Salvage local treatment for localized radio-recurrent prostate cancer: a narrative review and future perspectives.

Although dose escalation protocols have improved biochemical control in prostate cancer radiotherapy, 10-45% of patients will experience disease recurrence. The prostate and seminal vesicles are the most frequent site of the first relapse. Traditionally, these patients have been managed with hormonal therapy, which is not curative. Recent improvements in diagnostic tests (e.g., multiparametric magnetic resonance and molecular imaging, including PET/CT scan with choline or Ga-PSMA) and new treatment techniques (e.g., stereotactic body radiation therapy or other minimally invasive alternatives like high-intensity focus ultrasound, cryoablation or high-dose-rate brachytherapy) offer new therapeutic strategies with the potential to cure some patients with limited adverse effects. In this narrative review, the authors present the most recent evidence to help identify the most suitable candidates for salvage treatment.

Salvage brachytherapy for locally recurrent prostate cancer after single-fraction 19 Gy high-dose-rate brachytherapy: toxicity, prostate-specific antigen kinetics, and cancer control.

PURPOSE: To evaluate toxicity, prostate-specific antigen (PSA) kinetics, and cancer control of high-dose-rate brachytherapy (HDR-BT) as a salvage modality for men with locally recurrent prostate cancer, after primary HDR-BT failure. MATERIAL AND METHODS: Twelve patients with biochemical failure and a local relapse after 19 Gy single-fraction high-dose-rate brachytherapy (HDR-BT 19 Gy) were salvaged using two HDR-BT fractions. Salvage treatment consisted of two HDR-BT applications, one week apart, delivering 12 Gy to the prostate per application (HDR-BT 12 × 2). RESULTS: Median age and initial PSA prior to rescue treatment were 74 years (range, 65-80) and 5.29 ng/ml (range, 2.37-16.40), respectively. Forty-two percent had a low-risk and 58% presented with intermediate-risk prostate cancer. Median follow-up period was 26 months (range, 10-42). Median time to PSA nadir was 12 months, with a median value of 0.21 ng/ml. Most of the patients (11 of 12) achieved a PSA decline ≥ 90%. Acute grade 2 genitourinary (GU) toxicity occurred in 4 patients (33.3%) and none presented with acute gastrointestinal (GI) toxicity. Two patients (16.7%) suffered from late GU grade 2 toxicity. No grade 3 toxicity were recorded. To date, 2 patients (16.7%) have experienced biochemical failure after salvage treatment. CONCLUSIONS: Salvage HDR-BT 12 × 2 is a feasible and well-tolerated treatment, with acceptable toxicity rates for men with locally recurrent prostate cancer, who failed after HDR-BT with 19 Gy. Moreover, PSA kinetics and cancer control after salvage treatment suggest that this strategy might be efficacious in this clinical setting.

Pattern of relapse and dosimetric analysis of a single dose 19 Gy HDR-brachytherapy phase II trial.

PURPOSE: To report the pattern of relapse within the prostate with reference to the initial site of disease in patients treated with single fraction 19-Gy. METHODS AND MATERIALS: Forty-four patients were treated according to a prospective study of single-fraction HDR-brachytherapy. Treatment was delivered using 192Ir to a dose of 19 Gy prescribed to the prostate. Patients who experienced a biochemical failure underwent a re-staging multiparametric MRI (mpMRI) and MRI-TRUS fusion biopsy to rule-out local recurrence. In patients with visible Dominant intraprostatic lesions (DIL) on pretreatment mpMRI, the site of local relapse was compared with the initial site of disease. The dose received by the site of recurrence was investigated. RESULTS: The median follow-up period was 48 months (range 29-63). The PSA nadir was reached at 24 months follow-up, with a median value of 1.07 ng/mL. To date, 14 patients (32%) have experienced biochemical failure (4 patients low-risk and 10 intermediate-risk; p = 0.013). Re-staging mpMRI was performed in 11/14 patients. Eleven patients underwent MRI-TRUS fusion biopsy confirming local relapse in all patients. The analysis of DVH of all 44 patients revealed that patients with biochemical failure had received significantly lower doses in terms of V100, V125 and D90 (p = 0.032, p = 0.018 and p = 0.018 respectively). In patients with DILs on diagnostic mpMRI, the mean D90 and D98 on DIL were lower for patients with biochemical failure. CONCLUSIONS: This dosimetric analysis demonstrates a dose-response relationship in patients treated with single fraction 19 Gy. Patients with intermediate risk disease, with visible DIL on mpMRI and patients treated with cooler implants have higher incidence of biochemical and local failure.