Updated report of ProtecT trial which reported intention-to-treat analysis of UK men with localized prostate cancer randomized to active monitoring (AM), radical prostatectomy (RP), or radiation (RT). 1643 men included. More men in AM group died of PCa (AM=1.85%, RP=0.67%, RT=0.73%), p= 0.003 when comparing AM vs treatment arms. Metastases (AM 5.6%, RP 2.4%, RT 2.7%) and disease progression (AM 20.35%, RP 5.87%, RT 6.62%) were both more common in AM arm. There were higher risks of sexual dysfunction (95% at 6 mo) and urinary incontinence (55% at 6 mo) after RP, and of sexual dysfunction (88% at 6 mo) and bowel dysfunction (5% at 6 mo) after RT. Overall, more than 95% of patients with low or intermediate risk localized prostate cancer do not die of prostate cancer within 10 year, irrespective of treatment or active monitoring, though risk of disease progression is higher with AM.  

(Open Access)

Reference (PubMed Link): Neal DE, Metcalfe C, Donovan JL, et al. Ten-year mortality, disease progression, and treatment-related side effects in men with localised prostate cancer from the protect randomised controlled trial according to treatment received. Eur Urol 2019.

Key Institution: Multi-Institutional (UK)
Keywords: Prostate cancer, active monitoring, prostatectomy, radiation therapy

The purpose of this retrospective study was to evaluate the efficacy and toxicity profile of salvage SBRT in patients with locally recurrent prostate cancer who were previously treated with definitive RT.

This study examined 100 patients treated between 2010 and 2017 across 7 centers. Local recurrence was determined by pelvic MRI and choline PET scans, and all patients were required to undergo biopsies to prove recurrence. Primary endpoint was second biochemical RFS (bRFS) defined by the Phoenix criteria. Median SBRT dose was 36 Gy in 6 fractions

The median follow-up was 29.3 months. The second bRFS at 3 years was 55%.. The authors found that no patient developed higher than grade 1 acute GI toxicity. There were approximately 21% and 1% of patients who developed 3-year grade 2 or greater GU and GI toxicity, respectively.

This retrospective study showed promising results regarding efficacy and toxicity outcomes of salvage SBRT in patients with prostate cancer who were previously irradiated. SBRT in this setting needs to be evaluated in a prospective manner and with longer follow-up to confirm these results.

Reference (PubMed Link): Pasquier D, Martinage G, Janoray G, et al. Salvage stereotactic body radiation therapy for local prostate cancer recurrence after radiation therapy: A retrospective multicenter study of the getug. Int J Radiat Oncol Biol Phys 2019;105:727-734.

Key Institution: Centre Oscar Lambret, Lille, France
Keywords: Prostate cancer, salvage radiation, SBRT, reirradiation, biochemical failure 

There is randomized evidence that moderately hypofractionated radiation therapy (typically 2.5 – 4 Gy per fraction) is a valid alternative for some patients with prostate cancer. Extreme hypofractionation, typically defined as >6 Gy per fraction, delivered with SBRT in 4 or 5 treatments, also has some encouraging supportive data. 

The present study, the ONE-SHOT trial, addresses the role of single fraction SBRT in prostate cancer. The radiation therapy was 19 Gy in a single fraction of SBRT designed to spare the urethra, with the Calypso System used to continuously track motion. 6 patients with localized (low or intermediate risk) prostate cancer received this treatment. There was no acute toxicity greater than grade 2 during the 3-month follow-up. 50% of patients experienced grade 1 or 2 GU toxicities which decreased to baseline at week 12. 33% of patients had grade 1 rectal toxicity at week 6 which was resolved by week 12.  

Although the results are intriguing and warrant further study, this is a very small number of patients and there is no long-term follow-up data available, so it should remain investigational for the time being. Longer follow-up and larger prospective comparative studies would be needed before adopting this into practice.  

Reference (PubMed Link): Zilli T, Franzese C, Bottero M, et al. Single fraction urethra-sparing prostate cancer sbrt: Phase i results of the one shot trial. Radiother Oncol 2019;139:83-86.

Key Institution: Geneva University Hospital, Switzerland 
Keywords: Prostate SBRT, urethral sparing radiation therapy, single-fraction treatment 

More ultra-hypofractionated regimens are being implemented in treatment of prostate cancer. This study is a phase 3 non-inferiority study comparing prostate stereotactic body radiation therapy (SBRT) to conventionally-fractionated radiation therapy with co-primary endpoints of acute gastrointestinal (GI) and genitourinary (GU) toxicity. Very early outcomes (median follow-up of 12 weeks) are reported. At 12 weeks, SBRT appeared non-inferior to conventionally-fractionated radiation therapy in regards to acute GI and GU toxicity. Though this information is important to physicians, we need longer follow-up to determine the risks of late toxicity before broad application in the clinic. 

(Open Access)

Reference (PubMed Link): Brand DH, Tree AC, Ostler P, et al. Intensity-modulated fractionated radiotherapy versus stereotactic body radiotherapy for prostate cancer (pace-b): Acute toxicity findings from an international, randomised, open-label, phase 3, non-inferiority trial. Lancet Oncol 2019;20:1531-1543.

Key Institution: Multi-Institutional (Royal Marsden Hospital, Institute of Cancer Research, London, UK)
Keywords: Prostate cancer,  SBRT, acute toxicity