Urologic Oncology: Seminars and Original Investigations
Seminar articleWhat is the best way to radiate the prostate in 2016?
Section snippets
Introduction: Historical perspective
Radiation therapy (RT) has a long track record as a curative treatment modality for localized prostate cancer. Overall, 2 large randomized trials compared androgen deprivation therapy (ADT) vs. ADT plus RT for patients with high-risk/locally advanced prostate cancer, and both showed that RT improves overall survival by an absolute difference of 8% to 10% [1], [2]. Radiation delivered in the form of X-rays or protons causes DNA damage, which is preferentially repaired in the normal tissue
Current standards
In addition to the decreased rates of toxicities, the use of more conformal radiation treatment techniques also enabled safer delivery of higher doses of radiation to the prostate. At least 5 randomized trials have compared traditional radiation doses (64–70 Gy) to dose-escalated RT (74–80 Gy) [11], [12], [13], [14], [15], and all consistently demonstrated improved disease-free survival with escalated doses, and this has become current standard of care (Table 1). By 2011, 90% of patients in the
Brachytherapy
Brachytherapy involves inserting radioactive sources directly into the prostate, and has been used for the treatment of prostate cancer since the 1920s. Low dose rate brachytherapy consists of placing permanent seed implants (either Iodine-125 or Pallidium-103) in the prostate, whereas high dose rate brachytherapy entails temporary insertion of high energy radioactive isotope such as Iridium-192. The direct delivery of radioactive sources into the prostate significantly reduces radiation doses
Proton therapy
Proton therapy uses a different radiation particle (protons) than X-ray (photon radiation). A heavy, charged particle such as a proton deposits most of its dose at a prescribed depth in the body with a rapid dose fall-off beyond this point; this phenomenon is called the “Bragg peak.” This means that proton therapy can reduce radiation dose delivered to tissues beyond the target compared to photon radiation. Although proton and photon particles are deemed to be similarly effective in prostate
Conclusion
Definitive RT for prostate cancer has evolved dramatically in the past 2 decades. Once treated with a few fields based on the patient׳s bony anatomy on X-ray, prostate cancer patients now receive higher doses of radiation using IMRT with image guidance. The “best” way to deliver radiation for prostate cancer continues to evolve through clinical studies including many randomized trials. For low-risk prostate cancer patients, active surveillance is the recommended disease management strategy in
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Cited by (33)
HDR brachytherapy boost using MR-only workflow for intermediate- and high-risk prostate cancer: 8-year results of a pilot study
2021, BrachytherapyCitation Excerpt :Existing evidence shows that biochemical control rates are improved if the delivered dose to the prostate gland is increased (1).
Factors Influencing Noncompletion of Radiation Therapy Among Men With Localized Prostate Cancer
2021, International Journal of Radiation Oncology Biology PhysicsCitation Excerpt :Greater understanding of predictors of treatment noncompletion may therefore nuance how providers guide shared decision-making in an effort to promote equity. Certain fractionation schedules for prostate cancer, including stereotactic body radiation therapy (SBRT), are undergoing active investigation; these fractionation schedules may provide acceptable tumor control compared with standard regimens.6-9 Importantly, rates of treatment noncompletion for different fractionation schedules merit further study.
Sexual Function in Patients Treated With Stereotactic Radiotherapy For Prostate Cancer: A Systematic Review of the Current Evidence
2019, Journal of Sexual MedicineCitation Excerpt :An enormous benefit of SBRT is the considerable reduction of treatment course duration: SBRT can be completed within 1 week, whereas the conventionally fractionated EBRT regimens are generally delivered in 6–8 weeks.1 At present, no treatment modality has proven to be superior in terms of long-term efficacy, and the choice of the therapeutic option is often influenced by the expected balance between efficacy and risk of adverse events.5 In particular, sexual function can be severely affected by all traditional prostate cancer treatment modalities6 and represents an important source of distress for patients.
Patient-reported Quality of Life Following Stereotactic Body Radiotherapy and Conventionally Fractionated External Beam Radiotherapy Compared with Active Surveillance Among Men with Localized Prostate Cancer
2019, European UrologyCitation Excerpt :These results are consistent with the data reported in Table 2. There is intense research interest in shortening the RT course in prostate cancer due to the improved patient convenience of fewer treatments, associated cost savings, and potential radiobiological advantages of delivering high doses per fraction [16]. Nine randomized trials have been published comparing conventionally fractionated RT (8–9 wk) with moderately hypofractionated RT (4–5 wk), demonstrating similar cancer-control outcomes, although some trials have shown increased toxicity from hypofractionation [17].
Prostate MR Imaging for Posttreatment Evaluation and Recurrence
2018, Urologic Clinics of North AmericaCitation Excerpt :The seeds internally give off radiation to treat the prostate, and this is best used for low-grade disease and in smaller prostates. For higher-grade disease, brachytherapy may be combined with EBRT for improved cancer treatment.43 All RT may be combined with hormonal therapy in an effort to shrink the prostate for maximal treatment efficacy.11