Incidence and survival of Swedish patients with differentiated thyroid cancer.
Papillary (PTC) and follicular (FTC) thyroid cancers are rare disorders but are, nevertheless, among the most common cancers in individuals below 40 years of age. From the population-based Swedish Cancer Registry we identified 3,588 individuals with PTC and 1,966 with FTC during 1958-87. Histopathology was determined by examining the original histopathology reports. The relative survival ratio (RSR) was used as the measure of patient survival. Incidence of both PTC and FTC was higher among women, especially for PTC and particularly during the fertile part of female life. Incidence of PTC increased significantly over time, a trend that was not observed for FTC. Five-year relative survival appeared to be higher for patients diagnosed with PTC compared to FTC, although this difference was almost completely explained by the confounding effect of age. Patients with PTC experience lower mortality during the period 7-20 years after diagnosis. Excess mortality was lower among women, although the magnitude of the difference varied with age and histopathology. In contrast to our perceptions based on clinical practice, we observed no difference in excess mortality between patients diagnosed with PTC and FTC during the years immediately after diagnosis (where the majority of deaths occur). Our data suggest that there may exist a subgroup of thyroid tumors with superior prognosis diagnosed in women during the fertile part of female life. Sex hormones may play a role in the etiology of these tumors.
Lundgren
Catharina Ihre
CI
Department of Surgery, Center for Metabolism and Endocrinology, Karolinska Institutet, Huddinge University Hospital, Stockholm, Sweden.|Department of Medical Epidemiology, Karolinska Institutet, Stockholm, Sweden.
Hall
Per
P
Department of Medical Epidemiology, Karolinska Institutet, Stockholm, Sweden.
Ekbom
Anders
A
Unit of Clinical Epidemiology, Department of Internal Medicine, Karolinska Hospital, Stockholm, Sweden.
Frisell
Jan
J
Department of Surgery, Center for Metabolism and Endocrinology, Karolinska Institutet, Huddinge University Hospital, Stockholm, Sweden.
Zedenius
Jan
J
Department of Surgery, Center for Metabolism and Endocrinology, Karolinska Institutet, Huddinge University Hospital, Stockholm, Sweden.
Dickman
Paul W
PW
Department of Medical Epidemiology, Karolinska Institutet, Stockholm, Sweden.
D018263:Adenocarcinoma, Follicular / Q000401:mortality* / Q000473:pathology; D000328:Adult; D017677:Age Distribution; D017668:Age of Onset; D000368:Aged; D002291:Carcinoma, Papillary / Q000401:mortality* / Q000473:pathology; D002454:Cell Differentiation; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012042:Registries; D015996:Survival Rate; D013548:Sweden / Q000453:epidemiology; D013964:Thyroid Neoplasms / Q000401:mortality* / Q000473:pathology; D013997:Time Factors