Progression of incidence and estimate of net survival from papillary thyroid cancers diagnosed between 2008 and 2016 in France.

Background: After several decades of increasing incidence of papillary thyroid cancer (PTC), a change in this trend has been recently observed, particularly in the United States. This is attributed to the impact of new guidelines for the management of thyroid disease. The objective of this study was to describe the recent situation in France in terms of incidence and survival, taking account of tumor size.

Methods: Data from the FRANCIM network cancer registries, covering around 25% of the French metropolitan population, were analyzed. Distribution according to tumor size was determined in terms of frequency, trends in incidence and spatial distribution for the period 2008-2016. Analysis of net survival considered gender, age and tumor size.

Results: Cancers of size≤5mm were predominant in patients diagnosed between 55 and 74 years of age. Incidence of≤5mm tumors in women and of 5-10mm tumors in men began declining in the early 2010s. Incidence of 10-20mm and 20-40mm tumors in men increased significantly throughout the period 2008-2016. For both men and women, the incidence of the largest tumors (>40mm) also increased, but not significantly. The spatial distribution of incidence showed great heterogeneity. Net survival was generally high, although decreasing with age and tumor size.

Conclusion: The recent epidemiological situation in France is consistent with the hypothesis of recent progress in medical management of thyroid pathologies. Variations in incidence should be monitored for both small (<10mm) and larger tumors, and notably>40mm tumors. Net survival is generally high, although decreasing with age and tumor size.