greater in the LE group. The 3-year disease-free survival rate was significantly lower in the LE group (SE 83.3% vs. LE 50.0%, P = 0.004). The area under the ROC curve for mapping extent was 0.743, which was greater than that of the other tumor response scoring systems.

CONCLUSIONS

Microscopic tumor mapping of the residual tumor in post-NAT specimens is a significant predictor of post-surgical recurrence, and offers better prognostic performance than the current grading systems.

Evidence for molecular subtyping in pancreatic ductal adenocarcinoma: a systematic review

BACKGROUND

Pancreatic Ductal Adenocarcinoma (PDAC) patients exhibit varied responses to multimodal therapy. RNA gene sequencing has unravelled distinct tumour biology subtypes, forming the focus of this review exploring its impact on survival outcomes.

METHODS

A systematic search across PubMed, Medline, Embase, and CINAHL databases targeted studies assessing long-term overall and disease-free survival in PDAC patients with molecular subtyping.

RESULTS

Fifteen studies including 2731 patients were identified. Molecular subtyping was performed by RNA sequencing and Immunohistochemistry in 14 studies and by Mass Spectrometry in 1 study. Two main tumour subtypes were identified (classical and basal-like or squamous) with basal like associated with poorer outcomes. Further subtypes were identified in individual studies. Superior survival was seen with classical subtype in all other analyses that compared the classical and basal subtypes. High risk stromal subtypes were identified on further analysis of the stroma and were associated with a worse survival independent of the tumour subtype.

CONCLUSION

Molecular subtyping of PDAC specimens can identify patients with high-risk tumour biology and poor survival outcomes. Routine subtyping is limited by the cost of RNA sequencing and the volume of raw data generated which has made its translation into routine clinical practice difficult.

Immature stroma and high infiltration of CD15+ cells are predictive markers of poor prognosis in different subsets of patients with pancreatic cancer

Preoperative treatment is commonly carried out for borderline resectable pancreatic ductal adenocarcinoma (PDAC). However, the relationship between the combination of immune cells in the tumor microenvironment and their intratumoral heterogeneity along with their association with histological findings remains unclear, especially in patients receiving preoperative chemotherapy. We aimed to explore the therapeutic strategies for patients with PDAC with poor prognosis after receiving chemotherapy based on histological and immunological microenvironmental classifications. We investigated the correlation between the prognosis and histological immune microenvironmental factors of patients who initially underwent surgery (n = 100) and were receiving gemcitabine plus nab-paclitaxel (GEM + nabPTX) as preoperative chemotherapy (n = 103). Immune profiles were generated based on immune cell infiltration into the tumor, and their correlation with patient outcomes and histological features was analyzed. Tumor-infiltrating neutrophils (TINs) were identified as independent poor prognostic factors using multivariate analysis in both surgery-first and preoperative chemotherapy groups. The patients were further classified into four groups based on immune cell infiltration into the tumor. Patients with high CD15 infiltration into the tumor and immature stroma at the cancer margins showed the worst prognosis in the preoperative chemotherapy group. The analysis of mRNA expression and immunohistochemical features revealed that CXCR2, the receptor for CXCL8, was correlated with disease-free and overall survival. We inferred that patients with immature stroma at the margins and high infiltration of CD15+ neutrophils within the tumor showed the worst prognosis and they could particularly benefit from treatment with inhibitors targeting CXCR2 or CXCL8.

[Histopathologic diagnosis of solid and cystic pancreatic lesions with a focus on ductal adenocarcinoma : A vademecum for daily practice]

Pancreas pathology is constantly evolving and can present various challenges for pathologists. This paper is focused on providing helpful hints for daily routine diagnostics. During histopathological analysis of pancreas biopsies, pancreatic ductal adenocarcinoma must be distinguished not only from other solid neoplasms, but especially from its mimicker, autoimmune pancreatitis. This can be achieved by a systematic workup following clear diagnostic criteria. When analyzing samples from cystic pancreatic lesions, mucin-producing neoplasms must be detected due to their role as pancreatic cancer precursors; molecular analyses can help considerably with their detection and distinction. During frozen section examination, evaluation of the pancreatic neck margin and analysis of unclear lesions of the liver are two important tasks, which are explained further in this article. A special challenge is the evaluation of neoadjuvant treated pancreatic cancer, which requires a detailed macroscopic and microscopic workup. Finally, current advances in precision oncology and emerging approaches for pancreatic cancer within this field are discussed. With the advancement of technical possibilities and their increasingly broad implementation, the classification systems in pancreatic pathology will continue to gain in complexity, but also in accuracy.

