A revised edition (7th edition) of the General Rules for the Study of Pancreatic Cancer was published in 2016 after 7 years. Among the most significant highlights of the revision are the user-friendly descriptions and tumor classification consistent with the tumor-node-metastasis (TNM) classification of the Union for International Cancer Control (UICC) (7th edition), which are easy to understand not only for surgeons and pathologists, but also for internists. Furthermore, the tradition from previous editions, wherein the addition of detailed items unique to General Rules that allows the emphasis of correlations of the stage classification with the prognosis based on the enormous data on pancreatic cancer registration, has been carried forward. Based on these two policies, the General Rules is highly appreciated, not only in Japan, but also in foreign countries, and is expected to be used widely by more doctors and researchers than ever.

Revision concepts and major revision points of the seventh edition of Japanese classification of the pancreatic cancers were reviewed. The Japanese classification of pancreatic cancer was released in the seventh edition of the General Rules for the Study of Pancreatic Cancer by the Japan Pancreas Society (JPS) in July 2016. The principal points of revision are as follows: (1) definition of the parts of the pancreas, (2) T categories: consistency with those of the UICC seventh edition and reappraisal of the anatomy of the extrapancreatic nerve plexuses, (3) N categories: classification based on numbers of lymph nodal metastasis among the regional lymph nodes; N1a: metastasis in 1 to 3 regional lymph nodes and N1b: metastasis in 4 or more regional lymph nodes, (4) Staging system: consistency with those of the UICC seventh edition, and (5) histopathological classification which is consistent with the WHO classification. The following new items have been added: (1) diagnostic guidelines of tumor extension and lymph node metastasis based on multi-detector CT (MD-CT), (2) objective criteria defining resectability status based only on findings from MD-CT, (3) cytopathology guidelines, and (4) criteria of histological response to drug therapy and/or radiotherapy. The revised seventh edition of JPS pancreatic cancer classification focuses on establishing consistency to UICC (seventh edition), while maintaining the originality of JPS classification.

In the 7th edition of General Rules for the Study of Pancreatic Cancer by the Japan Pancreas Society (JPS), criteria defining resectability status based on dynamic CT findings have been established after thorough discussion among pancreatic surgeons, gastroenterologist, radiologist, and pathologist, taking into consideration the National Comprehensive Cancer Network (NCCN) 2015 guidelines. The purpose of defining resectability criteria is to improve patient selection for surgery and to identify the likelihood of an R0 resection. These criteria are considered to be utilizable by pancreatic surgeons, as well as gastroenterologist and radiologist alike. Since the criteria are objective, based solely on dynamic CT findings, they avoid subjective definitions such as "SMV/PV involvement allowing for safe and complete resection and vein reconstruction" in BR pancreatic cancer and "unreconstructable SMV/PV due to tumor involvement or occlusion" in UR pancreatic cancer. Instead of subjective definitions for SMV/PV involvement, we have adopted the objective definition: SMV/PV involvement exceeding or not exceeding the inferior border of the duodenum. Proper R0 resection and treatment option of adjuvant and neo-adjuvant therapy should be compared and discussed on common criteria.

The 7th edition of the General Rules for the Study of Pancreatic Cancer was published in 2016. Rules for imaging diagnosis of pancreatic cancers were recently added in this edition. We present methods for dynamic CT and CT evaluations of extension of pancreatic cancers, including serosal and retroperitoneal invasion, peripancreatic nerve plexus invasion. As for lymph node metastases, we illustrate numbering of lymph nodes on CT images and give an explanation of CT criteria for the diagnosis of lymph nodes metastases from pancreatic cancers.

A grading system of histological response to neoadjuvant therapy was recently adopted in the 7^th Edition of the General Rules for the Study of Pancreatic Cancer. In this grading system, unlike Japanese general rules for other types of cancer that focus on the evaluation of the remaining tumor cells, it requires the evaluation of both host reactions to tumor destruction and cytologic changes of tumor cells. The effects of neoadjuvant therapy are graded by the ratio of residual viable tumor cells to the estimated tumor volume based on host reaction to tumor destruction. The clinical significance of histological responses to neoadjuvant therapy in pancreatic cancer is not well established. Thus, by establishing a grading system for neoadjuvant therapy for pancreatic cancer, further evidences for clinical significance would be provided.

