SITE SPECIFIC DATA ITEMS (SSDI)/ GRADE

Description

The esophagus chapter of the AJCC Cancer Staging Manual 8th edition includes the esophagogastric junction (also called the cardia or gastroesophageal junction) and the proximal 2 cm of the stomach. The cardia is defined as the opening or junction between the esophagus and the stomach, and it is between 0.1 and 0.4 cm in length. This 2-cm boundary measurement is based on the Siewert classification of gastroesophageal cancers, which defines an area 2 cm above and 2 cm below the cardia or esophagogastric junction. Both of these areas are coded to primary site C160, so a discriminator is needed to get to the correct chapter. To determine whether a cancer of the cardia should be coded according to the esophagus schema or the stomach system, it is necessary to identify the midpoint or epicenter of the tumor. If the midpoint is at or above the cardia, the tumor is esophageal. If the midpoint of the tumor is within 2 cm distal to the gastroesophageal junction (GEJ) and the lesion extends to or across the GEJ, the case should be coded with the esophagus system. If the midpoint of the tumor is within 2 cm distal to the GEJ and the lesion does not extend to the GEJ, the case should be coded with the stomach schema. Any tumor with a midpoint more distal than 2 cm from the GEJ is coded with the stomach schema.

Notes

**Note 1:** **Schema Discriminator for C160** * Under primary site code C160, there are two different structures that are staged differently. * Esophagogastric junction (Esophagus schema) * Cardia of the Stomach (Stomach schema) **Note 2:** **The gastroesophageal junction** * The gastroesophageal junction (GEJ) (primary site C160) is a poorly defined anatomic area that represents the junction between the distal esophagus and the proximal stomach (cardia). * The true anatomic GEJ corresponds to the most proximal aspect of the gastric folds, which represents an endoscopically apparent transition point in most individuals. **Note 3:** **The cardia** * The cardia (also assigned primary site C160) is the **first part of the stomach. It is the region where the stomach meets the end of the esophageal tube. * This region is also referred to as the Z-line or the esophagogastric junction. **Note 4:** **Physician's statement** * Physician's statement can be used to code this data item when no other information is available. * ***Example:*** Patient diagnosed with tumor involving the cardia. No other information available. Physician stages the patient using the Esophagus Staging System/CAP protocol * ***Answer:*** Code 2 based on physician using the Esophagus Staging System **Note 5:** **Midpoint (epicenter)** * Tumors with their midpoint (epicenter) in the GE Junction are staged as Esophagus, while tumors with their midpoint (epicenter) in the cardia/stomach are staged using the Stomach Staging System. * **Note:** The CAP protocol uses "midpoint" instead of "epicenter." This is the pathologist's assessment of the point of tumor origin, regardless of tumor extension into other tissues.