Histopathological tumour viability after neoadjuvant chemotherapy influences survival in resected pancreatic cancer: analysis of early outcome data

Promising biomarker panel to monitor therapeutic efficacy of neoadjuvant chemotherapy in pancreatic cancer patients

BACKGROUND

Neoadjuvant chemotherapy (NAC) can provide improved survival outcomes in pancreatic ductal adenocarcinoma (PDAC) patients who respond to treatment, but currently available biomarkers cannot reliably predict NAC response. This study aimed to determine the potential of a previously identified diagnostic and prognostic biomarker panel (i.e. Ca-125, S100A2, S100A4, Mesothelin and Ca19-9) for the monitoring of NAC-response in PDAC patients.

METHODS

This single-centre, retrospective study, utilised serum from NAC treated PDAC patients to determine the levels of biomarkers by Enzyme-Linked Immunosorbent Assay (ELISA). The percentage of the tumour bed occupied by viable carcinoma (PVC) was used to divide patients into good (PVC < 50%) and poor (PVC ≥ 50%) NAC-responders. Statistical analysis was performed to measure the ability of individual biomarkers and a biomarker panel in NAC treatment response and patient survival.

RESULTS

Serum specimens from a total of 108 PDAC patients were assessed. Ca-125, Ca19-9 and S100A2 showed a significant positive correlation with PVC. Ca-125 demonstrated a superior ability to monitor NAC treatment response (Area under receiver operating curve (AUC): .6954) compared to the more widely used clinical biomarker, Ca19-9 (AUC: .6291). A panel of Ca-125 and Ca19-9 showed good ability to monitor NAC response in PDAC patients (AUC: .7349). Patients with high levels of both Ca-125 and Ca19-9 were shown to have the poorest overall survival (median overall survival: 17 vs. 30 months).

CONCLUSION

A serum biomarker panel of Ca-125 and Ca19-9 could be used for effective clinical management of PDAC patients undergoing NAC treatment.

Neoadjuvant chemo- or chemo-radiation-therapy of pancreatic ductal adenocarcinoma differentially shift ECM composition, complement activation, energy metabolism and ribosomal proteins of the residual tumor mass

Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal cancer, often diagnosed at stages that dis-qualify for surgical resection. Neoadjuvant therapies offer potential tumor regression and improved resectability. Although features of the tumor biology (e.g., molecular markers) may guide adjuvant therapy, biological alterations after neoadjuvant therapy remain largely unexplored. We performed mass spectrometry to characterize the proteomes of 67 PDAC resection specimens of patients who received either neoadjuvant chemo (NCT) or chemo-radiation (NCRT) therapy. We employed data-independent acquisition (DIA), yielding a proteome coverage in excess of 3500 proteins. Moreover, we successfully integrated two publicly available proteome datasets of treatment-naïve PDAC to unravel proteome alterations in response to neoadjuvant therapy, highlighting the feasibility of this approach. We found highly distinguishable proteome profiles. Treatment-naïve PDAC was characterized by enrichment of immunoglobulins, complement and extracellular matrix (ECM) proteins. Post-NCT and post-NCRT PDAC presented high abundance of ribosomal and metabolic proteins as compared to treatment-naïve PDAC. Further analyses on patient survival and protein expression identified treatment-specific prognostic candidates. We present the first proteomic characterization of the residual PDAC mass after NCT and NCRT, and potential protein candidate markers associated with overall survival. We conclude that residual PDAC exhibits fundamentally different proteome profiles as compared to treatment-naïve PDAC, influenced by the type of neoadjuvant treatment. These findings may impact adjuvant or targeted therapy options.

