The role of image-guided radiotherapy in prostate cancer: A systematic review and meta-analysis

Background: Image-guided radiotherapy (IGRT) has gradually been widely promoted in clinical procedure. However, there has been no consensus on the effects of IGRT on toxicity and survival, and no clear level 1 evidence has even been promulgated. Methods: Medline, EMBASE, PubMed, Cochrane databases and ClinicalTrials.gov were searched for studies comparing IGRT vs non-IGRT or higher frequency IGRT vs lower frequency IGRT during prostate radiotherapy, indexed from database inception to April 2022. Results: The review included 18 studies (3 randomized clinical trial and 15 cohort studies) involving 6521 men, with a median duration of patient follow-up of 46.2 months in the IGRT group vs 52.7 months in the control group. The meta-analysis demonstrated that IGRT significantly reduced acute GU (risk ratio [RR], 0.78; 95 % confidence interval [CI], 0.69-0.88; P < 0.001 [9 studies]) and GI toxicity (RR, 0.49; 95 % CI, 0.35-0.68; P < 0.001 [4 studies]) and late GI toxicity (HR, 0.25; 95 % CI, 0.07-0.87; P = 0.03 [3 studies]) compared with non-IGRT. Meanwhile, compared with prospective studies, retrospective studies showed that IGRT had a more significant effect in reducing the late GI toxicity. Compared with non-daily IGRT, daily IGRT significantly improved 3-year PRFS (HR, 0.45; 95 % CI, 0.28-0.72; P = 0.001 [2 studies]) and BFFS (HR, 0.57; 95 % CI, 0.39-0.83; P = 0.003 [3 studies]). Furthermore, high-frequency daily IGRT could lead to greater 3-year BFFS benefit in prostate cancer patients than weekly IGRT. However, no significant effects of IGRT on acute rectal toxicity, late GU toxicity, 5-year OS and SCM were found. Conclusions: For men receiving prostate radiotherapy, IGRT was associated with an improvement in biochemical tumor control and a reduction in GI and acute GU toxicity, but did not significantly improve 5-year OS or increase 5-year SCM.