Japanese Classification of Esophageal Cancer, 11th Edition: part I

English Edition Committee Members Kenji Nemoto Yamagata University Naohisa Yahagi Keio University Soji Ozawa Tokai University Yoshiaki Kajiyama Juntendo University Tatsuyuki Kawano Tokyo Medical and Dental University Tomio Arai Tokyo Metropolitan Geriatric Hospital and Institute of Gerontology Yuji Tachimori National Cancer Center Hospital Shoji Natsugoe Kagoshima University Kumiko Momma Tokyo Metropolitan Cancer and Infectious Diseases Center Komagome Hospital Yasuyuki Seto Tokyo University Yuichiro Doki Osaka University


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Preface to the 11th Edition Eight years after the publication of the 10th edition in 2007, the 11th edition of the Japanese Classification of Esophageal Cancer has now been published. During this period, supplements to the 10th edition involving the revision of ''disease typing'' and terminology were published in 2008; in addition, following the adoption of criteria for the diagnosis of lesions located at the gastroesophageal junction that was made in cooperation with the Japanese Gastric Cancer Association, a 7-page leaflet was attached to this Classification in September 2013. The present revision was aimed at ensuring consistency with other general rules for surgical and pathological studies on cancer as far as possible, reflecting the latest advances in the diagnosis and treatment of esophageal cancer in Japan and providing a set of rules that are easier to use and that facilitate improvements in treatment outcomes. During this revision, we attempted to secure consistency with the UICC's TNM classification as far as possible. However, this attempt was skipped for the N classification, since the current edition (7th) of the TNM classification does not reflect the nationwide registry data of the Japan Esophageal Society and because the rules for studies on supraclavicular lymph nodes are completely different between our classification and the N classification. This is a significant issue that will need to be addressed in the next revision.
Using nationwide registry data, the effects of regional lymph node excision were reviewed from the viewpoints of lymph node metastasis and the survival rate. As a result, the lymph node groupings were modified (T4 was subdivided into two subtypes, similar to the TNM classification). Following recent advances and the spread of endoscopic treatment, findings from endoscopic treatment have now been incorporated into the description methods, and the exclusion of cancer from intraepithelial neoplasms has been clarified. This revised edition has been prepared as a result of numerous discussions among committee members. Although there are still some questions to be discussed, we wish to take this opportunity to thank the considerable efforts made by the individual committee members.
October, 2015 Esophagus (2017)  General principles of this edition 1. Following the spread of endoscopic treatment, findings from endoscopic treatment (e) have been added to the methods used to describe findings.
2. The criteria for the diagnosis of lesions located at the gastroesophageal junction, which have been jointly adopted by the Japanese Gastric Cancer Association, have been added to the main text.
3. Regarding the depth of tumor invasion, the subgroup T1b-has been added to the subgroup T1b, similar to that for T1a, and the subgroup T4 has been further subdivided into T4a and T4b so as to be consistent with the UICC's TNM classification.
4. Regarding lymph nodes, No. 112ao has been divided into the esophageal side and the dorsal side. Furthermore, to secure consistency with the general rules for surgical and pathological studies on gastric cancer, No. 3 has been divided into No. 3a and No. 3b.
5. Regarding lymph node grouping, modifications have been made to Ut (Group 3 only), Mt/Lt (Groups 1, 2, 3), and Ae (Groups 2, 3). In accordance with the revision of the criteria for the diagnosis of lesions located at the gastroesophageal junction, the same lymph node classification as that used for Ae will now be applied to cancer of the gastroesophageal junction.
6. Regarding the stage of cancer, T1aN1 is now classified as Stage II, as is the case with T1bN1. T4a up to N3 is now classified as Stage III. T4b, beginning with N0, is now classified as Stage IVa.
7. Regarding the extent of residual cancer, classification into R1 based on macroscopic findings is now avoided, consistent with the general rules for surgical and pathological studies on colorectal cancer. 8. Regarding histopathological findings, it has now been made clear that carcinoma in situ is not to be included among neoplasms within the squamous epithelium. The extent of differentiation of both squamous cell carcinoma and adenocarcinoma is now described as ''well differentiated'' or a similar expression, omitting any description of type. Endocrine cell neoplasm is now called neuroendocrine tumor, consistent with the WHO classification. Also, concerning extralymph node metastasis, the expression ''tumor nodule'' has been adopted, consistent with the general rules for surgical and pathological studies on colorectal cancer. Vascular invasion in specimens collected during endoscopic treatment is now rated as (-) or (?), consistent with the method used for gastric cancer.
9. The TNM classification adopted for the revised classification has been switched to the Japanese translation of the TNM classification, 7th edition.
10. Regarding the number of lymph node metastases, the conventional rule for the correction of grouping according to the number of metastases was too complex and was not used frequently. This rule has been deleted from the revised edition.
11. The endoscope pictures have been replaced with clearer ones.
12. Regarding the extents and borders of the lymph nodes, not only schematic figures, but also actual CT images have been provided to simplify understanding, accompanied by the presentation of features that will also be useful for radiotherapy. Since then, the Society has changed its name in 2003 to become the Japan Esophageal Society, and has published the ''Japanese Classification of Esophageal Cancer'' in Japanese with some revisions to keep up to date with treatment results and to provide a standard nomenclature.

