Bronchopulmonary cancer is the first cause of mortality in the world. We want to update the margins used in stereotactic radiotherapy, in the context of localized lung cancer, of non-surgical management.

The investigators wish to redefine the stereotactic radiotherapy margins according to the histological type in localized non-small cell lung cancer.

Indeed, these criteria were previously defined on a smaller cohort, in the context of 3D radiotherapy (mainly T3, T4 tumors). In addition, the incidence of radiation pneumonitis is highly dependent on the irradiated lung volume, which in turn depends on the CTV margins used.

Inclusion criteria:

• Major subject (≥18 years old)
• Subject operated on at HUS for T1/T2a N0 stage lung adenocarcinoma or squamous cell carcinoma before 30/09/2019
• CT scan available on the HUS imaging server or on CD
• Subject who has not expressed opposition to the use of his or her data for research purposes

Exclusion Criteria:

• Subject who has expressed opposition to participating in the study
• Impossibility to give the subject informed information (difficulties in understanding the subject, ...)
• Subject under legal protection
• Subject under guardianship or curatorship

Major subject (≥18 years old) operated on at HUS for T1/T2a N0 stage lung adenocarcinoma or squamous cell carcinoma before 30/09/2019