abstract: Reduction of population-based cancer survival estimates by trace back of death certificate notifications: An empirical illustration

Reduction of population-based cancer survival estimates by trace back of death certificate notifications: An empirical illustration

Source:European Journal of Cancer, Volume 48, Issue 6


Background 
Survival studies using data from population-based cancer registries allow assessing effectiveness of cancer care on a population level. However, population-based cancer registries differ in the proportion of cases first notified by death certificate, as well as in the efforts to trace back such death certificate notifications (DCN). We aimed to assess the impact of such trace back on population-based cancer survival estimates.

Materials and methods 
In this study from the population-based Saarland Cancer Registry (Germany) we investigated the survival experience of successfully traced back DCN cases from 1994 to 2003. Five-year relative survival of patients with DCN cancers and the effect of trace back on population-based 5-year relative survival estimates were analysed by age and tumour site.

Results 
Twelve percent of all cancers were DCN and such cases occurred most often amongst sites with poor prognosis and amongst elderly patients. Approximately half of DCN cases could be successfully traced back. Five-year relative survival of patients with DCN cancers with trace back was 2%. The inclusion of DCN cancers with additional registrations reduced the 5-year relative survival estimate for all cancers combined by 4% points. Reductions were stronger for older patients and highly fatal cancers.

Conclusions
Trace back results in increased inclusion of patients with very poor prognosis. Varying extent of trace back across registries may compromise comparability of cancer survival estimates and should be taken into account in comparative cancer survival studies.

Weighing the Chances at Life's End - NYTimes.com

Weighing the Chances at Life's End - NYTimes.com


"........But the grimmer the prognosis, the more inaccurate and more optimistic the surrogates’ responses became. Only 22 percent correctly interpreted a statement about what a “5 percent chance of surviving” meant, while 65 percent answered with greater optimism.
“They clearly grasped the meaning of these statements,” Dr. White said. “They were not misunderstanding the numbers. They weren’t misunderstanding the language.” If that had been the case, you’d expect them to have been inaccurate about good news, too.
Instead, relatives hearing doctors deliver dire prognoses just didn’t accept or believe them. They displayed, in medspeak, “a systematic optimism bias.”
Such bias has shown up many times before in the medical literature. Cancer patients enrolled in early phases of clinical trials, for instance,....."