Reusing Peptide Spectral Reference Libraries to Discover Putative Plasma Biomarkers of Response to Cancer Chemotherapy

Biofluids such as blood plasma are rich reservoirs of potential biomarkers for disease diagnosis, prognosis, and prediction of treatment response. However, mass spectrometry analysis of circulating plasma proteins remains challenging. The introduction of data-independent acquisition mass spectrometry (DIA-MS) is an important step toward addressing detection of less abundant plasma proteins. Numerous plasma peptide MS/MS spectral library datasets produced from extensive plasma fractionation are accessible from public archives, and these can be repurposed as spectral reference libraries to increase the depth of proteomic analysis when DIA-MS is used. Here we describe the workflow that relies on reusing the existing spectral reference libraries by populating them with locally obtained peptide MS/MS data acquired by DIA-MS. This approach was demonstrated effectively to identify putative plasma biomarkers of response to neoadjuvant chemotherapy in the setting of pancreatic ductal adenocarcinoma (PDAC) (O'Rourke et al., J Proteomics 231:103998, 2021).

Gene expression profiling of pancreatic ductal adenocarcinomas in response to neoadjuvant chemotherapy

AIM

Pancreatic ductal adenocarcinoma (PDAC) has the lowest survival rate of all major cancers. Chemotherapy is the mainstay systemic therapy for PDAC, and chemoresistance is a major clinical problem leading to therapeutic failure. This study aimed to identify key differences in gene expression profile in tumors from chemoresponsive and chemoresistant patients.

METHODS

Archived formalin-fixed paraffin-embedded tumor tissue samples from patients treated with neoadjuvant chemotherapy were obtained during surgical resection. Specimens were macrodissected and gene expression analysis was performed. Multi- and univariate statistical analysis was performed to identify differential gene expression profile of tumors from good (0%-30% residual viable tumor [RVT]) and poor (>30% RVT) chemotherapy-responders.

RESULTS

Initially, unsupervised multivariate modeling was performed by principal component analysis, which demonstrated a distinct gene expression profile between good- and poor-chemotherapy responders. There were 396 genes that were significantly (p < 0.05) downregulated (200 genes) or upregulated (196 genes) in tumors from good responders compared to poor responders. Further supervised multivariate analysis of significant genes by partial least square (PLS) demonstrated a highly distinct gene expression profile between good- and poor responders. A gene biomarker of panel (IL18, SPA17, CD58, PTTG1, MTBP, ABL1, SFRP1, CHRDL1, IGF1, and CFD) was selected based on PLS model, and univariate regression analysis of individual genes was performed. The identified biomarker panel demonstrated a very high ability to diagnose good-responding PDAC patients (AUROC: 0.977, sensitivity: 82.4%; specificity: 87.0%).

CONCLUSION

A distinct tumor biological profile between PDAC patients who either respond or not respond to chemotherapy was identified.

The Prognostic and Predictive Role of the Neutrophil-to-Lymphocyte Ratio (NLR), Platelet-to-Lymphocyte Ratio (PLR), and Lymphocyte-to-Monocyte Ratio (LMR) as Biomarkers in Resected Pancreatic Cancer

Pancreatic cancer has poor survival despite modern-day advances in its management. At present, there are no available biomarkers that can predict chemotherapy response or help inform prognosis. In more recent years, there has been increased interest in potential inflammatory biomarkers, with studies revealing a worse prognosis of patients with a higher neutrophil-to-lymphocyte ratio in a range of tumour types. Our aim was to assess the role of three inflammatory biomarkers in peripheral blood in predicting chemotherapy response in patients with earlier disease treated with neoadjuvant chemotherapy and as a prognostic marker in all patients that underwent surgery for pancreatic cancer. Using retrospective records, we discovered that patients with a higher neutrophil-to-lymphocyte ratio (>5) at the time of diagnosis had worse median overall survival than those with ratios ≤5 at 13 and 32.4 months (p = 0.001, HR 2.43), respectively. We were able to appreciate a correlation between a higher platelet-to-lymphocyte ratio and increased residual tumour in the histopathological specimen in patients receiving neoadjuvant chemotherapy; however, the association was weak (p = 0.03, coefficient 0.21). Due to the dynamic relationship between the immune system and pancreatic cancer, it is unsurprising that immune markers may be useful as potential biomarkers; however, larger prospective studies are needed to validate these findings.

Tumor size measurements of pancreatic cancer with neoadjuvant therapy based on RECIST guidelines: is MRI as effective as CT?

OBJECTIVES

To compare tumor size measurements using CT and MRI in pancreatic cancer (PC) patients with neoadjuvant therapy (NAT).