Prognostic significance of tumor budding in patients with pancreatic invasive ductal carcinoma who received neoadjuvant therapy

Neoadjuvant therapy is commonly used for invasive pancreatic ductal carcinoma (PDAC). Tumor budding and high podoplanin expression in cancer-associated fibroblasts (CAFs) are prognostic factors in patients with various carcinomas including PDAC who have not received neoadjuvant therapy. In this study, we investigated whether tumor budding and podoplanin-positive CAFs are associated with outcomes in Japanese PDAC patients with neoadjuvant therapy. Histopathological findings of surgically resected PDACs with neoadjuvant therapy from 2005 to 2018 were reviewed (n = 97). With reference to International Tumor Budding Consensus Conference recommendations, tumors were evaluated for budding at 20 × magnification (/0.785 mm2) and at 40 × magnification (/0.237 mm2; mean number of fields: 3) for podoplanin expression in CAFs (%). Overall survival, disease-free survival, and disease-specific survival (DSS) were analyzed using the log-rank test and Cox proportional hazards model. After adjusting for T category, N category, resection margin, and adjuvant therapy, multivariate analyses demonstrated that tumor budding at 40 × magnification was an independent prognostic factor for worse DSS (hazard ratio: 2.41, p = 0.022). Tumor budding at 20 × magnification and podoplanin-positive CAFs tended to be associated with worse DSS; however, these findings were not statistically significant. Our findings indicate that tumor budding is an independent prognostic factor in PDAC patients with neoadjuvant therapy.

Single-organoid analysis reveals clinically relevant treatment-resistant and invasive subclones in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal diseases, characterized by a treatment-resistant and invasive nature. In line with these inherent aggressive characteristics, only a subset of patients shows a clinical response to the standard of care therapies, thereby highlighting the need for a more personalized treatment approach. In this study, we comprehensively unraveled the intra-patient response heterogeneity and intrinsic aggressive nature of PDAC on bulk and single-organoid resolution. We leveraged a fully characterized PDAC organoid panel (N = 8) and matched our artificial intelligence-driven, live-cell organoid image analysis with retrospective clinical patient response. In line with the clinical outcomes, we identified patient-specific sensitivities to the standard of care therapies (gemcitabine-paclitaxel and FOLFIRINOX) using a growth rate-based and normalized drug response metric. Moreover, the single-organoid analysis was able to detect resistant as well as invasive PDAC organoid clones, which was orchestrates on a patient, therapy, drug, concentration and time-specific level. Furthermore, our in vitro organoid analysis indicated a correlation with the matched patient progression-free survival (PFS) compared to the current, conventional drug response readouts. This work not only provides valuable insights on the response complexity in PDAC, but it also highlights the potential applications (extendable to other tumor types) and clinical translatability of our approach in drug discovery and the emerging era of personalized medicine.

Relationships between physical and immunological tumor microenvironment in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is physically palpated as a hard tumor with an unfavorable prognosis. Assessing physical features and their association with pathological features could help to elucidate the mechanism of physical abnormalities in cancer tissues. A total of 93 patients who underwent radical surgery for pancreatic and bile duct cancers at a single center hospital during a 28-month period were recruited for this study that aimed to estimate the stiffness of PDAC tissues compared to the other neoplasms and assess relationships between tumor stiffness and pathological features. Physical alterations and pathological features of PDAC, with or without preoperative therapy, were analyzed. The immunological tumor microenvironment was evaluated using multiplexed fluorescent immunohistochemistry. The stiffness of PDAC correlated with the ratio of Azan-Mallory staining, α-smooth muscle actin, and collagen I-positive areas of the tumors. Densities of CD8+ T cells and CD204+ macrophages were associated with tumor stiffness in cases without preoperative therapy. Pancreatic ductal adenocarcinoma treated with preoperative therapy was softer than that without, and the association between tumor stiffness and immune cell infiltration was not shown after preoperative therapy. We observed the relationship between tumor stiffness and immunological features in human PDAC for the first time. Immune cell densities in the tumor center were smaller in hard tumors than in soft tumors without preoperative therapies. Preoperative therapy could alter physical and immunological aspects, warranting further study. Understanding of the correlations between physical and immunological aspects could lead to the development of new therapies.

Relationship between histopathological therapeutic effect and prognosis in oral cancer patients after preoperative S-1 chemotherapy followed by surgery

OBJECTIVES

Preoperative S-1 chemotherapy is administered to prevent tumor proliferation before surgery in oral squamous cell carcinoma (OSCC). The aim of this study was to investigate the relationship between the histological therapeutic effect and prognosis in patients with OSCC after pre-operative S-1 chemotherapy.

MATERIALS AND METHODS

Among 461 OSCC cases, 281 patients who received preoperative S-1 chemotherapy were compared with 180 patients that did not receive chemotherapy to determine the histological therapeutic effect in the resected specimens and the differences in relapse-free survival.

RESULTS

The histological chemotherapeutic effect was well correlated with the subsequent prognosis. In an examination of the combined effect of treatment and ypStage, the groups with good S-1 treatment effects had extremely good prognoses, even if the postoperative resection specimens were within the same ypStage. In a stratified search of patients who received S-1 for more than 7 days and who had a significantly better prognosis than those who did not receive S-1, it was found that the prognosis was significantly better for patients with tongue cancer according to site; furthermore, tongue cancer, age under 70 years of age, male sex, and clinical stage I were factors associated with a significantly better prognosis.

CONCLUSIONS

Even if the postoperative resection specimens were within the same ypStage, the groups that responded to S-1 treatment were considered to have extremely good prognoses.

CLINICAL RELEVANCE

A good adaptation for S-1 was tongue cancer, and especially tongue cancer with cStage I, male sex, and age less than 70 years old.