Abbreviations
To promote the international use of the Guidelines and the Classification, the Society is publishing this handbook in English entitled ''The Japanese Classification of Esophageal Cancer''.

Object
The term esophageal cancer in the Japanese Classification refers to cancer originating in the esophagus, and cancer metastatic to the esophagus is excluded. All primary malignant tumors in the esophagus should be described according to the Japanese Classification. Checklists for descriptions of the Japanese Classification of Esophageal Cancer are shown in the following tables (Tables 1-3, 1-4).
The order of clinicopathological description is: Tumor location (in addition to describing the distance from the incisor), circumferential extent, tumor length, macroscopic tumor type, histological type (when identified), depth of tumor invasion, lymph node metastasis, distant organ metastasis and stage. Note: In cases in which any findings are modified by combined treatment, findings should be recorded as the estimated most advanced condition throughout the treatment Tracheal invasion was observed from clinical findings; cT4, cN2, cM0, cStage IVa As the tumor responded to chemoradiotherapy, surgery was performed; CRT-sT3, sN2, sM0, sStage III Although the tumor completely responded to chemoradiotherapy on pathological findings, metastasis to Group 3 lymph nodes was observed; CRT-pT0 (T3), pN3, sM0, pStage III Maximum length (mm) and orthogonally oriented maximum width (mm), center of circumferential extent, and circumferential ratio of the tumor to the entire esophagus should be described. In addition, the methods used for diagnosis, such as barium X-ray, endoscopy and EUS, should be recorded. The esophagus is defined anatomically from the esophageal orifice to the esophagogastric junction. The esophageal orifice is at the lower margin of the cricoid cartilage. The identification of the esophagogastric junction (EGJ) will be described later.

Anatomical regions (subsites) of the esophagus
The esophagus lies between the hypopharynx and stomach, and can be anatomically divided into the following portions; cervical esophagus (Ce), thoracic esophagus (Te) and abdominal esophagus (Ae). The zone of the esophagogastric junction is divided into the esophageal side (E) and gastric side (G) ( Fig. 1-1   Vertical margin: pVMX, pVM0, pVM1 Residual tumor: pRX, pR0, pR1, pR2 Curativity: pCur A, pCur B, pCur C superior margin of the esophageal hiatus to the esophagogastric junction).
Note: The zone of the esophagogastric junction is defined as the region between 2 cm in esophagus and 2 cm in the stomach from the esophagogastric junction. The abdominal esophagus is included in this zone.

