Gantry-based 5-fraction Elective Nodal Irradiation in Unfavorable-Risk Prostate Cancer: Outcomes from 2 Prospective Studies comparing SABR Boost with MR Dose Painted HDR Brachytherapy Boost

328 Background: The ASCO/CCO guidelines recommend brachytherapy boost for all eligible intermediate- or high-risk localized prostate cancer patients. We present efficacy, survival and late toxicity outcomes in patients treated on a prospective, single institutional protocol of MRI dose painted HDR brachytherapy boost (HDR-BT) followed by pelvic stereotactic body radiotherapy (SBRT) and androgen deprivation therapy (ADT). Methods: A phase I/II study was performed where intermediate (IR) or high-risk (HR) prostate cancer patients received HDR-BT 15Gy x 1 to the prostate and up to 22.5Gy to the MRI nodule and followed by gantry-based SBRT 25Gy in 5 weekly fractions delivered to pelvis, seminal vesicles and prostate. ADT was used for 6-18 months. CTCAEv3 was used to assess toxicities and was captured q6months x 5 years. Biochemical failure (BF; nadir + 2 definition), nadir PSA, proportion of patients with PSA < 0.4 ng/ml at 4 years (4yPSARR), incidence of salvage therapy, cause specific survival and overall survival were calculated. Day 0 was HDR-BT date for all time-to-event analyses. Results: Thirty-two patients (NCCN 3% favorable IR, 47% unfavorable IR and 50% HR) completed the planned treatment with a median follow-up of 50 months; 31 of these had an MRI nodule. Four patients had BF with actuarial 4-year BF rate of 11.5%; 3 of these received salvage ADT. Median nPSA was 0.02 ng/ml; 4yPSARR was 68.8%. One patient died (of prostate cancer) at 45 months. For late toxicities, grade 1, 2 and 3+ GU and GI toxicities were: 40.6%, 37.5%, 3% and 28.1%, 0%, 0%, respectively. Conclusions: This novel treatment protocol incorporating MRI-dose painted HDR brachytherapy boost and SBRT pelvic radiation for intermediate- and high-risk prostate cancer in combination with ADT is feasible, effective and well tolerated. Clinical trial information: 12345678. [Table: see text]

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Pelvic SABR with HDR boost in intermediate- and high-risk prostate cancer (SPARE): Favorable early toxicity and quality-of-life outcomes.

Journal of Clinical Oncology ◽

10.1200/jco.2017.35.6_suppl.60 ◽

2017 ◽

Vol 35 (6_suppl) ◽

pp. 60-60 ◽

Cited By ~ 1

Author(s):

Hima Bindu Musunuru ◽

Andrea Deabreu ◽

Melanie Davidson ◽

Ananth Ravi ◽

Joelle Antoine Helou ◽

...

Keyword(s):

Quality Of Life ◽

Prostate Cancer ◽

High Risk ◽

Hdr Brachytherapy ◽

High Risk Prostate Cancer ◽

Risk Prostate Cancer ◽

Brachytherapy Boost ◽

Early Toxicity

60 Background: ASCENDE-RT has provided level 1 evidence supporting the use of androgen deprivation therapy (ADT), external beam radiotherapy and brachytherapy boost in intermediate- and high-risk prostate cancer. The objectives of this study are to report early toxicity and quality of life (QOL) outcomes in patients treated on a hybrid protocol using five-fraction pelvic stereotactic ablative radiotherapy (SABR) with a MRI dose painted HDR brachytherapy boost (HDR-BT). Methods: A phase I/II study was performed where intermediate (IR) and high-risk (HR) prostate cancer patients received HDR-BT 15Gy in single fraction to the prostate and up to 22.5Gy to the MRI nodule. Gantry-based 25Gy SABR was delivered to pelvis, seminal vesicles and prostate in 5 weekly fractions. ADT was used for 6-18 months. Common Terminology Criteria for Adverse Events version 3.0 was used to assess toxicities. QOL was captured using EPIC at every follow-up. A minimally clinically important change (MCIC) definition was triggered if the EPIC QOL score at each time point decreases > 0.5 SD, where SD is the standard deviation of baseline scores. Results: Thirty-three patients (NCCN 6.0% low IR, 45.5% high IR and 48.5% HR) completed this treatment with a median follow-up of 13.8 months (IQR 12.1, 18.8). The incidence of worst toxicities is shown in Table 1.The 3 grade 3 GU patients were due to temporary urinary catheterization in the acute period following HDR-BT. Mean (95% SD) EPIC urinary QOL scores were 82.5 (16.5), 83.2 (12.9) and 83.7 (16.3) at baseline, 3 months and 12 months and the bowel scores were 95.9 (3.8), 92.6 (8.2) and 90.5 (8.3), respectively. Proportion of patients experiencing MCIC at 3 months and 12 months were 20.8% and 14.3% for urinary domain, 47.8% and 53.9% for bowel domain; respectively (see Table). Conclusions: This novel treatment protocol incorporating MRI dose painted HDR brachytherapy boost and SABR pelvic radiation for intermediate- and high-risk prostate cancer in combination with ADT is feasible and well tolerated in the acute setting. Clinical trial information: REB 269-2014. [Table: see text]

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