• Age \> or = 18 years,

• Performance Status 0 to 2,

• Patient with an histologically non-metastatic localized (or extensive SCLC sub-group) Small cell lung cancer,

• Patient who must start radiotherapy treatment combined with chemotherapy with platinum and etoposide (localized SCLC sub-group) or Patient who received 4 cycles of chemoimmunotherapy with platinum salts, etoposide and immunotherapy (atezolizumab or durvalumab) as the first treatment (extensive SCLC sub-group) Note: The decision of the Multidisciplinary Consultation Team must be notified in the patient's medical file,

• Evaluation lesion according to the criteria RECIST 1.1 and / or according to the criteria PERCIST 1.0,

• Women of childbearing potential must have a negative serum pregnancy test within 72 hours of the first administration of the study treatment,

• If the patient is a woman of childbearing potential, she must be surgically sterile or agree to use two adequate methods of contraception throughout the duration of the study until 1 month after the last administration of the study treatment. Subjects of childbearing potential are those who have not been surgically sterilized or have not been free from menses for \> 1 year, Note: Abstinence is acceptable if it is the patient's usual and preferred form of contraception,

• If the male patient has one or more female partners of childbearing age, he / she must agree to use an adequate method of contraception, starting at the first administration of the study treatment up to 1 month after the last administration of the treatment. of the study, Note: Abstinence is acceptable if it is the patient's usual and preferred form of contraception,

• Patient willing and able to provide written informed consent/assent for the trial,

• Patient affiliated with a health insurance system.