Prognosis and treatment are often determined by the stage of lung cancer at the time of diagnosis. According to the American Cancer Society, with regard to non-small cell lung cancer (NSCLC), the prognosis is based on stages, which range from stages 0 through IV.

NSCLC Stages

• Stage 0: This stage is called “in situ” disease, indicating that the cancer is “in place” and has not metastasized from where it first developed.

• Stage I: During this stage, lung cancer tumors are small primary tumors that are in one lung only. Stage I lung cancer has not spread to any lymph nodes and has not metastasized. Stage I lung cancer is divided into two substages, stage IA and stage IB, based primarily on the size of the tumor.

• Stage II: Similar to stage I lung cancer, stage II lung cancer is located in the lung where it has started. Stage II lung cancer has not metastasized to distant parts of the body. Stage II lung cancer is divided into two stages: stage IIA and stage IIB.

• Stage III: During this stage, lung cancer has spread within the chest but has not metastasized to distant parts of the body. This stage is sometimes referred to as “locally advanced.” Stage III lung cancer is divided into three stages: stage IIIA, stage IIIB, and stage IIIC.

• Stage IV: Unlike the earlier stages of lung cancer, stage IV lung cancer has metastasized to distant parts of the body. These tumors may be any size and may or may not have spread to lymph nodes. Stage IV lung cancer is divided into two stages: stage IVA and stage IVB.

• Recurrent lung cancer is lung cancer that has returned after treatment. If there is a recurrence, the cancer may need to be staged again (“re-staged”) using the staging system described above.

More information about each stage of NSCLC can be found on the National Comprehensive Cancer Network website at: https://www.nccn.org/guidelines/guidelines-detail?category=1&id=1450

The tumor-node-metastasis (TNM) staging system from the American Joint Committee for Cancer Staging and End Results Reporting is used for all lung carcinomas except small-cell lung cancer (SCLC). The TNM takes into account the following key pieces of information:

• T describes the size of the primary tumor
• N describes the spread of cancer to regional lymph nodes
• M indicates whether the cancer has metastasized.

Primary tumor (T) involvement is as follows:

• Tx: primary tumor cannot be assessed
• T0: no evidence of tumor
• Tis: carcinoma in situ
• T1, T2, T3, T4: size and/or extension of the primary tumor.

Lymph node (N) involvement is as follows:

• Nx: regional nodes cannot be assessed
• N0: no regional node metastasis
• N1: metastasis in ipsilateral peribronchial and/or ipsilateral hilar nodes and intrapulmonary nodes, including involvement by direct extension
• N2: metastasis in ipsilateral mediastinal and/or subcarinal node
• N3: metastasis in contralateral mediastinal, contralateral hilar, ipsilateral or contralateral scalene node, or supraclavicular node.

Metastatic (M) involvement is as follows:

• M0: no metastasis
• M1: distant metastasis.

Positive pleural effusion is classified as stage IV.

SCLC

SCLC is typically divided into two stages: limited stage and extensive stage.

Limited-stage disease is defined as cancer confined to one hemithorax (including ipsilateral lymph nodes) that can be included within one tolerable radiation therapy port, unless there is a pleural or pericardial effusion.

Extensive-stage disease is defined as cancer outside a single hemithorax or the presence of malignant cells detected in pleural or pericardial effusions. Fewer than one-third of patients with SCLC will present with limited-stage disease; the remainder of patients frequently have widespread, distant metastases.

Overall, the prognosis for SCLC is generally poor, and the average survival time for limited-stage SCLC is 20 months, with a 5-year survival rate of 20%. Patients with extensive-stage SCLC do especially poorly, with a 5-year survival rate of <1%. An estimated 60% to 70% of patients with SCLC have clinically disseminated or extensive disease at presentation. Extensive-stage SCLC is incurable.


When given combination chemotherapy, patients with extensive-stage disease have a comple response rate of more than 20% and an average survival time longer than 7 months; however, only 2% are alive at 5 years. For individuals with limited-stage disease that is treated with combination chemotherapy plus chest radiation, a complete response rate of 80% and survival time of 17 months have been reported; 12% to 15% of patients are alive at 5 years. 

More information about the stages of SCLC can be found on the National Comprehensive Cancer Network website at: https://www.nccn.org/guidelines/guidelines-detail?category=1&id=1462

The content contained in this article is for informational purposes only. The content is not intended to be a substitute for professional advice. Reliance on any information provided in this article is solely at your own risk.

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