Sex Differences in Papillary Thyroid Cancer

Abstract

Papillary thyroid cancer (PTC) is three times more common in women than men. However, PTC in men appears to be associated with poorer outcomes than in women. This study compares the clinical presentation and pathologic features of men and women with PTC. A retrospective review of prospectively collected data for patients with PTC who underwent fine needle aspiration (FNA) of a solitary thyroid nodule and thyroidectomy at a single institution was performed. Factors including age, ultrasound features, FNA results, extent of surgical operation and final histopathology were compared between male and female patients. Descriptive statistics using chi-square and t-test statistics compared outcomes by sex. Of the 851 patients with PTC, 158 (19%) were men and 693 (81%) were women. Mean age and standard deviation (SD) of patients was 48 (± 14) years, and most were of Hispanic origin (69%). Men had a significantly higher rate of radiation exposure relative to women, respectively (8% vs. 2%, P<0.01). There were no ultrasonographic or FNA cytologic differences among sexes. Men had more aggressive pathologic features including lymphovascular invasion (LVI) (47% vs. 34%, P<0.01) and positive lymph nodes (LN) (36% vs. 27%, P<0.05) compared to women. Thyroid lobectomy with isthmusectomy was more commonly performed among men compared to women (24% vs. 13%, P<0.01). Men with PTC have higher rates of radiation exposure associated with more aggressive disease with LVI and LN involvement on final histopathology compared to women. Total thyroidectomy with possible central neck dissection should further be considered when counseling men with PTC.