From the Guidelines
Lung adenocarcinoma that has not metastasized to lymph nodes is typically classified as stage I or II.
Staging of Lung Adenocarcinoma
The staging of lung adenocarcinoma is based on the TNM system, which takes into account the size and location of the tumor (T), the presence of lymph node metastases (N), and the presence of distant metastases (M) 1.
- The T stage is divided into several sub-stages based on the size of the tumor, with T1a being the smallest and T4 being the largest 1.
- The N stage is divided into three sub-stages: N0 (no lymph node metastases), N1 (metastases to ipsilateral peribronchial and/or hilar lymph nodes), and N2 (metastases to ipsilateral mediastinal and/or subcarinal lymph nodes) 1.
- The M stage is divided into two sub-stages: M0 (no distant metastases) and M1 (distant metastases) 1.
Stage I and II Lung Adenocarcinoma
Stage I lung adenocarcinoma is typically characterized by a small tumor (T1a or T1b) with no lymph node metastases (N0) and no distant metastases (M0) 1.
- Stage IA1: T1a(mi) or T1a, N0, M0
- Stage IA2: T1b, N0, M0
- Stage IA3: T1c, N0, M0
- Stage IB: T2a, N0, M0 Stage II lung adenocarcinoma is typically characterized by a larger tumor (T2a or T2b) with no lymph node metastases (N0) and no distant metastases (M0) 1.
- Stage IIA: T2b, N0, M0
- Stage IIB: T1a-c, N1, M0 or T2a-b, N1, M0 or T3, N0, M0 In summary, lung adenocarcinoma that has not metastasized to lymph nodes is typically classified as stage I or II, depending on the size and location of the tumor 1.
From the Research
Lung Adenocarcinoma Staging
- Lung adenocarcinoma that has not metastasized to lymph nodes is typically classified as stage I, according to the TNM staging system 2.
- Stage I lung adenocarcinoma is further subdivided into stage IA and stage IB, based on the size of the tumor and the presence of other factors such as pleural invasion or intrapulmonary metastasis 3, 4.
- In stage IA lung adenocarcinoma, the tumor is typically small (less than 4 cm in size) and there is no evidence of lymph node metastasis or distant metastasis 5.
- The prognosis for stage IA lung adenocarcinoma is generally good, with 5-year survival rates ranging from 90% to 100% 3, 5.
- However, some studies have identified factors that can affect the prognosis of stage IA lung adenocarcinoma, such as the presence of a micropapillary pattern or tumor spread through air spaces (STAS) 3, 4.
Factors Affecting Prognosis
- The presence of a micropapillary pattern in stage IA lung adenocarcinoma has been associated with a poorer prognosis, with 5-year survival rates ranging from 79% to 93% 3.
- Tumor spread through air spaces (STAS) has also been identified as a predictor of occult lymph node metastasis in clinical stage IA lung adenocarcinoma, and is associated with a higher risk of recurrence 4.
- Systematic mediastinal lymphadenectomy is crucial for determining the stage of the disease and identifying patients who may benefit from additional therapy 6.
- Age has been identified as a significant factor associated with long-term survival in patients with stage IA lung adenocarcinoma, with older patients having a poorer prognosis 5.