BES2005 Oral Communications Oral Communication 5: Thyroid (7 abstracts)
1Metabolic Unit, Western General Hospital, Edinburgh, UK; 2Scottish Cancer Registry, Edinburgh, UK; 3Gene-Environment Epidemiology Group, Genetics and Epidemiology Cluster, International Agency for Research on Cancer (IARC), Lyon, France; 4Finnish Cancer Registry, Institute for Statistical and Epidemiological Cancer Research, Helsinki, Finland; 5Division of Molecular Genetic Epidemiology, German Cancer Research Center (DKFZ), Heidelberg, Germany; 6Department of Biosciences at Novum, Karolinska Institute, Hudinge, Sweden. 7Institute of Population-Based Cancer Research, Oslo, Norway 8Central Cancer Registry, Woolloomooloo, New South Wales, Australia 9Institute of Cancer Epidemiology, Danish Cancer Society, Copenhagen, Denmark. 10Cancer Control Research Programme, British Columbia Cancer Registry, Vancouver, British Columbia, Canada.11Center for Molecular Epidemiology, Singapore. 12Cancer Registry of Slovenia, Institute of Oncology, Ljubljana, Slovenia. 13Epidemiology and Cancer Registry, CancerCare Manitoba, Winnipeg, Canada, 14Community Health Sciences, University of Manitoba, Winnipeg, Canada.15Program Evaluation and Surveillance, Saskatchewan Cancer Agency, Regina, Saskatchewan, Canada. 16Icelandic Cancer Registry, Icelandic Cancer Society, Reykjavik, Iceland 17The Medical Faculty, University of Iceland, Reykjavik, Iceland. 18Cancer Registry of Zaragoza, Health Department of Aragon Government, Zaragoza, Spain
Background
Increasing incidence of thyroid cancer together with improved prognosis raises a concern regarding development of second primary cancers. Moreover, little is known about the incidence of thyroid cancer as a second primary neoplasm after other cancers.
Methods
A cohort of 39002 people (356034.5 person years) with primary thyroid cancer was identified in 13 population-based cancer registries in Europe, Canada, Australia and Singapore and followed for second primary cancers over 25 years. We used cancer incidence rates of first primary cancer to calculate standardized incidence ratios (SIRs). Risk of second primary thyroid cancer after other cancer types was also calculated.
Results
During the observation period there were 2821 second primary cancers after primary thyroid cancer, SIR 1.31 (95% CI 1.26-1.36). The overall increased risk was irrespective of sex, type of thyroid cancer, age at first cancer or follow up period. Following primary thyroid cancer there was increased risk (SIRs) of developing cancer of adrenal (8.34), soft tissue sarcoma (3.63), bone (2.62), kidney (2.33), leukaemia (2.26). Conversely there was an increased incidence of subsequent thyroid cancer following a primary cancer at these sites [adrenal (13.0), soft tissue sarcoma (2.94), bone (3.36), kidney (2.91), leukaemia (2.49)]. There was an increased incidence of breast cancer and lymphoma after thyroid cancer and of thyroid cancer after cancer of lung and larynx.
Conclusion
In conclusion, the pooled data from 13 worldwide cancer registries shows that there is an excess of second primary cancer following primary thyroid cancer. Common environmental and genetic factors may explain the concurrence at those sites where a primary tumour was also associated with an increased incidence of subsequent thyroid cancer. The increased incidence of breast cancer and lymphoma after thyroid cancer and of thyroid cancer after cancer of lung and larynx could be a consequence of therapy for the first primary.