The area of residual tumor predicts esophageal squamous cell carcinoma prognosis following neoadjuvant chemotherapy

PURPOSE

To clarify the utility of the area of residual tumor for patients with esophageal squamous cell cancer treated with neoadjuvant chemotherapy.

METHODS

We enrolled 186 patients with esophageal squamous cell cancer who underwent surgical resection following neoadjuvant chemotherapy at our hospital. Using digital images, we measured the area of residual tumor at the maximum plane of the specimen and divided the patient into three groups as follows: 0 (area = 0 mm2), low (area = 0-40 mm2), and high (area ≥ 40 mm2). The clinicopathological factors and prognosis were compared among these groups.

RESULTS

The median area of the residual tumor was 15.0 mm2　(range 0-1,448.8 mm2). Compared with the 0 and low group, the high group was significantly associated with poorer recurrence-free survival (all P < .001) and overall survival (P < .001 [vs. 0] and P = .017 [vs low]). The area of residual tumor, ypN, tumor regression grade, and lymphovascular invasion were independent predictors of recurrence-free survival. By dividing the patients using a combination of the area of residual tumor and lymphovascular invasion, the high and/or lymphovascular invasion ( +) group displayed significantly poor recurrence-free survival than the 0 group and low/lymphovascular invasion ( -) group. However, there was no significant difference in the recurrence-free survival between the 0 group and low/lymphovascular invasion ( -) group.

CONCLUSION

The area of residual tumor is a promising histopathological prognostic factor for patients with esophageal squamous cell cancer treated with neoadjuvant chemotherapy. Moreover, it is a possible candidate histopathological factor for postoperative chemotherapy selection.

Phosphoproteomics guides effective low-dose drug combinations against pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is a devastating disease with a limited set of known driver mutations but considerable cancer cell heterogeneity. Phosphoproteomics provides a readout of aberrant signaling and has the potential to identify new targets and guide treatment decisions. Using two-step sequential phosphopeptide enrichment, we generate a comprehensive phosphoproteome and proteome of nine PDAC cell lines, encompassing more than 20,000 phosphosites on 5,763 phospho-proteins, including 316 protein kinases. By using integrative inferred kinase activity (INKA) scoring, we identify multiple (parallel) activated kinases that are subsequently matched to kinase inhibitors. Compared with high-dose single-drug treatments, INKA-tailored low-dose 3-drug combinations against multiple targets demonstrate superior efficacy against PDAC cell lines, organoid cultures, and patient-derived xenografts. Overall, this approach is particularly more effective against the aggressive mesenchymal PDAC model compared with the epithelial model in both preclinical settings and may contribute to improved treatment outcomes in PDAC patients.

Prognosticators for Patients with Pancreatic Ductal Adenocarcinoma Who Received Neoadjuvant FOLFIRINOX or Gemcitabine/Nab-Paclitaxel Therapy and Pancreatectomy

Neoadjuvant FOLFIRINOX and gemcitabine/nab-paclitaxel (GemNP) therapies are increasingly used to treat patients with pancreatic ductal adenocarcinoma (PDAC). However, limited data are available on their clinicopathologic prognosticators. We examined the clinicopathologic factors and survival of 213 PDAC patients who received FOLFIRINOX with 71 patients who received GemNP. The FOLFIRINOX group was younger (p < 0.01) and had a higher rate of radiation (p = 0.049), higher rate of borderline resectable and locally advanced disease (p < 0.001), higher rate of Group 1 response (p = 0.045) and lower ypN stage (p = 0.03) than the GemNP group. Within FOLFIRINOX group, radiation was associated with decreased lymph node metastasis (p = 0.01) and lower ypN stage (p = 0.01). The tumor response group, ypT, ypN, LVI and PNI, correlated significantly with both DFS and OS (p < 0.05). Patients with the ypT0/T1a/T1b tumor had better DFS (p = 0.04) and OS (p = 0.03) than those with ypT1c tumor. In multivariate analysis, the tumor response group and ypN were independently prognostic factors for DFS and OS (p < 0.05). Our study demonstrated that the FOLFIRINOX group was younger and had a better pathologic response than the GemNP group and that the tumor response group, ypN, ypT, LVI and PNI, are significant prognostic factors for survival in these patients. Our results also suggest that the tumor size of 1.0 cm is a better cut off for ypT2. Our study highlights the importance of systemic pathologic examination and the reporting of post-treatment pancreatectomies.

Targeted therapy for pancreatic ductal adenocarcinoma: Mechanisms and clinical study

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive and lethal malignancy with a high rate of recurrence and a dismal 5-year survival rate. Contributing to the poor prognosis of PDAC is the lack of early detection, a complex network of signaling pathways and molecular mechanisms, a dense and desmoplastic stroma, and an immunosuppressive tumor microenvironment. A recent shift toward a neoadjuvant approach to treating PDAC has been sparked by the numerous benefits neoadjuvant therapy (NAT) has to offer compared with upfront surgery. However, certain aspects of NAT against PDAC, including the optimal regimen, the use of radiotherapy, and the selection of patients that would benefit from NAT, have yet to be fully elucidated. This review describes the major signaling pathways and molecular mechanisms involved in PDAC initiation and progression in addition to the immunosuppressive tumor microenvironment of PDAC. We then review current guidelines, ongoing research, and future research directions on the use of NAT based on randomized clinical trials and other studies. Finally, the current use of and research regarding targeted therapy for PDAC are examined. This review bridges the molecular understanding of PDAC with its clinical significance, development of novel therapies, and shifting directions in treatment paradigm.

