CONFORMAL RADIOTHERAPY OF THE PELVIS - ASSESSMENT OF ACUTE TOXICITY

During the last 3 years the Royal Marsden Hospital (RMH) has conducted a prospective randomised trial of conformal pelvic radiotherapy in wh ich dose/volume data and acute toxicity scores have been determined pr ospectively. Pending completion of the trial, a preliminary analysis h as been undertaken of the volume reductions achieved, and of some of t he symptom scores. The average symptom score increased during radiothe rapy, more markedly for bowel than bladder symptoms. In comparing tota l doses of 30-38 Gy with 56-65 Gy, watery bowel motions were more freq uent with the higher doses (p = 0.013) but in the high-dose group neit her this symptom nor tenesmus correlated with volume of rectum treated to at least 90% of the prescribed dose. We conclude that the assessme nt of the impact of volume on the level of acute symptoms in pelvic ra diotherapy is complex, and requires analysis of a range of symptoms, d ose levels and normal-tissue volumes. The degree of symptom reduction from conformal radiotherapy will emerge from the RMH randomised trial within the next 12 months.