The Japan Pancreas Society published the 7^th Edition of the General Rules for the Study of Pancreatic Cancer in 2016. Revised points in pathology-related matters were as follows: 1) histological criteria for local tumor extension were clarified, 2) histological classification of pancreatic neoplasms was revised on the basis of the WHO histological typing. In addition, sessions for: "criteria of histological response to drug therapy and/or radiotherapy", "pancreatic biopsy reporting formats" and "pancreas related cytology reporting formats" were newly proposed. Here we summarize principal points of revision and its concepts.

Previously, only two cases of pathological T1 anaplastic carcinoma of the pancreas have been reported in Japan, this case marks the third. A 77-year-old man was admitted to our hospital for epigastric discomfort and bloody stools. Computed tomography (CT) revealed a high density 1.8×1.5cm diameter pancreatic head tumor. Enhanced CT revealed a low density area in the center of tumor during the late phase. Colonoscopy revealed a type 2 tumor occupying two thirds of the circumference in the rectum (Ra-Rb). Biopsy revealed a well differentiated tubular adenocarcinoma. Preoperative diagnosis was primary rectal cancer and invasive pancreatic ductal cancer. We performed a subtotal stomach-preserving pancreaticoduodenectomy with portal vein resection and a Hartmann's procedure. The pancreatic tumor was 1.8×1.3cm in size and showing components of hemorrhage and necrosis. Pathological diagnosis was anaplastic carcinoma of the pancreas, giant cell type, pT1, pN0, M0, Stage I. The rectal tumor was diagnosed as well differentiated adenocarcinoma, pT3, pN0, M0, stage II. Postoperative prognosis was good, and the patient remains recurrence free 7 months after surgery.

This case involved a 43-year-old man who was diagnosed with severe acute gallstone pancreatitis and immediately admitted to a nearby hospital. Despite medication, the amount of fluid collected around the pancreas increased, he was transported to the Emergency Department of this Hospital. The patient was diagnosed with acute necrotic collection with infection resulting from necrotizing pancreatitis and CT-guided drainage was performed. ERP revealed that the pancreatic duct was obstructed at the head of the pancreas, and the patient was diagnosed with a pancreatic leak and disruption of the main pancreatic duct in the pancreatic body. Pancreatic necrosis had caused an abscess, but the abscess cavity diminished in size as a result of drainage. However, the cavity reappeared, and endoscopic gastric drainage and abscess drainage were performed. The abscess cavity disappeared, but persistent inflammation of the pancreatic tail and dilation of the pancreatic duct in the pancreatic body were noted. The patient was diagnosed with disconnected pancreatic duct syndrome and obstruction of the pancreatic duct in the pancreatic head and body. The parenchyma of the pancreatic head had detached, and pancreatic function was dependent upon the pancreatic tail. In addition, HbA1c levels began to worsen. Because there were concerns that pancreatic atrophy would occur and the patient would develop diabetes, side-to-side pancreaticojejunostomy was performed to preserve remnant pancreatic function. The patient's postoperative course was satisfactory, there were no symptoms of pancreatitis, and the patient's HbA1c levels also improved.

A 65-year-old male with elevated CA19-9 levels was diagnosed as locally advanced unresectable pancreatic head cancer, which was over 5cm in size and had invaded to the celiac artery and portal vein by computed tomography (CT). He underwent a regimen of chemoradiotherapy (CRT) with gemcitabine (GEM) and S-1. At 1 year and 4 months after the initial treatment, tumor had disappeared. At 2 years, PET/CT showed no accumulation of FDG. After 5 years, lung metastasis appeared and progressed slowly. He survived 10 years and 7 months after the initial treatment.