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*.