br Materials and methods The study design is
Materials and methods The study design is a national cohort study. Since 1996 thyroid cancer patients in Denmark, have been prospectively registered in the validated Danish Thyroid Cancer (DATHYRCA) database . Patients diagnosed with PMC were found using the DATHYRCA database with the following inclusion criteria: Incidental : Non-incidental tumors were divided to either: To determine outcome, follow-up data from the validated DATHYRCA database  was used and supplied with information regarding recurrence status from the Danish Pathology Register . Wilcoxon rank sum and chi-square test were adopted to examine the relationship between variables, and Cuzick’s test for trend was used to explore changes in incidence . P-values of <0.05 were considered significant. All tests were two-sided. The Kaplan–Meier method was used to estimate survival. Age-adjusted incidences were calculated for the years from 1996 to 2015 according to the WHO World Standard Population (W) 2000–2025 . Data of the Danish population were retrieved from StatBank Denmark (www.statbank.dk). STATA 14 (StataCorp LP, College Station, TX, USA) was used for statistical analyses. The project was approved by the Regional Ethics Committee (S-20160178) and by the National Danish Data Protection Agency (17/6146).
Results A total of 803 patients met the inclusion criteria. The crude incidence rate for PMC in the SB 203580 1996–2015 was 0.73 cases per 100,000 per year. A rise in age-adjusted incidence rate was seen from 0.35 per 100,000 per year [95% confidence interval (CI) 0.27–0.43] in 1996 to 1.19 per 100,000 per year [CI 1.06–1.32] in 2015, and this was significant for Cuzick’s test for trend (p < 0.01). Crude and age-adjusted incidence rates are shown in Fig. 1. Characteristics for patients with PMC according to way of detection are shown in Table 1. The annual cases of IPMC, NIPMC and NIMPMC is shown in Fig. 2, where an increased incidence of IPMC and NIMPMC seems to be present. Cuzick’s test for trend proved significant for both the IPMC and the NIMPMC cases (p < 0.05) whereas no significant trend could be found for NIPMC (p = 0.083). During this period 26 cases of recurrences occurred; 10 in the IPMC group, three in the NIPMC group and 13 in the NIMPMC group. Crude and recurrence free survival was equal for the IPMC and NIPMP as shown in Table 2. Fig. 3 shows a Kaplan-Meier plot of recurrence-free survival for all groups. During follow-up, two patients died from PMC, one in IPMC group and one in the NIMPMC group. 45 patients died of other causes. Among these, 18 died from another cancer, 22 died from other diseases, two committed suicide, and in three cases, the cause of death could not be determined. No patients in the NIPMC group died of their thyroid cancer. The crude and cause-specific survival is shown in Fig. 4.
Author contributions The ICMJE recommends that authorship be based on the following 4 criteria:
Introduction Myeloma is a malignancy characterised by clonal expansion of plasma cells in the bone marrow causing anaemia, hypercalcaemia, lytic bone lesions, renal failure, recurrent infection, and other end-organ damage with significant patient morbidity [1,2]. Although prognosis has improved, myeloma remains incurable and prognosis, particularly in the elderly, is still poor. Although myeloma is one of the most common haematological malignancies worldwide, it is still a rare form of cancer, contributing about 1.5% of new cancer diagnoses [, , ]. It has been shown that almost all cases of myeloma arise from the precursor monoclonal gammopathy of unknown significance (MGUS) [6,7] but only a minority of MGUS progress to myeloma, with a risk of progression to myeloma (or related disorder) of about 1% per annum . Incidence rates increase with age and are also known to vary by ethnicity, with blacks having higher rates and Asians lower rates  than people of European descent; however, recently myeloma incidence has increased in some Asian countries .