Intensity‐modulated radiotherapy reduces toxicity with similar biochemical control compared with 3‐dimensional conformal radiotherapy for prostate cancer: A randomized clinical trial

Abstract

BACKGROUND:The objective of this article was to report the results from a randomized clinical trial comparing intensity-modulated radiotherapy (IMRT) with 3-dimensonal conformal radiotherapy (3DCRT) for the treatment of prostate cancer on a hypofractionated schedule. METHODS: The authors randomly assigned 215 men who had localized prostate cancer to receive hypofractionated radiotherapy to a total dose of 70 grays (Gy) in 25 fractions (at 2.8 Gy per fraction) using either IMRT or 3DCRT. Acute and late gastrointestinal (GI) and genitourinary (GU) toxicity were prospectively evaluated according to modified Radiation Therapy Oncology Group criteria. Biochemical control was defined according to the Phoenix criteria (prostate-specific antigen nadir 1 2 ng/mL). RESULTS: In total, 215 patients were enrolled in the IMRT group (n 5 109) or the 3DCRT group (n 5 106). The 3DCRT arm had a 27% rate of grade 2 acute GU toxicity compared with a 9% rate in the IMRT arm (P 5.001) and a 24% rate of grade 2 acute GI toxicity compared with a 7% rate in the IMRT arm (P 5.001). The maximal rate of grade 2 late GU toxicity during the entire period of follow-up was 3.7% in the IMRT group versus 12.3% in the 3DCRT group (P 5.02). The maximal rate of grade 2 late GI toxicity during the entire follow-up was 6.4% in the IMRT group versus 21.7% in the 3DCRT group (P 5.001). The 5-year rate of freedom from biochemical failure was 95.4% in the IMRT arm and 94.3% in the 3DCRT arm (P 5.678). CONCLUSIONS: IMRT reduced the delivery of significant radiation doses to the bladder and rectum using a similar target volume. This dosimetric advantage resulted in a lower rate of acute/late grade 2 GI and GU toxicity for IMRT compared with 3DCRT.

Clinical Outcomes of Dose-escalated Radiotherapy for Localised Prostate Cancer: A Single-institution Experience

“…anticoagulation, comorbidities such as diabetes mellitus, inflammatory bowel disease) (31,36), disease and radiation characteristics (e.g. total dose, dose per fraction, irradiated organ-at-risk volume, delivery modality) (9,10,35,37) have been suggested to play a part. Unfortunately, there is considerable variation amongst studies looking at the incidence of chronic radiation proctitis/cystitis owing to the lack of consensus on its reporting and definition.…”

Current status of intensity‐modulated radiation therapy for prostate cancer: History, clinical results and future directions

“…IMRT has been shown in dosimetric studies to substantially decrease the dose of OARs . Unfortunately, there are no randomized controlled trials directly comparing dose‐escalated IMRT and 3D‐CRT in prostate cancer.…”

“…The developers have solved these problems, and recently MRI‐guided treatment equipment are commercial‐based. The ViewRay magnetic resonance system (ViewRay, Cleveland, OH, USA) is the first commercial MR‐guided RT system with Co sources . Recently, the MRI LINAC system has been developed and clinical use has started .…”

Readressing the rationale of irradiation in stage I seminoma guidelines: a critical essay

“…In the MRC TE19 trial, conventional radiation techniques were used, thereby exposing large parts of normal tissue to high doses. With intensity‐modulated RT (IMRT) and volumetric arc therapy (VMAT), more healthy tissue can be spared from receiving a unnecessary high dose, as has been demonstrated in numerous tumour types . It is therefore very unlikely that the risk of SMN will be as high with IMRT or VMAT when compared to conventional RT, in addition to the significant decrease in acute and late toxicity .…”