Estimation of age- and stage-specific Catalan breast cancer survival functions using US and Catalan survival data
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Background: During the last part of the 1990s the chance of surviving breast cancer increased. Changes in survival functions reflect a mixture of effects. Both, the introduction of adjuvant treatments and early screening with mammography played a role in the decline in mortality. Evaluating the contribution of these interventions using mathematical models requires survival functions before and after their introduction. Furthermore, required survival functions may be different by age groups and are related to disease stage at diagnosis. Sometimes detailed information is not available, as was the case for the region of Catalonia (Spain). Then one may derive the functions using information from other geographical areas. This work presents the methodology used to estimate age- and stage-specific Catalan breast cancer survival functions from scarce Catalan survival data by adapting the age- and stage-specific US functions. Methods: Cubic splines were used to smooth data and obtain continuous hazard rate functions. After, we fitted a Poisson model to derive hazard ratios. The model included time as a covariate. Then the hazard ratios were applied to US survival functions detailed by age and stage to obtain Catalan estimations. Results: We started estimating the hazard ratios for Catalonia versus the USA before and after the introduction of screening. The hazard ratios were then multiplied by the age- and stage-specific breast cancer hazard rates from the USA to obtain the Catalan hazard rates. We also compared breast cancer survival in Catalonia and the USA in two time periods, before cancer control interventions (USA 1975–79, Catalonia 1980–89) and after (USA and Catalonia 1990–2001). Survival in Catalonia in the 1980–89 period was worse than in the USA during 1975–79, but the differences disappeared in 1990–2001. Conclusion: Our results suggest that access to better treatments and quality of care contributed to large improvements in survival in Catalonia. On the other hand, we obtained detailed breast cancer survival functions that will be used for modeling the effect of screening and adjuvant treatments in Catalonia.
Is part ofBMC Cancer, 2009, vol. 9, núm. 98, p. 1-14
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Except where otherwise noted, this item's license is described as cc-by, (c) Vilaprinyo et al., 2009
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Martínez Alonso, Montserrat; Vilaprinyo Terré, Ester; Marcos-Gragera, Rafael; Rué i Monné, Montserrat (BioMed Central, 2010)Introduction: Early detection of breast cancer (BC) with mammography may cause overdiagnosis and overtreatment, detecting tumors which would remain undiagnosed during a lifetime. The aims of this study were: first, to ...
Rué i Monné, Montserrat; Vilaprinyo Terré, Ester; Lee, Sandra; Martínez Alonso, Montserrat; Carles Lavila, Misericordia; Marcos-Gragera, Rafael; Pla, Roger; Espinàs, Josep Alfons (BioMed Central, 2009)Background: At present, it is complicated to use screening trials to determine the optimal age intervals and periodicities of breast cancer early detection. Mathematical models are an alternative that has been widely used. ...
Vilaprinyo Terré, Ester; Gispert i Magarolas, Rosa; Martínez Alonso, Montserrat; Carles Lavila, Misericordia; Pla, Roger; Espinàs, Josep Alfons; Rué i Monné, Montserrat (BioMed Central, 2008)Background: Breast cancer mortality has experienced important changes over the last century. Breast cancer occurs in the presence of other competing risks which can influence breast cancer incidence and mortality trends. ...