Participants receive chemotherapy with BrECADD in standard doses and cycle length. After the first two cycles, a restaging is performed by contrast-enhanced computed tomography (ceCT) and PET (PET/CT) in order to guide response-adapted continuation of therapy consisting of 4 or only 2 additional cycles of BrECADD in case of a PET-positive or -negative staging result, respectively. A second restaging will be performed after completion of chemotherapy. In patients with PET-positive residual disease, local irradiation followed by another restaging is recommended. ART should be continued during chemotherapy.