Prognostic value of major pathological response following neoadjuvant therapy for non resectable pancreatic ductal adenocarcinoma

BACKGROUND

The aim of this study is to evaluate the impact of major pathological response on overall survival (OS) in borderline resectable and locally advanced pancreatic ductal adenocarcinoma following neoadjuvant treatment, and to identify predictors of major pathological response.

METHODS

Patients surgically resected following neoadjuvant treatment between 2010 and 2020 at the Pederzoli Hospital were retrospectively analyzed. Pathologic response was assessed using the College of American Pathologists (CAP) score, and major pathological response was defined as CAP 0-1. OS was estimated and compared using the Kaplan-Meier method and log-rank test. A logistic and Cox regression model were performed to identify predictors of major pathologic response and OS.

RESULTS

Overall, 200 patients were included in the study. A major and complete pathological response were observed in 52(26.0%) and 15(7.3%) patients respectively. The 1-, 3-, 5-year OS was 92.7, 67.2, and 41.7%, and 71.0, 37.4, and 20.8% in patients with or without major pathologic response respectively (log-rank test p < 0.001). Major pathologic response was confirmed as independent predictor of OS (OR 0.50 95%CI 0.29-0.88, p = 0.01). Post-treatment CA19-9 normalization (OR 4.20 95%CI 1.14-10.35, p = 0.02) and radiological post-treatment tumor residual size<25 mm (OR 2.71 95%CI 1.27-5.79, p = 0.01) were found to be independent predictors of major pathologic response.

CONCLUSION

Patients experienced a major pathological response after neoadjuvant treatment have an increased survival, and major pathologic response is an independent predictor of OS. A normal CA19-9 value and radiological tumor size at restaging are confirmed to be independent predictors of major pathologic response.

Use of time‑density curves of dynamic contrast‑enhanced computed tomography for determination of the histological therapeutic effects of neoadjuvant chemotherapy for pancreatic ductal adenocarcinoma

The present study aimed to investigate the histological changes caused by neoadjuvant chemotherapy (NAC) for pancreatic ductal adenocarcinoma (PDAC), and to demonstrate the use of time‑density curves (TDCs) of dynamic contrast‑enhanced computed tomography (CECT) for determination of the histological therapeutic effects of NAC for PDAC. A total of 96 patients with PDAC were examined; 46 underwent NAC (NAC group) and 50 did not undergo NAC (non‑NAC group). Based on histological therapeutic effect and using the area of residual tumor (ART) grading system, the NAC group was divided into low‑responders and high‑responders. Histological analysis was used to evaluate the densities of cancer cells, cancer‑associated fibroblasts (CAFs), microvessels and stromal collagen fibers in the NAC and non‑NAC groups. Radiological analysis was used to evaluate the TDCs of three slopes of the NAC group, namely slopes between the non‑contrast and arterial phases (δ1 and δ1'), between the arterial and portal phases (δ2 and δ2'), and between the portal and equilibrium phases (δ3 and δ3'). δ1‑δ3 were before NAC, whereas δ1'‑δ3' were after NAC. Changes in δ1, δ2 and δ3 before and after NAC were denoted as δδ1 (=δ1'‑δ1), δδ2 (=δ2'‑δ2) and δδ3 (=δ3'‑δ3). ART grading system, histological examination and radiological examination data were also statistically analyzed. Histological examination revealed a significant decrease in cancer cells and CAFs, and a significant increase in stromal collagen fibers due to NAC (P<0.01). Radiological examination revealed that δ1' was significantly higher than δ1 in low‑responders (P<0.05), whereas δ2' was significantly lower than δ2 in high‑responders (P<0.01). δδ2 was significantly lower and δδ3 was significantly higher in high‑responders than in low‑responders (P<0.01 and P<0.05, respectively). Receiver operating characteristic curve showed that δδ2 and δδ3 were effective indicators of the histological therapeutic effect of NAC. In conclusion, the TDC of dynamic CECT may be useful for determining the histological therapeutic effect of NAC for PDAC.

Sequential therapy of portal vein embolization and systemic chemotherapy for locally advanced perihilar biliary tract cancer

BACKGROUND

Curative resection is the only potential treatment for cure in patients with perihilar biliary tract cancer (PBTC). However, post hepatectomy liver failure (PHLF) due to insufficient future liver remnant volume (FRLV) remains a lingering risk even after portal vein embolization (PVE). This study aimed to investigate the feasibility and efficacy of a sequential treatment strategy consisting of PVE followed by preoperative chemotherapy before surgery.

