Pilot Study of Focal Salvage HDR Brachytherapy After Local Recurrence from Brachytherapy
Dr. Hans Chung, Sunnybrook Odette Cancer Centre
Dr. Hans Chung is an Assistant Professor, Department of Radiation Oncology, University of Toronto. He is based at the Sunnybrook Odette Cancer Centre and specializes in prostate brachytherapy.
Brachytherapy is a commonly used treatment for prostate cancer. While the outcomes of brachytherapy are very good, approximately 5% of patients with low or favorable intermediate-risk prostate cancer will recur within the prostate. Those with higher risk disease would have an even higher risk of local recurrence. The standard treatment for this is hormonal therapy, which is associated with significant toxicities and is not curative. Leveraging Sunnybrook’s considerable experience in brachytherapy as the largest centre globally, we aim to study the toxicities, quality of life and efficacy of focal salvage HDR prostate brachytherapy in patients who fail within the prostate after previous brachytherapy.
Results of studies of whole-gland salvage brachytherapy demonstrate approximately 50% PSA control rates. However, significant toxicities occur in 10-15%. Since most local recurrences occur in the initial site of disease rather than extensively throughout the prostate, we hypothesize that focal salvage brachytherapy may be as effective as whole-gland salvage brachytherapy but with less morbidity. Indeed, we recently presented our data of focal salvage HDR brachytherapy for those with local recurrence after previous external-beam radiotherapy and demonstrated similar biochemical control rates, but without any acute or late grade 3-5 genitourinary or gastrointestinal toxicities. This prompted us to initiate a similar study of focal salvage HDR brachytherapy, but for those with local recurrence after previous brachytherapy, either as monotherapy or combined with external-beam radiotherapy. Our objectives are to explore the toxicities, quality of life, biochemical control rates and MRI response rates.
Impact on prostate cancer patients:
For patients who were treated with brachytherapy and subsequently developed a local recurrence, the standard treatment is hormonal therapy. While hormonal therapy is effective in controlling prostate cancer, it is not curative and is associated with much toxicity. If this study demonstrates low toxicities and reasonable efficacy, it would offer a potential curative option for these patients and the avoidance or delay of having to start hormonal therapy.