A new analysis has found that adolescents and young adults who develop thyroid cancer as a secondary cancer have a significantly greater risk of dying than those with primary thyroid cancer.
The findings stress the importance of screening young cancer survivors to detect early signs of a potentially life-threatening thyroid malignancy, researchers wrote.
To compare the tumor characteristics, treatment, and survival of such primary versus secondary thyroid cancers in adolescent and young adult patients, researchers reviewed all adolescent and young adult thyroid cancer cases documented in the 1998-2010 American College of Surgeons National Cancer Database. Results appeared online Feb. 24 in CANCER, a peer-reviewed journal of the American Cancer Society.
Of 41,062 cases, 1,349 (3.3%) 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 6.63 times as likely to die than patients with primary cancer (95% CI, 4.97 to 8.86, P<0.001) after adjusting for demographic, tumor and thyroid treatment factors, though survival with treatment is excellent for both at greater than 95%.
This study suggests that there may be differences between thyroid cancers seen with or without a prior malignancy, the authors wrote.
Primary thyroid cancers occurred more often in early teens and 20s compared to those who were 15 to 19 years old or over 30, where secondary thyroid cancers were more common. Researchers suggested that there may be a long latency—up to 30 years—in developing clinically apparent thyroid cancer after radiation or chemotherapy. Or, it is possible that older patients have had more time to develop secondary thyroid conditions such as multinodular goiter or hyperthyroidism, and then discover incidental, secondary thyroid cancer in a thyroidectomy pathology specimen.
“This is an important new observation for the 3% to 4% of this population who are already survivors of pediatric or other AYA (adolescent or young adult) cancers,” the authors wrote. “These numbers are not insignificant considering that thyroid cancer is one of the most common AYA cancers, especially among females, and patients need to be counseled appropriately. In addition, differences in thyroid cancer survival usually require 15 to 20 years of follow-up, rendering the results of this study quite significant.”
Learn more about treating adult survivors of pediatric cancers.
History is key after childhood disease, according to a previous article in ACP Internist. For people who have survived a childhood disease and those living with a chronic disease or disability, making a successful transition to adult health care means finding a physician who is informed about the special and sometimes surprising challenges ahead. Read more.
It’s tough to navigate return from cancer care to primary care, ACP Internist covered in a second article. Both the general medicine and oncology communities have paid increased attention in recent years to the transition of cancer patients back to their primary care physician after active cancer treatment has been completed. Read more.
And, most survivors of childhood cancers at highest risk for a second neoplasm in adulthood didn’t follow recommended screening intervals, according to a study reported in ACP InternistWeekly.