Principles of description of tumor location
Describe the tumor location identified by examinations according to the following order of priority: barium X-ray, CT, and endoscopic measurements. Include the distance from the incisor in addition to the tumor location. When the tumor location is uncertain because examinations other than endoscopy have yet to be performed, describe only the distance from the incisor. When the tumor extends continuously in more than one portion of the esophagus, the main tumor location is that with the deepest tumor invasion. If it is difficult to determine the site of deepest tumor invasion, the portion at the central point of the tumor can be recorded as the main tumor location. In the case of multiple primary lesions, the locations of the lesions are described in the order of depth of tumor invasion. The deepest lesion is described first. If it is difficult to determine the order of the depth, the description order depends on the size of the area occupied by the lesion. The largest lesion is described first. e.g.: MtLt, LtAeG. Tumors in which invasion is macroscopically diagnosed to be limited to within the submucosa are classified as superficial type, while tumors in which invasion is diagnosed to extend to the muscularis propria or beyond are classified as advanced type. The superficial type has the prefix '0' and is classified into 0-I, 0-II or 0-III. The advanced type is divided into 4 categories: 1, 2, 3, or 4. When a tumor cannot be classified into any of the 5 (0-4) categories or their combinations, it is classified as 5.
2.1.3.2. Macroscopic classification ( Fig. 1-2 Note 1: The macroscopic tumor type before chemotherapy and/or radiotherapy is described. Previous treatment is indicated. Cases with minor changes following treatment and which fit the macroscopic tumor type(s) are classified as type 1-4 and cases of major changes are designated as unclassifiable type. Note 2: Any former treatment(s) is mentioned before the macroscopic tumor type. e.g.: CT-3, CRT-5b, EMR-0-IIc  Type 0-I Superficial and protruding type Type 0-Ip Pedunculated type Type 0-Is Sessile (broad based) type Type 0-II Superficial and flat type Type 0-IIa Slightly elevated type Type 0-IIb Flat type Type 0-IIc Slightly depressed type Type 0-III Superficial and excavated type Other notations Note 1: Combined type: When multiple macroscopic tumor types are mixed in one lesion, it is called a combined type. The wider type is described first and types are connected with ?. Double quotation marks ('''') are placed around the macroscopic tumor type that has the deepest tumor invasion. In this case, the main macroscopic tumor type is the deepest one. However, when an advanced type is mixed with a superficial type, the advanced type is described first and double quotation marks are unnecessary. e.g.: 0-IIc?''0-Is'', 3?0-IIc. Note 2: Superficial spreading type: superficial type 0-II in which the maximal length of the tumor extends 5 cm or more longitudinally. It may be noted additionally in the macroscopic tumor type.   Fig. 1-4. The stations of cervical and thoracic lymph nodes are shown in Figs. 1-5, 1-6 and 1-7. The names and numbers of abdominal lymph node stations are defined in the Japanese Classification of Gastric Carcinoma (Table 1-5).
Note: In deciding the lymph node group of multiple esophageal cancers and widely extending esophageal cancer, the location of the deepest tumor invasion takes precedence in documentation.

Grading of lymph node metastasis (N)
NX Lymph node metastasis cannot be assessed N0 No lymph node metastasis N1 Metastasis involving only Group 1 lymph nodes N2 Metastasis to Group 2 lymph nodes, regardless of involvement of Group 1 lymph nodes N3 Metastasis to Group 3 lymph nodes, regardless of involvement of Group 1 or 2 lymph nodes N4 Metastasis to distant (Group 4) lymph nodes, regardless of whether any other group(s) of regional lymph nodes are involved or not Nodes other than N1 through N3 are expressed as N4 a Limited to the area which can be dissected from the cervical incision Fig. 1-8 Lymph node groups for tumors located in Ce Fig. 1-9 Lymph node groups of tumors located in Ut The stage should be recorded based on the following TNM stage classification. e.g.: T2N2M0, Stage III.

