Pathomorphological features of metastatic lymph nodes as predictors of postoperative prognosis in pancreatic cancer

Preoperative Prediction of Lymph Node Metastasis of Pancreatic Ductal Adenocarcinoma Based on a Radiomics Nomogram of Dual-Parametric MRI Imaging

Purpose

This study aims to uncover and validate an MRI-based radiomics nomogram for detecting lymph node metastasis (LNM) in pancreatic ductal adenocarcinoma (PDAC) patients prior to surgery.

Materials and Methods

We retrospectively collected 141 patients with pathologically confirmed PDAC who underwent preoperative T2-weighted imaging (T2WI) and portal venous phase (PVP) contrast-enhanced T1-weighted imaging (T1WI) scans between January 2017 and December 2021. The patients were randomly divided into training (n = 98) and validation (n = 43) cohorts at a ratio of 7:3. For each sequence, 1037 radiomics features were extracted and analyzed. After applying the gradient-boosting decision tree (GBDT), the key MRI radiomics features were selected. Three radiomics scores (rad-score 1 for PVP, rad-score 2 for T2WI, and rad-score 3 for T2WI combined with PVP) were calculated. Rad-score 3 and clinical independent risk factors were combined to construct a nomogram for the prediction of LNM of PDAC by multivariable logistic regression analysis. The predictive performances of the rad-scores and the nomogram were assessed by the area under the operating characteristic curve (AUC), and the clinical utility of the radiomics nomogram was assessed by decision curve analysis (DCA).

Results

Six radiomics features of T2WI, eight radiomics features of PVP and ten radiomics features of T2WI combined with PVP were found to be associated with LNM. Multivariate logistic regression analysis showed that rad-score 3 and MRI-reported LN status were independent predictors. In the training and validation cohorts, the AUCs of rad-score 1, rad-score 2 and rad-score 3 were 0.769 and 0.751, 0.807 and 0.784, and 0.834 and 0.807, respectively. The predictive value of rad-score 3 was similar to that of rad-score 1 and rad-score 2 in both the training and validation cohorts (P > 0.05). The radiomics nomogram constructed by rad-score 3 and MRI-reported LN status showed encouraging clinical benefit, with an AUC of 0.845 for the training cohort and 0.816 for the validation cohort.

Conclusions

The radiomics nomogram derived from the rad-score based on MRI features and MRI-reported lymph status showed outstanding performance for the preoperative prediction of LNM of PDAC.

Current Pathology Model of Pancreatic Cancer

Pancreatic cancer (PC) is one of the most aggressive and lethal malignant neoplasms, ranking in seventh place in the world in terms of the incidence of death, with overall 5-year survival rates still below 10%. The knowledge about PC pathomechanisms is rapidly expanding. Daily reports reveal new aspects of tumor biology, including its molecular and morphological heterogeneity, explain complicated "cross-talk" that happens between the cancer cells and tumor stroma, or the nature of the PC-associated neural remodeling (PANR). Staying up-to-date is hard and crucial at the same time. In this review, we are focusing on a comprehensive summary of PC aspects that are important in pathologic reporting, impact patients' outcomes, and bring meaningful information for clinicians. Finally, we show promising new trends in diagnostic technologies that might bring a difference in PC early diagnosis.

Rethinking the TNM Classification Regarding Direct Lymph Node Invasion in Pancreatic Ductal Adenocarcinoma

Simple Summary

Due to the rising burden of pancreatic cancer and poor outcomes, a precise, post-operative cancer staging for further and individualized therapy is needed. In the latest cancer classification system, the lymph node invasion mechanism is not addressed. Due to different outcomes regarding the lymph node invasion, we suggest a rethinking of the current system.

