(HealthDay News) — Among adolescents and young adults, those who develop thyroid cancer as a secondary malignant neoplasm have decreased overall survival than those with primary thyroid cancer, according to research published online February 24 in Cancer.
Melanie Goldfarb, MD, and David R. Freyer, DO, of the University of Southern California in Los Angeles, analyzed data for 41,062 adolescents and young adults with thyroid cancer from the 1998–2010 American College of Surgeons National Cancer Database.
The researchers found that 1,349 (3.3%) of the cases had a prior malignancy. Secondary malignant neoplasms, compared with primary thyroid cancers, were significantly more likely to be multifocal microcarcinomas less than 1 cm with tall/columnar cells, with cases occurring in those of white race and age 35–39 years. Relative risk of death was 6.63 times (95% CI, 4.97–8.86) greater for secondary versus primary thyroid cancers. Factors that decreased overall survival for secondary malignant neoplasms were Hispanic origin, tall/columnar cell histology, and distant metastases.
“Adolescents and young adults who develop thyroid cancer as a secondary malignant neoplasm have a significantly decreased overall survival compared to adolescents and young adults with primary thyroid cancer,” the authors write.