Multivariable Survival Analysis Comparing Proton Therapy and IMRT for Localized Prostate Cancer: A Retrospective Observational Study
Department
Eastern Virginia Medical School
Graduate Level
Doctoral
Graduate Program/Concentration
Doctor of Medicine
Presentation Type
Oral Presentation
Abstract
Purpose/Objectives: This study retrospectively compares the clinical outcomes and side effects of proton therapy (PT) and intensity-modulated radiation therapy (IMRT) for localized prostate cancer while controlling for relevant covariates, with the objective of informing treatment decisions.
Materials/Methods: We analyzed data from the electronic medical record system of a single institution, from the period of January 1, 2010, to December 15, 2023. Inclusion criteria comprised all men diagnosed with localized prostate cancer who underwent PT or IMRT with curative intent. The primary outcomes evaluated were overall survival (OS), metastasis-free survival (MFS), biochemical failure-free survival (BFFS), and treatment-related side effects. Survival analysis was then performed using a multivariate Cox proportional hazards model and Kaplan-Meier plots. Covariates included patient age and race, initial androgen-deprivation therapy (ADT), and NCCN risk stratification.
Results:
The cohorts were of similar age, but had statistically significant differences in racial makeup, risk scores, and use of ADT, with the PT group having a lower proportion of Black patients, high and very high-risk patients, and patients receiving ADT in combination with RT.
Survival analysis using a multivariate Cox proportional hazards model showed no significant differences between the Proton and IMRT cohorts. Patients receiving PT had similar rates of BFFS (Hazard ratio (HR) = 0.97, p=0.83), MFS (HR=0.81, p=0.27), and OS (HR=0.82, p=0.44). Both cohorts had similar results across risk stratifications. Consistent with prior studies regarding the use of hormonal therapies combined with RT, patients receiving ADT had significantly higher BFFS and MFS compared to RT alone (BFFS: HR=0.25, p
Conclusions:
In this retrospective analysis, we compared the efficacy of PT and IMRT for initial treatment in patients with localized prostate cancer, controlling for patient age, race, risk stratification, and the use of hormonal therapy in combination with RT. We find no evidence of any significant differences in rates of biochemical failure, metastasis, or overall survival between the PT and IMRT cohorts. Regardless of radiation modality, patients receiving ADT in addition to RT for initial treatment experienced lower rates of BCR or metastasis. We will need further chart review and analysis to compare treatment-related side effects.
Keywords
Prostate Cancer, Radiation Oncology, Proton Therapy, Survival Analysis
Multivariable Survival Analysis Comparing Proton Therapy and IMRT for Localized Prostate Cancer: A Retrospective Observational Study
Purpose/Objectives: This study retrospectively compares the clinical outcomes and side effects of proton therapy (PT) and intensity-modulated radiation therapy (IMRT) for localized prostate cancer while controlling for relevant covariates, with the objective of informing treatment decisions.
Materials/Methods: We analyzed data from the electronic medical record system of a single institution, from the period of January 1, 2010, to December 15, 2023. Inclusion criteria comprised all men diagnosed with localized prostate cancer who underwent PT or IMRT with curative intent. The primary outcomes evaluated were overall survival (OS), metastasis-free survival (MFS), biochemical failure-free survival (BFFS), and treatment-related side effects. Survival analysis was then performed using a multivariate Cox proportional hazards model and Kaplan-Meier plots. Covariates included patient age and race, initial androgen-deprivation therapy (ADT), and NCCN risk stratification.
Results:
The cohorts were of similar age, but had statistically significant differences in racial makeup, risk scores, and use of ADT, with the PT group having a lower proportion of Black patients, high and very high-risk patients, and patients receiving ADT in combination with RT.
Survival analysis using a multivariate Cox proportional hazards model showed no significant differences between the Proton and IMRT cohorts. Patients receiving PT had similar rates of BFFS (Hazard ratio (HR) = 0.97, p=0.83), MFS (HR=0.81, p=0.27), and OS (HR=0.82, p=0.44). Both cohorts had similar results across risk stratifications. Consistent with prior studies regarding the use of hormonal therapies combined with RT, patients receiving ADT had significantly higher BFFS and MFS compared to RT alone (BFFS: HR=0.25, p
Conclusions:
In this retrospective analysis, we compared the efficacy of PT and IMRT for initial treatment in patients with localized prostate cancer, controlling for patient age, race, risk stratification, and the use of hormonal therapy in combination with RT. We find no evidence of any significant differences in rates of biochemical failure, metastasis, or overall survival between the PT and IMRT cohorts. Regardless of radiation modality, patients receiving ADT in addition to RT for initial treatment experienced lower rates of BCR or metastasis. We will need further chart review and analysis to compare treatment-related side effects.