Prostate Stereotactic Body Radiation Therapy With a Focal Simultaneous Integrated Boost: Acute Toxicity and Dosimetry Results From a Prospective Trial

• Published in: Advances in radiation oncology Vol. 4; no. 1; pp. 90 - 95
• Main Authors: McDonald, Andrew M., MD, MS, Dobelbower, Michael C., MD, PhD, Yang, Eddy S., MD, PhD, Clark, Grant M., MD, Jacob, Rojymon, MD, Kim, Robert Y., MD, Cardan, Rex A., PhD, Popple, Richard, PhD, Nix, Jeffrey W., MD, Rais-Bahrami, Soroush, MD, Fiveash, John B., MD
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.01.2019; Elsevier
• Subjects: Genitourinary Cancer; Hematology, Oncology, and Palliative Medicine
• ISSN: 2452-1094; 2452-1094
• DOI: 10.1016/j.adro.2018.09.007

Abstract Purpose This study aimed to report the early toxicity results of a prospective clinical trial of prostate stereotactic body radiation therapy (SBRT) to the entire prostate with a simultaneous integrated boost (SIB) to magnetic resonance imaging (MRI)-defined focal lesions. Methods and materials Eligible patients included men with biopsy-proven prostate stage T1c to T2c adenocarcinoma, a Gleason score ≤7, and prostate-specific antigen values of ≤20 ng/mL, who had at least 1 focal lesion visible on MRI and a total prostate volume no greater than 120 cm3 . SBRT consisted of a dose of 36.25 Gy to the entire prostate with an SIB of 40 Gy to the MRI-defined lesions, delivered in 5 fractions. The primary purpose of the study was to confirm the feasibility of treatment planning/delivery and to estimate the rate of urinary retention requiring placement of a Foley catheter within 90 days of treatment. This study was to be considered successful if urinary retention occurred in no more than 15% of cases, with a planned enrollment of at least 25 patients. Results A total of 26 men were enrolled, and all underwent SBRT as planned. Twenty patients (77%) had intermediate-risk features, and the remainder were low risk. A treatment plan that met the protocol-defined goals for all cases was developed. Two patients (7.7%) developed acute urinary symptoms that required the temporary placement of a Foley catheter. No grade 3+ toxicity events were observed. Conclusions Planning and delivery of prostate SBRT with a whole prostate dose of 36.25 Gy and a focal 40 Gy SIB is feasible. Early follow-up suggests that this treatment is not associated with undue morbidity.