Intensity modulated radiation therapy is a specialised form of conformal radiation therapy and isn’t widely available across the UK. The radiation can be adjusted to vary the doses given to different parts of the prostate. This can reduce the amount of radiation that the bowel and bladder receive and help to reduce local damage and side effects. Currently there is no evidence to confirm that this is a more effective form of radiation treatment.
The acute and late toxicities of high-dose radiation using conformal radiotherapy and intensity modulated radiation therapy have been compared in a study that reported in 2000 (21). Acute and late urinary toxicities were not significantly different for the two methods. However, the combined rates of acute grade 1 and 2 rectal toxicities and the risk of late grade 2 rectal bleeding were lower in the IMRT patients. Unfortunately this study is not conclusive and the full effectiveness of IMRT is unknown at present.
The differences between the delivery of different external radiation techniques
Conformal Radiotherapy
- Single radiation beam
- The treatment field is tightly controlled using special blocks or collimators (21)
- Planning session required
Intensity Modulated Radiation Therapy
- Beams are made up of hundreds of small components
- The treatment field can follow curves and contours of the target allowing more precise shaping of the field and delivery of the radiation (21)
- Very detailed planning required along with a computer analysis, which is labour intensive (21)