Trends in Thyroid Pathology. Steady Prevalence of PTC and Rise of Nodular Goiter in Thyroidectomies.
Saul Lino-Silva, Erla Medina-Lopez, Denise Acuna-Gonzalez, Ofelia Gonzalez-Trevino, Armando Gamboa-Dominguez. INCMN Salvador Zubiran, Mexico City, DF, Mexico
Background: Changes in the prevalence of papillary thyroid carcinoma (PTC) have been reported in institutions and national cancer registries. Objective: to describe time trends in benign and malignant thyroid diseases in a national endocrine referral center.
Design: Systematic review and classification of consecutive specimens with slides/paraffin blocks in surgical pathology archives (January 1990 to December 2009). Institutional registries, size, type of surgery and number of inclusion blocks were recorded. Patients whose registries were granted before January 1990 without nodules, but treated after twelve months for a suspicious thyroid lesion, were included. These patients in a passive follow-up, permitted incidence density calculations. Cases were grouped by quinquennium.
Results: Institutional registers were conceded to 103,961 persons worthy of attention, and 1,269 were submitted to thyroidectomies (1.2%). One hundred twenty four patients, none treated for thyroid diseases before 1990, developed thyroid nodules after 1991. The incidence density for goiter was 0.05 person/year and for PTC 0.04 person/year in that group. In all series woman to man ratio was 9:1 with a mean age of 45 years. Total or near total thyroidectomies were performed in 60% patients and benign diseases were diagnosed in 732 (52%) cases. Thyroid surgeries increased since 2005 with a rise in goiter prevalence (0.25, 0.31, 0.35, 0.38), without significant increase in PTC prevalence (0.41, 0.43, 0.35, 0.40) in thyroidectomies. When PTC prevalence was analyzed by size a 520% rise in microscopic carcinomas was evident (0.015, 0.027, 0.047, 0.093), and a 76% increase for those between 1.1 and 3cm (0.097, 0.143, 0.167, 0.171), but not for tumors >3cm (0.297, 0.258, 0.138, 0.143).
Conclusions: Goiter as the only finding in thyroid specimens increased 52% in the last 20 years. In contrast to previous reports, PTC prevalence was steady. The higher prevalence of lesions <3cm in thyroidectomies, is a reflection of screen-detected papillary carcinomas (high definition ultrasonography and FNA biopsy). The incidence density of 0.05 and 0.04 person/year for goitre and PTC respectively, is in soundness with data from prospective cohort studies.
Tuesday, March 1, 2011 1:00 PM
Poster Session IV # 32, Tuesday Afternoon