http://repub.eur.nl/res/aut/46212/ List of Publications en http://repub.eur.nl/static-eur/img/logo.png http://repub.eur.nl http://repub.eur.nl/res/pub/35025/ 2012-01-04T00:00:00Z Background Population-based basal cell carcinoma (BCC) incidences are based on cancer registry data; however, these only include histologically diagnosed tumours. Objectives First, to investigate the number of subsequent non-histologically diagnosed BCC(s) in patients with a first histologically diagnosed BCC in 2004. Secondly, to observe differences in tumour characteristics between subsequent histologically and subsequent non-histologically diagnosed BCC(s). Methods All patients, from four hospitals located in the serving area of the Eindhoven Cancer Registry, with a first histologically diagnosed BCC in 2004 (n=1290) were selected. A linkage was made with PALGA, the nationwide network and registry of histo- and cytopathology, to obtain pathology reports of subsequent histologically diagnosed BCC(s) up to 1 November 2010. Patient records were extracted from the participating dermatology departments and reviewed up to 1 November 2010 to identify non-histologically diagnosed BCC(s). Results Overall, 33.2% of the 1089 followed up patients developed subsequent histologically and/or non-histologically diagnosed BCCs. In total, 1974 BCCs were observed of which 1833 were histologically and 141 were non-histologically diagnosed BCCs. The distribution of tumour site and subtype differed significantly between subsequent histologically and subsequent non-histologically diagnosed BCCs. Conclusions The total burden of BCC is underestimated by the absence of data on the occurrence of non-histologically diagnosed BCCs in daily dermatological practice. It is pivotal for Dutch healthcare policy makers to acknowledge this to make accurate BCC-related cost estimates. © 2012 The Authors. Journal of the European Academy of Dermatology and Venereology http://repub.eur.nl/res/pub/30738/ 2011-10-01T00:00:00Z Background The incidence of multiple basal cell carcinomas (BCCs) is not well documented. Objectives To calculate the cumulative risks, rates and risk factors for the development of subsequent histologically confirmed BCCs. Methods For this cohort study the Dutch nationwide network and registry of histopathology and cytopathology (PALGA) was used. The first 2483 patients diagnosed with a first histologically confirmed BCC in the year 2004 were followed for 5 years. Multifailure survival models were used to study whether gender or age affected the risk of developing subsequent tumours. Results During our observational period, the 2483 patients developed a total of 3793 histologically confirmed BCCs. The 5-year cumulative risk of developing one or more subsequent BCCs was 29·2%. Incidence rates were 25 318 per 100 000 person-years in the first 6 months after first BCC diagnosis, decreasing to 6953 per 100 000 person-years after 5 years of follow-up. Males compared with females had a 30% [adjusted hazard ratio (HR) 1·30, 95% CI (confidence interval) 1·11-1·53] higher risk of developing multiple BCCs and those aged 65-79 years had more than 80% (adjusted HR 1·81, 95% CI 1·37-2·41) higher risk of having subsequent tumours compared with patients younger than 50 years. Conclusions The high incidence rate of subsequent BCCs among patients with a first BCC is highest in the first months after diagnosis of the first BCC but persists long term, indicating that patients with BCC should undergo full-body skin examinations at first presentation and subsequent follow-up visits. Special attention should be paid to males and persons of older age at index lesion.