METHODS

Between April 2019 and December 2021, 15 patients with locally advanced PBTC (LA-PBTC) underwent sequential treatment consisting of PVE followed by preoperative chemotherapy. The feasibility and efficacy, including resection rate, changes of FRLV, and chemotherapeutic effect, were investigated retrospectively.

RESULTS

Thirteen of 15 patients (86.6%) underwent curative resection. The median duration time between PVE and surgery was 144 days. FRLV/TLV ratio was 31.3% at prePVE, 38.4%, at two weeks after PVE, and 45.7% before surgery, respectively. There was significant increase in FRLV/TLV ratio two weeks after PVE. Additional increase in FRLV/TLV ratio was significantly achieved before surgery. PHLF occurred in 5 patients (38.4%). Pathological complete response was found in 2 of 13 patients (15.3%).

CONCLUSIONS

Sequential PVE and systemic chemotherapy contribute to the sufficient hypertrophy of FRLV without compromising resectability in patients with LA-PBTC.

Histopathological tumour response scoring in resected pancreatic cancer following neoadjuvant therapy: international interobserver study (ISGPP-1)

BACKGROUND

Most tumour response scoring systems for resected pancreatic cancer after neoadjuvant therapy score tumour regression. However, whether treatment-induced changes, including tumour regression, can be identified reliably on haematoxylin and eosin-stained slides remains unclear. Moreover, no large study of the interobserver agreement of current tumour response scoring systems for pancreatic cancer exists. This study aimed to investigate whether gastrointestinal/pancreatic pathologists can reliably identify treatment effect on tumour by histology, and to determine the interobserver agreement for current tumour response scoring systems.

METHODS

Overall, 23 gastrointestinal/pancreatic pathologists reviewed digital haematoxylin and eosin-stained slides of pancreatic cancer or treated tumour bed. The accuracy in identifying the treatment effect was investigated in 60 patients (30 treatment-naive, 30 after neoadjuvant therapy (NAT)). The interobserver agreement for the College of American Pathologists (CAP) and MD Anderson Cancer Center (MDACC) tumour response scoring systems was assessed in 50 patients using intraclass correlation coefficients (ICCs). An ICC value below 0.50 indicated poor reliability, 0.50 or more and less than 0.75 indicated moderate reliability, 0.75 or more and below 0.90 indicated good reliability, and above 0.90 indicated excellent reliability.

RESULTS

The sensitivity and specificity for identifying NAT effect were 76.2 and 49.0 per cent respectively. After NAT in 50 patients, ICC values for both tumour response scoring systems were moderate: 0.66 for CAP and 0.71 for MDACC.

CONCLUSION

Identification of the effect of NAT in resected pancreatic cancer proved unreliable, and interobserver agreement for the current tumour response scoring systems was suboptimal. These findings support the recently published International Study Group of Pancreatic Pathologists recommendations to score residual tumour burden rather than tumour regression after NAT.

Neoadjuvant Chemotherapy Is Associated with Altered Immune Cell Infiltration and an Anti-Tumorigenic Microenvironment in Resected Pancreatic Cancer

PURPOSE

Neoadjuvant chemotherapy is increasingly administered to patients with resectable or borderline resectable pancreatic ductal adenocarcinoma (PDAC), yet its impact on the tumor immune microenvironment is incompletely understood.

EXPERIMENTAL

DESIGN

We employed quantitative, spatially resolved multiplex immunofluorescence and digital image analysis to identify T-cell subpopulations, macrophage polarization states, and myeloid cell subpopulations in a multi-institution cohort of up-front resected primary tumors (n = 299) and in a comparative set of resected tumors after FOLFIRINOX-based neoadjuvant therapy (n = 36) or up-front surgery (n = 30). Multivariable-adjusted Cox proportional hazards models were used to evaluate associations between the immune microenvironment and patient outcomes.

RESULTS

In the multi-institutional resection cohort, immune cells exhibited substantial heterogeneity across patient tumors and were located predominantly in stromal regions. Unsupervised clustering using immune cell densities identified four main patterns of immune cell infiltration. One pattern, seen in 20% of tumors and characterized by abundant T cells (T cell-rich) and a paucity of immunosuppressive granulocytes and macrophages, was associated with improved patient survival. Neoadjuvant chemotherapy was associated with a higher CD8:CD4 ratio, greater M1:M2-polarized macrophage ratio, and reduced CD15+ARG1+ immunosuppressive granulocyte density. Within neoadjuvant-treated tumors, 72% showed a T cell-rich pattern with low immunosuppressive granulocytes and macrophages. M1-polarized macrophages were located closer to tumor cells after neoadjuvant chemotherapy, and colocalization of M1-polarized macrophages and tumor cells was associated with greater tumor pathologic response and improved patient survival.

CONCLUSIONS

Neoadjuvant chemotherapy with FOLFIRINOX shifts the PDAC immune microenvironment toward an anti-tumorigenic state associated with improved patient survival.

The Histopathology of Neoadjuvant-Treated (NAT) Pancreatic Ductal Adenocarcinoma

Examination of pancreatic ductal adenocarcinoma after NAT with the intent of diagnosis and outcome prediction remains a challenging task. The lack of a uniform approach to macroscopically assess these cases along with variations in sampling adds to the complexity. Several TRG systems have been proposed to correlate with an overall survival. In clinical practice, most of these TRG schemes have shown low level of interobserver agreement arguing for a need of larger studies and more innovative ways to assess outcome in this population.