Multiple primary cancers
Multiple primary cancers of the esophagus: The term ''multiple primary cancers of the esophagus'' is used to refer to the presence of two or more primary esophageal cancers.  Multi-organ primary cancers including the esophagus: The term ''multi-organ primary cancers including the esophagus'' is used to refer to the presence of one or more primary malignant diseases other than esophageal cancer in a patient with primary esophageal cancer. Multiple primary cancers including the esophagus: The term ''multiple primary cancers including the esophagus'' indicates the concept combining both ''multiple primary cancers of the esophagus'' and ''multi-organ primary cancers including the esophagus''.
Note 1: In cases with multi-organ primary cancers including the esophagus, organs other than the esophagus should be specified in parentheses. Note 2: Whether the multiplicity is synchronous or metachronous should be recorded. e.g.: Multi-organ primary cancers: stomach (synchronous).

Handling of the resected specimen
The resected esophagus should be cut and opened along the longitudinal line on the side opposite to the lesion. The opened esophagus should be gently stretched longitudinally and fixed so that the length of the specimen becomes similar to its size in vivo. The specimen should be treated with iodine solution after fixation in order to accurately describe the macroscopic findings. This is particularly important in superficial carcinoma. Photographic recording is recommended for both fresh and fixed specimens.

Description of surgical findings and macroscopic findings of primary tumor
Operative findings should be identified in the record putting ''s'' in front of each factor. e.g.: sT2, sStageII.
3.2.1. Tumor size ( Fig. 1-13) The greatest longitudinal dimension in millimeters and the greatest transverse (at 90°to the longitudinal tumor axis) dimension in millimeters: a 9 b (mm)  N0  N1  N2  N3  N4  M1   T0, T1a  0  II  II  III  IVa  IVb   T1b  I  II  II  III  IVa  IVb   T2  II  II  III  III  IVa  IVb   T3  II  III  III  III  IVa  IVb   T4a  III  III  III  III  IVa  IVb   T4b  IVa  IVa  IVa  IVa  IVa  IVb T4a pleura, pericardium, diaphragm, lung, thoracic duct, azygos vein, nerve T4b aorta (large vessel), trachea, bronchus, pulmonary vein, pulmonary artery, vertebra 3.2.2. Distance from surgical margin to the tumor ( Fig. 1-13 Surgically dissected lymph nodes are classified according to the definition of regional lymph nodes, given individual names or numbers and sent to pathologists. The lymph nodes dissected en bloc with the esophagus should be isolated from the specimen before fixation.

Grading of lymph node metastasis (N)
The surgical diagnosis of the grading of lymph node metastasis (sN) should be made comprehensively with intraoperative findings of macroscopic observation, imaging examinations, immediate pathological diagnosis with frozen section, and macroscopic findings obtained during postoperative preparation.

Field of lymph node dissection
Three-field dissection Dissection of cervical, thoracic and abdominal lymph nodes through cervical, thoracic and abdominal approaches, respectively Note Two-field dissection Dissection of thoracic and abdominal lymph nodes through thoracic and abdominal approaches, respectively.Dissection of cervical and abdominal lymph nodes through cervical and abdominal approaches, respectively.Dissection of cervical and thoracic lymph nodes through cervical and thoracic approaches, respectively.

One-field dissection
Dissection of a single field of cervical, thoracic and abdominal lymph nodes through cervical, thoracic or abdominal approaches, respectively. Note: The term ''three-field dissection'' should not be applied when only the cervical paraesophageal nodes (101R, 101 L) are dissected in the neck. 3.6. Residual tumor (R) Note 1 (Fig. 1-14 Cur A Complete removal of the tumor is strongly believed. sStage 0-III, and sR0, and sD [ sN ( Fig. 1-14).

