Clinical Implications of the Degree of Pancreatic Invasion in Ampulla of Vater Carcinoma.

BACKGROUND: Ampulla of Vater carcinoma (AVC) stage T3 was subdivided according to the degree of pancreatic invasion into T3a (≤ 0.5 cm) and T3b (> 0.5 cm) by the 8th edition of the Union for International Cancer Control (UICC)/American Joint Committee on Cancer (AJCC) cancer staging system. However, the differences in clinicopathological features and survival outcomes between the two categories have not been well discussed. PATIENTS AND METHODS: We retrospectively analyzed 133 consecutive patients who underwent pancreatoduodenectomy for AVC at our institution between 2002 and 2020. Clinicopathological features and survival outcomes of patients with AVC were analyzed, with a focus on the depth of pancreatic invasion. In addition, the survival outcomes of patients with T3 AVC were compared with those of patients with resectable pancreatic head carcinoma (R-PhC) who underwent pancreatoduodenectomy during the same period. RESULTS: The overall survival (OS) in patients with T3b AVC (n = 12) was significantly worse than that in patients with T3a AVC (n = 39) [median survival time (MST) 9.2 vs. 74.5 months, p < 0.001). A multivariate analysis identified T3b tumor (hazard ratio 5.64, p = 0.009) as an independent prognostic factor. The OS of patients with T3a AVC was significantly better than that of patients with R-PhC who received adjuvant chemotherapy (n = 276, MST 35.0 months, p = 0.007). In contrast, the OS of patients with T3b AVC tended to be worse than that of patients with R-PhC managed without adjuvant chemotherapy, although this difference was not statistically significant (n = 163; MST, 17.5; p = 0.140). CONCLUSIONS: AVC with > 0.5 cm invasion into the pancreas was associated with poor survival and represented advanced tumor progression to systemic disease.

Subgrading of G2 Pancreatic Neuroendocrine Tumors as 2A (Ki67 3% to < 10%) Versus 2B (10% to ≤ 20%) Identifies Behaviorally Distinct Subsets in Keeping with the Evolving Management Protocols.

BACKGROUND: Grade 1/2 PanNETs are mostly managed similarly, typically without any adjunct treatment with the belief that their overall metastasis rate is low. In oncology literature, Ki67-index of 10% is increasingly being used as the cutoff in stratifying patients to different protocols, although there are no systematic pathology-based studies supporting this approach. METHODS: Ki67-index was correlated with clinicopathologic parameters in 190 resected PanNETs. A validation cohort (n = 145) was separately analyzed. RESULTS: In initial cohort, maximally selected rank statistics method revealed 12% to be the discriminatory cutoff (close to 10% rule of thumb). G2b cases had liver/distant metastasis rate of almost threefold higher than that of G2a and showed significantly higher frequency of all histopathologic signs of aggressiveness (tumor size, perineural/vascular invasion, infiltrative growth pattern, lymph node metastasis). In validation cohort, these figures were as striking. When all cases were analyzed together, compared with G1, the G2b category had nine times higher liver/distant metastasis rate (6.1 vs. 58.5%; p < 0.001) and three times higher lymph node metastasis rate (20.5 vs. 65.1%; p < 0.001). CONCLUSIONS: G2b PanNETs act very similar to G3, supporting management protocols that regard them as potential therapy candidates. Concerning local management, metastatic behavior in G2b cases indicate they may not be as amenable for conservative approaches, such as watchful waiting or enucleation. This substaging should be considered into diagnostic guidelines, and clinical trials need to be devised to determine the more appropriate management protocols for G2b (10% to ≤ 20%) group, which shows liver/distant metastasis in more than half of the cases, which at minimum warrants closer follow-up.

Investigation of the usefulness of a bile duct biopsy and bile cytology using a hyperspectral camera and machine learning.

To improve the efficiency of pathological diagnoses, the development of automatic pathological diagnostic systems using artificial intelligence (AI) is progressing; however, problems include the low interpretability of AI technology and the need for large amounts of data. We herein report the usefulness of a general-purpose method that combines a hyperspectral camera with machine learning. As a result of analyzing bile duct biopsy and bile cytology specimens, which are especially difficult to determine as benign or malignant, using multiple machine learning models, both were able to identify benign or malignant cells with an accuracy rate of more than 80% (93.3% for bile duct biopsy specimens and 83.2% for bile cytology specimens). This method has the potential to contribute to the diagnosis and treatment of bile duct cancer and is expected to be widely applied and utilized in general pathological diagnoses.

Interobserver agreement of pathologic classification and grading of tumoral intraductal pre-invasive neoplasms of the bile duct.

Current WHO terminology and recent publications have classified tumoral (grossly visible) intraductal pre-invasive neoplasms of bile duct (TIDN) into three categories: intraductal papillary neoplasm of bile duct (IPNB), intraductal papillary oncocytic neoplasm (IOPN), and intraductal tubulopapillary neoplasm (ITPN). A total of 227 cases of TIDN and related lesions ≥3 mm in height were examined by 10 biliary pathologists referring to these 3 categories and two pathologic gradings: two-tiered system (low- and high-grade dysplasia) and modified types 1 and 2 subclassification. Among them, IPNB was the most frequent (183 cases), followed by IOPN (28 cases), while ITPN was rare (2 cases), and interobserver agreement in this classification was "substantial" (κ-value, 0.657). The interobserver agreement of two-tiered grading system of TIDN was "slight" (κ-value, 0.201), while that of modified types 1 and 2 subclassification was "moderate" (κ-value, 0.515), and 42 % were of type 1, and 58 % were of type 2. Type 1 TIDN showed occasional stromal invasion (6.7 %), whereas type 2 TIDN was frequently associated with stromal invasion (49.6 %) (p < 0.01). In conclusion, the classification of TIDN into three categories and modified types 1 and 2 subclassification are a practically applicable classification and grading system for TIDN.

