Background Health professionals are challenged by a growing number of young long-term cancer survivors with their specific needs with regard to family planning. This study aimed at assessing decisional conflict (DC) in young female cancer patients regarding fertility preservation, identifying demographic, fertility and fertility preservation related factors, which may affect DC, and assessing the helpfulness of various decision-supports.

Methods A retrospective, cross-sectional, web-based survey via an online questionnaire available in three languages with specific items concerning cancer, fertility, fertility preservation and the validated Decisional Conflict Scale targeted at current or former female cancer patients aged 18–45 years, with cancer types or treatment potentially affecting reproductive function.

Results The 155 participating women showed considerable DC, especially with regard to missing information and support. DC was significantly lower in patients when the risk of infertility was discussed with a health professional, when they had undergone any procedure to preserve fertility, and when they had a university education. A longer time interval since cancer diagnosis was associated with higher DC. The most helpful decision-support tools were specialised websites and leaflets.

Conclusions Young female cancer patients’ DC with regard to fertility preservation is very high. Information and support seem to be deficient. More information through standardised information tools might be an effective strategy to lower their DC at the time when treatment decisions need to be taken, and to improve their reproductive health after they have overcome cancer in the future.