Pathological findings
4.1. Handling of the surgically resected specimens ( Fig. 1-15) Before cutting the resected esophagus, the formalin-fixed specimen should be treated with iodine solution to confirm the unstained area. Rinsing the sample with tap water for at least 1 h can result in a good staining condition. To increase the contrast between stained and unstained areas, the sample should be treated with a relatively low concentration (0.1-0.5%) of iodine solution for a long time.
The resected specimen should be cut parallel along the long axis of the esophagus. Whole step sections are made in superficial type cancer. One representative section of an advanced tumor at the site of deepest invasion, parallel or perpendicular to the esophagus should be blocked and used for microscopic examination. Schemas or photographs of the sites of cut sections should be preserved.

Description of pathological findings
The p (pathology) mark is prefixed to the pathological findings except for vascular invasion as follows. e.g.: p0-Is, pType 2, pT2, pStagedII.
carcinoma (pT1a-EP carcinoma) or squamous cell carcinoma in situ can be diagnosed when cellular and structural atypia are sufficient to suggest malignancy. The 10th edition mentioned that low-grade intraepithelial neoplasia might contain basal-type squamous cell carcinoma. When such lesions are distributed in the lower half of the epithelium and are sufficiently atypical to suggest malignancy, the lesion can be diagnosed as squamous cell carcinoma according to the classification of the 11th edition. Note 4: Most ''squamous intraepithelial neoplasias'' according to the definition of the 11th edition are endoscopically or macroscopically recognized as a ''small unstained or tan-stained area''. The lesion may be solitary or multiple. Note 5: According to the definition of the 11th edition, intraepithelial neoplastic lesion without atypia sufficient to suggest malignancy is termed as squamous intraepithelial neoplasia. Thus, intraepithelial neoplasia does not include squamous cell carcinoma in situ. Please be careful to note the differences in the definitions of intraepithelial neoplasia between the 10th and 11th editions. A two-tier subclassification of intraepithelial neoplasia (low grade and high grade) is not used in the 11th edition. In making a diagnosis of intraepithelial neoplasia based on a biopsy specimen, the inclusion of one of the following comments is recommended: ''follow-up is needed'', ''re-biopsy after a short time period should be recommended'', or ''immediate rebiopsy is strongly recommended because of suspicious carcinoma''. Note 6: When the determination of a biopsy specimen as ''neoplastic'' or ''reactive'' is difficult, the specimen should not be diagnosed as ''intraepithelial neoplasia'', but rather as ''atypical epithelium'' or ''atypical epithelium, indefinite for neoplasia''. For clinicians, the inclusion of instructions such as the need for a re-biopsy is recommended. Note 7: Squamous cell carcinoma, which is limited to within the epithelial layer without invasion, is different from squamous intraepithelial neoplasia. Squamous cell carcinoma in situ is equal to squamous cell carcinoma with a depth of pT1a-EP. Note 8: Neuroendocrine tumor and neuroendocrine carcinoma are formally classified as carcinoid tumor and endocrine cell carcinoma, respectively. These terms have been adopted according to the WHO classification. In Japan, however, ''endocrine cell carcinoma'' is considered to be the correct term, since endocrine cells in the gastrointestinal tract originate from gastrointestinal stem cells.

Depth of tumor invasion (pT) Note 1-7
Note 1: Intraductal spreading of cancer is categorized as pT1a-EP, and if the tumor invades beyond the duct of the esophageal gland, the depth of tumor invasion is defined as the layer presenting extraductal invasion of cancer. Note 2: The vertical depth of submucosal invasion is measured from the muscularis mucosae, and the depth is recorded in parentheses. e.g.: pT1b-SM2 (400 lm). Note 3: The depth of tumor invasion is defined histologically as the point of deepest direct invasion by the primary tumor. Vascular invasion within the confines of the primary tumor should be regarded as the depth of direct tumor invasion. However, when vascular invasion is found outside the confines of the primary tumor, the depth of such invasion should be specified in parentheses after the depth of direct invasion. For example, when a primary tumor has invaded into the submucosa (pT1b) but lymphatic invasion is found in the muscularis propria outside the main tumor, this is designated as pT1b (ly-T2). Note 4: Cancer that has macroscopically invaded adjacent organ(s) (sT4) and histologically diagnosed malignant tissue recognized on the surgical radial margin (pRM1) are categorized as pT4.
Note 5: Direct invasion of tumor from lymph node metastasis to the adjacent organ(s) is categorized as pT4. e.g.: Direct invasion from No.108 lymph node metastasis to the lung: pN1 (108-lung) T4a Note 6: In determining the depth of invasion of an advanced cancer after preoperative treatment, both the depth of invasion by residual tumor and the estimated depth of tumor invasion prior to treatment should be considered. The type of adjuvant therapy (RT-, CT-, CRT-, EMR-), depth of invasion by the residual tumor, and estimated depth of tumor invasion prior to treatment should be specified in the given order, with the last item in parentheses. e.g.: RT-pT1b (T4). Note 7: If no residual tumor is found in an entire specimen after preoperative treatment, the designation should be pT0, and its stage is recognized as the same as T1a. e.g.: CRT-pT0 (T3), N0, M0, CRT-pStage 0.

