Doctor of Philosophy (PhD)
The Department of Physics and Astronomy
Purpose: The purpose of this dissertation is to compare treatment outcomes and cost-effectiveness of various radiotherapy techniques for post-mastectomy radiotherapy (PMRT) and whole breast radiotherapy (WBRT) patients.
Methods: Treatment planning comparison of standard volumetric modulated arc therapy (STD-VMAT), multiple arc VMAT (MA-VMAT), non-coplanar VMAT (NC-VMAT), intensity modulated radiotherapy (IMRT), helical tomotherapy (HT), mixed beam therapy and proton therapy was performed for 9 PMRT patients, and cost-effectiveness of those PMRT techniques compared to standard of care (SOC) were evaluated using a Markov model. Treatment planning comparison of SOC, field-in-field (FIF), hybrid IMRT, full IMRT, STD-VMAT, MA-VMAT and NC-VMAT was performed for 15 WBRT patients, and cost-effectiveness of those WBRT techniques were also evaluated.
Results: For PMRT patients, IMRT exhibited the lowest lifetime attributable risk (LAR) of contralateral breast cancer; NC-VMAT exhibited the lowest LAR of lung cancer; mixed beam therapy exhibited the lowest risk of coronary events (RCE). Probability sensitivity analyses (PSAs) show that all advanced PMRT techniques are more cost-effective than SOC at a willingness-to-pay (WTP) threshold of 100,000 $/QALY, while only IMRT has a 30.7% probability of being more cost-effective than SOC at a WTP threshold of $50,000/QALY. For WBRT patients, MA-VMAT exhibited the lowest LAR of lung cancer, contralateral breast cancer and RCE. NC-VMAT plans provided the second lowest LAR of lung cancer and RCE. PSAs show FIF is more cost effective than SOC at WTP threshold of 50,000 $/QALY, while FIF, hybrid IMRT and MA-VMAT are more cost-effective than SOC at WTP of 100,000 $/QALY, respectively.
Conclusions: IMRT, NC-VMAT, and mixed beam therapy could be the optimal radiation techniques for certain PMRT patients, and MA-VMAT and NC-VMAT could be the optimal radiation technique for WBRT patients. Advanced PMRT techniques are more cost-effective for breast cancer patients at a WTP threshold of 100,000 $/QALY, and IMRT might be the most cost-effective option for PMRT patients at a WTP of 50,000 $/QALY. FIF, MA-VMAT and NC-VMAT are more cost-effective for WBRT patients at a WTP of 100,000 $/QALY, and FIF might be the most cost-effective option at a WTP of 50,000 $/QALY.
Xie, Yibo, "Comprehensive Investigation of Radiation Techniques for Whole Breast and Post-Mastectomy Irradiations" (2020). LSU Doctoral Dissertations. 5200.
Available for download on Monday, March 13, 2023