Thoracic radiotherapy schedules in limited-stage small cell lung cancer: A systematic review and network meta-analysis

Abstract

Background

Currently, the accepted standard management of limited-stage small cell lung cancer (LS-SCLC) is concurrent chemoradiotherapy; however, the thoracic radiotherapy regimen remains controversial. Therefore, this meta-analysis aims to compare efficacy and safety of different thoracic radiotherapy regimens.

Methods

Relevant randomized controlled trials (RCTs) were sourced in PubMed, Cochrane Library, Web of Science, and EMBASE to assess antitumor effects (overall survival, OS; progression-free survival, PFS; overall response rate, ORR) and toxicity (adverse effects, AEs).

Results

Of the 2225 screened articles, 8 RCTs (involving 2363 patients) were included. The control arm was defined as 45 Gy/30f BID. The experimental arms were categorized into three groups: high-dose hyper-fractionation (hHyper-RT: 54 Gy/30f BID, 60 Gy/40f BID), hypo-fractionation (Hypo-RT: 42 Gy/15f QD, 65 Gy/26f QD), and conventional fractionation (Conv-RT: 45 Gy/25f QD, 66 Gy/33f QD, 70 Gy/35f QD). Compared with 45 Gy/30f BID, hHyper-RT (54 Gy/30f BID and 60 Gy/40f BID) showed improved OS (HR = 0.55, 95 % CI: 0.37–––0.82; HR = 0.69, 95 % CI: 0.48–––0.99), hHyper-RT (54 Gy/30f BID) and Hypo-RT (65 Gy/26f QD) improved PFS (HR = 0.70, 95 % CI: 0.49–––0.99; HR = 0.78, 95 % CI: 0.62–––0.98), whereas OS and PFS with Conv-RT was comparable to that of 45 Gy/30f BID. AE development was comparable among 45 Gy/30f, hHyper-RT, and Hypo-RT, whereas Conv-RT (45 Gy/25f QD) reduces the risk of esophagitis and grade 3–5 esophagitis (RR = 0.70, 95 % CI: 0.58–0.85; RR = 0.50, 95 % CI: 0.35–0.72). No significant difference was found for ORR, pneumonitis or grade 3–5 pneumonitis between the study arms.

Conclusions

Compared with 45 Gy/30f BID, hHyper-RT (54 Gy/30f BID and 60 Gy/40f BID) improved OS, while hHyper-RT (54 Gy/30f BID) and Hypo-RT (65 Gy/26f QD) prolonged PFS in LS-SCLC patients, with accepted toxicity.