Thoracic re-irradiation with 3D-conformal or more advanced techniques: A systematic review of treatment safety by the Re-irradiation Study Group of the Italian Association of Radiation and Oncology AIRO

Re-irradiation (re-RT) is a treatment modality that has been actively investigated in recurrent lung cancer or in lung metastases appeared in previously irradiated areas. A literature search, according PRISMA recommendations and a meta-analysis technique were performed with the aims to identify possible factors related to the toxicity incidence and severity of ≥ G3 acute toxicity. 1243 patients and 36 studies, met inclusion criteria. Our results, showed that there was no difference in ≥ G3 acute (10,5%) toxicity rate with respect to different radiation techniques, cumulative dose and re-irradiation total dose and fractionation. Factors eventually related to severe toxicity were described. The frequent lack of a sufficient description of the treatment's intent, the heterogeneity in technique and radiotherapy regimen, makes balancing risk and benefit of re-RT based on published data even more difficult.