Source of diagnosis     Chart review    
    Incident
cancer
No
cancer
Total  
VACCR Incident cancer 219 10 229 Sensitivity=219/252=87%
Specificity=2982/2992=99.67%
PPV =219/229=96%
NPV =2982/3015=99%
No cancer 33† 2,982 3,015
Total 252 2,992 3,244
ICD-9 Incident cancer 233 136 369 Sensitivity=233/252=92%
Specificity  =2926/3062=96%
PPV =233/369=63%
NPV =2926/2945=99%
No cancer 19† 2,926 2,945
Total 252 3,062 3,314
PPV=Positive Predictive Value, NPV=NEGATIVE PREDICTIVE VALUE
*For subjects with >1 potential cancer, each cancer was counted separately. Subjects with no potential cancers were counted once.ICD-9 codes identified more subjects with >1 potential cancer, resulting in a higher total.
†False negative diagnoses include those with no cancer diagnosis according to VACCR or ICD-9 code, respectively, as well as those with incorrect coding of the cancer type (two VACCR diagnoses and nine ICD-9 code diagnoses).
Table 2: Validity of Veterans Affairs Central Cancer Registry (VACCR) versus ICD-9 code cancer-type-specific diagnoses, with medical chart review as the gold standard*.