Age, Lymph Node Positivity Link in Thyroid Cancer

Younger patients with papillary thyroid cancer (PTC) are more likely to exhibit lymph node positivity (LN+), a finding that could be useful to surgeons, according to a new study published in Cancer Management and Research.

“The correlation between LN+ and [the] patient’s age at diagnosis in PTC is still inconclusive,” wrote lead study author Jing Wang, of the Department of Head, Neck, and Breast Surgery at The First Affiliated Hospital of the University of Science and Technology of China, Anhui Provincial Cancer Hospital, Hefei, China, and colleagues. “While several studies claimed that young age at diagnosis could be an independent predictor of LN+, one study showed that older PTC patients were more likely to exhibit higher LN+ rates, and another study did not find a correlation between age and LN+.”

Due to better screening and diagnostic testing, thyroid cancer is one of the most frequent cancers in the United States, and a substantial number of patients are young. Despite a 5-year survival rate of 98%, recurrence occurs in between 5% and 21% of cases.

Several studies have reported that the number of positive lymph nodes (PLNs) increases the risk of PTC recurrence. Additionally, research has found that the patient’s age at diagnosis impacted LN+ status in rectal cancer, breast cancer, and melanoma.

Using the high-powered SEER Incidence Database, Wang and colleagues set out to determine whether a younger age was correlated with elevated LN+ rates in patients with PTC. After assessing data for 46,077 PTC patients of various age groups, they found that, at each T stage, LN+ status was negatively correlated with age at diagnosis based on a multivariate logistic regression (P < .001) that accounted for sex, age, and surgery types. Patients aged 30 years or younger (18.2% of the sample) had the highest lymph node ratio (LNR) when compared with other age groups.

The team also discovered that younger age was correlated with a higher PLN and LNR when compared with older PTC patients at the equivalent T stage.

“Although the presence or absence of cervical LN+ does not affect mortality in younger PTC patients, locoregional LN recurrence would inevitably result in reoperation,” the authors wrote. “Indeed, the rate of injuring the recurrent nerve, parathyroid glands, or their circulation during reoperation is much higher than initial surgery.”

The researchers added that the higher risk associated with reoperations may impact quality of life, thus making age an important factor in surgical decision-making.

“Based on these data, I may consider a prophylactic central neck dissection in a younger patient with other features that put me ‘on the fence’ for considering this approach, but I would not use this information to start universally recommending this approach in our younger patients,” Bryan R. Haugen, MD, a professor of medicine and pathology at the University of Colorado Boulder, told Cancer Network.  “This should alert our community to try [to] design prospective studies to better answer these questions.”

Clinicians should bear in mind that use of the SEER database limited the clinical significance of the current study, noted Ryan K. Orosco, MD, a head and neck surgeon and an assistant professor of surgery at the University of California San Diego.

“The SEER database does not contain information about cancer recurrence, which is the critical outcome in the thyroid cancer population,” Orosco said during an interview with Cancer Network. “Although provocative, the data from the study do not tell us the downstream clinical significance of having a higher risk of positive lymph nodes at the time of thyroid surgery.”