Stage 1A2 may or may not be squamous lung cancer in situ. Stage 1A2 squamous lung cancer indicates that the mass is relatively small, the tumor is mainly confined to the lung and the visceral pleura, without involving the main bronchus, the maximum diameter of the primary mass is less than 2cm, and there is no mediastinal and hilar lymph node metastasis and distant metastasis, which is usually early squamous lung cancer with a better prognosis for treatment. If the cancer cells are confined to the epithelial layer without destroying the basal lamina to invade the mesenchymal or dermal tissues underneath, then stage 1A2 may be squamous lung cancer in situ. If the cancer cells have invaded the basal layer causing damage to its mesenchymal or dermal tissues, it is usually not squamous lung cancer in situ. Lung squamous carcinoma in situ is a kind of early stage squamous carcinoma, and the cancer cells are more differentiated and more similar to normal cells, which can usually be treated by postoperative treatment, basically all the lesion areas can be removed, and the prognosis is relatively good. If early squamous lung cancer is diagnosed, it is recommended to go to specialized hospitals and under the guidance of doctors for further examination and treatment after completing relevant examinations.