Subdivision of pT1N0 (American Joint Committee on Cancer 8th edition) distal cholangiocarcinoma for adjuvant chemotherapy consideration.

BACKGROUND: The adjuvant S-1 trial affirmed adjuvant chemotherapy for biliary tract cancer but excluded pT1N0 distal cholangiocarcinoma (DCC) according to the seventh edition of the American Joint Committee on Cancer (AJCC) classification. The introduction of tumor depth of invasion (DOI) for T-classification in the eighth edition complicates identifying DCC patients less likely to benefit from adjuvant chemotherapy. METHODS: Our cohort consisted of 185 patients with DCC who underwent pancreaticoduodenectomy between 2002 and 2019. We compared clinicopathological factors and survival outcomes between pT1N0 patients in the seventh edition and those in the eighth edition. New DOI cutoffs for subdividing pT1N0 (8th edition) patients were evaluated to identify patients less likely to benefit from adjuvant chemotherapy. RESULTS: Transitioning to the eighth edition increased in pT1N0 cases from eight to 46. The 5-year cumulative recurrence rates of them were 14.3% for the seventh edition and 28.3% for the eighth edition. We proposed a DOI cutoff of <2 mm, at which the 5-year cumulative recurrence rate was 11.5%. CONCLUSION: The eighth AJCC classification revealed that a significant proportion of pT1N0 DCC patients were at risk for recurrence. A DOI cutoff of <2 mm may be considered to potentially improve patient selection for adjuvant chemotherapy.

High-grade Solid Pseudopapillary Neoplasms of the Pancreas: Distinct Clinicopathological Malignant Features With Intriguing Gene Alterations through a Comparison With the Conventional Type.

Pancreatic solid pseudopapillary neoplasm (SPN) is a low-grade malignant neoplasm with a good prognosis. Clinically aggressive SPNs have rarely been reported but have not been analyzed in detail. In this study, we referred to this highly malignant type of SPN as high-grade SPN (HG-SPN) and compared its clinicopathological and genetic characteristics with conventional SPN (C-SPN) using immunohistochemistry and gene panel analyses. Five HG-SPNs and 15 C-SPNs were evaluated in this study. HG-SPNs share many pathologic characteristics: macroscopically, solid/cystic appearances, microscopically, pseudopapillary/pseudorosette pattern (100%), tumor cell loose cohesiveness (100%), thin/delicate vasculature (100%), tumor cell cytoplasmic vacuolization (100%), immunohistochemical positivity for ß-catenin (nuclear expression) (100%), CD10 (80%), CD56 (80%), and vimentin (100%). Conversely, HG-SPNs showed distinct malignant features compared with C-SPNs: mean tumor size (11.7 vs. 2.9 cm, P <0.001); true necrosis (100% vs. 0%, P <0.001); high-grade nuclear atypia (100% vs. 0%, P <0.001); lymphatic and/or venous invasion (100% vs. 20%, P =0.004); mean mitotic count (4.38 vs. 0.05/high-power field, P <0.001); and mean Ki-67 labeling index (33.9% vs. 3.4%, P <0.001). All HG-SPN patients died of primary disease 3 to 36 months after surgery, while all C-SPN patients were alive without disease. Genetic studies have shown that all analyzed HG-SPNs have CTNNB1 mutations. Two HG-SPN cases showed RB1 mutations with altered immunohistochemical findings for RB1 and p16. Two HG-SPN cases had TP53 mutation and/or p53 overexpression. In conclusion, HG-SPNs show distinct malignant features and some genetic alterations that differ from C-SPNs, indicating the importance of differentiating between these 2 subtypes.

The response of pancreatic acinar cell carcinoma to platinum and olaparib therapy in a germline BRCA2 variant carrier: case report and literature review.

A 73-year-old Japanese man with a history of distal biliary cancer treated by pancreatoduodenectomy developed pancreatic acinar cell carcinoma (PACC) treated by remnant pancreatectomy and adjuvant chemotherapy. Thirteen months after surgery, multiple liver metastases developed and FOLFOX chemotherapy was initiated. Based on the PACC diagnosis and a positive family history for breast and ovarian cancer genetic testing was performed which revealed a pathogenic germline BRCA2 variant (c.8629G > T, p.Glu2877Ter). Olaparib therapy was initiated and the metastases responded well (partial response). PACC is a BRCA2-associated cancer which may respond well to PARP inhibitors.

Japanese classification of pancreatic carcinoma by the Japan Pancreas Society: Eighth edition.

In 2023, the Japan Pancreas Society (JPS) published the new eighth edition of the Japanese classification of pancreatic carcinoma. We present here an excerpted version in English, based on the latest edition. The major changes in this revision are as follows: In the eighth edition of the Union for International Cancer Control (UICC), the T category was changed to be based on tumor size; however, the eighth edition of the Japanese classification retains the previous T category based on local invasion factors. Lymph nodes have been renamed, and regional lymph nodes have been defined by location. Peritoneal cytology, which was not previously included in distant metastasis (M), has now been included in the M category. Moreover, significant additions have been made regarding the pathological diagnosis of endoscopic ultrasound-guided fine-needle aspiration biopsy (EUS-FNAB) and criteria for histological assessment of the effects after chemotherapy and radiation therapy. Although this classification is aimed at carcinoma originating in the pancreas, not in the bile duct or duodenum, if the differentiation of the primary organ is difficult, this classification should be applied. It is also desirable to describe tumors other than carcinoma and metastatic tumors to the pancreas in accordance with this classification.