Proposal for a New Pathologic Prognostic Index After Neoadjuvant Chemotherapy in Pancreatic Ductal Adenocarcinoma (PINC)

BACKGROUND

Limited information is available on the relevant prognostic variables after surgery for patients with pancreatic ductal adenocarcinoma (PDAC) subjected to neoadjuvant chemotherapy (NACT). NACT is known to induce a spectrum of histological changes in PDAC. Different grading regression systems are currently available; unfortunately, they lack precision and accuracy. We aimed to identify a new quantitative prognostic index based on tumor morphology.

PATIENTS AND METHODS

The study population was composed of 69 patients with resectable or borderline resectable PDAC treated with preoperative NACT (neoadjuvant group) and 36 patients submitted to upfront surgery (upfront-surgery group). A comprehensive histological assessment on hematoxylin and eosin (H&E) stained sections evaluated 20 morphological parameters. The association between patient survival and morphological variables was evaluated to generate a prognostic index.

RESULTS

The distribution of morphological parameters evaluated was significantly different between upfront-surgery and neoadjuvant groups, demonstrating the effect of NACT on tumor morphology. On multivariate analysis for patients that received NACT, the predictors of shorter overall survival (OS) and disease-free survival (DFS) were perineural invasion and lymph node ratio. Conversely, high stroma to neoplasia ratio predicted longer OS and DFS. These variables were combined to generate a semiquantitative prognostic index based on both OS and DFS, which significantly distinguished patients with poor outcomes from those with a good outcome. Bootstrap analysis confirmed the reproducibility of the model.

CONCLUSIONS

The pathologic prognostic index proposed is mostly quantitative in nature, easy to use, and may represent a reliable tumor regression grading system to predict patient outcomes after NACT followed by surgery for PDAC.

Critical issues in pathologic evaluation of pancreatic ductal adenocarcinoma resected after neoadjuvant treatment: a narrative review

BACKGROUND AND OBJECTIVE

Preoperative neoadjuvant therapy (NAT) is increasingly used in the treatment of patients with potentially resectable pancreatic ductal adenocarcinoma (PDAC). Because NAT often induces heterogeneous tumor response and extensive fibrosis both in tumor and adjacent pancreatic tissue, pathologic assessment of posttherapy pancreatectomy specimens is challenging. A limited number of studies examined the optimal grossing and sampling methods, tumor response grading (TRG), and the prognostic value of posttherapy tumor (ypT) and lymph node (ypN) stages of treated PDAC patients. In this review, we will provide an overview of the current status and critical issues in pathologic evaluation of PDAC resected after NAT.

METHODS

In PubMed, Google Scholar and Web of Science, we reviewed existing English literature (published up to December 2021) highlighting the most recent ones using electronic databases and authors' experience to outline the challenging aspects and new perspectives on pathologic assessment of the treated PDAC.

KEY CONTENT AND FINDINGS

The recent recommendations from the Pancreatobiliary Pathology Society (PBPS) provide the much-needed guidelines for systematic and standardized pathologic evaluation and reporting of treated PDAC for optimal patient care. For treated PDAC, tumor size measured by gross and radiology is not reliable. Histologic validation of tumor size on consecutive mapping sections is recommended for accurate ypT stage. A tumor size of 1.0 cm seems to be a better cutoff for ypT2 for treated PDACs. The published data suggested that the MD Anderson Cancer Center (MDA) TRG system is easy to use, has a better interobserver agreement and better correlation with patient prognosis compared to the College of American Pathologists (CAP) and Evans grading systems and may be used as an alternative TRG system for the CAP cancer protocol.

CONCLUSIONS

Systemic and standardized grossing and sampling are essential for accurate pathologic evaluation and reporting for optimal care of PDAC patients who received NAT. Future studies on optimal sampling and integration of histopathology with artificial intelligence (AI), molecular and immunohistochemical markers are needed for better and personalized care of treated PDAC patients.

Pathologic Examination of Pancreatic Specimens Resected for Treated Pancreatic Ductal Adenocarcinoma: Recommendations From the Pancreatobiliary Pathology Society

Currently, there are no internationally accepted consensus guidelines for pathologic evaluation of posttherapy pancreatectomy specimens. The Neoadjuvant Therapy Working Group of Pancreatobiliary Pathology Society was formed in 2018 to review grossing protocols, literature, and major issues and to develop recommendations for pathologic evaluation of posttherapy pancreatectomy specimens. The working group generated the following recommendations: (1) Systematic and standardized grossing and sampling protocols should be adopted for pancreatectomy specimens for treated pancreatic ductal adenocarcinoma (PDAC). (2) Consecutive mapping sections along the largest gross tumor dimension are recommended to validate tumor size by histology as required by the College of American Pathologists (CAP) cancer protocol. (3) Tumor size of treated PDACs should be measured microscopically as the largest dimension of tumor outer limits that is bound by viable tumor cells, including intervening stroma. (4) The MD Anderson grading system for tumor response has a better correlation with prognosis and better interobserver concordance among pathologists than does the CAP system. (5) A case should not be classified as a complete response unless the entire pancreas, peripancreatic tissues, ampulla of Vater, common bile duct, and duodenum adjacent to the pancreas are submitted for microscopic examination. (6) Future studies on tumor response of lymph node metastases, molecular and/or immunohistochemical markers, as well as application of artificial intelligence in grading tumor response of treated PDAC are needed. In summary, systematic, standardized pathologic evaluation, accurate tumor size measurement, and reproducible tumor response grading to neoadjuvant therapy are needed for optimal patient care. The criteria and discussions provided here may provide guidance towards these goals.

