Gastric Cancer Staging Explained

The internationally recognized standard staging system for gastric cancer is known as the AJCC-TNM classification. This system evaluates the extent of cancer based on three key factors: tumor depth, lymph node involvement, and distant metastasis.

T-stage refers to the depth of tumor invasion:
In gastric cancer, the T classification is based on how deep the tumor has penetrated the stomach wall. If the tumor is limited to the mucosa, it is classified as T1. When it invades the muscular layer, it is categorized as T2. T3 indicates the tumor has reached the serosal layer, and T4 means the cancer has breached the serosa and is invading nearby organs.

N-stage indicates lymph node involvement:
Lymph node spread is a critical factor in staging. If cancer has spread to 1-2 regional lymph nodes, it is classified as N1. If 3-6 lymph nodes are affected, it's N2. When 7 or more lymph nodes are involved, the classification is N3.

M-stage refers to distant metastasis:
M0 means there is no distant spread, while M1 indicates that the cancer has metastasized to distant organs or tissues.

Overall staging of gastric cancer:
Combining the TNM classifications allows doctors to assign an overall stage to the cancer. Stage I is considered early-stage disease, with minimal spread and high treatability. Stage II indicates slightly more advanced disease, often referred to as early-advanced. Stage III is classified as locally advanced or mid-late stage, and Stage IV is considered advanced or late-stage cancer, often involving distant metastasis.

Understanding the stage of gastric cancer is essential for determining the most effective treatment plan and predicting patient outcomes. Early detection significantly improves the chances of successful treatment.