Background: Following treatment with chemoradiotherapy (CRT), approximately 30 % of patients with stage III unresectable non-small cell lung cancer (NSCLC) can achieve long-term remission with the possibility of a cure. [1,2,3]. CRT was deemed to be underutilized in Finland compared with the lung cancer incidence. Herein, we examined the potential increase in CRT use following the introduction of national guidelines to improve and standardize NSCLC treatment nationally.

Materials and methods: We compared the use of CRT before and after the implementation of updated CRT guidelines in 2016 and 2020. Data was gathered on all patients treated with CRT from every radiotherapy unit, in Finland, for a total of 13 radiotherapy units.

Results: Overall, 53 and 77 patients with NSCLC were treated with CRT in 2016 and 2020, respectively; thus, CRT use increased significantly by 45 %. There was only a slight overall increase in the incidence of lung cancer, with 2734 patients reported in 2016 and 2801 in 2020, according to the Finnish Cancer Registry report from 2020. Overall (OS) and progression-free survival (PFS) were analyzed over 2 years. The median PFS was 10 and 15 months in patients treated in 2016 and 2020, respectively. The median OS was not reached in either group. There were no statistically significant differences between the groups.

Conclusion: Implementation of the national guideline increased CRT use and altered clinical practice across the country, without compromising treatment efficacy or survival. CRT was provided more uniformly after the implementation of national guidelines.