Neoadjuvant chemoradiation alters the immune microenvironment in pancreatic ductal adenocarcinoma

Patients with pancreatic ductal adenocarcinoma (PDAC) have a grim prognosis despite complete surgical resection and intense systemic therapies. While immunotherapies have been beneficial with many different types of solid tumors, they have almost uniformly failed in the treatment of PDAC. Understanding how therapies affect the tumor immune microenvironment (TIME) can provide insights for the development of strategies to treat PDAC. We used quantitative multiplexed immunofluorescence (qmIF) quantitative spatial analysis (qSA), and immunogenomic (IG) analysis to analyze formalin-fixed paraffin embedded (FFPE) primary tumor specimens from 44 patients with PDAC including 18 treated with neoadjuvant chemoradiation (CRT) and 26 patients receiving no treatment (NT) and compared them with tissues from 40 treatment-naïve melanoma patients. We find that relative to NT tumors, CD3+ T cell infiltration was increased in CRT treated tumors (p = .0006), including increases in CD3+CD8+ cytotoxic T cells (CTLs, p = .0079), CD3+CD4+FOXP3- T helper cells (Th, p = .0010), and CD3+CD4+FOXP3+ regulatory T cells (Tregs, p = .0089) with no difference in CD68+ macrophages. IG analysis from micro-dissected tissues indicated overexpression of genes involved in antigen presentation, T cell activation, and inflammation in CRT treated tumors. Among treated patients, a higher ratio of Tregs to total T cells was associated with shorter survival time (p = .0121). Despite comparable levels of infiltrating T cells in CRT PDACs to melanoma, PDACs displayed distinct spatial profiles with less T cell clustering as defined by nearest neighbor analysis (p < .001). These findings demonstrate that, while CRT can achieve high T cell densities in PDAC compared to melanoma, phenotype and spatial organization of T cells may limit benefit of T cell infiltration in this immunotherapy-resistant tumor.

A pathologic method for extracting good prognosis group in triple negative breast cancer after neoadjuvant chemotherapy

The area of residual tumor (ART) is a prognostic factor in patients treated with neoadjuvant chemotherapy (NAC) for lung, pancreatic, and rectal cancers. This study aimed to evaluate the usefulness of ART as a method for predicting the prognosis of triple-negative breast cancer (TNBC) patients after neoadjuvant chemotherapy. We included 143 patients with TNBC treated with NAC. The ART at the maximum cut surface of the residual tumor was measured. We divided the patients into three groups: ART-0 (ART=0 mm² ), ART-low (0 mm² < ART ≤ 136mm² ), and ART-high (ART > 136 mm² ), and compared their clinicopathological factors and prognosis. There were no significant differences in both recurrence-free survival (RFS) and overall survival (OS) between ART-0 and ART-low; however, the ART-high group had significantly shorter RFS and OS than the ART-0 and ART-low groups. Multivariate analysis showed that ART-0, and -low and ypN (-) were independent favorable prognostic factors for RFS. Groups with both ART-low and ypN(-) as well as those with ART-0 and ypN(-) showed significantly longer OS and RFS than the other groups (p<0.05). Moreover, there was no significant difference in the RFS and OS between the ART-0 and ypN(-) groups and the ART-low and ypN(-) groups (p=0.249 and p=0.554, respectively). We concluded that ART is a candidate histopathological evaluation method for predicting the prognosis of TNBC patients treated with NAC. Furthermore, postoperative chemotherapy could be omitted in patients with ART-0 and ypN(-) (pathological complete response) and those with ART-low and ypN(-).

Reproducibility and prognostic significance of area of residual tumor (ART) in post-neoadjuvant resections of pancreatic ductal adenocarcinoma

BACKGROUND

The pathologic assessments of tumor response after neoadjuvant chemoradiotherapy (NACRT) are critical to improving the prognostic stratification for patients with pancreatic ductal adenocarcinoma (PDAC). Here we clarified the utility of our new grading system based on the area of residual tumor (ART) as compared to existing systems, such as the College of American Pathologists (CAP) and MD Anderson (MDA) score.

METHODS

Eight reviewers individually evaluated the tumor regression grade of 30 patients with PDAC based on three types of grading systems. The interobserver concordance and clinicopathological characteristics were compared between the three systems.

