SURVIVAL OF WOMEN WITH BREAST CANCER IN EUROPE: VARIATION WITH AGE, YEAR OF DIAGNOSIS AND COUNTRY Milena SANT 1 *, Riccardo CAPOCACCIA 2 , Arduino V ERDECCHIA 2 , Jacques ESTE ` VE 3 , Gemma GATTA 1 , Andrea MICHELI 1 , Michel P. COLEMAN 4 , Franco BERRINO 1 and THE EUROCARE WORKING GROUP 5 1 Divisione di Epidemiologia, Istituto Nazionale per lo Studio e la Cura dei Tumori, Milan, Italy 2 Laboratorio di Epidemiologia e Biostatistica, Istituto Superiore di Sanita ` , Rome, Italy 3 Special Adviser on Biostatistics, International Agency for Research on Cancer, Lyon, France 4 Department of Epidemiology and Population Sciences, London School of Hygiene and Tropical Medicine, London, UK Breast cancer is the most frequent malignancy among women in developed countries. Prognosis is better than for other major cancers, and an improvement in survival has been reported for several populations in recent decades. W ithin the framework of EUROCARE, a population-based project concerned with the survival and care of cancer patients in Europe, we analysed data from 119,139 women diagnosed with breast cancer between 1978 and 1985 in 12 countriesand followed for at least 6 years. Multiple regression models of relative survival, which take mortality from all other causesin each area into account, were used to estimate the effect of age, period of diagnosis and country on survival. For the comparison between countries, survival rates were age-standardised to the age structure of the entire study population. W omen aged 40–49 years at diagnosis had the best prognosis in all countries and throughout the study period. W omen younger than 30 years at diagnosis had a worse prognosis than those aged 30–39. The highest relative survival at 5 years was in Finland and Switzerland (about 74%), intermediate levels were found for Italy, France, The N etherlands, Denmark and Germany (about 70%) and the lowest rates were in Spain, the United Kingdom, Estonia and Poland (55–64%). During the 6 months following diagnosis, survival was highly dependent on age and was sharply lower in women older than 49 years. For women surviving more than 6 months after diagnosis, survival was similar for all ages, although women aged 40–49 still had the better prognosis. The average rate of death from breast cancer fell by about 2.5%for each year of diagnosis between 1978 and 1985. This improvement manifested mainly in younger and older women, for whom survival wasinitially lessgood. T he largest improve- ment was seen in Poland ( 15% death risk per year). W e suggest that the better survival of women aged 40–49 at diagnosis is related to lower levels of circulating sex hor- mones, resulting in reduced stimulation of tumour cell growth. Early diagnosismay also be important in the peri-menopausal period due to increased diagnostic attention. Low survival in the United Kingdom may be due to inadequate adherence to consensus treatment guidelines and greater variation in treatment. Int. J. Cancer 77:679–683, 1998.  1998 Wiley-Liss, Inc. Breast cancer is the most frequent malignancy among women in developed countries. Prognosis is better than for other major cancers, and an improvement in survival has been reported for several populations in recent decades (Carstensen et al., 1993; Nab et al., 1994; Ries et al., 1991; Berrino et al., 1995). This improvement can be variously ascribed to earlier diagnosis, including widespread use of mammography; to increasing use of effective adjuvant therapy; and, more recently, to the advent of mass screening campaigns (Miller et al., 1990). For most tumours, survival decreases with increasing age at diagnosis (Berrino et al., 1995). The relationship between age and survival in breast cancer is more complex. Women aged 40–49 years at diagnosis have the best prognosis (Mohle-Boetani et al., 1986; Sant et al., 1991), and in some studies the prognosis for very young women is poor (Host and Lund, 1986). The available results on the prognostic significance of age at diagnosis are difficult to compare, however, because age classes differ among studies and some are too wide to be useful. Quantitative comparison of the overall improvement in breast cancer survival between countries or regions is also difficult, because interpretation of the results published by various Cancer Registries (CRs) is complicated by differences in data collection, follow-up, analytical methods and reporting, as well as considerable differences in mortality from other causes between countries. Multivariate analysis of data from the 25 population-based CRs participating in EUROCARE (Berrino et al., 1995) provides an efficient method of assessing the role of age and period of diagnosis in determining the probability of survival, and also highlights differences and similarities between the participating countries with respect to these factors. The data were prepared using a common protocol, with central quality control and analysis (Ber- rino et al., 1995). MATERIAL AND METHODS The methods of data collection have been described in detail elsewhere (Berrino et al., 1995). Briefly, 31 population-based CRs covering a population of about 100 million people were involved. The registries supplied data conforming to a common protocol on patients diagnosed between 1978 and 1985 and followed for 6–13 5 EUROCARE Working Group: Denmark: H. Storm (Danish Cancer Registry); Estonia: T. Aareleid (Estonian Cancer Registry); Finland: T. Hakulinen (Finnish Cancer Registry); France: J. Este `ve (International Agency for Research on Cancer), P.M. Carli (Co ˆte-d’Or Malignant Haemopathies Registry), J. Faivre (Co ˆte-d’Or Digestive Cancer Registry), D. Pottier (Calvados Digestive System Cancer Registry), J. Robillard (Calvados Cancer Registry), N. Raverdy (Somme Cancer Registry) and S. Schraub (Doubs Cancer Registry); Germany: P. Kaatsch, J. Michaelis (German Registry of Childhood Malignancies) and H. Ziegler (Saarland Cancer Registry); Italy: F. Berrino, G. Gatta, A. Micheli and M. Sant (Lombardy Cancer Registry), A. Barchielli (Tuscan Cancer Registry), E. Conti (Latina Cancer Registry), L. Gafa ´ and R. Tumino (Ragusa Cancer Registry), C. Magnani (Piedmont Childhood Cancer Registry), M. Ponz de Leon (Colorectal Cancer Registry of Modena) and R. Capocaccia, A. Verdecchia and F. Valente (National Institute of Health); The Netherlands: J.W. Coebergh (Eindhoven Cancer Registry); Poland: J. Pawlega (Cracow Cancer Registry); Spain: C. Martinez Garcia (Granada Cancer Registry), P. Viladiu (Girona Cancer Registry), I. Garau (Mallorca Cancer Registry) and J. Galceran (Tarragona Cancer Registry); Switzerland: L. Raymond (Geneva Cancer Registry) and J. Torhorst (Basel Cancer Registry); United Kingdom: R. Black (Scottish Cancer Registry), J. Bell (South Thames Cancer Registry), M.P. Coleman (London School of Hygiene and Tropical Medi- cine), S. Moss and J. Smith (South and West Cancer Intelligence Unit), M. Page (East Anglia Cancer Registry), L. Rider (Northern and Yorkshire Cancer Registry), S. Wilson (North Western Cancer Registry) and J. Youngson (Mersey Regional Cancer Registry). Grant sponsor: European Union Concerted Action; Grant number MR4*-0226-I. *Correspondence to: Epidemiology Division, Istituto Nazionale per lo Studio e la Cura dei Tumori, Via Venezian 1, 20133 Milan, Italy. Fax: (39)2-2390-762/236-2692. E-mail: eurocare@istitutotumori.mi.it Received 25 September 1997; Revised 14 January 1998 Int. J. Cancer: 77, 679–683 (1998)  1998 Wiley-Liss, Inc. Publication of the International Union Against Cancer Publication de l’Union Internationale Contre le Cancer