Jeremy Millar
Alfred Health Radiation Oncology
Director

Aaron Kent
Senior Registrar
Alfred Health Radiation Oncology

Bronwyn Matheson
Radiation Oncologist
Alfred Health Radiation Oncology

Ryan Smith
Radiation Oncology Medical Physicist
Alfred Health Radiation Oncology

Cath Beaufort
Head Radiation Therapist
Gippsland / Alfred Health Radiation Oncology

Daniel Zwahlen
Radiation Oncologist
Kantonsspital Graubunden, Chur, Switzerland

Ben Hindson
Radiation Oncologist
Christchurch Hospital, Christchurch, New Zealand

Peter Royce
Director
Urology, Alfred Health

Background and Purpose: Either low dose-rate (LDR) or high dose-rate (HDR) brachytherapy added to external beam radiation treatment (EBRT) for prostate cancer (PCa) has shown better disease-control in retrospective and randomised studies, but typically not in survival; and not usually with long-term adverse-effect (AE) descriptions. We report long-term follow-up with patient-reported quality-of-life (QoL) measures in a cohort of men with PCa treated with EBRT with or without an HDR "boost".

Materials and Methods: Consecutive men presenting 1998-2004 with localised PCa treated using departmental protocols including the clinician- and patient-choice optional addition of HDR boost to EBRT (HDR-EBRT) or EBRT alone (EBRT). NCCN intermediate risk (IR) men were offered neoadjuvant androgen deprivation (AD) and those with high risk (HR) were also offered adjuvant AD. Patient-completed QoL surveys were recorded at least annually to assign RTOG grades to bowel and bladder AE, and the 5-item international index of erectile function (IIEF-5) to assess erectile function (EF). Strictures were defined as time-to-first-urethrotomy. The Phoenix consensus defined biochemical failure (BF). EF was a IIEF-5 score>7. Times-to-event were assessed with Kaplan-Meyer methods.

Results: 654 patients received either HDR-EBRT (median 46Gy in combination with a HDR median 18Gy/3 boost; 215 patients) or EBRT (median 70Gy; 440 patients).The median age was 69yrs and 72yrs, and median presenting PSA 12.2ng/mL and 9.9ng/mL, for HDR-EBRT and EBRT groups respectively. The HDR-EBRT group had less low risk patients (3.3% vs 19.4%) and more HR (50.7% versus 37.4%) compared to the EBRT group. The 15-year estimates of BF-free survivals were 0.68 and 0.54 (P=0.03) for the HDR-EBRT and EBRT men respectively and the 15-year estimates for cause-specific and overall survivals were 0.87 and 0.79 (P=0.036), and 0.67 and 0.52 (P=0.0008). In HDR-EBRT men bowel and bladder AE prevalence peaked at 3-6 months, and the point prevalence of RTOG grade >1 bowel AE was never >5% after 7 years. The estimated probability of stricture was 11% at 15 years. Of men with documented EF pre-treatment, 42% had EF at 10 years.

Conclusions: In our cohort HDR-EBRT was associated with better disease control and survival than EBRT (noting EBRT dose was lower than current standards), despite these men having some features suggesting a poorer prognosis. Overall long-term AE prevalence was low, and EF was preserved in a proportion of men even 10 years after treatment. Our results add weight to observations from randomised trials and provide long-term statistics on AE associated with HDR-EBRT.


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