Infiltrative growth pattern (INF)
The growth and infiltrative pattern of tumor can be classified into one of the following three types, with regard to the predominant pattern observed at tumor margins. Esophagus (2017)  Note 1: Examination using immunohistochemical staining with an anti-D2-40 antibody should be described. e.g.: ly1 (D2-40). Note 2: Carcinomatous lymphangiosis in distant organ(s) is categorized as M1. Note 3: A tumor mass found in the thoracic duct is described as positive lymphatic invasion. 4.2.9. Pathological criteria for the effects of radiation and/ or chemotherapy (Fig. 1-16) In cases of preoperative radiation and/or chemotherapy, the radiation dose and method of administration, type and dose of chemotherapy, and time interval between preoperative therapy and surgical resection of the tumor are described. In cases of preoperative treatment, all the specimens in which the primary tumor is macroscopically possibly present should be examined histologically.
Grade 0: ineffective No recognizable cytological or histological therapeutic effect.
Grade 1: slightly effective Apparently viable cancer cells (including cells having eosinophilic cytoplasm with vacuolation and swollen nuclei) account for 1/3 or more of tumor tissue, but there is some evidence of degeneration of cancer tissue or cells.
Grade 1a: Viable cancer cells accounting for 2/3 or more tumor tissue. Grade 1b: Viable cancer cells accounting for 1/3 or more, but less than 2/3, of tumor tissue.

Tumor types
The tumor types are classified into Type 0-I, Type 0-IIa, Type 0-IIb, Type 0-IIc, Type 0-III, combined type, and others. propria mucosae have been confirmed on all horizontal resection margins. eHM1 The tumor is exposed on one of its horizontal resection margins.

Vertical margin (eVM)
eVMX Whether residual tumor is present on the vertical margin cannot be assessed. eVM0 The tumor is not exposed on any of its vertical margins. eVM1 The tumor is exposed on one of its vertical margins. Presence of an iodine-unstained area on the margin of the resected specimen. eR2 (incomplete resection) Presence of residual tumor.
Note 1: The clinical assessment of the residual tumor, referring to the iodine staining of the resected specimen, should be performed immediately after the endoscopic resection. In cases with a piecemeal resection, iodine staining of the ulcer margin after resection should be referenced.
Note 2: This assessment method should be applied to squamous cell carcinoma. (Fig. 1-17) Before cutting, formalin-fixed specimen should be stained with iodine solution to confirm unstained area. Note Cutting lines are decided as crossing lines at right angles to the tangent line at the resection margin closest to the tumor, and a whole resected specimen is cut in slice each 2-3 mm thick.

Preparation for pathological examination
Note: Rinsing the sample with tap water for at least 30 min can result in a good staining condition. To make a clearer contrast between stained and unstained areas, the sample should be treated with relatively low concentration (0.1-0.5%) of iodine solution for a little bit longer time.

Description of pathological findings
The pathological diagnosis of an endoscopically resected specimen is summarized by the histological type, depth of tumor invasion, assessment of resection margin (horizontal and vertical), and vascular invasion.

