ANALYSIS OF OPTIMAL DOSE FRACTIONATION SCHEDULES IN STEREOTACTIC BODY RADIATION THERAPY (SBRT) FOR PROSTATE CANCER

• Main Author: Aqilah Zahroh, Salma
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/87545
• Institution: Institut Teknologi Bandung

The stereotactic body radiation therapy (SBRT) technique enables the precise delivery of high radiation doses in cancer treatment while significantly reducing the overall treatment time. However, the optimal dose fractionation schedule for prostate cancer SBRT remains undetermined. Factors such as accelerated tumor cell repopulation and variations in patient risk profiles must also be considered when determining the optimal fractionation schedule. This study aims to determine the optimal dose fractionation schedule for prostate cancer SBRT by incorporating tumor cell repopulation and patient risk variations. The methodology involves calculating various fractionation schedules using radiobiological models, namely tumor control probability (TCP) and equivalent dose at 2 Gy (EQD2). Prostate cancer radiobiological parameters were optimized using the maximum likelihood estimation (MLE) method. The results show that fractionation schedules of 40 Gy in 5 fractions and 38 Gy in 4 fractions yield the highest probability of cancer control, at 99%. The 38 Gy in 4 fractions schedule delivers the highest total effective dose, amounting to 89 Gy. When the repopulation factor is not considered, the calculations for tumor control probability and total effective dose tend to be overestimated. On the other hand, patient risk variations do not significantly influence the results. However, determining the optimal fractionation schedule for prostate cancer SBRT requires further consideration of complication probabilities using the normal tissue complication probability (NTCP) model.