Risk adapted dose-intensified postoperative radiation therapy in prostate
cancer patients using a simultaneous integrated boost technique applied with
helical Tomotherapy
Background Postoperative adjuvant radiation therapy (ART) in T3 and R1
prostate cancer as well as salvage radiation therapy (SRT) in case of
postoperative biochemical failure (BF) are established treatments. Dose-
intensified postoperative radiation therapy (RT) schemes have shown superior
biochemical control accompanied by increased toxicity rates. In our study we
evaluate a novel risk adapted dose-intensified postoperative RT scheme.
Methods A consecutive series of prostate cancer patients receiving
postoperative RT after radical prostatectomy using helical Tomotherapy between
04/2012 and 04/2015 was analyzed retrospectively. RT was administered using a
simultaneous integrated boost (SIB) to the area at risk (37 fractions of 1.9
Gy, total dose: 70.3 Gy) being defined based on histopathological findings
(T3/R1 region) and in few cases according to additional diagnostic imaging.
The whole prostate bed was treated with a dose of 66.6 Gy (37 fractions of 1.8
Gy). Primary endpoints were acute and late genitourinary (GU) and
gastrointestinal (GI) toxicities. Secondary endpoints included patient
reported outcome as assessed by the International Prostate Symptom Score
(IPSS), the International Consultation on Incontinence questionnaire (ICIQ)
and prostate cancer specific Quality of Life questionnaire QLQ-PR25, as well
as rates of BF. Results A total of 69 patients were analyzed. Sixteen patients
underwent ART and 53 patients SRT, respectively. The median follow-up was 20
months (range, 8–41 months). Seven (10.1%) and four (5.8%) patients
experienced acute grade 2 GU and GI toxicity. Two patients (2.9%) had late
grade 2 GU toxicity, whereas no late grade 2 GI nor any grade 3 acute or late
GU or GI events were observed. When compared to the baseline IPSS scores (p =
1.0) and ICIQ scores (p = 0.87) were not significantly different at the end of
follow-up. Patient reported Quality of life (QoL) showed also no significant
difference. A total of seven patients (10.1%) experienced a biochemical
recurrence with the 2-year biochemical progression-free survival (bPFS) being
91%. Conclusions Postoperative RT for prostate cancer patients with a risk
adapted dose-intensified SIB using helical tomotherapy is feasible and
associated with favorable acute and late GU and GI toxicity rates, no
significant change of IPSS-, ICIQ scores and patient reported QoL and results
in promising bPFS rates
