Study Status: Recruiting
Recruit Status: Recruiting
Study Type: Observational
Official Title:
Brief Summary:
Radiotherapy (combined with chemotherapy) is commonly used in the curative treatment of pelvic tumours, such as in cervical, vulvar and anal cancer. In these patients, cure rates are high but may be associated with significant treatment-related toxicities, especially dermatologic, gastrointestinal, genitourinary and hematologic toxicity.
Accurate treatment planning and dose delivery is essential for radiotherapy in order to be effective in terms of local tumour control and to reduce radiation-induced side effects. However, accuracy is challenged by tumour and organ motion from fraction to fraction (interfraction movements). At present, radiotherapy treatment planning is typically performed on one planning-CT scan which is performed before the start of the treatment. However, interfraction set up variations and organ motions can lead to differences between the calculated dose distribution on the planning-CT and the radiation dose actually received by the tumour and normal organs (actual given dose). Current photon radiotherapy of the pelvic area is relatively insensitive to these changes and margins from CTV to PTV ensures an adequate dose coverage of the tumour area. Despite newer techniques in photon therapy, like intensity modulated radiotherapy (IMRT), critical organs still receive a substantial amount of dose leading to clinically relevant acute and late side effects. With proton beam therapy, the amount of radiation dose to the organs at risk can be significantly reduced.
For proton beam therapy (PBT) however, knowledge of tumour and organ motion will be more important. The major potential advantages of PBT for tumours in the pelvic area in terms of prevention of radiation-induced side effects are challenged by differences in bladder volume, rectal filling and air gaps especially in the small bowel, sigmoid and rectum