Dose–Volume Constraints to Reduce Rectal Side Effects From Prostate Radiotherapy: Evidence From MRC RT01 Trial ISRCTN 47772397

Dosimetric influence of filtered and flattening filter free photon beam on rapid arc (RA) radiotherapy planning in case of cervix carcinoma

“…Boice et al 19 reported that doses as low as 30 Gy increase the relative risk of secondary bladder cancer to a similar degree as 80 Gy in cervical cancer. Similar Gulliford et al 20 found that the volume of the rectum receiving as low as 30 Gy reduced the incidence of several types of patient reported late rectal toxicities by 10-18%. Hence, dosimetric benefits are larger for FB as compared to FFFB for both types of photon energies in cervix carcinomas RA planning to avoid late complication related to the bladder and rectum.…”

Parametrized rectal dose and associations with late toxicity in prostate cancer radiotherapy

“…Most work has looked at dose-volume histogram (DVH) parameters and whether any significant links with toxicity can be identified. [8][9][10][11] Further studies 12,13 have looked at not only the rectum but also additional structures, e.g. pelvic floor muscles.…”

Image-guided radiotherapy of the prostate using daily CBCT: the feasibility and likely benefit of implementing a margin reduction

“…No loss of TCP was observed when plans using the standard 5-mm CTV 2 to PTV 2 margin of the centre were reoptimized with a 4-or 3-mm margin. Margin reduction was associated with a significant decrease in rectal NTCP (5-4 mm; p , 0.05 and 5-3 mm; p , 0.01).…”

“…Methods: The prostate-only clinical target volume (CTV 2 ) and rectum were delineated on 1 pre-treatment CBCT each week in 18 randomly selected patients. By transposing these contours onto the original plan, dosevolume histograms (DVHs) for CTV 2 and the rectum were each calculated and combined, for each patient, to produce a single mean DVH representative of the dose delivered over the treatment course. Plans were reoptimized using reduced CTV 2 to PTV 2 margins and the consequent radiobiological impact modelled by the tumour control probability (TCP) and normal tissue complication probability (NTCP) of the rectum.…”

“…The rectum is the critical dose-limiting structure, and there is a close relationship between the radiation dose received and subsequent risk of late toxicity. 2 Late effects, including diarrhoea, incontinence, tenesmus and bleeding can have a significant impact on quality of life. 3 A course of radical radiotherapy is delivered over more than 7 weeks but is usually planned on a single planning CT scan.…”