Status and practice of proton therapy of pregnant patients in Europe

Objective: To assess the current status of PT for pregnant patients across Europe, to initiate the standardisation of measuring, evaluating and reporting the intrauterine dose, and to provide guidance for treatment planning.

Methods

A survey gathered clinical experience from proton centres across Europe. The status in terms of epidemiology of intrauterine dose exposure effects was summarised. Current recom-mendations were reviewed in two on-line meetings and in an on-site meeting.

Experts discussed ways to condense experience gained in clinics and in out-of-field dosimetry. Results: Eighteen PT facilities responded to the survey. It showed that 9 out of the 18 answering PT centres treated in total 26 pregnant patients using mainly pencil-beam scanning (PBS), and with treatment initiation most often in the last two trimesters.

A proposal for reporting the fetal dose has been drafted. Checklists for image guidance, treatment planning and fetal dosimetry have been created. Conclusions: Available European experience suggests that PBS with modern image guidance can achieve acceptably low intrauterine doses for maternal target volumes localised between head and mediastinum.

Nevertheless, dosimetric validation is necessary for individual patients. This will be the content of future guidelines, for which a start towards harmonisation has been made. Dataset: The data publication at hand contains the questionnaire of the survey and provides detailed results.