Pathological diagnosis
The diagnosis is based on the histological classification (4.2.1). Although most esophageal tumors are squamous cell carcinoma, the evaluation of histological differentiation is omitted for intraepithelial carcinoma.

Depth of tumor invasion (pT)
A mucosal cancer is categorized in three depths of pT1a-EP, pT1a-LPM and pT1a-MM. In a submucosal cancer, the Fig. 1-17 How to cut endoscopically resected specimens distance from the lamina muscularis mucosae is described because the entire submucosal layer cannot be examined in an endoscopically resected specimen. A submucosal cancer is sub-classified as pT1b-SM1 (submucosal tumor invasion limited to within 200 lm) and pT1b-SM2 (invasion to more than 200 lm). e.g.: pT1b-SM2, 300 lm. propria mucosae are confirmed on all horizontal resection margins. pHM1 The tumor is exposed on any horizontal resection margin.

Vertical margin (pVM)
pVMX It cannot be assessed whether there is residual tumor on the vertical margin or not. pVM0 No tumor is exposed on any vertical margin. pVM1 The tumor is exposed on any vertical margin.
Note 1: When no tumor is recognized in any resection margin, it is defined as a complete resection (pR0), and when a tumor is recognized in any resection margin, it is defined as an incomplete resection (pR1). Note 2: When vascular invasion is present in the resection margin, it is defined as a positive resection margin (pHM1, pVM1).

Non-assessable resection margin (pRX)
1. Because of crushing injury or the burn effect in the specimen during endoscopic resection, non-cancerous tissue in the resection margin cannot be confirmed. 2. Reconstruction after piecemeal resection is impossible. Note 3. Suspected residual tumor in the basal layer because of non-continuous tumor extension. 4. Possible residual tumor in the vertical margin because of intra-ductal spread. 5. Indeterminable residual tumor because of other reasons.
Note: In piecemeal resection pR0 is confirmed only when restructuring is possible and only non-cancerous tissue is recognized at the resection margins of the restructured specimen. Infiltrative growth of tumor nests with an ill-defined border from the surrounding tissue.

Vascular invasion (ly/v) Note
It is not necessary to evaluate the degree of vascular involvement: only its presence or absence should be described. Note: A special staining method for elastic fibers of the vascular wall, such as Elastica van Gieson (EVG) or Victoria blue (VB) staining, is needed to determine venous invasion. Immunostaining with an anti-D2-40 antibody is useful to confirm lymphatic invasion. When differentiating between lymphatic and venous invasion is difficult, the case should be described as ly/v. When lymphatic and/or venous invasion is prominent, this evaluation should be included in addition to ly (?) or v (?).

Report of pathological findings
All the above-mentioned factors should be described, and the attachment of a figure showing the general view of the resected specimen with the regional depths of tumor invasion and vascular invasion is recommended. It is better to attach a schematic figure showing pathological findings on the cut surface if necessary. 5.5 Residual tumor (pR) Note 1,2 pRX The existence of residual tumor at the resection margin cannot be assessed pathologically. Esophagus (2017)  The EGJ should be defined systematically in accordance with the criteria listed below. Among these criteria, endoscopic findings should be given priority over findings obtained using other diagnostic modalities.

Endoscopic findings
Lower margin of palisading small vessels If the palisading small vessels are unclear, the oral margin of the longitudinal folds of the greater curvature of the stomach is defined as the EGJ.

Upper gastrointestinal series (UGI)
Narrowest locus of the lower esophagus In the presence of a sliding hiatal hernia, the upper end of the longitudinal folds is defined as the EGJ.
In the presence of Barrett esophagus, the upper end of the longitudinal folds is defined as the EGJ.

Pathological study
Macroscopic For a non-intact mucosal layer, the EGJ should be defined based on the macroscopic findings of the surgical specimen, and the EGJ should be presumed based on the presence of histological structures associated with the esophagus or stomach.