METHODS

This study included 125 histologically confirmed PC patients who underwent NAT. The tumor sizes from CT and MRI before and after NAT were compared by using Bland-Altman analyses and intraclass correlation coefficients (ICCs). Variations in tumor size estimates between MRI and CT in relationship to different factors, including NAT methods (chemotherapy, chemoradiotherapy), tumor locations (head/neck, body/tail), tumor regression grade (TRG) levels (0-2, 3), N stages (N0, N1/N2) and tumor resection margin status (R0, R1), were further analysed. The McNemar test was used to compare the efficacy of NAT evaluations based on the CT and MRI measurements according to RECIST 1.1 criteria.

RESULTS

There was no significant difference between the median tumor sizes from CT and MRI before and after NAT (P = 0.44 and 0.39, respectively). There was excellent agreement in tumor size between MRI and CT, with mean size differences and limits of agreement (LOAs) of 1.5 [-9.6 to 12.7] mm and 0.9 [-12.6 to 14.5] mm before NAT (ICC, 0.93) and after NAT (ICC, 0.91), respectively. For all the investigated factors, there was good or excellent correlation (ICC, 0.76 to 0.95) for tumor sizes between CT and MRI. There was no significant difference in the efficacy evaluation of NAT between CT and MRI measurements (P = 1.0).

CONCLUSION

MRI and CT have similar performance in assessing PC tumor size before and after NAT.

Radiological tumour invasion of splenic artery or vein in patients with pancreatic body or tail adenocarcinoma and effect on recurrence and survival

BACKGROUND

Major vessel invasion is an important factor for determining the surgical approach and long-term prognosis for patients with pancreatic head cancer. However, clinical implications of vessel invasion have seldom been reported in pancreatic body or tail cancer. This study aimed to evaluate the clinical relevance of splenic vessel invasion with pancreatic body or tail cancer compared with no invasion and investigate prognostic factors.

METHODS

This study enrolled patients who underwent upfront distal pancreatectomy from 2005 to 2018. The circular degree of splenic vessel invasion was investigated and categorized into three groups (group 1, no invasion; group 2, 0-180°; group 3, 180° or more). Clinicopathological variables and perioperative and survival outcomes were evaluated, and multivariable Cox proportional analysis was performed to evaluate prognostic factors.

RESULTS

Among 249 enrolled patients, tumour size was larger in patients with splenic vessel invasion (3.9 versus 2.9 cm, P = 0.001), but the number of metastatic lymph nodes was comparable to that in patients with no vessel invasion (1.7 versus 1.4, P = 0.241). The 5-year overall survival rates differed significantly between the three groups (group 1, 38.4 per cent; group 2, 16.8 per cent; group 3, 9.7 per cent, P < 0.001). Patients with both splenic artery and vein invasion had lower 5-year overall survival rates than those with one vessel (7.5 versus 20.2 per cent, P = 0.021). Cox proportional analysis revealed adjuvant treatment, R0 resection and splenic artery invasion as independent prognostic factors for adverse outcomes in pancreatic body or tail cancer.

CONCLUSION

Splenic vessel invasion was associated with higher recurrence and lower overall survival in pancreatic body or tail cancers suggesting a need for a neoadjuvant approach.

Optimal Upfront Treatment in Surgically Resectable Pancreatic Cancer Candidates: A High-Volume Center Retrospective Analysis

