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High‐dose‐rate brachytherapy boost to the dominant intra‐prostatic tumor region: Hemi‐irradiation of prostate cancer
Author(s) -
Schick Ulrike,
Popowski Youri,
Nouet Philippe,
Bieri Sabine,
Rouzaud Michel,
Khan Haleem,
Weber Damien Charles,
Miralbell Raymond
Publication year - 2011
Publication title -
the prostate
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.295
H-Index - 123
eISSN - 1097-0045
pISSN - 0270-4137
DOI - 10.1002/pros.21347
Subject(s) - brachytherapy , prostate cancer , medicine , prostate , dose rate , prostate disease , urology , cancer , oncology , radiation therapy , medical physics
BACKGROUND To assess the feasibility, toxicity, and outcome of prostate hemi‐irradiation with a high‐dose‐rate brachytherapy (HDR‐BT) boost for patients presumed to harbor dominant intra‐prostatic tumors in a single lobe. METHODS After 3D conformal external radiotherapy (3DCRT) to 64–64.4 Gy, 77 patients with non‐metastatic locally aggressive prostate cancer have been treated from 2000 to 2004, with HDR‐BT using temporary open MRI‐guided 192 Ir implants, to escalate the dose in the boost region. Twenty patients (26%) had one lobe involvement (i.e., one sided endorectal MRI, rectal examination, and biopsies) and were boosted to one side of the gland only. A dose of 12, 14, and 16 Gy in two fractions was delivered to 5, 6, and 9 patients, respectively. RESULTS After a median follow‐up 69 months, no differences in late rectal toxicity were observed between the unilaterally and bilaterally irradiated cohorts. Although, grade 2 late urinary toxicity was worse in the hemi‐irradiated group ( P = 0.03), severe grade ≥3 late urinary toxicity at 5 years was not different: 10% versus 8.8% in the unilaterally and bilaterally irradiated cohorts, respectively. Grade 4 late urinary toxicity, however, was exclusively observed in patients boosted to both lobes (5/57, 8.8%). Five‐year biochemical relapse‐free survival was 79.7% versus 70.5% for the unilateral and bilateral boost groups, respectively ( P = 0.99). CONCLUSION Prostate hemi‐irradiation with a HDR‐BT boost to the dominant tumor region may be considered when rectal examination, MRI, and biopsies suggest one lobe involvement. Nevertheless, strict dosimetric optimization is needed in order to further reduce the risk of late severe toxicity. Prostate 71:1309–1316, 2011. © 2011 Wiley‐Liss, Inc.