Patient-Reported Outcomes in the Acute Phase of the Randomized Hypofractionated Irradiation for Prostate Cancer (HYPRO) Trial

Acute toxicity patterns and their management after moderate and ultra- hypofractionated radiotherapy for prostate cancer: A prospective cohort study

Objective

Hypofractionation has become the new clinical standard for prostate cancer. We investigated the management of acute toxicity in patients treated with moderate hypofractionation (MHF) or Ultrahypofractionation (UHF).

Methods

In a prospective cohort setting, patients (N=316) received either MHF (20 fractions of 3/3.1 Gy, 5 fractions per week, N=156) or UHF (7 fractions of 6.1 Gy, 3 fractions per week, N=160) to the prostate +/- (base of the) seminal vesicles between 2019 and 2023. UHF was not indicated in case of significant lower urinary tract symptoms (LUTS) or T3b disease. Patient-reported outcomes (PRO) were online distributed at baseline, end of treatment (aiming at last fraction +/- 3 days), 3 months. Acute toxicity rates, management, and associations with baseline factors were analysed using Chi-square test and logistic regression. CTCAE scores (version 5) were calculated.

Results

Treatment for acute urinary complaints was prescribed in 46 % (MHF) and 29 % (UHF). Taking into consideration baseline LUTS, MHF and UHF showed similar rates of PROs and management. Medication for acute gastrointestinal (GI) symptoms was prescribed for 21.1 % (MHF) and 14.1 % (UHF) with more loperamide for diarrhea in MHF (9.0 %) vs UHF (1.9 %, p = 0.005). Grade ≥ 2 (MHF / UHF) was scored in 40 % / 28 % for GI (p = 0.03) and 50 % / 31 % for GU (p < 0.01). PROs for GI reported after last fraction of UHF were significantly worse compared to before last fraction.

Conclusion

UHF was safe with respect to acute toxicity risks in the selected population. MHF is associated with risks of significant diarrhea which needs further investigation. Furthermore, optimal registration of acute toxicity for UHF requires measurements up to 1-2 weeks after the last fraction.

Clinical Outcomes of Prostate SBRT Using Non-adaptive MR-Guided Radiotherapy

OBJECTIVES

Stereotactic body radiotherapy (SBRT) is widely used for localized prostate cancer and implementation of MR-guided radiotherapy has the advantage of tighter margins and improved sparing of organs at risk. Here we evaluate outcomes and time required to treat using non-adaptive MR-guided SBRT (MRgSBRT) for localized prostate cancer at our institution.

METHODS

From 9/2019 to 11/2021 we conducted a retrospective review of 80 consecutive patients who were treated with MRgSBRT to the prostate. Patients included low (LR) (5%), favorable intermediate (FIR) (40%), unfavorable intermediate (UIR) (49%), and high risk (HR) (6%). Short-term androgen deprivation therapy was used in 32% of patients. Target volumes included prostate gland and proximal seminal vesicles with an isotropic 3 mm margin. Treatment was prescribed to 36.25 Gy in 5 fractions every other day with urethral sparing. Hydrogel spacer was used in 18% of patients. Time on the linac was recorded as beam on time (BOT) plus total treatment time (TTT) including gating. Analyzed outcomes included PSA response and patient reported outcomes scored by the American Urological Association (AUA) questionnaire and toxicity per CTCAE v5. General linear regression model was used to analyze factors affecting PSA and AUA in longitudinal follow up, and chi-square test was used to assess factors affecting toxicity.