Pancreatic adenocarcinoma is a devastating disease with only 15-20% of patients resectable at diagnosis. Neoadjuvant chemotherapy for this cohort is becoming increasingly popular; however, there are no published randomized trials that support the use of neoadjuvant chemotherapy over upfront surgery in resectable disease. This retrospective cohort analysis was conducted to compare both treatment pathways and to identify any potential prognostic markers. Medical records from one large volume pancreatic cancer center from 2013-2019 were reviewed and 126 patients with upfront resectable disease were analyzed. Due to a change in practice in our center patients treated prior to December 2016 received upfront surgery and those treated after this date received neoadjuvant chemotherapy. Of these, 86 (68%) patients were treated with upfront surgery and 40 (32%) of patients were treated with neoadjuvant chemotherapy. Our results demonstrated that patients treated with upfront surgery with early-stage (1a) disease had a longer median OS compared to those treated with neoadjuvant chemotherapy (24 vs. 21 months, p = 0.028). This survival difference was not evident for all patients (regardless of stage). R0 resections were similar between groups (p = 0.605). We identified that both tumor viability (in neoadjuvant chemotherapy-treated patients) and tumor grade were useful prognostic markers. Upfront surgery for certain patients with low volume disease may be suitable despite the global trend towards neoadjuvant chemotherapy for all upfront resectable patients. A prospective clinical trial in this cohort incorporating biomarkers is needed to determine optimal therapy pathway.

A Critical Assessment of Postneoadjuvant Therapy Pancreatic Cancer Regression Grading Schemes With a Proposal for a Novel Approach

Currently, there is no consensus on the optimal tumor response score (TRS) system to assess regression in pancreatic cancers resected after neoadjuvant therapy. We developed a novel TRS (Royal North Shore [RNS] system) based on estimating the percentage of tumor bed occupied by viable cancer and categorized into 3 tiers: grade 1 (≤10%), grade 2 (11% to 75%), and grade 3 (>75%). We assessed 147 resected carcinomas with this and other TRS systems (College of American Pathologists [CAP], MD Anderson Cancer Center [MDACC], and Evans). The 3-tiered RNS system predicted median survival after surgery for grades 1, 2, and 3 of 54, 23, and 9 months, respectively (P<0.05). The CAP, MDACC, and Evans systems also predicted survival (P<0.05) but less consistently. The median survival for MDACC and CAP grade 0 (complete regression) was less than MDACC grade 1 and CAP grades 1 and 2. There was no difference in survival between CAP grades 2 and 3 (P=0.960), Evans grades 1 and 2a (P=0.395), and Evans grades 2a and 2b (P=0.587). Interobserver concordance was weak for CAP (κ=0.431), moderate for MDACC (κ=0.691), minimal for Evans (κ=0.307), and moderate to strong for RNS (κ=0.632 to 0.84). Of age, sex, size, stage, grade, perineural and vascular invasion, extrapancreatic extension, margin status, and RNS score, only RNS score, vascular invasion, and extrapancreatic extension predicted survival in univariate analysis. Only extrapancreatic extension (P=0.034) and RNS score (P<0.0001) remained significant in multivariate analysis. We conclude that the RNS system is a reproducible and powerful predictor of survival after resection for pancreatic cancers treated with neoadjuvant therapy and should be investigated in larger cohorts.

Scoring of tumour response after neoadjuvant therapy in resected pancreatic cancer: systematic review

BACKGROUND

Preoperative chemo(radio)therapy is used increasingly in pancreatic cancer. Histological evaluation of the tumour response provides information on the efficacy of preoperative treatment and is used to determine prognosis and guide decisions on adjuvant treatment. This systematic review aimed to provide an overview of the current evidence on tumour response scoring systems in pancreatic cancer.

METHODS

Studies reporting on the assessment of resected pancreatic ductal adenocarcinoma following neoadjuvant chemo(radio)therapy were searched using PubMed and EMBASE. All original studies reporting on histological tumour response in relation to clinical outcome (survival, recurrence-free survival) or interobserver agreement were eligible for inclusion. This systematic review followed the PRISMA guidelines.

RESULTS

The literature search yielded 1453 studies of which 25 met the eligibility criteria, revealing 13 unique scoring systems. The most frequently investigated tumour response scoring systems were the College of American Pathologists system, Evans scoring system, and MD Anderson Cancer Center system, investigated 11, 9 and 5 times respectively. Although six studies reported a survival difference between the different grades of these three systems, the reported outcomes were often inconsistent. In addition, 12 of the 25 studies did not report on crucial aspects of pathological examination, such as the method of dissection, sampling approach, and amount of sampling.

