A first-ever analysis by Keck Medicine of USC clinician scientists indicates that adolescents and young adults who develop thyroid cancer as a secondary cancer are six times more likely to die than those with primary thyroid cancer.

The findings, published online Feb. 24, 2014 in the journal CANCER, a peer-reviewed journal of the American Cancer Society, stress the importance of screening young cancer survivors to detect early signs of a potentially life-threatening thyroid malignancy.

The research was conducted by Melanie Goldfarb, MD, assistant professor of surgery, endocrine surgery, and David Freyer, DO, MS, professor of clinical pediatrics, both with Keck Medicine of USC. Freyer is also director of the LIFE Cancer Survivorship and Transition program at Keck Medicine-affiliated Children’s Hospital Los Angeles.

“The issue for adolescent and young adult cancer patients is that they have a long survivorship period that typically lasts many years,” said Goldfarb, corresponding author. “Thyroid cancer is a common secondary cancer for the adolescent and young adult (AYA) population. This study tells us that it’s important for these patients to discuss the possibility of a secondary thyroid cancer diagnosis with their doctor, because it indicates they do have an increased risk, although we don’t yet know why.”

The research is one of the few studies on adolescent and young adult cancer, Goldfarb said, though there is increasing interest in the field. USC Norris Comprehensive Cancer Center (part of Keck Medicine of USC) and Children’s Hospital two years ago developed AYA@USC, the Adolescent and Young Adult Cancer program, dedicated to calling awareness to the need for more research and improved treatment of adolescents and young adults to improve survival rates and outcomes for this age group.

Thyroid cancer is one of the five most common malignancies in adolescent and young adult patients (ages 15 to 39 years). It can develop as an initial cancer or rarely after treatment for a previous cancer. In their research, Goldfarb and Freyer compared the tumor characteristics, treatment, and survival of primary versus secondary thyroid cancers in adolescent and young adult patients.

Their analysis included all adolescent and young adult thyroid cancer cases documented in the 1998-2010 American College of Surgeons National Cancer Database. Of 41,062 cases, 1,349 (3.3 percent) had experienced a prior malignancy. Compared with cases of primary thyroid cancer, cases of secondary thyroid cancer were more likely to be small but to occur in more than one location. Also, patients with secondary thyroid cancer were more than 6.6-times as likely to die than patients with primary cancer, though survival with treatment is excellent for both primary and secondary cancers at greater than 95 percent. This study suggests that there may be differences between thyroid cancers seen with or without a prior malignancy.

Goldfarb is currently working on designing a study that looks into the reason why AYA patients with a secondary thyroid cancer diagnosis have higher risk of death than those with primary thyroid cancer.

– By Leslie Ridgeway