%0 Journal Article
%T Methodological issues in estimating survival in patients with multiple primary cancers: an application to women with breast cancer as a first tumour
%A Stefano Rosso
%A Fulvio Ricceri
%A Lea Terracini
%A Roberto Zanetti
%J Emerging Themes in Epidemiology
%D 2009
%I BioMed Central
%R 10.1186/1742-7622-6-2
%X We studied the survival probabilities modelling mortality rates according to hypotheses A), B) and C). Mortality rates were calculated using Aalen-Johansen estimators which allowed to discount for the lag-time survival before developing a second tumour. We applied this approach to a cohort of 436 women with breast cancer (BC) and a subsequent tumour in the resident population of Turin, Italy, between 1985 and 2002.We presented our results in term of a Standardised Mortality Ratio calculated (SMRAJ) after 10 years of follow-up. For hypothesis A we observed a significant excess mortality of 2.21 (95% C.I. 1.94 每 2.45). Concerning hypothesis B we found a not significant SMRAJ of 0.98 (95% C.I. 0.87 每 1.10). The additivity hypothesis (C) was not confirmed as it overestimated the risk of death, in fact SMRsAJ were all below 1: 0.75 (95% C.I. 0.66 每 0.84) for BC and all subsequent cancers, 0.72 (95% C.I. 0.55 每 0.94) for BC and colon-rectum cancer, 0.76 (95% C.I. 0.48 每 1.14) for BC and corpus uteri cancer (not significant).This method proved to be useful in disentangling the effect of different subsequent cancers on mortality. In our application it shows a worse long-term mortality for women with two cancers than that with BC only. However, the increase in mortality was lower than expected under the additivity assumption.The improvement of patients survival for the vast majority of neoplasms led to a substantial increase in the probability of further developing subsequent primary tumours. However, the study of multiple primary tumours on a population basis posed many additional problems. There is, indeed, a problem of differential diagnosis, when it comes to distinguish between local and distant metastases, recurrences and the onset of a truly new lesion. Classifications may also vary leading to substantial differences in rates. For example Surveillance Epidemiology and End Results (SEER) rules [1] differ substantially from those adopted by International Agency for Resea
%U http://www.ete-online.com/content/6/1/2