International Journal of Radiation Oncology*Biology*Physics
Clinical InvestigationDaily Versus Weekly Prostate Cancer Image Guided Radiation Therapy: Phase 3 Multicenter Randomized Trial
Introduction
Prostate intrapelvic interfraction displacement can be as large as 2 cm, typically in the anteroposterior direction, exposing the patient to an increased risk of both recurrence and toxicity if not corrected using bone anatomy alignment.1, 2 Image guided radiation therapy (IGRT) includes various recently developed techniques, allowing direct or indirect prostate visualization at treatment fractions. The most commonly used IGRT modalities are intraprostatic fiducials visualized on 2 orthogonal planes (kV or portal imaging) and cone beam computed tomography (CBCT).3 The clinical benefit of prostate IGRT has been demonstrated primarily by nonrandomized studies retrospectively comparing non-IGRT and IGRT techniques.4, 5, 6, 7, 8, 9, 10, 11 IGRT has been found to decrease the risk of genitourinary and gastrointestinal (GI) toxicities. However, the role of IGRT in decreasing the risk of recurrence has not been demonstrated because of the short follow-up in these studies.4, 5, 6, 7, 8, 9 Moreover, the optimal frequency of prostate cancer IGRT has not been identified.
Whereas daily control corrects both systematic and random prostate displacement, weekly control solely corrects systematic displacement, with the advantage of being faster and less expensive.12 Systematic errors occur if the mean irradiation geometry in the fractionated treatment differs from the geometry of the treatment plan. Fraction-to-fraction variations around the mean deviation are called random errors.13 The dosimetric consequences of systematic and random geometrical uncertainties differ, with significantly less deleterious effects (increased local failure and toxicity) caused by random deviations.14
This study sought to assess the benefit of daily prostate control compared with weekly control in a prospective multicenter randomized study.
Section snippets
Inclusion criteria and pretreatment workup
In this phase 3 multicenter open randomized trial, we included patients with localized histologically proven prostate adenocarcinoma—N0 or pN-stage—without metastasis. Pretreatment workup imaging included systematic abdominopelvic computed tomography (CT) and bone scans. Prostate magnetic resonance imaging was not required for all patients and was performed in 62% of patients. Patients with hip prostheses, pacemakers, or target volume including the pelvic lymph nodes were excluded.
Study design
The study
Results
Between June 20, 2007, and November 16, 2012, 470 patients were included in the randomized stage: 236 patients in the daily IGRT group and 234 patients in the weekly IGRT group. Two patients (1 from each group) withdrew consent, although both patients allowed their data to be used (Fig. E1; available online at https://dx.doi.org/10.1016/j.ijrobp.2018.07.2006). The baseline patient and tumor characteristics are presented in Table 1. Table E1 (available online at //dx.doi.org/10.1016/j.ijrobp.2018.07.2006
Discussion
We believe that this is the first randomized phase 3 trial evaluating the benefits of IGRT in prostate cancer for toxicity and recurrence. By improving prostate targeting, daily control outperforms weekly control, significantly decreasing the risk of biochemical and clinical recurrences and rectal toxicity.
The combination of IMRT and daily IGRT has become the standard of care for external-beam radiation treatment (EBRT) in prostate cancer, particularly when delivering a high dose or using a
Conclusions
Compared with weekly control, daily control in prostate-cancer IGRT decreases the risks of biochemical and clinical recurrences and rectal toxicity. However, longer follow-up is needed to confirm the results.
Acknowledgment
We thank the reviewers for enhancing the quality of the article.
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2023, Clinical and Translational Radiation OncologyCitation Excerpt :However, the heterogeneity of both analyses was large, with I2 = 71 % and I2 = 73 %, respectively. Among them, de Crevoisier et al. [23] showed that daily IGRT significantly reduced the 5-year OS of patients and potentially increased the SCM. However, Kuo et al. [51] believed that daily IGRT had no effect on 5-year OS and SCM.
Conflict of interest: none.
This study was funded by the French National Cancer Institute. The financers had no role in study design, data collection, analysis, or interpretation, nor in the writing of the report.