Initial treatment patterns in younger adult patients with differentiated thyroid cancer in California

Differentiated thyroid cancer (DTC) is among the most common malignancies in the adolescent and young adult (age 15-39 years) population, and its incidence is rising. Younger age (<45 years) is an important prognostic indicator and is incorporated into the TNM classification system. This study hypothesized that this would result in distinct treatment patterns for younger and older patients.

Using the California Cancer Registry, 24,362 patients with DTC from 2004 to 2011 were identified, and they were divided into younger (<45 years) and older (≥45 years) cohorts. Demographic and clinical variables were tabulated and then compared using chi-square tests. Treatment variables included total or near total thyroidectomy, other types of thyroid surgery, and the administration of radioiodine as part of the initial treatment. Multivariable logistic regression was used to identify independent predictors of treatment administered.

Younger patients were more likely to be Hispanic (32.5% vs. 21.2%) and female (82.7% vs. 74.7%), and to have papillary carcinoma (92.9% vs. 90.9%) and lymph node involvement (32.8% vs. 19.7%; p<0.0001). On multivariable analysis, younger patients (OR 1.20 [CI 1.11-1.30]), higher T-stage tumors, higher socioeconomic status (SES), and papillary carcinoma were predictors of undergoing total thyroidectomy versus less than total thyroid surgery. After adjustment, predictors of radioiodine administration included younger age (OR 1.12 [CI 1.05-1.18]), higher SES, total thyroidectomy, higher T stage, and lymph node positivity.

Younger patients with DTC in California are more likely to be female and Hispanic with papillary histology. After adjustment for disease and demographic characteristics, younger patients are more likely to undergo total thyroidectomy as their initial surgery and are more likely to receive radioiodine. Given their excellent prognosis and the potential for adverse sequelae from initial treatment for DTC, these findings warrant consideration when managing younger patients with DTC.