Age increased the cancer-specific mortality risk of thyroid cancer with lung metastasis

To investigate the relationship between age and cancer-specific mortality in thyroid cancer (TC) with lung-metastasis.

A total of 1418 patients with initial distant metastases from Surveillance, Epidemiology, and End Results databases were investigated. Patients with a median follow-up time of 8 months (interquartile range [IQR]: 2-27] and a median age of 66 years (IQR: 55-76) were divided into five groups by age and the association between age and TC-specific mortality was analysed.

The TC-specific mortality rates were 32.78% (118/360), 46.71% (156/334), 53.93% (199/369), 58.96% (158/268) and 82.76% (72/87) in patients aged ≤55 years, >55 but ≤65 years, >65 but ≤75 years, >75 but ≤85 years and >85 years. Kaplan-Meier curves showed that TC-specific mortality rate was associated with increased age (p < .001). Compared with patients ≤55 years, patients aged >55 but ≤65 years, >65 but ≤75 years, >75 but ≤85 years and >85 years had significantly higher hazard ratios (HRs) of 1.69 (1.26-2.26), 1.97 (1.47-2.64), 2.18 (1.59-2.99) and 3.24 (2.08-5.06) after adjustments for sex, tumour size and radiation therapy (all p < .001). In TC with initial lung-metastasis, compared with patients ≤55 years, patients aged >55 but ≤65 years, >65 but ≤75 years, >75 but ≤85 years and >85 years had significantly higher adjusted HRs of 1.68 (1.20-2.36; p = .003), 2.18 (1.57-3.02), 2.16 (1.51-3.08) and 2.91 (1.79-4.75; p < .001). Similar results were obtained in papillary TC.

The TC-specific mortality was increased with age in TC patients with initial lung-metastasis, indicating that further risk stratification based on age was necessary for TC over 55 years with lung-metastasis. Individual treatment strategies maybe recommended for such patients.