Background — The management of differentiated thyroid cancer has traditionally consisted of total thyroidectomy with or without adjuvant radioactive iodine. However, in the last two decades this approach has been challenged with the consideration of more conservative approaches such as less radical surgery and deferring adjuvant treatment especially in lower risk patients. The objective of this study was to compare the effectiveness of current treatment options by comparing the survival outcomes from different geographic regions with different treatment philosophies. This study design is based on the concept of natural experiments in patient care that occur when physicians in different regions treat the spectrum of typical patients with varying treatments.
Method — A population-based retrospective cohort study of 2444 patients with differentiated thyroid cancer ≤ 4 cm in size between 1990 and 2001 from Ontario Canada. Extent of disease and extent of surgery was abstracted from pathology reports and was linked to downstream administrative medical information on treatments and outcomes. We compared the patient demographics, tumor characteristics, treatments and outcomes between the geographic regions with more aggressive treatments to regions with less aggressive treatments.
Results — Treatment varied across the province. When comparing the outcomes from the patients in the regions who had more extensive treatment compared to regions with less extensive therapy, we found similar 15 year survival, rates of recurrence, and survival after recurrence.
Conclusion — There were significant variations in treatment but no differences in outcomes between regions with more versus less aggressive approaches. These findings support the trend toward more conservative management approaches in the treatment of thyroid cancer.