Cancers bronchiques non à petites cellules oligo-métastatiques, oligo-persistance, oligo-progression, maladie résiduelle : de quoi parle-t-on ? Quelle prise en charge ?

The oligo-metastatic disease concept refers to a tumor type having a limited ability for metastazing, with the still speculative idea that loco-regional treatments could be curative in a subset of patients with oligo-metastases. It would imply an intermediary state between a cancer tumor with diffuse metastatic effusion and a tumor purely localized to the primitive organ (i.e. the lung), that is to say a cancer disease with a limited number of metastatic sites, the definition according to different authors, ranging from 1 to 5 metastases, most often in no more than 1 to 2 organs. Such concepts emerged from mainly retrospective studies, regional or national databases, or meta-analyses, most of them before the targeted therapies and modern immunotherapy eras, suggesting that adding locoregional treatments (surgery, radiotherapy, thermos-ablation, radio-frequence) to systemic treatments would increase survival, although all those studies are debatable, because of their retrospective design. Prospective trials are still rare, essentially with phase 2 trials, often accruing patients with different cancer and organ types, with modest sample size of patients with NSCLC, limiting their meaning. Because of the unprecedently observed efficacy of new systemic targeted therapies and immunotherapy in NSCLC, new concepts also emerged such as oligo-progression, oligo-persistence or residual tumor disease, although previously described for other tumor types. The current review aims to precise some complex and sometimes contradictory definitions, to synthetize the results of the main retrospective studies and meta-analyses, to examine the rare prospective studies and decipher the current situation cases that could occur. Actually, the medical reasoning differs according to the addictive mutational tumor status with efficient available targeted therapy, or in patients without addictive mutation, according to immuno-or immunochemotherapy response, or according to the timepoint, at diagnosis, during treatment, or after the two years of immunotherapy, all these different situations leading to possibly different approaches, the evidence from literature being still fragmentary.