Objectives: The objective of this work was to undertake a non-judgemental study of prostate planning practice across the UK by inviting all departments to undertake the same case.
Methods: An invitation to take part in the study was sent to the Heads of all UK radiotherapy departments and posted on the UK Medical Physics mailbase. Individuals interested in participating were able to access a single anonymised CT dataset for download with the prostate gland, seminal vesicles, bladder, rectum, bowel, femoral heads, and penile bulb outlined. A brief patient history was also supplied. Participants were asked to create planning target volumes (PTVs) according to their local clinical protocol and plan to give 60 Gy in 20 fractions to the PTV receiving the highest dose. No guidance was given for acceptable organ at risk doses. Dicom plan and dose information was loaded back into ProKnow for analysis by contributors.
Results: There were 102 plan submissions made to the study representing 48 different UK radiotherapy departments. Seventeen distinct methodologies for creating the prescription PTV from the prostate and seminal vesicles were identified with the ethos of the CHHIP trial protocol for margin growing followed in nearly two-thirds of cases. Positive correlations were found when assessing the doses received by the bladder and rectum against the volume of the PTV to which 60 Gy was prescribed.
Conclusions: A national planning study whereby staff from a multitude of radiotherapy departments create plans based solely on a single dataset is feasible. The cohort of data was made available to all participants following the study to enable self-assessment and benchmarking against that of their peers.
Advances in knowledge: This is the first UK wide treatment planning study to investigate local clinical prostate planning practice. This has given UK departments the opportunity to evaluate their planning practices against those of their peers.