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BACKGROUND The highest rates of thyroid cancer are observed in Pacific Island nations as well as Australia and Asian countries bordering the Pacific. The objective of this study was to determine the risk for thyroid cancer among immigrants to Canada from Southeast and East Asia compared with immigrants from other regions and nonimmigrants. METHODS This was a population-based, longitudinal cohort study using health care administrative data to examine all residents of Ontario without pre-existing thyroid cancer. Individuals were followed from January 1997 or 5 years after they became eligible for health care coverage in Ontario, whichever came later. Patients were followed until March 2015 for incident-differentiated thyroid cancer, and then for recurrence. RESULTS The study followed 14,659,733 individuals for a median of 17 years. Thyroid cancer incidence was 43.8 cases per 100,000 person-years among Southeast Asian immigrants, 28.6 cases per 100,000 person-years among East Asian immigrants, 21.5 cases per 100,000 person-years among other immigrants, and 14.5 cases per 100,000 person-years among nonimmigrants. Incidence was highest among immigrants from the Philippines (52.7 cases per 100,000 person-years), South Korea (33.5 cases per 100,000 person-years), and China (30.0 cases per 100,000 person-years). Adjusted hazard ratios for thyroid cancer compared with nonimmigrants were 2.66 (95% confidence interval, 2.48-2.84) for Southeast Asian immigrants, 1.87 (95% confidence interval, 1.75-2.00) for East Asian immigrants, and 1.51 (95% confidence interval, 1.45-1.57) for other immigrants. Immigrants were more likely to have papillary histology and stage I cancer. East Asian immigrants, but not Southeast Asian immigrants, had a lower risk of recurrence (hazard ratio, 0.73 [95% confidence interval, 0.57-0.94] and 1.01 [95% confidence interval, 0.81-1.26], respectively). CONCLUSIONS Immigrants from Southeast and East Asia had markedly higher thyroid cancer incidence than nonimmigrants. At particularly elevated risk were immigrants from the Philippines, South Korea, and China. Cancer 2017;123:3320-5. © 2017 American Cancer Society.

The highest rates of thyroid cancer are observed in Pacific Island nations as well as Australia and Asian countries bordering the Pacific. The objective of this study was to determine the risk for thyroid cancer among immigrants to Canada from Southeast and East Asia compared with immigrants from other regions and nonimmigrants.This was a population-based, longitudinal cohort study using health care administrative data to examine all residents of Ontario without pre-existing thyroid cancer. Individuals were followed from January 1997 or 5 years after they became eligible for health care coverage in Ontario, whichever came later. Patients were followed until March 2015 for incident-differentiated thyroid cancer, and then for recurrence.The study followed 14,659,733 individuals for a median of 17 years. Thyroid cancer incidence was 43.8 cases per 100,000 person-years among Southeast Asian immigrants, 28.6 cases per 100,000 person-years among East Asian immigrants, 21.5 cases per 100,000 person-years among other immigrants, and 14.5 cases per 100,000 person-years among nonimmigrants. Incidence was highest among immigrants from the Philippines (52.7 cases per 100,000 person-years), South Korea (33.5 cases per 100,000 person-years), and China (30.0 cases per 100,000 person-years). Adjusted hazard ratios for thyroid cancer compared with nonimmigrants were 2.66 (95% confidence interval, 2.48-2.84) for Southeast Asian immigrants, 1.87 (95% confidence interval, 1.75-2.00) for East Asian immigrants, and 1.51 (95% confidence interval, 1.45-1.57) for other immigrants. Immigrants were more likely to have papillary histology and stage I cancer. East Asian immigrants, but not Southeast Asian immigrants, had a lower risk of recurrence (hazard ratio, 0.73 [95% confidence interval, 0.57-0.94] and 1.01 [95% confidence interval, 0.81-1.26], respectively).Immigrants from Southeast and East Asia had markedly higher thyroid cancer incidence than nonimmigrants. At particularly elevated risk were immigrants from the Philippines, South Korea, and China. Cancer 2017;123:3320-5. © 2017 American Cancer Society.

BACKGROUND The combination of T, N, and M classifications into stage groupings was designed to facilitate a number of activities including: the estimation of prognosis and the comparison of therapeutic interventions among similar groups of cases. The authors tested the UICC/AJCC 5th edition stage grouping and seven other TNM-based groupings proposed for head and neck cancer to determine their ability to meet these expectations in a specific site: carcinoma of the tonsillar region. METHODS The authors defined four criteria to assess each stage grouping scheme: 1) The subgroups defined by T and N comprising a given group within a grouping scheme have similar survival rates (hazard consistency); 2) The survival rates differ across the groups (hazard discrimination); 3) The prediction of cure is high (outcome prediction); and 4) The distribution of patients among the groups is balanced. The authors identified or derived a measure for each criterion and the findings were summarized using a scoring system. The range of scores was from 0 (best) to 7 (worst). Data were from a retrospective chart review on 642 cases of carcinoma of the tonsillar region treated with radiotherapy for cure at the Princess Margaret Hospital from 1970–1991. None of the patients had distant metastases. RESULTS The scheme proposed by Synderman and Wagner, which was published in Otolaryngology Head and Neck Surgery in 1995 (vol.112, pages 691–4), scored best at 1.2. The UICC/AJCC scheme scored worst at 6.1. The hazard consistency ranged from a 3.1% average survival difference to 6.7% across the 8 schemes. The hazard discrimination measure varied by 28% from the best to worst scheme. Prediction varied by up to almost twofold across the schemes assessed. The distribution of patients varied from expected by between 0.13% and 0.57%. CONCLUSION UICC/AJCC stage groupings were defined without empirical investigation. When tested, this scheme did not perform as well as any of seven empirically-derived schemes the authors evaluated. The results of the current study suggest that the usefulness of the TNM system can be enhanced by optimizing the design of stage groupings through empirical investigation. Cancer 2001;92:1484–94. © 2001 American Cancer Society.

BACKGROUND: The authors compared the survival outcomes of radiotherapy +/− salvage surgery to surgery +/− postoperative radiotherapy for patients with squamous cell cancer of the hypopharynx. There was no evidence beyond observational studies and no consensus on the which treatment is most effective for this patient group. METHODS: The authors conducted a retrospective population-based study of 595 patients from Ontario Canada diagnosed between January 1, 1990 and December 31, 1999. Three different methodological approaches were used for the survival analysis including a restricted cohort study, a matched case-control study, and a natural experiment study across defined geographic regions. RESULTS: The authors found no survival advantage for either radiotherapy +/− salvage surgery or surgery +/− postoperative radiotherapy. CONCLUSIONS: This study set the baseline for clinical decisions that was not previously established there is no difference in survival for patients with hypopharynx comparing primary surgery to primary radiotherapy. This information is essential for the interpretation of current treatment results, the planning of future clinical studies and the treatment of patients who are not having chemoradiotherapy. Cancer 2009. © 2009 American Cancer Society.