High-Dose-Rate (HDR) Intracavitary Brachytherapy (ICBT) for cervical cancer: Advances for better local control and complications sparing

High-dose-rate (HDR) intracavitary brachytherapy (ICBT) is widely applied for patients with cervical cancer. The advantages of HDR-ICBT are time and resource conservation, outpatient service, convenience, and optimal cost-effectiveness. Meta-analysis shows similar local control and complications in comparison with low dose rate ICBT. The rectum is the most common organ at risk (OAR) in the reports about HDR-ICBT. The International Commission on Radiation Units and Measurements (ICRU) 38 report defined reference points for dosimetry. The rectal complications are related not only to cumulative ICRU doses to the rectum, but also to external parametrial doses (PMD). For diminishing biologically effective dose (BED) of the rectum, rectal balloon inflation, small fraction size of point A, or intensity modulated radiation therapy (IMRT) may be beneficial to patients with potentially high rectal doses. Correlations between dosimetry and complications of the urinary bladder and sigmoid colon are controversial due to organ movement. CT/MRI-based treatment planning is suggested for more accurate dosimetry because doses of ICRU reference points are typically underestimated using orthogonal radiography-based dosimetry. To improve local control rate, MRI-guided brachytherapy is preferred for better target delineation and dose coverage. The unsolved issues of HDR-ICBT are weighting relative to external beam radiation therapy, dose rate effect, impact of concurrent chemotherapy, optimal dose-fraction, interfractional dose variation, brachytherapy devices, dosimetry using 3D planning, and reference points/volume for OAR. This chapter presents a comprehensive literature review and discussion.