High-dose-rate brachytherapy delivered in two fractions as monotherapy for low-risk prostate cancer

Abstract

PurposeHigh-dose-rate (HDR) brachytherapy has been accepted as an effective and safe method to treat prostate cancer. The aim of this study was to describe acute toxicity following HDR brachytherapy to the prostate, and to examine the association between dosimetric parameters and urinary toxicity in low-risk prostate cancer patients.Material and methodsPatients with low-risk prostate cancer were given HDR brachytherapy as monotherapy in two 12.5 Gy fractions. Planning objectives for the planning target volume (PTV) were V100% ≥ 90% and V150% ≤ 35%. Planning objectives for organs at risk were V75% ≤ 1 cc for the bladder, rectum and perineum, and V125% ≤ 1 cc for the urethra. Toxicity was assessed three months after treatment using the Common Terminology Criteria for Adverse Events.ResultsSeventy-three patients were included in the analysis. Thirty-three patients (45%) reported having any type of toxicity in the three months following HDR brachytherapy. Most toxicity cases (26%) were grade 1 urinary toxicity. Mean coverage index was 0.89 and mean V100 was 88.85. Doses administered to the urethra were associated with urinary toxicity. Patients who received more than 111.3% of the prescribed dose in 1 cc of the urethra were four times more likely to have urinary toxicity compared to patients receiving less than 111.3% (OR = 4.71, 95% CI: 1.43-15.6; p = 0.011).ConclusionsHigh-dose-rate brachytherapy administered as monotherapy for prostate cancer proved to be a safe alternative treatment for patients with low-risk prostate cancer. Urinary toxicity was associated with the dose administered to 1 cc and 0.1 cc of the urethra and was remarkably inferior to the reported toxicity in similar studies.

An evaluation of the robustness of organ-at-risk recommendations made by GEC/ESTRO according to interobserver variability: a single-center experience

“…published local control outcomes as high as 96.9% [ 7 ]. Similar urinary toxicity has been observed in patients treated with HDR monotherapy [ 8 ].…”

Prostate-specific antigen nadir after high-dose-rate brachytherapy predicts long-term survival outcomes in high-risk prostate cancer

“…High-dose-rate (HDR) brachytherapy has been accepted as a useful method to control localized and locally advanced prostate cancers [ 1 , 2 , 3 ]. The combination of HDR brachytherapy and external beam radiation therapy (EBRT) is expected to provide an effective approach for delivering radiation doses more safely and precisely compared to EBRT alone in high-risk and locally advanced prostate cancer, even if patients have extracapsular invasion and seminal vesicle invasion [ 4 , 5 , 6 , 7 ].…”

Template guided transperineal saturation biopsy of the prostate: lessons for focal and urethra-sparing high-dose-rate brachytherapy for localized prostate cancer

“…High clinical efficacy of HDR brachytherapy as a monotherapy of patients with low- and intermediate-risk localized PCa and as a component of combined treatment of high-risk patients is confirmed by numerous clinical studies [ 9 , 17 , 18 ]. The standard HDR brachytherapy technique suppose fractionated irradiation (from 2 to 6 fractions) of the whole prostate with biologically effective dose equivalent to 200 Gy (α/β = 1.5), or higher.…”

“…Cendales et al . [ 18 ] analyzed the toxicity profile of HDR monotherapy by 2 fractions of 12.5 Gy each. They noted a significant relationship between radiation doses administered to the urethra and the risk of genitourinary complications.…”