Background <p>Patients with intermediate risk thyroid cancer face the decision of whether or not to undergo radioactive iodine (RAI) treatment after total thyroidectomy. This process is challenging due to the unclear risks and benefits of RAI treatment for intermediate risk disease. The study identified the decisional needs of patients offered RAI treatment for thyroid cancer to inform the development of a web-based patient decision aid (PtDA).</p> Method <p>We used purposive sampling to recruit 23 adult patients with thyroid cancer (<i>M</i>_age = 39.1; 83% female) from three metropolitan hospitals who were offered RAI treatment. Participants completed an online survey before taking part in one of four 2-h focus groups moderated by a clinical psychologist. Semi-structured interviews explored patients’ experiences, decisional needs, and recommended elements for a PtDA. Two raters independently coded transcripts and used content analysis to analyze qualitative data. </p> Results <p>Content analysis revealed three broad domains: (1) the range of patient involvement in the RAI treatment decision-making process, (2) personal values-based decisional outcomes, and (3) decision aid content recommendations on the basis of patients’ knowledge gaps about RAI treatment. Patients’ recommendations included the need for information on the RAI dose and common side effects, risk stratification, safety precautions for radioactivity, low-iodine diet guidance, and financial costs.</p> Conclusion <p>The study provides patient insights for a targeted web-based PtDA that integrates personal values, risk information, and logistical considerations to support informed decision-making about RAI treatment. Future research to examine the benefits of PtDAs for treatment of intermediate-risk thyroid cancer is needed.</p>