局所再発軟部肉腫に対する再照射：システマティックレビュー

Locally recurrent soft tissue sarcomas (LRSTS) present a significant clinical challenge.There are major limitations to secondary treatment modalities. Reirradiation in such cases has traditionally been considered contraindicated due to the risk of severe normal tissue toxicity. On the other hand, there is evidence showing that multimodality salvage treatment can improve outcomes in some patients. The objective of this systematic review is to determine the feasibility of reirradiation in LRSTS. This systematic review included clinical studies that presented outcomes of patients who underwent any form of repeated radiation treatment for LRSTS. Authors used PubMed Medline, Embase and Scopus databases. This review follows the PRISMA guidelines. The search and selection identified 20 studies involving reirradiation for LRSTS, encompassing a total of 437 patients. Reirradiation modalities comprised brachytherapy, intraoperative radiotherapy (RT), external-beam RT, carbon ion RT and proton RT, as either definitive or perioperative treatment. Reirradiation doses varied across studies, with cumulative nominal doses exceeding 100 Gy in some cohorts. Local control rates ranged from 15 % to 100 %, with most studies reporting the range of 50-70 %. Overall survival rates were similarly variable. Acute and late toxicities were significant, with grade ≥3 complications reported in up to 50 % of patients. The analysis showed that reirradiation, both definitive or as a part of multimodality treatment, can be used in selected patients with LRSTS. This review is limited by retrospective study designs, and a large heterogeneity in patient populations and treatment regimens. Further quality investigation is needed to clearly determine the indications for reirradiation in LRSTS.