Trends in Use and Comparison of Stereotactic Body Radiation Therapy, Brachytherapy, and Dose-Escalated External Beam Radiation Therapy for the Management of Localized, Intermediate-Risk Prostate Cancer
Menée aux Etats-Unis à partir des données de la base nationale des cancers portant sur 30 766 patients atteints d'un cancer de la prostate diagnostiqué entre 2004 et 2014, de stade localisé et à risque intermédiaire de récidive (âge médian au diagnostic : 69 ans ; durée médiane de suivi : 6,7 ans), cette étude analyse l'utilisation de trois modalités de radiothérapie (radiothérapie externe avec escalade de dose, radiothérapie corporelle stéréotaxique et curiethérapie) et compare leur efficacité du point de vue de la survie globale
Introduction : Whereas brachytherapy (BT) and dose-escalated external beam radiotherapy (DE-EBRT) have longstanding use in the treatment of patients with localized prostate cancer (CaP), stereotactic body radiation therapy (SBRT) is an emerging option owing to cost effectiveness, patient convenience, and noninferior tumor control and acute toxic effects.1,2 The increase in radiation options and paucity of comparative evidence present challenges in guiding patient-centered care.3 Using the National Cancer Database, we compared use and outcomes between SBRT, BT, and EBRT for the treatment of patients with intermediate risk CaP. Methods : Patient Population. For this cohort study, patients were identified in the National Cancer Database who had National Comprehensive Cancer Network intermediate risk CaP (Gleason score of 6-7, clinical stage T1-T2, and prostate-specific antigen <20 ng/mL [to convert to micrograms per liter, multiply by 1.0]) diagnosed between January 1, 2004, and December 31, 2014. For EBRT, only
≥
75 Gy or
≥
42 fractions of treatment were included. Stereotactic body radiation therapy was defined as 5 fractions of
≥
7 Gy per fraction. The University of California, Los Angeles granted institutional review board exemption for the use of a deidentified national database. This study followed the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) reporting guideline. Data were analyzed from February 1 to March 1, 2020. Cox proportional hazards were calculated to assess factors independently associated with overall survival (OS). To account for potential confounders, propensity score matching was performed in a 1:1 manner, and the distribution of propensity scores in matched cohorts were then verified (eFigure in the Supplement). Two-sided P values were calculated using the log-rank test, and statistical significance was considered if P
≤
.05. Statistical analysis was performed using JMP, version 11.2.1 (SAS Institute Inc) and R, version 4.0.2 (R Project for Statistical Computing) (MatchIt package, version 3.3.0). Results : Overall, 30 766 men (median age at diagnosis, 69 years [interquartile range, 63-74 years]) were eligible for analysis: 24 953 (81.1%) had favorable intermediate risk, and 5813 (18.9%) had unfavorable intermediate risk. A total of 12 864 patients (41.8%) received BT, 17 247 (56.1%) received DE-EBRT, and 655 (2.1%) received SBRT (Table). From 2004 to 2014, SBRT use (0.03% to 10.6%) and DE-EBRT use (48.3% to 62.0%) steadily increased, with a corresponding decline in BT use (48.3% to 27.4%) (Figure). The median follow-up was 6.7 years (range, 0-11.9 years). In the favorable intermediate risk cohort, there was no significant OS difference in pairwise comparisons of BT vs SBRT (HR, 0.804; 95% CI, 0.593-1.09; P
=
.16; 10-year OS, 67.02% vs 64.2%) or SBRT vs DE-EBRT (HR, 1.096; 95% CI, 0.810-1.48; P
=
.55; 10-year OS, 64.2% vs 70.9%). Men receiving BT had a small but statistically significant improvement in OS compared with those receiving DE-EBRT (HR, 0.881; 95% CI, 0.829-0.938; P
<
.001; 10-year OS, 69.8% vs 66.1%). In the unfavorable intermediate risk cohort, there were no OS differences in pairwise comparisons between BT and SBRT (HR, 0.749; 95% CI, 0.419-1.34; P
=
.33; 10-year OS, 64.9% vs 63.2%) and between SBRT and DE-EBRT (HR, 1.36; 95% CI, 0.746-2.69; P
=
.32; 10-year OS, 63.2% vs 66.6%). Men receiving BT demonstrated a small but statistically significant improvement in OS compared with those receiving DE-EBRT (HR, 0.818; 95% CI, 0.716-0.936; P
<
.001; 10-year OS, 61.2% vs 58.7%).
JAMA Network Open 2020