Abstract

Mechanisms of lymph node invasion seem to play a prognostic role in pancreatic ductal adenocarcinoma (PDAC) after resection. However, the 8th edition of the TNM classification of the American Joint Committee on Cancer (AJCC) does not consider this. The aim of this study was to analyse the prognostic role of different mechanisms of lymph node invasion on PDAC. One hundred and twenty-two patients with resected PDAC were examined. We distinguished three groups: direct (per continuitatem, Nc) from the main tumour, metastasis (Nm) without any contact to the main tumour, and a mixed mechanism (Ncm). Afterwards, the prognostic power of the different groups was analysed concerning overall survival (OS). In total, 20 patients displayed direct lymph node invasion (Nc = 16.4%), 44 were classed as Nm (36.1%), and 21 were classed as Ncm (17.2%). The difference in OS was not statistically significant between N0 (no lymph node metastasis, n = 37) and Nc (p = 0.134), while Nm had worse OS than N0 (p < 0.001). Direct invasion alone had no statistically significant effect on OS (p = 0.885). Redefining the N0 stage by including Nc patients showed a more precise OS prediction among N stages (p = 0.001 vs. p = 0.002). Nc was more similar to N0 than to Nm; hence, we suggest a rethinking of TNM classification based on the mechanisms of lymph node metastases in PDAC. Overall, this novel classification is more precise.

A radiomics model that predicts lymph node status in pancreatic cancer to guide clinical decision making: A retrospective study

Purpose: To construct a radiomics-based model for predicting lymph node (LN) metastasis status in pancreatic ductal adenocarcinoma (PDAC) before therapy and to evaluate its prognostic clinical value. Materials and Methods: We retrospectively collected preoperative CT scans of 130 PDAC patients who underwent original tumor resection and LN dissection in the entire cohort between January 2014 and December 2017. Radiomics features were systematically extracted and analyzed from CT scans of 89 patients in the primary cohort. To construct a radiomics signature, the least absolute shrinkage and selection operator methods were employed with LN metastasis status as classification labels. Pathological analysis of LN status which were assessed by experienced pathologists was used as the evaluation label. We subjected the clinical nomogram to multivariable logistic regression analysis and conducted performance evaluation based on its discrimination, calibration, and clinical value. The model was tested and validated in 41 patients with PDAC in a separate validation cohort. Results: Four radiomics features closely associated with LN metastasis were selected in the primary and validation cohorts (P < 0.01). Following the integration of CT-reported results and radiomics signatures into the radiomics nomogram, we reported better performance in the primary (area under the curve, 0.80) and validation (area under the curve, 0.78) cohorts. Conclusion: The noninvasive tool constructed from the portal venous phase CT based on radiomics showed better performance for LN metastasis prediction than traditional approaches in pancreatic cancer. It may assist surgeons in crafting detailed procedures before treatment, this subsequently improves tumor staging and resection of patients.

Peritumoral lymph nodes in pancreatic cancer revisited; is it truly equivalent to lymph node metastasis?

BACKGROUND

Lymph node (LN) metastasis is a well-known poor prognostic factor of pancreatic cancer. LN metastasis, through direct invasion of tumor cell to peritumoral lymph nodes (PTLN), is treated as the same as those which spread through lymphatic channels. This study aimed to evaluate the impact of PTLN invasion on the oncologic outcome of pancreatic cancer.

METHODS

Five hundred and six patients who underwent operation for pancreatic ductal adenocarcinoma from 2012 to 2018 were reviewed. PTLN invasion was defined as direct invasion of tumor cells in contact with main tumor.

RESULTS

Among the 506 patients, 112 patients (22.1%) had PTLN invasion. PTLN invasion group (PTLNI) showed better disease-free survival than regional LN metastasis group (RLNM) and combined LN metastasis group (CLNM) (PTLNI 21 vs RLNM 11 vs CLNM 12 months, P = .003). There was no significant difference between N0 and PTLNI (PTLNI 21 vs N0 23 months, P = .999). In multivariate analysis, conventional LN metastasis was a significant factor compared to N0, but PTLN invasion was not (hazard ratio 0.786 [0.507-1.220], P = .283).

CONCLUSION

Because PTLN invasion does not adversely affect survival in the same way as LN metastasis does, pancreatic cancer-may be overstaged if PTLN invasion were dealt in the same manner as a metastatic LN. Therefore, PTLN invasion should be disregarded from current nodal staging system.