Barrett mucosa
Columnar epithelium continuous from the stomach with or without intestinal metaplasia

Barrett esophagus
An esophagus containing Barrett mucosa should be designated as Barrett esophagus. Note 1 At least one of the following conditions must be satisfied.
1. Presence of esophageal gland ducts in the mucosal layer or proper esophageal glands in the submucosal layer within the area of columnar epithelium. 2. Presence of squamous islands in the columnar epithelium. Lower esophagectomy: the lower esophagus (including abdominal esophagus) is resected Partial esophagectomy: resection of full-thickness partial esophagus Note 2 Mucosal resection: resection of mucosal and submucosal layers Others Note 1: Lower esophagectomy includes resection of the lower esophagus and cardia. Note 2: In partial esophagectomy, the location of the esophagus resected should be described.

Combined resection
The organ(s) resected together because of cancer invasion should be described.
Note: Total or partial resection of the organ(s) should be described.
One-piece resection rate = (number of patients who underwent one-piece resection/total number of patients who underwent endoscopic resection) 9 100 Note Curativity rate = (number of patients who underwent curative endoscopic resection/total number of patients who underwent endoscopic resection) 9 100 Note: The number of patients who underwent endoscopic resection indicates those who underwent endoscopic mucosal dissection and endoscopic submucosal dissection. It does not include the number of patients treated by laser therapy or photodynamic therapy.

Patients with chemotherapy and/or radiotherapy
Total numbers and rates according to response evaluation criteria after treatment.

Operative mortality Note
Operative mortality = (operative deaths/patients operated) 9 100 Mortality after esophagectomy = (deaths after esophagectomy/patients who underwent esophagectomy) 9 100 Note: Operative death means death within 30 days after operation in or out of hospital.
8.6. Hospital mortality Notes 1, 2 Hospital mortality = (hospital deaths/patients operated) 9 100 Hospital mortality after esophagectomy = (hospital deaths after esophagectomy/patients who underwent esophagectomy) 9 100 Note: Hospital death is defined as death during the same hospitalization, regardless of department at time of death.

Long-term outcome
The following items should be recorded for survival analysis. This is the period during which the esophagus is preserved in patients with esophageal cancer who underwent nonesophagectomy treatment such as endoscopic mucosal resection, endoscopic submucosal dissection, chemotherapy and/or radiotherapy. The rate of those patients per all patients who underwent treatment for esophageal cancer is described. [Reference] Murakami Time until death regardless of cause from the initial date. In observation studies, the day starting treatment, or the day confirming diagnosis is used as the initial date. In clinical trials, the ''registration date'' (the allocation day in the case of a randomized controlled trial) is used.

Median survival time (MST)
Period from the initial date to the first date of the survival rate being less than 50% in the survival curve calculated by the Kaplan-Meier method. The initial date is the same as described in 8.9.2.

Survival rate
The rate of survivors at a given time 8.9.5. Progression-free survival (PFS), time to progression (TTP) It is the shortest period among periods from the initial date to progression or recurrence, or death. Death from any cause is regarded as an event, in PFS. Death is only regarded as an event if it is caused by esophageal cancer, in TTP.
8.9.6. Relapse-free survival, recurrence-free survival (RFS) This is the period between the initial date to recurrence or death.
The day when the disease-free state was achieved such as an operation day, is used as the initial date.

Disease-free survival (DFS)
It is the shortest period among the periods from the initial date to a recurrence, death, or diagnosis of a second primary cancer. The day when the disease-free state such as an operation day was achieved, is used as the initial date.

Time to treatment failure (TTF)
This is the shortest period among the periods from the initial date to treatment cessation, progression, and death.

Response duration
Period from the first day when the disease was assessed as CR or PR until progression.

Complete response duration
Period from the first day when the disease was assessed as CR until recurrence. [Reference] Japan Society for Clinical Oncology. Terminology in Clinical Oncology 2013 (in Japanese) Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://crea tivecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.