strel and strel2 (relative survival analysis and estimation of excess hazards)
Bernard Rachet and Milena Falcaro
The computer program strel is designed for relative survival analysis. It is based on the maximum likelihood approach to survival estimation using individual tumour records (Estève et al., 1990). You will need a licence for Stata®, in which the program is written, but our program strel is free. It has been widely used for cancer survival analyses in the UK and many other countries. You can download the most recent version of strel once you have registered. To do this, go to the ‘Register for Access’ page, complete and submit the form, and a username and password will be sent to you.
Relative survival is the ratio of the observed cumulative probability of survival in the study group and the survival that would have been expected if the group had only been subject to the background mortality in the general population (obtained from life tables).
We have consolidated and extended our statistical software for the analysis of cancer survival data, strel. The new version, strel2, incorporates a multivariable functionality, enabling estimation of covariable-specific excess hazards of death in large population-based datasets. This simple tool is convenient for users without strong statistical skills who want to analyse large datasets. A paper has been published in the Stata Journal. The new features of the software were presented at a methodological workshop in Paris in March 2012.
References and further reading
Estève J., Benhamou E., Croasdale M. and Raymond L. (1990). Relative survival and the estimation of net survival: elements for further discussion. Statistics in Medicine 9, 529-538. Coleman M., Babb P. and Damiecki P. (1999). Cancer Survival Trends in England and Wales, 1971-1995: Deprivation and NHS Region. TSO.