The investigators propose to study the carbonic anhydrase inhibition (acetazolamide) associated with concomitant radiochemotherapy or radioimmunotherapy in small cell lung cancer due to:
1. The over-expression of carbonic anhydrases in this type of cancer, 2. The Anti-tumor effect in preclinical acetazolamide in various tumor lines including neuroendocrine tumor lines, 3. The observed synergy between irradiation and inhibition of carbonic anhydrases, 4. Potential anti-tumor immune effect caused by decreased extracellular acidity.
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,
Patient with metastatic disease,
History of thoracic irradiation or near / in the thoracic irradiation field,
Patient who refuses to participate in the study or unable to agree,
COPD grade IV according to the GOLD classification,