Iosif Strouthos

High dose rate brachytherapy as monotherapy for localised prostate cancer

BACKGROUND AND PURPOSE To evaluate the oncological outcome of a three-implant high dose rate (HDR) brachytherapy (BRT) protocol as monotherapy for clinically localised prostate cancer. MATERIAL AND METHODS Between February 2008 and December 2012, 450 consecutive patients with clinically localised prostate cancer were treated with HDR monotherapy. The cohort comprised of 198 low-, 135 intermediate- and 117 high risk patients being treated with three single-fraction implants of 11.5Gy delivered to an intraoperative real-time, transrectal ultrasound defined planning treatment volume up to a total physical dose of 34.5Gy with an interfractional interval of 21days. Fifty-eight patients (12.8%) received ADT, 32 of whom were high- and 26 intermediate-risk. Biochemical failure was defined according to the Phoenix Consensus Criteria and genitourinary/gastrointestinal toxicity evaluated using the Common Toxicity Criteria for Adverse Events version 3.0. RESULTS The median follow-up time was 56.3months. The 60-month overall survival, biochemical control and metastasis-free-survival rates were 96.2%, 95.0% and 99.0%, respectively. Toxicity was scored per event with late Grade 2 and 3 genitourinary adverse events of 14.2% and 0.8%, respectively. Late Grade 2 gastrointestinal toxicity amounted 0.4% with no instances of Grade 3 or greater late adverse events to be reported. CONCLUSIONS Our results confirm HDR BRT to be a safe and effective monotherapeutic treatment modality for clinically localised prostate cancer.

Outcome after PSMA PET/CT based salvage radiotherapy in patients with biochemical recurrence after radical prostatectomy: a bi-institutional retrospective analysis

Prostate-specific membrane antigen (PSMA) PET/CT detects prostate cancer recurrence at low levels of prostate-specific antigen (PSA). Radiotherapy with dose escalation to the former prostate bed has been associated with improved biochemical recurrence-free survival (BRFS). Thus, we hypothesized that PSMA PET/CT-guided salvage radiotherapy leads to improved BRFS. Methods: In total, 204 consecutive patients were referred for salvage radiotherapy after radical prostatectomy. PSMA PET/CT scans were performed, and patients with PSA persistence (109 patients) or evidence of distant metastases (5 patients) were excluded from this analysis. Thus, the following analysis is based on a total of 90 patients who underwent PSMA PET/CT before radiotherapy due to biochemical recurrence and received salvage radiotherapy. In cases of PET-positive findings, antiandrogen therapy was commenced before initiation of radiotherapy. BRFS (PSA ≤ 0.2 ng/mL) was defined as the study endpoint. Results: PET-positive lesions were detected in 42 of 90 (47%) patients, 24 of 42 (27%) being fossa recurrence only, 12 of 42 (13%) pelvic lymph node only, and 6 of 42 (7%) both fossa and pelvic lymph node. The median PSA before radiotherapy was 0.44 ng/mL (range, 0.11–6.24 ng/mL). Cumulatively, a total dose of 70.0 Gy (range, 67.2–72 Gy) was delivered to local macroscopic tumor, 66 Gy (range, 59.4–70.2 Gy) to the prostatic fossa, 60.8 Gy (range, 54–66 Gy) to PET-positive lymph nodes, and 50.4 Gy (range, 45–50.4 Gy) to the lymphatic pathways. After a median follow-up of 23 mo, BRFS was 78%. Antiandrogen therapy was ongoing in 4 patients at the last follow-up. No significant difference in BRFS between PET-positive patients (74%) and PET-negative patients (82%; P > 0.05) was observed at the last follow-up. Two patients had late genitourinary toxicity, grade 3, and no patient had gastrointestinal toxicity of grade 3 or higher (National Cancer Institute common terminology criteria for adverse events, version 4.03). Conclusion: PSMA PET/CT-guided salvage radiotherapy is an effective and safe local treatment option. No difference in BRFS between PET-positive and PET-negative patients was observed, indicating effective targeting of PET-positive lesions. PSMA PET/CT when readily available should be offered to patients with PSA recurrence for treatment individualization.

Combined high dose rate brachytherapy and external beam radiotherapy for clinically localised prostate cancer

PURPOSE To report the clinical outcomes and treatment-related toxicities after combined high-dose-rate (HDR) brachytherapy (BRT) with external beam radiotherapy (EBRT) for patients with clinically localised high-risk prostate cancer. MATERIAL AND METHODS Between 2008 and 2012, three hundred and three consecutive patients with organ-confined high-risk prostate cancer were treated with definitive radiotherapy consisting of HDR-BRT followed by supplemental EBRT. The transrectal 3D-ultrasound-based HDR-BRT boost consisted of two single-fraction implants of 10.5 Gy, prescribed to the 90% of the gland (D90), for a total physical dose of 21.0 Gy delivered to the prostatic gland. EBRT was delivered with conventional fractionation, prescribing 45.0 Gy to the prostatic gland and seminal vesicles. Biochemical failure was defined according to the Phoenix Consensus Criteria, genitourinary (GU)/gastrointestinal (GI) toxicity was evaluated using the Common Toxicity Criteria for Adverse Events (version 3.0). RESULTS The median follow-up was 71.6 months. The 7-year overall survival, biochemical control and metastasis-free-survival rates for the entire cohort were 85.7%, 88.3% and 93.8%, respectively. Androgen deprivation therapy was initiated prior to treatment for 92.7% of patients with a median duration of 12 months. Toxicity was scored per event with late Grade 2, 3 and 4 GU adverse events and was found to be 15.3%, 2.2% and 0.3%, respectively. Late Grade 2 GI toxicity accounted for 0.3% with no instances of Grade 3 or higher late adverse events. CONCLUSION HDR-BRT with supplemental EBRT results in low biochemical relapse-free survival rates associated with a very low incidence of higher-grade late adverse events.

Inverse planning and inverse implanting for breast interstitial brachytherapy. Introducing a new anatomy specific breast interstitial template (ASBIT)

An innovative template, based on thoracic cage surface reconstructions for breast interstitial brachytherapy was developed. Hybrid-inverse-planning-optimisation-based implantations and brachytherapy plans, using three custom anthropomorphic breast phantoms, were utilised for its validation. A user independent, inverse planning and inverse implanting technique is proposed.