(P004) A Retrospective Study to Assess Disparities in the Utilization of Intensity-Modulated Radiotherapy (IMRT) and Proton Therapy (PT) in the Treatment of Prostate Cancer (PCa)

Publication
Article
OncologyOncology Vol 29 No 4_Suppl_1
Volume 29
Issue 4_Suppl_1

Disparities exist in PT utilization compared with IMRT by age, race, and SES and merit further investigation.

Kristina L. Demas, MD, Neha Vapiwala, MD, Stefan Both, PhD, Curtiland Deville, MD; University of Pennsylvania

BACKGROUND: Despite its increase in use, proton therapy (PT) is a relatively limited resource. The purpose of this study was to examine clinical and demographic differences in intensity-modulated radiotherapy (IMRT) and PT utilization for prostate cancer (PCa).

METHODS: All patients with low- and intermediate-risk PCa (n = 350) undergoing definitive RT (2.5 Gy × 28 fractions or 1.8 Gy ×44 fractions) between 2010–2012 at a single institution were divided into IMRT (n = 58) and PT (n = 292) comparison groups. Pretreatment characteristics, including age, race, socioeconomic status (SES) (low vs high, defined as geocoded census tract 20% below or above poverty level, respectively), prostate-specific antigen (PSA), clinical tumor stage, Gleason score, risk group, prostate volume, and patient-reported outcomes, were retrospectively collected. Chi-square and independent sample t-tests were used for analyses.

RESULTS: Of PT patients, 228 (78%), 51 (18%), 4 (1%), and 9 (3%) were white, black, Asian, or other, respectively; 256 patients (88%) had high SES, and 36 (12%) had low SES. Mean age, distance from center, PSA level, prostate volume, International Prostate Symptom Score (IPSS), and International Index of Erectile Function (IIEF) in the PT group were 65 ± 7.1 years, 86 ± 190 miles, 5.6 ± 2.9 ng/mL, 41 ± 18 cc, 8 ± 6, and 19 ± 6, respectively; 142 (49%) patients were low-risk, and 150 (51%) were intermediate-risk. A total of 236 (81%), 46 (16%), and 10 (3%) PT patients were T1c, T2a, and T2b, respectively; 154 (53%) and 138 (47%) patients were Gleason 6 and 7.

In the IMRT group (n = 58), 28 (48%), 24 (42%), 3 (5%), and 3 (5%) patients were white, black, Asian, or other, respectively; 40 (69%) patients had higher SES, and 18 (31%) had low SES. Mean age, distance, PSA, prostate volume, IPSS, and IIEF were 69 ± 8.6, 16 ± 18 miles, 7.4 ± 4.5 ng/mL, 54 ± 40 cc, 8 ± 7, and 14 ± 8, respectively; 142 (49%) were low-risk, and 150 (51%) were intermediate-risk patients. A total of 236 (81%), 46 (16%), and 10 (3%) IMRT patients were T1c, T2a, and T2b, respectively; 154 (53%) and 138 (47%) patients were Gleason 6 and 7.

The cohorts varied in average age (P = .0005), race (P < .0001), SES status (P = .0007), and average miles traveled to the facility (P = .0054)-ie, IMRT patients were older, resided closer, and consisted of more black and low-SES patients. Baseline PSA (P = .0001), Gleason score (P = .0244), prostate volume (P = .0040), and IIEF (P < .001) were significantly increased for IMRT, while risk group, T stage, and IPSS were not (P > .05 for all). Therapeutically, IMRT patients were less likely to receive hypofractionated therapy (P < .0001) and more likely to receive androgen deprivation therapy (P = .0006).

CONCLUSION: Disparities exist in PT utilization compared with IMRT by age, race, and SES and merit further investigation.

Proceedings of the 97th Annual Meeting of the American Radium Society - americanradiumsociety.org

Articles in this issue

(P005) Ultrasensitive PSA Identifies Patients With Organ-Confined Prostate Cancer Requiring Postop Radiotherapy
(P001) Disparities in the Local Management of Breast Cancer in the United States According to Health Insurance Status
(P002) Predictors of CNS Disease in Metastatic Melanoma: Desmoplastic Subtype Associated With Higher Risk
(P003) Identification of Somatic Mutations Using Fine Needle Aspiration: Correlation With Clinical Outcomes in Patients With Locally Advanced Pancreatic Cancer
(P004) A Retrospective Study to Assess Disparities in the Utilization of Intensity-Modulated Radiotherapy (IMRT) and Proton Therapy (PT) in the Treatment of Prostate Cancer (PCa)
(S001) Tumor Control and Toxicity Outcomes for Head and Neck Cancer Patients Re-Treated With Intensity-Modulated Radiation Therapy (IMRT)-A Fifteen-Year Experience
(S003) Weekly IGRT Volumetric Response Analysis as a Predictive Tool for Locoregional Control in Head and Neck Cancer Radiotherapy 
(S004) Combination of Radiotherapy and Cetuximab for Aggressive, High-Risk Cutaneous Squamous Cell Cancer of the Head and Neck: A Propensity Score Analysis
(S005) Radiotherapy for Carcinoma of the Hypopharynx Over Five Decades: Experience at a Single Institution
(S002) Prognostic Value of Intraradiation Treatment FDG-PET Parameters in Locally Advanced Oropharyngeal Cancer
(P006) The Role of Sequential Imaging in Cervical Cancer Management
(P008) Pretreatment FDG Uptake of Nontarget Lung Tissue Correlates With Symptomatic Pneumonitis Following Stereotactic Ablative Radiotherapy (SABR)
(P009) Monte Carlo Dosimetry Evaluation of Lung Stereotactic Body Radiosurgery
(P010) Stereotactic Body Radiotherapy for Treatment of Adrenal Gland Metastasis: Toxicity, Outcomes, and Patterns of Failure
(P011) Stereotactic Radiosurgery and BRAF Inhibitor Therapy for Melanoma Brain Metastases Is Associated With Increased Risk for Radiation Necrosis
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