Oligometastatic disease and remote stereotactic ablative radiotherapy of the body (general issues)

At present, the concept of oligometastases is associated with the notion that cancer patients with 1-5 metastatic foci can be treated, or even, in some cases, cured by the application of non- invasive local antitumor methods in combination with systemic therapy. Numerous, though small in number, clinical observations, as well as several randomized studies show that the application of remote stereotactic body ablative radiotherapy (SABR) to foci of metastasis, with quite satisfactory tolerability and rather low toxicity rates, can contribute to achieving a sufficiently high level of local control over the metastatic process in oligometastatic status. In this article the issues related to the current understanding of oligometastatic disease and the results of already conducted (or currently being conducted) prospective studies to evaluate the results of SABR in patients with oligometastatic, oligorecurrent and oligoprogressive oncologic process, as well as the prospects for further research in this direction are highlighted. The material is presented taking into account the new classification adopted by the group of international experts of the European Organization for Research and Treatment of Cancer (EORTC) and the European Society for Radiotherapy and Oncology (ESTRO), which allows more meaningful definition of radiotherapy treatment strategies in various states of oligometastatic disease and published in 2020 consensus recommendations of European and American experts ESTRO-ASTRO on this classification and in general on the nomenclature of oligometastatic disease.