Are survival rates for Tyrol published in the Eurocare studies biased?

Figures & data

Figure 1.  Estimated completeness of incidence dataset for Tyrol, year of diagnosis 1999.

Figure 2.  Time trend of age-standardized incidence rate for all sites combined except NMSC and for the most frequent sites (SEGI weights).

Figure 3.  M:I ratio (2002–2006) versus 1- relative 5-year survival rate (1998–2002).

Figure 4.  M:I ratio Tyrol versus that of neighboring countries* by cancer site; data from Cancer Incidence in Five Continents, Vol. IX (1998–2002). *Northern Italy, Germany (Saarland), Austria (Vorarlberg), Switzerland (St. Gallen), Switzerland (Graubünden/Glarus)

Figure 5.  Proportion of microscopically verified cases in Tyrol versus in neighboring countries^* by cancer site; data from Cancer Incidence in Five Continents, Vol. IX (1998–2002).

Table I.  Childhood cancer in Tyrol: Age-specific rates (years of diagnosis 1997–2006) and reference deciles.

	Girls		Boys
Age group	Age-specific rate	Reference deciles	Age-specific rate	Reference deciles
0–4	16.3	<9.7 > 21.4	14.5	<12.3 > 24.7
5–9	9.4	<6.9 > 12.0	16.0	<8.5 > 15.6
10–14	17.2	<6.8 > 13.6	16.9	<8.5 > 15.0

Table II.  Corrected patient survival status for all malignant cancer cases diagnosed in 1997 and still alive at 31.12.2007 (N = 1026)

Corrected Survival Status	N (%)
Alive at 31-12-2007	992 (96.7%)
Deceased before 31-12-2007 in Tyrol	4 (0.4%)
Deceased before 31-12-2007 outside Austria^a	5 (0.5%)
Emigration^b	21 (2.0%)
No regular residence in Austria at diagnosis^c	4 (0.4%)

^aPersons living in Tyrol, who die outside Austria, are not registered in the mortality file

^bOf 21 emigrants, seven moved to other Austrian states, four to Germany, two to former Yugoslavia, one to Italy, one to Great Britain, one to Spain, two to South America and for three cases we were not able to determine the destination

^cIn Austria, we have two types of residence, a primary and a secondary residence. All four cases had only a secondary residence in Austria, and mortality information is provided only for persons holding a primary residence.

Table III.  Uncorrected and corrected observed and relative survival rates for patients diagnosed in year 1997 (n = 2559)

	Observed Survival Rate^a		Relative Survival Rate^a
	Uncorrected	Corrected	Uncorrected	Corrected
One-year survival	73.4	73.2	76.0	75.9
Three-year survival	60.6	60.3	66.8	66.4
Five-year survival	53.8	53.4	63.4	62.9
Ten-year survival	41.1	40.4	58.1	57.1

^aBoth observed and relative survival rates were calculated with the STATA procedure strs written by Paul Dickman, which is used by our registry to compute survival rates

Table IV.  Analysis of a subset of 295 patients for re-abstracting date of diagnosis, difference between documented and corrected date of diagnosis.

Difference in months^a	N (%)
−2	1 (0.3%)
−1	4 (1.4%)
0	286 (96.9%)
1	2 (0.7%)
3	1 (0.3%)
4	1 (0.3%)

^aThe difference was defined by subtracting the corrected date of diagnosis from the uncorrected date of diagnosis. For a positive difference, this means that the corrected date of diagnosis was before the uncorrected date of diagnosis (thus underestimating the published survival rate), and for a negative difference the corrected data of diagnosis was after the uncorrected date of diagnosis (thus overestimating the published survival time).