st: Relative survival using matched controls

[Katja Maretty Nielsen <KATJA.MARETTY.NIELSEN@ki.au.dk>]

Dear all

I'm trying to figure out how to calculate relative survival in cancer patients where I have the "expected survival" as a general population cohort of individually matched controls (5 controls for each cancer patient matched on age and sex at the date of cancer diagnosis).

I have a data set containing the following variables:

idno            identification number, unique to each individual
age             age at diagnosis of cancer/index date
gender
type            type of individual. 1 Cancer patient   2 control
group          number correlating each cancer patient with his/hers 5 individually matched controls
foll              follow up time (years) since diagnosis/indexdate
status         status at end of follow up.   1 dead    2   alive/censored
com           comorbidity according to the charlson index categorized in 3 levels; no, mild, moderate, and severe comorbidity
diayear       year of diagnosis/index year

+ some additional prognostic variables for the cancer patients such as stage at diagnosis, tumor size, location of primary tumor etc.

What I would like to do is to produce Kaplan Meier curves for the relative survival, both as overall and for subgroups, e.g., adult patients with non-metastatic disease etc.

I have looked into some of the command such as -strel- and -stexpect-, however these methods seems to be based on population mortality rate tables.

I'm currently using stata version 11.2

Many thanks

Katja Nielsen


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