Mohamad Zalzali1, Adeline Debreuve2, Capucine Richard1, Carlo Filieri1, Claire Schvartz2. 1. Nuclear medicine-thyroid Unit, Institut Jean-Godinot de Reims, 1, rue du Général-Koenig, 51100 Reims, France. 2. Thyroid Cancer Registry of Marne-Ardennes, Institut Jean-Godinot, 1, rue du Général-Koenig, 51100 Reims, France.
Abstract
CONTEXT: Yearly incidence of thyroid cancer has nearly tripled in the past four decades, due to improvements in and better use of diagnostic procedures, enabling detection of smaller tumors, and notably micropapillary carcinoma (MPC: ≤10 mm). OBJECTIVES: The aim of our study was to confirm increasing incidence, to describe the characteristics and circumstances of discovery, and to examine the reasons for this rise in incidence of MPCs, based on the French Marne-Ardennes registry for 1975-2014. DESIGN: This was a retrospective observational cohort study. RESULTS: Two thousand six hundred and seventy-one patients with thyroid cancer were included for the period 1975-2014, with 966 (36.2%) MPCs. The percentage increased from 18.9% for 1975-1984 to 45.1% for 2005-2014. Standardized incidence per 100,000 patient-years increased from 0.86 for 1975-1984 to 6.20 for 2005-2014. Incidence increase was higher in women (ranging from 1.15 to 8.91) than in men (from 0.20 to 2.54). Incidence increased more in ≥50 year-olds (from 0.41 to 4.21) than in <50 year-olds (from 0.45 to 1.99). Most MPCs (84.6%) were discovered incidentally on histology, and were mainly unifocal (79.4%). Incidental MPCs were smaller, affected older patients and were less multifocal than those suspected before surgery. MPCs were associated with excellent survival and low morbidity, with <1.9% progression. CONCLUSION: The present study confirmed the large rise in incidence of MPCs reported elsewhere. Most MPCs were discovered incidentally on histological examination in the context of surgery for benign pathology. Changes in access to health care and in physicians' and pathologists' practices are likely explanations for our findings.
CONTEXT: Yearly incidence of thyroid cancer has nearly tripled in the past four decades, due to improvements in and better use of diagnostic procedures, enabling detection of smaller tumors, and notably micropapillary carcinoma (MPC: ≤10 mm). OBJECTIVES: The aim of our study was to confirm increasing incidence, to describe the characteristics and circumstances of discovery, and to examine the reasons for this rise in incidence of MPCs, based on the French Marne-Ardennes registry for 1975-2014. DESIGN: This was a retrospective observational cohort study. RESULTS: Two thousand six hundred and seventy-one patients with thyroid cancer were included for the period 1975-2014, with 966 (36.2%) MPCs. The percentage increased from 18.9% for 1975-1984 to 45.1% for 2005-2014. Standardized incidence per 100,000 patient-years increased from 0.86 for 1975-1984 to 6.20 for 2005-2014. Incidence increase was higher in women (ranging from 1.15 to 8.91) than in men (from 0.20 to 2.54). Incidence increased more in ≥50 year-olds (from 0.41 to 4.21) than in <50 year-olds (from 0.45 to 1.99). Most MPCs (84.6%) were discovered incidentally on histology, and were mainly unifocal (79.4%). Incidental MPCs were smaller, affected older patients and were less multifocal than those suspected before surgery. MPCs were associated with excellent survival and low morbidity, with <1.9% progression. CONCLUSION: The present study confirmed the large rise in incidence of MPCs reported elsewhere. Most MPCs were discovered incidentally on histological examination in the context of surgery for benign pathology. Changes in access to health care and in physicians' and pathologists' practices are likely explanations for our findings.