Intensity-modulated Radiotherapy in Anal Cancer - Where Do We Go from Here?

摘要

Although increasing in incidence, squamous cell carcinomas of the anal canal remain relatively rare (less than 1000 cases per annum in the UK). Preliminary results of the UK National Anal Cancer Trial (ACT II) show excellent complete response rates (95%), with 3 year recurrence-free survival rates of 75% in T1/T2 tumours, and 68% for more advanced T3/T4 tumours [1]. The dose and treatment schedule with concurrent 5-fluorouracil and mitomycin used in the ACT II trial is now the current standard of care in the UK for anal cancer. However, treatment planning with large parallel-opposed anterior-posterior/posterior-anterior (AP/PA) fields is inevitably associated with significant acute toxicity, with moist desquamation of the groins, perineum and scrotum. Severe genitourinary and gastrointestinal effects and 20-25% haematological grade 3 toxicity are also observed. This toxicity can result in significant delays in completing prescribed treatment on time without interruptions and frequent in-patient admission. Retrospective series also show poor bowel, urinary and sexual late function and impaired quality of life in this patient group.