Diagnosis and management of local recurrence after low-dose-rate brachytherapy

Objectives: To describe the diagnosis of local failure after prostate brachytherapy (BT) and treatment options when recurrence is present.

Methods and materials: Review of literature for local recurrence after prostate BT and salvage therapy was performed. A total of 6 patients with prostate-specific antigen increase were identified as local failures by transperineal mapping biopsy (TPMB) and treated with targeted focused therapy using cryoablation.

Results: Local recurrence after prostate BT occurs in 2-20% and is dose dependent. The biologic effective dose greater than 200 Gy(2) is associated with a less than 2% recurrence rate. Confirmatory biopsy should include both the prostate and seminal vesicles, as prostate cancer can be found in 20% of the latter. The pathologist should be experienced in evaluating post-irradiation tissue because of the difficulty in distinguishing benign irradiated prostate from residual or recurrent tumor. Whole gland salvage, whether by prostatectomy or cryoablation, is associated with high complication rates. Focal therapy has fewer complications but accurate targeting remains a concern. Newer diagnostic and targeting modalities such as multiparametric MRI and TPMB offer improved opportunity to increase lesion identification and ablation. A TPMB approach, which incorporates new biopsy needle design and interactive targeting software, may offer the best avenue to true focused therapy.

Conclusion: Local recurrences after prostate BT are uncommon because of high delivered radiation dose. When present, improved lesion identification and targeting may be associated with better cancer control and lower morbidity.