Objectives
To report clinical outcomes of the HemiâAblative Prostate Brachytherapy (HAPpy) trial evaluating treatmentârelated toxicity and effectiveness of hemiâgland (HG) lowâdoseârate (LDR) prostate brachytherapy as a focal approach to control unilateral localised prostate cancer.
Patients and Methods
Single institution phase IIS pilot study of patients treated with focal 4D Brachytherapyâą (BXTAccelyon, Burnham, Buckinghamshire, UK). The primary outcome was patientâreported toxicity 24Â months after implant. The secondary outcome was assessment of disease control. Outcomes in HG patients were compared to wholeâgland (WG) controls obtained from our prospective cohort registry by negative binomial and linear regression models.
Results
Preâtreatment demography was similar between the 30 HG patients and 362 WG controls. Postâimplant dosimetry was similar for the prostate gland target volumes and significantly reduced for the urethra and bowel in HG patients relative to WG controls, but this did not translate into a difference in postâimplant mean symptom scores between the two groups. Nevertheless, the change in score from baseline indicated that the impact on preâtreatment symptom status was less after HG implants. Only HG patients showed a return to baseline urinary scores as early as 12Â months. Sexual potency was conserved in 73% and 67% of HG and WG patients, respectively (PÂ =Â 0.84). Postâimplant prostateâspecific antigen (PSA) kinetics revealed that baseline PSA was reduced at 24Â months by 78% and 88% in HG and WG patients, respectively (PÂ <Â 0.05). Treatment relapse occurred in one (3%) HG patient 55Â months after implant and in nine (3%) WG patients at 32â67Â months after implant.
Conclusion
This pilot study suggests that treatmentârelated toxicity and biochemical outcomes after HG implants are broadly similar to those observed with WG treatment despite the lower dose delivered by HG implants.