BMC Cancer 2008, 8:355 http://www.biomedcentral.com/1471-2407/8/355 tic regimes. Country specific analyses in the Automated Childhood Cancer Information System (ACCIS) database show marked survival probability variations especially between childhood cancer in Eastern and Western-Euro- pean populations (overall survival 1988–97 East: 62%, West: 75%) [1,2], indicating an influence of socioeco- nomic conditions at the national level. Socioeconomic status has long been known to influence cancer survival [3]. Migrants and their families may be particularly affected by these effects because of difficulties to obtain and maintain appropriate access to care [4]. However, little is known about childhood cancer inci- dence and survival among migrants. Hemminki & Li [5] found increased cancer risks for migrant children of differ- ent origins and for different diagnoses compared to Swed- ish children. Data from Great Britain indicate that in 1991–92 children with South Asian ethnic background had an increased cancer incidence when compared to non South Asians [6]. For Germany no incidence comparisons exist, but evaluations of proportional cancer incidence ratios [7] showed little variation between children of Turkish descent as compared to other children. Few data exist on survival probabilities of migrants. Over- all survival seems not to differ between ethnic groups in Great Britain [8,9], with a possible exception of acute lym- phoid leukaemia with lower survival probability among UK children of South Asian ethnic background. In the US, there is conflicting evidence concerning ethnic differences in survival probability after childhood acute lymphoid leukaemia [10-12]. For acute myeloid leukaemia the sur- vival probability of US black and Hispanic children is lower than for white children [13]. Apart from ethnic German immigrants from the former USSR, Turkish people are the largest migrant group in Ger- many, comprising about 1.7 million people in 2007 according to nationality [14], and about 2.4 million when all persons with Turkish migration history are taken into account, including naturalised immigrants and their chil- dren [15]. We aimed to study whether a migration back- ground affects survival from childhood cancer in Germany. Therefore, we undertook a registry-based analy- sis of cancer survival of children with Turkish descent in Germany, using data from the German Childhood Cancer Registry (GCCR) for the period 1980–2005. Methods The GCCR is one of the largest cancer registries worldwide dedicated to children. Annually, about 1800 new cases under 15 years of age are recorded, and the completeness of registration exceeds 95% for all cancer types except cen- tral nervous system (CNS) tumours, where completeness is somewhat lower as expected by inter-registry compari- sons. No information on ethnicity, and consequently on completeness by ethnicity is available. The GCCR started registering cases in 1980. The current degree of complete- ness was reached around 1987. Registration with full identification is possible with parental consent, and almost all cases are registered with names. In addition, parents' names are available for about 50% of all cases. A vital status follow-up is conducted routinely using infor- mation from various sources (clinical studies, hospitals, communities, families). Close cooperation exists between paediatric oncologists and the registry. As almost all chil- dren with cancer in Germany enter into clinical trials, this cooperation substantially adds to the high completeness and quality of the registry [16]. Diagnoses are coded according to the International Classification of Diseases for Oncology ICD-O-3 and classified by the International Classification of Childhood Cancer ICCC-3 [17]. The methods for the retrospective identification of cases of Turkish descent in the registry have been described else- where in detail [7]. In short, the routinely collected regis- try data does not allow systematically determining patients' ethnic or geographical origins. We therefore used a validated name-based algorithm [18,19] to identify Turkish cases by name. The respective study base were all registered cancer cases during the period 1980–2005 for whom the full name was available (n = 37,259, 95% of all registered cases). The automated name – algorithm proce- dure was augmented by a manual search done by a research assistant with proficiency in Turkish language and names to check the validity of the automated proce- dure [20]. This procedure has been shown to identify cases of Turkish descent as indicated by their name (referred to as Turkish cases) with a high sensitivity (>97.5%) and specificity (>99%) compared to a complete manually checked gold standard. In order to maintain the high degree of confidentiality required, all data base work was performed at the premises and under surveillance of the GCCR. No information was available regarding migrant genera- tion, but it is likely that especially the more recently diag- nosed cases contain a large proportion of descendants of migrants from Turkey who came to Germany in the 1960s. We assessed the average duration and completeness of fol- low-up and specifically the percentage lost to follow-up from the routinely collected data for children of Turkish and non-Turkish descent. We calculated total and diagnosis-specific 5-year survival probabilities for different strata of age, sex and period of diagnosis (1980–87, 1988–95, 1996–2005) for Turkish and non-Turkish (largely German) childhood cancer Page 2 of 7 (page number not for citation purposes)