RESULTS

Median follow up was 19.3 months (3.8 - 36.6). Median BOT was 4.6 min (2.6 - 7.2) with a median TTT of 11 min (7.6 - 15.8). Pre-treatment vs post-RT median PSA was 6.36 (2.20 - 19.6) vs 0.85 (0.19 - 3.6), respectively (P < 0.001). PSA decrease differed significantly when patients were stratified by risk category, favoring LR/FIR vs UIF/HR group (P = 0.019). Four (5%) patients experienced a biochemical failure (BCF), with a median time to BCF of 20.4 months (7.9 - 34.5). Median biochemical failure free survival (BCFFS) was not reached, with 2-yr and 4-yr BCFFS of 97.1% and 72.1%, respectively. Patients with LR/FIR disease had 100% 2-yr and 4-yr BCFFS, whereas patients with UIF/HR had 95% and 41% 2-yr and 4-yr BCFFS (P = 0.05). Mean pre-treatment AUA was 7.3 (1 - 25) vs 11.3 (1 - 26) at first follow-up; however, AUA normalized to baseline over time. Urethral Dmax ≥35 Gy trended to lower AUA score at all follow-ups (P = 0.07). Forty-one (51%) patients reported grade 1-2 genitourinary toxicities at the 1 month follow up. Grade 3 toxicity (proctitis) was noted in 1 patient. There was no decrease in any grade rectal toxicity with use of hydrogel spacer (3 vs 6, P = 0.2). No grade ≥4 toxicities was observed.

CONCLUSIONS

MRgSBRT has the potential for treatment adaptation but this comes at the cost of increased resource utilization. Our experience with non-adaptive MRgSBRT of the prostate highlights its short treatment times as well as efficacy with good PSA control and low toxicity profile.

De-Escalation of Therapy for Prostate Cancer

Prostate cancer (PCa) is the second most commonly diagnosed cancer in men with around 1.4 million new cases every year. In patients with localized disease, management options include active surveillance (AS), radical prostatectomy (RP; with or without pelvic lymph node dissection), or radiotherapy to the prostate (with or without pelvic irradiation) with or without hormonotherapy. In advanced disease, treatment options include systemic treatment(s) and/or treatment to primary tumour and/or metastasis-directed therapies (MDTs). Specifically, in advanced stage, the current trend is earlier intensification of treatment such as dual or triple combination systemic treatments or adding treatment to primary and MDT to systemic treatment. However, earlier treatment intensification comes with the cost of increased morbidity and mortality resulting from drug-/treatment-related side effects. The main goal is and should be to provide the best possible care and oncologic outcomes with minimum possible side effects. This chapter will explore emerging possibilities to de-escalate treatment in PCa driven by enhanced insights into disease biology and the natural course of PCa such as AS in intermediate-risk disease or salvage versus adjuvant radiotherapy in post-RP patients. Considerations arising from advancements in PCa imaging and technological advancements in surgical and radiation therapy techniques including omitting pelvic lymph node dissection in the era of prostate-specific membrane antigen positron emitting tomography, the potential of MDT to delay/omit systemic treatment in metachronous oligorecurrence, and the efficacy of hypofractionation schemes compared with conventional fractionated radiotherapy will be discussed.

Acute and late toxicity patterns of moderate hypo-fractionated radiotherapy for prostate cancer: a systematic review and meta-analysis

Introduction

Moderate hypofractionated (HF) radiotherapy is becoming the new standard in radiotherapy for prostate cancer patients. It is established as safe, but it might be associated with increased acute toxicity levels. We conducted a systematic review on moderate HF to establish acute toxicity levels and their required clinical management; late toxicity was reported as a secondary outcome.

Material and methods

Using PRISMA guidelines, we conducted a systematic review for studies published until June 2022. We identified 17 prospective studies, with 7796 localised prostate cancer patients, reporting acute toxicity of moderate hypofractionation (2.5-3.4 Gy/fraction). A meta-analysis was done for 10/17 studies with a control arm (standard fractionation (SF)), including evaluation of late toxicity rates. We used Cochrane bias assessment and Newcastle-Ottawa bias assessment tools for randomized controlled trials (RCTs) RCT and non-RCTs, respectively.

Results

Pooled results showed that acute grade ≥ 2 gastro-intestinal (GI) toxicity was increased by 6.3 % (95 % CI for risk difference = 2.0 %-10.6 %) for HF vs SF. Acute grade ≥ 2 Genito-urinary (GU) and late toxicity were not significantly increased. The overall risk of bias assessment revealed a low risk in the meta-analysis of included studies. Data on management of toxicity (medication, interventions) was only reported in 2/17 studies.

Conclusion

HF is associated with increased acute GI symptoms, needing adequate monitoring and management. Reports on toxicity management were very limited. Pooled late GI and GU toxicity showed similar levels for SF and HF.