Large tumor size, lymphovascular invasion, and synchronous metastasis are associated with the recurrence of solid pseudopapillary neoplasms of the pancreas

BACKGROUND

Solid pseudopapillary neoplasms (SPNs) of the pancreas have low malignant potential. However, malignant SPNs are not fully understood.

METHODS

To evaluate risk factors affecting malignant potential, the clinicopathologic features of 375 surgically resected SPNs were compared.

RESULTS

Fifty (13.3%) had malignant histologic features. Twenty-seven and 22 had perineural and lymphovascular invasions, respectively. Adjacent organ invasion was noted in 9 cases. Recurrence occurred in 8 cases. The median recurrence time after surgical resection was 67 months and was associated with a higher pT category (P = 0.001), lymphovascular invasion (P < 0.001), and synchronous metastasis (P < 0.001). SPN patients with malignant histologic features had worse recurrence-free survival (RFS; 10-year survival rate, 73.2%) than those without malignant histologic features (96.3%; P = 0.01). Patients with a higher pT category (P = 0.04), synchronous metastasis (P < 0.01), and lymphovascular invasion (P < 0.01) had worse RFS. Lymphovascular invasion (P = 0.042) and a higher T category (P = 0.002) were poor prognostic factors for recurrence.

CONCLUSION

Lymphovascular invasion and a higher T category were worse prognostic factors for recurrence in SPN patients with malignant histologic features. For SPN patients with malignant histologic features, a longer follow-up may be required.

Impact of Neoadjuvant Chemoradiation on Pathologic Response in Patients With Localized Pancreatic Cancer

Introduction/Background: Multimodal neoadjuvant therapy has resulted in increased rates of histologic response in pancreatic tumors and adjacent lymph nodes. The biologic significance of the collective response in the primary tumor and lymph nodes is not understood.

Methods: Patients with localized PC who received neoadjuvant therapy and surgery with histologic assessment of the primary tumor and local-regional lymph nodes were included. Histopathologic response was classified using the modified Ryan score as follows: no viable cancer cells (CR), rare groups of cancer cells (nCR), residual cancer with evident tumor regression (PR), and extensive residual cancer with no evident tumor regression (NR). Nodal status was defined by number of lymph nodes (LN) with tumor metastases: N0 (0 LN), N1 (1–3), N2 (≥4).

Results: Of 341 patients with localized PC who received neoadjuvant therapy and surgery, 107 (31%) received chemoradiation alone, 44 (13%) received chemotherapy alone, and 190 (56%) received chemotherapy and chemoradiation. Histopathologic response consisted of 15 (4%) CRs, 59 (17%) nCRs, 188 (55%) PRs, and 79 (23%) NRs. Patients who received chemotherapy alone had the worst responses (n = 21 for NR, 48%) as compared to patients who received chemoradiation alone (n = 25 for NR, 24%) or patients who received both therapies (n = 33 for NR, 17%) (Table 1; p = 0.001). Median overall survival for all 341 patients was 39 months; OS by histopathologic subtype was not reached (CR), 49 months (nCR), 38 months (PR), and 34 months (NR), respectively (p = 0.004). Of the 341 patients, 208 (61%) had N0 disease, 97 (28%) had N1 disease, and 36 (11%) had N2 disease. In an adjusted hazards model, modified Ryan score of PR or NR (HR: 1.71; 95% CI: 1.15–2.54; p = 0.008) and N1 (HR: 1.42; 95% CI: 1.1.02–2.01; p = 0.04), or N2 disease (HR: 2.54, 95% CI: 1.64–3.93; p < 0.001) were associated with increased risk of death.

Conclusions: Neoadjuvant chemotherapy alone is associated with lower rates of pathologic response. Patients with CR or nCR have a significantly improved OS as compared to patients with PR or NR. Nodal status is the most important pathologic prognostic factor. Neoadjuvant chemoradiation may be an important driver of pathologic response.

