Pancreatic cancer; reporting and long-term survival in Sweden

Abstract

Background. The overall completeness of the Swedish Cancer Register is high, although underreporting for certain sites must be acknowledged. The aims of the present study were twofold. Firstly to assess the completeness of reporting of pancreatic cancer to the Swedish Cancer Register, and secondly to identify and characterise long-term survivors based on information from two separate population-based register resources. Material and Methods. To assess the completeness of the Cancer Register, pancreatic cancer cases registered in the National Patient Register between 1987 and 1999 were compared to cases reported to the Cancer Register. For estimations of long-term survival, the study population was restricted to 4321 cases identified both in the Cancer Register and the Patient Register with a histopathologically confirmed diagnosis of pancreatic ductal adenocarcinoma. A complete follow-up of survival in this group was performed till December 31, 2004. Results. There was a considerable underreporting of pancreatic cancer to the Cancer Register. During the period under study, a total of 19 745 patients were identified with a diagnosis of pancreatic cancer. Of these, only 73% had been reported to the Cancer Register. The underreporting increased markedly with age at diagnosis and was more pronounced during the second period under study. Only 2.8% of patients with a histopathologically confirmed diagnosis of pancreatic ductal adenocarcinoma survived five years or longer. The likelihood of long-term survival was strongly associated with younger age and surgery. Pancreatic resection was reported in 20.4% of all patients. Median survival among those operated on was 12 months compared to 4.6 months in all patients. Conclusions. Underreporting of pancreatic cancer to the Swedish Cancer Register was pronounced and increased with older age. Less than 3% of patients with a record of pancreatic cancer both in the Cancer Register and the Patient Register survived five years or longer.

Acknowledgements

The authors wish to thank Professor Jesper Lagergren for his valuable advice and comments. The study was supported by a grant from Karolinska Institutet Research Funds. The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.