CONCLUSION

Numerous scoring systems for the evaluation of tumour response after preoperative chemo(radio)therapy in pancreatic cancer exist, but comparative studies are lacking. More comparative data are needed on the interobserver variability and prognostic significance of the various scoring systems before best practice can be established.

Reshaping preoperative treatment of pancreatic cancer in the era of precision medicine

This review summarises the recent evidence on preoperative therapeutic strategies in pancreatic cancer and discusses the rationale for an imminent need for a personalised therapeutic approach in non-metastatic disease. The molecular diversity of pancreatic cancer and its influence on prognosis and treatment response, combined with the failure of 'all-comer' treatments to significantly impact on patient outcomes, requires a paradigm shift towards a genomic-driven approach. This is particularly important in the preoperative, potentially curable setting, where a personalised treatment allocation has the substantial potential to reduce pancreatic cancer mortality.

Amsterdam International Consensus Meeting: tumor response scoring in the pathology assessment of resected pancreatic cancer after neoadjuvant therapy

Histopathologically scoring the response of pancreatic ductal adenocarcinoma (PDAC) to neoadjuvant treatment can guide the selection of adjuvant therapy and improve prognostic stratification. However, several tumor response scoring (TRS) systems exist, and consensus is lacking as to which system represents best practice. An international consensus meeting on TRS took place in November 2019 in Amsterdam, The Netherlands. Here, we provide an overview of the outcomes and consensus statements that originated from this meeting. Consensus (≥80% agreement) was reached on a total of seven statements: (1) TRS is important because it provides information about the effect of neoadjuvant treatment that is not provided by other histopathology-based descriptors. (2) TRS for resected PDAC following neoadjuvant therapy should assess residual (viable) tumor burden instead of tumor regression. (3) The CAP scoring system is considered the most adequate scoring system to date because it is based on the presence and amount of residual cancer cells instead of tumor regression. (4) The defining criteria of the categories in the CAP scoring system should be improved by replacing subjective terms including "minimal" or "extensive" with objective criteria to evaluate the extent of viable tumor. (5) The improved, consensus-based system should be validated retrospectively and prospectively. (6) Prospective studies should determine the extent of tissue sampling that is required to ensure adequate assessment of the residual cancer burden, taking into account the heterogeneity of tumor response. (7) In future scientific publications, the extent of tissue sampling should be described in detail in the "Materials and methods" section.

Data independent acquisition of plasma biomarkers of response to neoadjuvant chemotherapy in pancreatic ductal adenocarcinoma

The detection of disease-related plasma biomarkers has challenged the proteomic community for years. Attractive features for plasma proteomics includes the ease of collection and small volume needed for analysis, but on the other hand, the presence of highly abundant proteins complicates sample preparation procedures and reduces dynamic range. Data independent acquisition label free quantitation (DIA-LFQ) by mass spectrometry partly overcomes the dynamic range issue; however, generating the peptide spectral reference libraries that allow extensive analysis of the plasma proteome can be a slow and expensive task which is unattainable for many laboratories. We investigated the re-purposing of publically available plasma proteome datasets and the impact on peptide/protein detection for DIA-LFQ. We carried out these studies in the context of identifying putative biomarkers of response to neoadjuvant chemotherapy (NAC) for pancreatic ductal adenocarcinoma, as no useful plasma biomarkers have been clinically adopted. We demonstrated the benefit in searching DIA data against multiple spectral libraries to show that complement proteins were linked to NAC response in PDAC patients, confirming previous observations of the prognostic utility of complement following adjuvant chemotherapy. Our workflow demonstrates that DIA-LFQ can be readily applied in the oncology setting for the putative assignment of clinically relevant plasma biomarkers. STATEMENT OF SIGNIFICANCE: The proteomic mass spectrometry analysis of undepleted, unfractionated human plasma has benefits for sample throughput but remains challenging to obtain deep coverage. This work evaluated the re-purposing of open source peptide mass spectrometry data from human plasma to create spectral reference libraries for use in Data independent acquisition (DIA). We showed how seeding in locally acquired data to integrate iRT peptides into spectral libraries increased identification confidence by facilitating querying of multiple libraries. This workflow was applied to the discovery of putative plasma biomarkers for response to neoadjuvant chemotherapy (NAC) in pancreatic ductal adenocarcinoma patients. There is a paucity of prior information in the literature on this topic and we show that good responder patients have reduced levels of complement proteins.