Resectable pancreatic ductal adenocarcinoma: association between preoperative CT texture features and metastatic nodal involvement

Background

To explore the relationship between the lymph node status and preoperative computed tomography images texture features in pancreatic cancer.

Methods

A total of 155 operable pancreatic cancer patients (104 men, 51 women; mean age 63.8 ± 9.6 years), who had undergone contrast-enhanced computed tomography in the arterial and portal venous phases, were enrolled in this retrospective study. There were 73 patients with lymph node metastases and 82 patients without nodal involvement. Four different data sets, with thin (1.25 mm) and thick (5 mm) slices (at arterial phase and portal venous phase) were analysed. Texture analysis was performed by using MaZda software. A combination of feature selection algorithms was used to determine 30 texture features with the optimal discriminative performance for differentiation between lymph node positive and negative groups. The prediction performance of the selected feature was evaluated by receiver operating characteristic (ROC) curve analysis.

Results

There were 10 texture features with significant differences between two groups and significance in ROC analysis were identified. They were WavEnLH_s-2(wavelet energy with rows and columns are filtered with low pass and high pass frequency bands with scale factors 2) from wavelet-based features, 135dr_LngREmph (long run emphasis in 135 direction) and 135dr_Fraction (fraction of image in runs in 135 direction) from run length matrix-based features, and seven variables of sum average from coocurrence matrix-based features (SumAverg). The ideal cutoff value for predicting lymph node metastases was 270 for WavEnLH_s-2 (positive likelihood ratio 2.08). In addition, 135dr_LngREmph and 135dr_Fraction were correlated with the ratio of metastatic to examined lymph nodes.

Conclusions

Preoperative computed tomography high order texture features provide a useful imaging signature for the prediction of nodal involvement in pancreatic cancer.

Stress-induced phosphoprotein 1 promotes pancreatic cancer progression through activation of the FAK/AKT/MMP signaling axis

BACKGROUND

Dependent on the extent of adenosine triphosphate (ATP) hydrolysis and/or ATP/ADP exchange, the stress-induced phosphoprotein 1 (STIP1) mediates molecular interaction and complex formation between the molecular chaperones heat shock protein (Hsp)70 and Hsp90. The overexpression of STIP1 is increasingly being documented in various human malignancies, including ovarian, cholangiocellular, renal and gastric cancers. However, the role of STIP1 in pancreatic cancer (PANC) and probable molecular mechanism remains largely unexplored.

METHODS & RESULTS

In the present study, using clinical samples (n = 88) and human PANC cell lines PANC-1, Capan-2, SW1990, and BxPC-3, we demonstrated that STIP1 is aberrantly expressed in human PANC tissues or cell lines compared to adjacent non-tumor pancreas samples or human pancreatic duct epithelial cells (HPDEC), respectively. Clinicopathological correlation studies revealed significant positive correlation between high STIP1 expression and lymph node involvement (p = 0.001), cancer metastasis (p = 0.002), microvascular invasion (p = 0.002), advance TNM stage (p = 0.024), perineural invasion (PNI; p = 0.013), and cancer-related death (p = 0.002) among patients with PANC. Univariate and multivariate analyses indicate that STIP1overexpression is an independent prognostic factor of PANC. Furthermore, STIP1 knockdown significantly inhibit the migration and invasive ability of PANC-1 and SW1990 cells, while downregulating N-cadherin and Vimentin, but upregulating E-cadherin mRNA expression levels, concurrently. We also demonstrated that STIP1 knockdown suppressed p-FAK, p-AKT, MMP2, MMP9, and Slug protein and mRNA expression levels, thus, indicating, at least in part, a role for STIP1 in the activation of FAK/AKT/MMP signaling.

CONCLUSION

Taken together, our results demonstrate a critical role for STIP1 in cancer metastasis, disease progression and poor prognosis, as well as, provide evidence suggestive of the therapeutic efficacy of STIP1-mediated targeting of the FAK/AKT/MMP signaling axis in patients with PANC.