Ultrahypofractionation of localized prostate cancer

Abstract

Due to its low fractionation sensitivity, also known as “alpha/beta ratio,” in relation to its surrounding organs at risk, prostate cancer is predestined for hypofractionated radiation schedules assuming an increased therapeutic ratio compared to normofractionated regimens. While moderate hypofractionation (2.2–4 Gy) has been proven to be non-inferior to normal fractionation in several large randomized trials for localized prostate cancer, level I evidence for ultrahypofractionation (>4 Gy) was lacking until recently. An accumulating body of non-randomized evidence has recently been strengthened by the publication of two randomized studies comparing ultrahypofractionation with a normofractionated schedule, i.e., the Scandinavian HYPO-RT trial by Widmark et al. and the first toxicity results of the PACE‑B trial. In this review, we aim to give a brief overview of the current evidence of ultrahypofractionation, make an overall assessment of the level of evidence, and provide recommendations and requirements that should be followed before introducing ultrahypofractionation into routine clinical use.

Current State of Personalized Genitourinary Cancer Radiotherapy in the Era of Precision Medicine

“…This indicates that hypofractionated radiation (delivery of a higher dose to the prostate gland per treatment, for fewer total treatments) may improve cancer control. Thus, there has been great interest in moderate hypofractionation (generally accepted as 2.4-3.4 Gy per fraction (fx)) as well as ultrahypofractionation (generally accepted as >4-5 Gy/fx) (71,72). Modern noninferiority trials have demonstrated excellent overall outcomes in comparison to standard fractionation (Table 4) (73-76).…”

Dosimetric comparison of MR-guided adaptive IMRT versus 3DOF-VMAT for prostate stereotactic radiotherapy

“…There is increasing evidence to support the adoption of ultrahypofractionated schedules (≥4Gy/fraction) delivered with Stereotactic Body Radiation Therapy (SBRT) for the treatment of low/intermediate risk prostate cancer [1] . Geometric precision is paramount when a small margin is used to minimize irradiation of the surrounding organs at risk (OARs).…”

Extreme Hypofractionation with SBRT in Localized Prostate Cancer

“…The use of SBRT in PCa has provided sufficient evidence in terms of tumor control results, quality of life reported by the patient, and low toxicity [4][5][6] to back its implementation in daily clinical practice. Moreover, the PCa working group of the German Society of Oncology (DEGRO) endorses the use of SBRT in the treatment of localized lowand intermediate-risk PCa, recommending its use in clinical trials in patients with the localized high-risk disease [7].…”