Table 4.

Stage Distribution Among Cancers Diagnosed in the LCSR and NLST^a,b,c

Stage	Baseline (T0)							Annual (T1)
	LCSR		NLST		LCSR vs NLST			LCSR		NLST		LCSR vs NLST
	No.	Percentage	No.	Percentage	PR	95% CI		No.	Percentage	No.	Percentage	PR	95% CI
IA, IB	2,326	53.5	160	54.6	0.98	0.85	1.13	307	59.8	108	59.0	1.01	0.85	1.22
IIA, IIB	551	12.7	22	7.5	1.69	0.38	7.47	61	11.9	18	9.8	1.21	0.26	5.77
IIIA, IIIB	850	19.6	64	21.8	0.90	0.55	1.46	84	16.4	33	18.0	0.91	0.38	2.18
IV	620	14.3	47	16.0	0.89	0.45	1.77	61	11.9	24	13.1	0.91	0.26	3.12
Unknowna	1,529	…	4	…	…	…	…	208	…	3	…	…	…	…
Total	5,882	…	297	…	…	…	…	513	…	186	…	…	…	…
Total known	4,347	…	293	…	…	…	…	721	…	183	…	…	…	…

LCSR = Lung Cancer Screening Registry; NLST = National Lung Cancer Screening Trial; PR = prevalence ratio.

^aNLST data are from Aberle et al. (2011)¹.

^bIn the LCSR, an additional six and two cancers were diagnosed at stage 0 at baseline and annually, respectively.

^cSE using the Delta method-derived formula: SE log(p1 / p2) = [(1 – p1) / (p1 × n1) + (1 – p2) / (p2 × n2)]^0.5; CI = exp[ln(p1 / p2) ± 1.96 SE], where p1 is the observed proportion, n1 is number of individuals in the LCSR, p2 is the expected proportion, and n2 is the expected number of individuals in the NLST.