Danish Medical Bulletin - No. 2. May 2008. Vol. 55 Page 127

ABSTRACT OF DISSERTATION

Chronic diseases and
non-melanoma skin cancer

The impact on risk and prognosis

Annette Østergaard Jensen, MD

PDF

This PhD dissertation was accepted by the Faculty of Health Sciences of the University of Aarhus, and defended on February 22, 2008.

Official opponents: Svend Juul, Gregor Jemec, and Leiv Bakketeig, Norge.

Tutors: Henrik Toft Sørensen and Anne Braae Olesen.

Correspondence: Annette Østergaard Jensen, Department of Dermatology, Århus Sygehus, THG, 8000 Århus C, Denmark.

E-mail: aoj@dce.au.dk

ABSTRACT

The PhD dissertation originates from the Faculty of Health Sciences, the University of Aarhus, and was performed at the Departments of Clinical Epidemiology and Dermatology, Aarhus University Hospital. The PhD dissertation was based on nationwide data from a prospectively assembled cohort (the Gerda Frentz cohort (GFC)), and from cancer registry data. The dissertation addresses how chronic diseases influence and associate with risk and prognosis of non-melanoma skin cancer (NMSC), including basal cell carcinoma (BCC) and squamous cell carcinoma (SCC).

Among 3209 NMSC patients, we found a reduced mortality due to cardiovascular and gastrointestinal diseases among BCC patients (overall mortality rate ratio (MRR) 0.89, 95% CI: 0.83-0.95) and an increased mortality of cardiovascular diseases and cancer among SCC patients (overall MRR 1.61, 95% CI: 1.27-2.02). Adjustments for comorbidity and civil status did not change the estimates substantially for the BCC patients but did influence the estimates for the SCC patients.

We found similar ten-year mortality of patients with first primary and new subsequent cases of NMSC registered in the GFC. Further, patients with first primary NMSC registered in the GFC had a similar mortality compared with patients with first primary NMSC registered in the Danish Cancer Registry (DCR).

Among 4187 primary NMSC cases, we found an increased risk of SCC among patients with a history of hospitalization for a chronic disease (incidence rate ratio (IRR) 1.47, 95% CI: 1.14-1.91). The increased risk persisted after excluding patients with diseases known to elevate the risk of NMSC. We found no increased risk of BCC among patients with a history of hospitalization for a chronic disease (IRR = 1.03, 95% CI: 0.93-1.14), although the risk was elevated among patients with certain disease categories. Additional analyses suggested that surveillance or selection bias were unlikely explanations for the findings.

Among 82,837 BCC patients and 13,453 SCC patients, registered in the DCR from 1978 to 2001, we were able to reproduce a reduced mortality among BCC patients from cardiovascular, chronic pulmonary diseases and diabetes; and the analyses further indicated that BCC patients in Denmark may have a better health status compared with the general population. Further, we reproduced an increased mortality among SCC patients from cardiovascular, chronic pulmonary diseases, genital diseases and acute infections.

Thus, BCC and SCC seem to be very different disease entities as far as their risk and prognosis are concerned. Our studies have shown that after carefully evaluating biases, observational studies of NMSC with use of clinical databases or registry data can be properly conducted.
DANISH MEDICAL BULLETIN
The Danish Medical Bulletin reserves the right to store and publish articles (texts and illustra-tions), electronically too, eg on CD-ROM and the Internet. All rights reserved, ie prohibition against publication of texts and illustrations from the Danish Medical Bulletin. Rights can only be obtained by written acceptance from the author and editors and by quoting the Danish Medical Bulletin as source. Quotations of information from the Danish Medical Bulletin may not be published until after the publication of the issue in question and quotation of the source.