[Interest of focal radiotherapy in case of oligoprogression under immunotherapy in the treatment of metastatic non-small cell lung cancer].

Introduction: The prognosis of metastatic non-small cell lung cancer (NSCLC) has been improved by the use of immune checkpoint inhibitors (ICI). Unfortunately, in some cases, cancer cells will develop resistance mechanisms. In case of progression in a limited number of lesions (oligoprogression), focal treatment with radiotherapy is proposed while continuing the ICI therapy.

Methods: A cohort of 37 patients with metastatic NSCLC treated with nivolumab (anti-PD-1) in second or subsequent line and who received focal radiotherapy for oligoprogression with continuation of nivolumab was compared with a control cohort of 87 patients no oligoprogressor treated par immunotherapy.

Results: After a median follow-up of 37 months [18; 62], the median progression free survival (PFS) in the radiotherapy-treated cohort was 15.04 versus 5.04 months in the control cohort, with a statistically significant difference (P=0.048). The median PFS following focal radiotherapy in the oligoprogressor group was 7.5 months. In univariate analysis, the presence of lung metastasis was associated with increased PFS, in contrast to the presence of brain metastases, which were associated with decreased PFS in the radiotherapy group. The median overall survival was not reached in both groups, with no significant difference between the two cohorts.

Conclusion: The combination of focal radiotherapy in case of oligoprogression and continued treatment with nivolumab in the treatment of metastatic NSCLC in the second or subsequent line of treatment seems to be with an increase in PFS.