Radioactive iodine therapy for malignant and benign thyroid disease: a Canadian national survey of physician practice

Background Radioactive iodine (as (NaI)-I-131) has been used in the diagnosis and treatment of thyroid disease for more than 60 years, but the various treatment centres in Canada have different practice patterns. Aim To determine whether there is a definable, nationwide pattern of practice which may be used to elucidate standards of practice and clarify some issues that arise when multiple care-givers are involved. Methods A survey questionnaire was mailed to all sites licensed by the Canadian Nuclear Safety Commission to administer (NaI)-I-131 for benign and malignant thyroid therapy. A second mailing was sent to non-responders. The questionnaire addressed the involvement of personnel: i.e., who prescribes, determines doses, obtains informed consent, counsels on radiation safety, administers the therapy, and follows the patient post-therapy. The survey also specifically addressed whether a nuclear medicine physician reviewed laboratory work or met with patients pre-therapy. Results The overall response rate was 60% (74/123) with representation from all Canadian provinces. The majority of respondents were physicians (78%). The data include 3447 benign thyroid therapies and 1202 malignant thyroid therapies. There are no significant regional differences in the average maximum dose administered for either benign or malignant thyroid therapies. The majority of therapies are administered in community and academic hospital settings. Endocrinologists most commonly prescribe (NaI)-I-131 for malignant thyroid therapies and nuclear medicine physicians for benign thyroid therapies. For all therapies nuclear medicine physicians most commonly obtain informed consent, determine the dose and provide radiation safety counselling. Nuclear medicine technologists most commonly administer the therapy and endocrinologists most commonly provide post-therapy follow-up. In the majority of centres, nuclear medicine physicians review the laboratory results for each patient's blood sample and meet with patients before therapy. Conclusions Multiple health care specialists take part in (NaI)-I-131 therapy for both benign and malignant thyroid disease. In most centres, nuclear medicine physicians have major roles in the delivery of the treatments, including reviewing clinical and biochemical information. The findings of this study should provide reassurance to many centres and guidance to others to allow closer harmonization of practice.