Four-Dimensional Image-Guided Adaptive Brachytherapy for Cervical Cancer: A Systematic Review and Meta-Regression Analysis

Abstract

PurposeThe ICRU/GEC-ESTRO released the ICRU Report No. 89, which introduced the concept of four-dimensional brachytherapy and ushered in a new era of brachytherapy for cervical cancer. The purpose of this study was to evaluate the local control and late toxicity of four-dimensional brachytherapy in cervical cancer through a systematic review and to reveal the dose-response relationship between the volumetric dose paraments and the local control rate via a probit model.Material and MethodsWe identified studies that reported the HR-CTV D90 and local control probabilities by searching the PubMed Database, the Web of Science Core Collection and the Cochrane Library Database through February 1st, 2022. Regression analyses were performed between the HR-CTV D90 and the local control probability using a probit model.ResultsNineteen studies enrolling 3,616 patients were included. The probit model showed a significant relationship between the HR-CTV D90 value and IR-CTV D90 Vs. the local control probability, P < 0.001 and P = 0.003, respectively. The D90 for HR-CTV and IR-CTV corresponding to a probability of 90% local control was 79.1 GyEQD2,10 (95% CI:69.8 – 83.7 GyEQD2,10) and 66.5 GyEQD2,10 (95% CI: 62.8 - 67.9 GyEQD2,10), respectively. The limits for the prescribed dose of 85 GyEQD2,10 for HR-CTV D90 theoretically warranted a 92.1% (95% CI: 90.2% - 95.3%) local control rate, and 87.2% (95% CI: 82.4% - 91.8%) local control probability was expected for 65 GyEQD2,10 to IR-CTV D90. The probit model showed no significant relationship between the D2cc to organs at risk and the probability of grade 3 and above gastrointestinal or genitourinary toxicity.ConclusionsFour-dimensional brachytherapy takes into account uncertain factors such as tumour regression, internal organ motion and organ filling, and provides a more accurate and more therapeutic ratio delivery through adaptive delineation and replanning, replacement of the applicator, and the addition of interstitial needles. The dose volume effect relationship of four-dimensional brachytherapy between the HR-CTV D90 and the local control rate provides an objective planning aim dose.

Dose-response relationship between volume base dose and tumor local control in definitive radiotherapy for vaginal cancer

“…Secondly, the total number of patients included in the probit analysis was not high due to the relative rarity of vaginal cancer, and they were all observational studies. Finally, the heterogeneity of the data remains an important limitation of this study, as previously stated [ 22 – 24 ].…”

“…For cervical cancer, we have previously analyzed the dose-response relationships in image-guided BT [ 22 ], three-dimensional intracavitary combined with interstitial BT [ 23 ], and four-dimensional adaptive BT [ 24 ], and obtained results consistent with current consensus of dose constraints [ 25 ]. The purpose of this study is to identify articles that reported volume base dose and local control in definitive radiotherapy for vaginal cancer through systematic literature screening, and to conduct probit model analysis in an attempt to find the optimal dose for definitive radiotherapy for vaginal cancer.…”

Current Status and Future Directions of Image-Guided Adaptive Brachytherapy for Locally Advanced Cervical Cancer

“…Over the past two decades, advancements in imaging technologies have enabled new methods of guidance for brachytherapy. The initial steps were made with CT-guided brachytherapy [ 12 ] and later with MRI-guided brachytherapy [ 8 , 9 , 13 , 14 ]. Over time, two-dimensional, point-A-based planning was replaced by three-dimensional, adaptive planning.…”

“…In the past two decades, several advances in brachytherapy technique have led to improved cure rates and reduced toxicity, notably the implementation of magnetic resonance imaging (MRI) before and during brachytherapy application, as well as the adoption of adaptive, three-dimensional planning [ 7 , 8 , 9 ]. Today cure rates remain high with negative pelvic lymphadenopathy, gross tumor volume (GTV) dose covering 90% of the target (GTV D90) of >110 Gy, and a treatment duration of ≤56 days predictive of better outcomes [ 10 ].…”

Dose-effect relationship of linear accelerator based stereotactic radiotherapy for brain metastases

“…Probit model regression analysis was conducted by XLSTAT 2016 (Addinsoft, Paris, France) as previously described [ 11 , 12 ]. The statistical significance was set at the level of P value < 0.05.…”