RESULTS

The interobserver concordance (kappa value) of the ART, CAP, and MDA score were 0.61, 0.48, and 0.53, respectively. Discrepant cases, which were 27% of the cases, exhibited smaller tumor and tumor bed sizes than concordant cases. The reduction in tumor size evaluated by microscopy showed a correlation with the rate of change in carcinoembryonic antigen (CEA) level, CA19-9 level, and tumor size on computed tomography (CT). The ART score was correlated with the tumor size on CT before and after NACRT and disease-free survival. The CAP and MDA scores were not associated with prognosis.

CONCLUSION

The ART grading system may be the most practical system to assess the tumor response in post-NACRT resections of PDAC.

Artificial Intelligence-Based Segmentation of Residual Tumor in Histopathology of Pancreatic Cancer after Neoadjuvant Treatment

Simple Summary

The use of neoadjuvant therapy (NAT) in patients with pancreatic ductal adenocarcinoma (PDAC) is increasing. Objective quantification of the histopathological response to NAT may be used to guide adjuvant treatment and compare the efficacy of neoadjuvant regimens. However, current tumor response scoring (TRS) systems suffer from interobserver variability, originating from subjective definitions, the sometimes challenging histology, and response heterogeneity throughout the tumor bed. This study investigates if artificial intelligence-based segmentation of residual tumor burden in histopathology of PDAC after NAT may offer a more objective and reproducible TRS solution.

Abstract

Background: Histologic examination of resected pancreatic cancer after neoadjuvant therapy (NAT) is used to assess the effect of NAT and may guide the choice for adjuvant treatment. However, evaluating residual tumor burden in pancreatic cancer is challenging given tumor response heterogeneity and challenging histomorphology. Artificial intelligence techniques may offer a more reproducible approach. Methods: From 64 patients, one H&E-stained slide of resected pancreatic cancer after NAT was digitized. Three separate classes were manually outlined in each slide (i.e., tumor, normal ducts, and remaining epithelium). Corresponding segmentation masks and patches were generated and distributed over training, validation, and test sets. Modified U-nets with varying encoders were trained, and F1 scores were obtained to express segmentation accuracy. Results: The highest mean segmentation accuracy was obtained using modified U-nets with a DenseNet161 encoder. Tumor tissue was segmented with a high mean F1 score of 0.86, while the overall multiclass average F1 score was 0.82. Conclusions: This study shows that artificial intelligence-based assessment of residual tumor burden is feasible given the promising obtained F1 scores for tumor segmentation. This model could be developed into a tool for the objective evaluation of the response to NAT and may potentially guide the choice for adjuvant treatment.

Dataset for the reporting of carcinoma of the exocrine pancreas: recommendations from the International Collaboration on Cancer Reporting (ICCR)

BACKGROUND AND OBJECTIVES

Current guidelines for the pathology reporting on pancreatic cancer differ in certain aspects, resulting in divergent reporting practice and a lack of comparability of data. Here we report on a new international dataset for the pathology reporting of resection specimens with cancer of the exocrine pancreas (ductal adenocarcinoma and acinar cell carcinoma). The dataset was produced under the auspices of the International Collaboration on Cancer Reporting (ICCR), a global alliance of major (inter-)national pathology and cancer organisations.

METHODS AND RESULTS

According to the ICCR's rigorous process for dataset development, an international expert panel consisting of pancreatic pathologists, a pancreatic surgeon and an oncologist produced a set of core and non-core data items based on a critical review and discussion of current evidence. Commentary was provided for each data item to explain the rationale for selecting it as a core or non-core element, its clinical relevance, and to highlight potential areas of disagreement or lack of evidence, in which case a consensus position was formulated. Following international public consultation, the document was finalised and ratified, and the dataset, which includes a synoptic reporting guide, was published on the ICCR website.

CONCLUSIONS

This first international dataset for cancer of the exocrine pancreas is intended to promote high quality, standardised pathology reporting. Its widespread adoption will improve consistency of reporting, facilitate multidisciplinary communication and enhance comparability of data, all of which will help to improve the management of pancreatic cancer patients.

Adequate tissue sampling for the assessment of pathological tumor regression in pancreatic cancer

Standardized pathological evaluation of the regression assessment of neoadjuvant pancreatic cancer is necessary to improve prognostication and compare treatment outcomes in clinical trials. However, appropriate tissue sampling from surgically resected pancreatic cancer after neoadjuvant therapy has not been elucidated. We compared the tumor regression scores in the largest cancer slide determined macroscopically or histologically. We reviewed all slides and macroscopic photos of cut surfaces from resected pancreas of patients treated with neoadjuvant chemotherapy (n = 137; chemoradiotherapy or chemotherapy). The tumor regression scores (the Evans, College of American Pathologists, Japanese Pancreas Society grading systems, and Area of Residual Tumor [ART] score) were evaluated for the largest tumor slide determined by macroscopy or histologically as well as all slides from the resected pancreas. The largest cancer slides determined macroscopically and histologically were discrepant in 26% of the cases. Cancer cells were not detected in the largest macroscopically defined cut slides in 3%. Only ART scores assessed in the largest histological slides displayed significant difference in overall survival. We recommend obtaining the largest histological slides to provide adequate assessment for regression of neoadjuvant-treated pancreatic cancer. Sufficient sampling to detect the largest histological slides would be mandatory.