An important diagnosis for patients when they are informed of a gastric cancer diagnosis is staging. What exactly does staging tell us?
Gastric cancer staging, what does it do?
Generally, it is believed that gastric cancer staging serves 3 purposes:
- Reflects the disease and facilitates communication among providers and with patients.
- To guide treatment, for different stages of gastric cancer, physicians will plan general treatment ideas based on guidelines and clinical reality.
- Predicting outcomes.
- Predicting outcomes, the outcome of gastric cancer is also closely related to its stage.
Staging of gastric cancer, how does it reflect the disease?
Staging represents what state the cancer is in. For example, if the pathologist tells the clinician that the patient is T3N0M0, which is stage IIA, it is easy for the clinician to understand what this patient’s disease is generally like, including the depth of tumor infiltration and the presence of lymph nodes and distant metastases.
Specifically, gastric cancer is divided into stages 0 to IV. Stage 0 (TisN0M0) represents carcinoma in situ, which is a very early stage of gastric cancer in which the tumor is present only in the innermost epithelial cells of the stomach wall. Stage IV represents the presence of distant metastasis, i.e. the stomach cancer has metastasized to the liver, lung and other organs not directly adjacent to the stomach. There are also differences in the depth of infiltration (T) and the extent of lymph node metastasis (N) for gastric cancer in stages I to III, as shown in the figure below.
| Eighth Edition American Joint Committee on Cancer (AJCC) Pathologic Staging of Gastric Cancer | |||||
|---|---|---|---|---|---|
| N0 | N1 | N2 | N3a | N3b | |
| T1 |
ⅠA |
ⅠB |
IIA |
IIB |
IIIB |
| T2 |
ⅠB |
IIA |
IIB |
IIIA |
IIIB |
| T3 |
IIA |
IIB |
IIIA |
IIIB |
IIIC |
| T4a |
IIB |
IIIA |
IIIA |
IIIB |
IIIC |
| T4b |
IIIA |
IIIB |
IIIB |
IIIC |
IIIC |
- Tis: tumor does not infiltrate the mucosal lamina propria
- T1: tumor is confined to the mucosa or submucosa
- T2: tumor infiltration beyond the submucosa but confined to the lamina propria
- T3: Tumor infiltration beyond the intrinsic muscular layer but confined to the subplasma tissue
- T4a: tumor invades the plasma membrane (visceral peritoneum)
- T4b: tumor invades adjacent tissue structures
- N0: no metastasis in regional lymph nodes
- N1: 1~2 regional lymph node metastases
- N2: 3~6 regional lymph node metastases
- N3a: 7~15 regional lymph node metastases
- N3b: 16 or more regional lymph node metastases
Stage of gastric cancer, how to guide treatment?
Determining the stage of gastric cancer is helpful for physicians to make initial choices about treatment options. For stage 0 and I gastric cancer, surgical resection is usually sufficient, usually without adjuvant radiotherapy, and the resected lesion can be removed endoscopically. For stage II and III gastric cancer, perioperative treatment with surgery as the core is usually required, and adjuvant radiotherapy is usually needed. For stage IV gastric cancer, a combination of systemic drug therapy is generally used, and only for patients with a single distant metastasis physicians will consider surgery based on multidisciplinary discussions.
Stage of gastric cancer, what does it suggest about outcome?
Stage of gastric cancer, to some extent, can indicate its outcome, but, of course, the exact survival depends on a number of factors, including the patient’s own condition and treatment. The 5-year survival rates were reported to be 93.8% and 80.8% for stage IA and IB, respectively, and 70.8% and 59.6% for stage IIA and IIB, respectively, dropping to 44.4%, 32.9%, and 18.9% for stage IIIA, IIIB, and IIIC, and 10.2% for stage IV.
Staging of gastric cancer can give us a lot of information to understand the disease, treatment plan, and outcome. Of course, a comprehensive assessment must be made in the context of the clinical situation. (Contributed by Peng Gao, Department of Gastrointestinal Oncology, The First Affiliated Hospital of China Medical University)