This is phase I/II study to evaluate the feasibility (phase I) and progression free survival (phase II) in patients with advanced NSCLC with ALK-rearrangement receiving consolidation radiation therapy (RT) to all known macroscopic tumour lesions present after 2-3 months of treatment with alectinib and then continuing with alectinib.~Eligible patients are those with an ALK-rearranged stage III (non-surgical/non-radiochemotherapy candidates) OR stage IV NSCLC who, after a 2-3-month-induction period of alectinib show stable disease/partial response to systemic therapy. When entering the trial, all known tumour lesions are treated with SBRT/RT/SRS with concomitant alectinib followed by continuation alectinib until disease progression, unacceptable toxicity or another discontinuation criterion is met.
The goal of this clinical trial is to learn evaluate the safety and efficacy of the addition of radiation therapy to all tumour lesions, to first line medical treatment with alectinib in non-small cell lung cancer harbouring ALK-rearrangements.~The main aims of the trial are to evaluate:~if the treatment combination is safe~if the treatment combination can inhibit progression~Participants who have responded to 1st line alectinib will be treated with consolidation radiation therapy to all remaining tumour lesions while continuing on alectinib until disease progression, unacceptable toxicity or another discontinuation criterion is met.