Identification of Novel Biomarkers in Pancreatic Tumor Tissue to Predict Response to Neoadjuvant Chemotherapy

Background: Neoadjuvant chemotherapy (NAC) has been of recent interest as an alternative to upfront surgery followed by adjuvant chemotherapy in patients with pancreatic ductal adenocarcinoma (PDAC). However, a subset of patients does not respond to NAC and may have been better managed by upfront surgery. Hence, there is an unmet need for accurate biomarkers for predicting NAC response in PDAC. We aimed to identify upregulated proteins in tumor tissue from poor- and good-NAC responders.

Methods: Tumor and adjacent pancreas tissue samples were obtained following surgical resection from NAC-treated PDAC patients. SWATH-MS proteomic analysis was performed to identify and quantify proteins in tissue samples. Statistical analysis was performed to identify biomarkers for NAC response. Pathway analysis was performed to characterize affected canonical pathways in good- and poor-NAC responders.

Results: A total of 3,156 proteins were identified, with 19 being were significantly upregulated in poor-responders compared to good-responders (log₂ ratio > 2, p < 0.05). Those with the greatest ability to predict poor-NAC response were GRP78, CADM1, PGES2, and RUXF. Notably, canonical pathways that were significantly upregulated in good-responders included acute phase signaling and macrophage activation, indicating a heightened immune response in these patients.

Conclusion: A novel biomarker signature for poor-NAC response in PDAC was identified.

Systemic neoadjuvant chemotherapy in modern pancreatic cancer treatment: a systematic review and meta-analysis

BACKGROUND

Pancreatic ductal adenocarcinoma remains a disease with a poor prognosis despite advances in surgery and systemic therapies. Neoadjuvant therapy strategies are a promising alternative to adjuvant chemotherapy. However, their role remains controversial. This meta-analysis aims to clarify the benefits of neoadjuvant therapy in resectable pancreatic ductal adenocarcinoma.

METHODS

Eligible studies were identified from MEDLINE, Embase, Web of Science and the Cochrane Library. Studies comparing neoadjuvant therapy with a surgery first approach (with or without adjuvant therapy) in resectable pancreatic ductal adenocarcinoma were included. The primary outcome assessed was overall survival. A random-effects meta-analysis was performed, together with pooling of unadjusted Kaplan-Meier curve data.

RESULTS

A total of 533 studies were identified that analysed the effect of neoadjuvant therapy in pancreatic ductal adenocarcinoma. Twenty-seven studies were included in the final data synthesis. Meta-analysis suggested beneficial effects of neoadjuvant therapy with prolonged survival compared with a surgery-first approach, (hazard ratio 0.72, 95% confidence interval 0.69-0.76). In addition, R0 resection rates were significantly higher in patients receiving neoadjuvant therapy (relative risk 0.51, 95% confidence interval 0.47-0.55). Individual patient data analysis suggested that overall survival was better for patients receiving neoadjuvant therapy (P = 0.008).

CONCLUSIONS

Current evidence suggests that neoadjuvant chemotherapy has a beneficial effect on overall survival in resectable pancreatic ductal adenocarcinoma in comparison with upfront surgery and adjuvant therapy. Further trials are needed to address the need for practice change.

Adjuvant or Neoadjuvant Therapy in the Treatment in Pancreatic Malignancies: Where Are We?

Since the advent of modern surgery for pancreatic cancer, clinicians have recognized this cancer's propensity to recur locally, metastasize, and cause death. Despite significant efforts to improve patient outcomes with better adjuvant therapy, only modest gains in survival have been observed. An alternative strategy of neoadjuvant therapy followed by surgery has the potential to improve patient selection and survival, and expand the pool of patients eligible for curative surgery. This article summarizes large, randomized trials of adjuvant therapy, explains the limitations imposed by up-front surgery, and suggests neoadjuvant therapy as a rational alternative to initial surgery and adjuvant therapy.