TY - JOUR
T1 - A modelled comparison of prostate cancer control rates after high-dose-rate brachytherapy (3145 multicentre patients) combined with, or in contrast to, external-beam radiotherapy
AU - Roberts, S A
AU - Mirlbell, R
AU - Zubizarreta, E H
AU - Fowler, J F
AU - Hendry, J H
N1 - Draft 2/4 - commented 17/4 Submitted 9/5/13 Reject but resubmit 20/10/13 resubmitted 15/11/13 minor revisions submitted 9/1/14 accepted 14/1/14 ePub 24/2/14
PY - 2014
Y1 - 2014
N2 - Background and purpose: To analyse biochemical relapse-free-survival results for prostate cancer patients receiving combined external beam and high-dose-rate brachytherapy, in comparison with expected results using projections based on dose/fractionation/response parameter values deduced from a previous external-beam-alone 5969-patient multicentre dataset. Material and methods: Results on a total of 3145 prostate cancer patients receiving brachytherapy (BT) as part or all of their treatment were collected from 10 institutions, and subjected to linear-quadratic (LQ) modelling of dose response and fractionation parameters. Results: Treatments with BT components of less than 25 Gy, 3–4 BT fractions, doses per BT fraction up to 6 Gy, and treatment times of 3–7 weeks, all gave outcomes expected from LQ projections of the external-beam-alone data (a/b = 1.42 Gy). However, BT doses higher than 30 Gy, 1–2 fractions, 9 fractions (BT alone), doses per fraction of 9–15 Gy, and treatment in only 1 week (one example), gave local control levels lower than the expected levels by up to 35%. Conclusions: There are various potential causes of the lower-than-projected control levels for some schedules of brachytherapy: it seems plausible that cold spots in the brachytherapy dose distribution may be contributory, and the applicability of the LQ model at high doses per fraction remains somewhat uncertain. The results of further trials may help elucidate the true benefit of hypofractionated high-dose-rate brachytherapy.
AB - Background and purpose: To analyse biochemical relapse-free-survival results for prostate cancer patients receiving combined external beam and high-dose-rate brachytherapy, in comparison with expected results using projections based on dose/fractionation/response parameter values deduced from a previous external-beam-alone 5969-patient multicentre dataset. Material and methods: Results on a total of 3145 prostate cancer patients receiving brachytherapy (BT) as part or all of their treatment were collected from 10 institutions, and subjected to linear-quadratic (LQ) modelling of dose response and fractionation parameters. Results: Treatments with BT components of less than 25 Gy, 3–4 BT fractions, doses per BT fraction up to 6 Gy, and treatment times of 3–7 weeks, all gave outcomes expected from LQ projections of the external-beam-alone data (a/b = 1.42 Gy). However, BT doses higher than 30 Gy, 1–2 fractions, 9 fractions (BT alone), doses per fraction of 9–15 Gy, and treatment in only 1 week (one example), gave local control levels lower than the expected levels by up to 35%. Conclusions: There are various potential causes of the lower-than-projected control levels for some schedules of brachytherapy: it seems plausible that cold spots in the brachytherapy dose distribution may be contributory, and the applicability of the LQ model at high doses per fraction remains somewhat uncertain. The results of further trials may help elucidate the true benefit of hypofractionated high-dose-rate brachytherapy.
KW - Prostate cancer
KW - Radiotherapy
KW - High dose-rate brachytherapy
KW - Biochemical relapse free survival
U2 - 10.1016/j.radonc.2014.01.008
DO - 10.1016/j.radonc.2014.01.008
M3 - Article
SN - 1879-0887
VL - 111
SP - 114
EP - 119
JO - Radiotherapy and Oncology
JF - Radiotherapy and Oncology
ER -
