Yifan Mao

Objective: Rurality is associated with higher incidence and higher disease-specific mortality for most cancers. Outcomes for rural and ultrarural (“frontier”) patients with thyroid cancer are poorly understood. This study aimed to identify actionable deficits in thyroid cancer outcomes for rural patients. Methods: We queried linked California Cancer Registry and California Office of Statewide Health Planning and Development databases for patients diagnosed with thyroid cancer (1999–2017). We analyzed time from disease stage at diagnosis, time from diagnosis to surgery, receipt of appropriate radioactive iodine ablation, surveillance status, and overall and disease-specific mortality for urban, rural, and frontier patients. Cox and logistic regression models controlled for clinical and demographic covariates a stepwise manner. All incidence figures are expressed as a proportion of newly diagnosed cases. Results: Our cohort comprised 92,794 subjects: (65,475 women [70.6%]; mean age 50.0 years). Compared to urban patients, rural and frontier patients were more likely to be American Indian, White, uninsured, and from lower quintiles of socioeconomic status ( p < 0.01). Distant disease at diagnosis was more common in rural (56.0 vs. 50.4 cases per 1000 new cases, p < 0.01) and frontier patients (80.9 vs. 50.4 per 1000, p < 0.01) compared to urban patients. The incidence of medullary thyroid cancer was greater in rural patients (17.9 vs. 13.6 cases per 1000, p < 0.01) and frontier patients (31.0 vs. 13.6 per 1000, p < 0.01) compared to urban patients. The incidence of anaplastic thyroid cancer was higher in frontier versus urban patients (15.5 vs. 7.1 per 1000, p < 0.01). When compared to urban patients, rural and frontier patients were more often lost to follow-up (odds ratio [OR] 1.69 [confidence interval, CI 1.54–1.85], and OR 3.03 [CI 1.89–5.26], respectively) and had higher disease-specific mortality (OR 1.18 [CI 1.07–1.30], and OR 1.92 [CI 1.22–2.77], respectively). Rural and frontier residence was independently associated with being lost to follow-up, suggesting that it is a key driver of disparities. Conclusion: Compared to their urban counterparts, rural and frontier patients with thyroid cancer present with later-stage disease and experience higher disease-specific mortality. They also are more often lost to follow-up, which presents an opportunity for targeted outreach to reduce the observed disparities in outcomes.

Background: Racially minoritized patients with thyroid cancer are less likely to receive high-quality and guideline-concordant care. Inaccessibility of high-volume centers may contribute to inequalities in thyroid cancer outcomes. This study sought to understand the extent to which access to higher volume thyroid cancer centers is associated with patient outcomes. Methods: We queried linked California Cancer Registry and California Office of Statewide Health Planning and Development databases for thyroid cancer patients who received thyroid surgery between 1999 and 2017. Hospitals were stratified by their median annual volume of thyroid cancer operations: ultra-low volume (0–5 cases/year), low-volume (6–25 cases/year), mid-volume (26–50 cases/year), and high-volume (>50 cases/year). We analyzed the rates of complications, rates of reoperation for cancer recurrence, use of radioactive iodine ( ¹³¹ I), and mortality by median hospital volume of thyroid surgery. A multivariable regression controlled for high-risk tumor features. Differences in access by center volume were assessed based on patient demographics. Results: We studied 52,599 thyroid cancer patients who underwent thyroidectomy. Patients who underwent thyroidectomy at ultra-low volume centers were more likely to undergo reoperations for recurrent/persistent disease compared with patients at low- (odds ratio [OR] 1.17 [CI 1.02–1.35]), mid- (OR 1.25 [CI 1.06–1.46]), and high-volume centers (OR 1.26 [CI 1.03–1.56]). Patients who received thyroid operations at ultra-low volume centers were also less likely to receive guideline-concordant ¹³¹ I ablation compared with patients at higher volume centers (OR 0.77 [CI 0.72–0.82]). A pair-wise comparison between all volume categories for all outcomes revealed no statistically significant differences in outcomes between low-, mid-, or high-volume centers. Only ultra-low volume centers had significantly higher rates of adverse outcomes. Ultra-low volume centers were disproportionately accessed by women ( p < 0.05), Hispanic, Asian/Pacific Islander, and American Indian people ( p < 0.01), those from the lowest three quintiles of socio-economic status ( p < 0.01), and the uninsured and those on Medicaid or Medicare ( p < 0.01) when compared with higher volume centers. Conclusions: Patients receiving thyroid cancer surgery at centers performing ≤5 such operations per year were more likely to require reoperation for recurrent/persistent disease and less likely to receive appropriate ¹³¹ I ablation. Ultra-low volume centers served higher proportions of socially and economically marginalized communities.