Predictors of Neck Reoperation and Mortality After Initial Total Thyroidectomy for Differentiated Thyroid Cancer.

BACKGROUND

In an era of rising differentiated thyroid cancer incidence, the rate and impact of neck reoperation may inform the intensity of earlier interventions and surveillance. This study sought to define predictors of neck reoperation and to assess its impact on survival.

METHODS

Using the California Cancer Registry linked to the California Office of Statewide Health Planning and Development records, a retrospective cohort study was performed of 24,230 patients with total or near-total thyroidectomy for papillary or follicular thyroid cancer between 1991 and 2008 and follow-up through 2013. The primary outcome was neck reoperation 91 days to 5 years after the initial thyroid surgery. Using logistic and Cox proportional hazards regression, the impact of sociodemographics, tumor staging, and hospital thyroid cancer surgery volume on neck reoperation and survival was determined.

RESULTS

Neck reoperation was identified in 1231 (5.1%) patients in increasing odds from 1991 to 2008. In multivariable models, male sex, papillary thyroid cancer, and advancing tumor stage were associated with neck reoperation. Among men, neck reoperation was associated with Asian/Pacific Islander (odds ratio [OR] = 1.44 [confidence interval (CI) 1.07-1.94]) race/ethnicity. Among women, neck reoperation was associated with younger age (15-34 years; OR = 1.50 [CI 1.17-1.92] versus ≥55 years), and Asian/Pacific Islander (OR = 1.24 [CI 1.02-1.51]) or Hispanic (OR = 1.20 [CI 1.00-1.44]) race/ethnicity. After controlling for baseline characteristics, neck reoperation predicted worse thyroid cancer-specific survival (hazard ratio = 4.26 [CI 3.50-5.19]). The effect differed between men and women, and was most pronounced among women who received radioiodine in initial treatment (hazard ratio = 8.32 [CI 6.14-11.27]).

CONCLUSIONS

Neck reoperation is becoming increasingly frequent and is strongly predictive of mortality. Advancing tumor stage, Asian/Pacific Islander race/ethnicity, male sex, as well as younger age and Hispanic ethnicity among women predict a higher risk for neck reoperation and subsequent mortality, reflecting a higher risk of persistent or more biologically aggressive disease.