Clinical application of DNA ploidy to cervical cancer screening: A review

Table 1 Cytology and DNA Cytometry results from Ref[76]

Cytology1		DNA Cytometry
NILM	18503	Negative	17855
ASCUS	720 (0.40)	Equivocal	1395
LSIL	296 (0.89)	Positive	371
HSIL	59 (1.00)
Total	19621	Total	19621

¹Number in parenthesis is the fraction with at least 1 aneuploid cell by DNA Cytometry. NILM: Negative for intraepithelial lesion or malignancy; ASCUS: Atypical squamous cells of undetermined significance; LSIL: Low grade squamous intraepithelial lesion; HSIL: High grade squamous intraepithelial lesion.

Table 2 Biopsy results vs Cytology from Ref[76]

		Cytology
Histology	Total	NILM/inflam	ASCUS	LSIL	HSIL
Ca	15		6	5	4
CIN3	43	5	10	14	14
CIN2	66	12	15	23	16
CIN1	98	42	22	21	13
CC/Neg	401	285	86	18	12
Total	623	344	139	81	59

NILM: Negative for intraepithelial lesion or malignancy; ASCUS: Atypical squamous cells of undetermined significance; LSIL: Low grade squamous intraepithelial lesion; HSIL: High grade squamous intraepithelial lesion; Ca: Invasive cancer; CIN: Cervical intraepithelial neoplasia; CC: Cervicitis.

Table 3 Biopsy results vs DNA Cytometry from Ref[76]

		DNA Cytometry
Histology	Total	Neg	Equiv	Pos
Ca	15		2	13
CIN3	43	1	12	30
CIN2	66	3	19	44
CIN1	98	15	55	28
CC/Neg	401	87	280	34
Total	623	106	368	149

Ca: Invasive cancer; CIN: Cervical intraepithelial neoplasia; CC: Cervicitis.

Table 4 2 × 2 Contingency Tables for Biopsy results vs Cytology and vs DNA Cytometry from Ref[76]

		Cytology		DNA Cytometry
Histology	Total	LSIL+	NILM/ASCUS	Pos	Neg/Equiv
CIN2+	124	76	48	87	37
Neg/CIN1	499	64	435	62	437
Total	623	140	483	149	474

NILM: Negative for intraepithelial lesion or malignancy; ASCUS: Atypical squamous cells of undetermined significance; LSIL+: Low grade squamous intraepithelial lesion or higher; CIN: Cervical intraepithelial neoplasia.

Table 5 Cytology and Cytometry test performance based on data and analysis from Ref[76]

	Cytology	DNA Cytometry
Sensitivity	61.3%	70.2%
Specificity	87.2%	87.6%
PPV	54.3%	58.4%
NPV	90.1%	92.2%

PPV: Positive predictive value; NPV: Negative predictive value.

Table 6 3 × 3 Contingency Table for Biopsy results vs Cytology from Ref[76]

		Cytology
Histology	Total	Positive (LSIL+)	Equivocal (ASCUS)	Negative
Positive (CIN2+)	124	76	31	17
Equivocal (CIN1)	98	34	22	42
Negative	18560	30	86	18444
Total	18782	140	139	18503

ASCUS: Atypical squamous cells of undetermined significance; LSIL+: Low grade squamous intraepithelial lesion or higher; CIN2+: Cervical intraepithelial neoplasia, grade 2 or higher; CIN1: Cervical intraepithelial neoplasia, grade 1.

Table 7 3 × 3 Contingency Table for Biopsy results vs DNA Cytometry from Ref[76]

		DNA Cytometry
Histology	Total	Positive	Equivocal	Negative
Positive (CIN2+)	124	87	33	4
Equivocal (CIN1)	98	28	55	15
Negative	18150	34	280	17836
Total	18372	149	368	17855

CIN2+: Cervical intraepithelial neoplasia, grade 2 or higher; CIN1: Cervical intraepithelial neoplasia, grade 1.

Table 8 Cytology and Cytometry test performance based on data from Ref[76] and revised analysis

	Cytology	DNA Cytometry
Sensitivity	73.4%	91.4%
Specificity	99.4%	98.3%
PPV	54.3%	58.4%
NPV	99.68%	99.89%

PPV: Positive predictive value; NPV: Negative predictive value.

Table 9 Descriptive summary of the data of Ref [76] as re-analyzed n (%)

	Clinical result	Cytology number of cases	DNA Cytometry number of cases	Cytometry-Cytology number (%)
1	Number of women immediately returned to routine screening	18503	17855	-648 (-3.5)
2	Number of CIN1+ cases (false negative cases) per 10000 women returned to routine screening	32	11	-21 (-66)
3	Number of women referred to immediate colposcopy	140	149	9 (6)
4	Number of cases of invasive cancer immediately diagnosed	9	13	4 (44)
5	Number of CIN3+ cases immediately diagnosed	37	43	6 (16)
6	Number of clinically positive cases (CIN2+) immediately diagnosed by colposcopy	76	87	11 (15)
7	Number of women requiring 6 mo follow-up due to equivocal result	139	368	229 (165)
8	Number of women with potentially delayed clinically positive (CIN2+) diagnosis	31	33	2 (6)
9	Number of CIN3+ cases missed	5	1	4 (80)
10	Number of CIN2+ cases missed	17	4	13 (76)

Table 10 Definitions of the biopsy data required for comparison of two screening tests independent of simple verification bias, Ref[80]

	Gold standard positive			Gold standard negative
	Test 1+	Test 1-	Total	Test 1+	Test 1-	Total
Test 2+	a	b	a + b	A	B	A + B
Test 2-	c	[d]	[c + d]	C	[D]	[C + D]
Total	a + c	[b + d]	[n]	A + C	[B + D]	[N]

Variables in square brackets have unknown values.

Table 11 Biopsy data from Ref[82] for simple verification bias free comparison of Cytology vs DNA cytometry

	Biopsy +			Biopsy -
	Cytology +	Cytology -	Total	Cytology +	Cytology -	Total
AQIC+	130	37	167	30	23	53
AQIC-	1	0	1	0	0	0
Total	131	37	168	30	23	53

AQIC+: Positive by automated quantitative image cytometry; AQIC-: Negative by automated quantitative image cytometry.

Table 12 Alternative presentation of Biopsy data from Ref[82] for simple verification bias free comparison of Cytology vs DNA Cytometry

	Cytology				DNA Cytometry
Histology	Total	ASCUS+	NILM	Histology	Total	Pos/equiv	Neg
CIN1+	168	131	37	CIN1+	127	167	1
Neg	53	30	23	Neg	121	53	0
Total	221	161	60	Total	221	220	1

NILM: Negative for intraepithelial lesion or malignancy; ASCUS: Atypical squamous cells of undetermined significance; CIN1+: Cervical intraepithelial neoplasia, grade 1 or higher.

Table 13 The test performance limits for the combination of two binary valued tests

	Sensitivity		Specificity
	Minimum	Maximum	Minimum	Maximum
Logical “AND”	(Se1 + Se2) - 11	Min (Se1, Se2)	Max (Sp1, Sp2)	(Sp1 + Sp2)3
Logical “OR”	Max (Se1, Se2)	(Se1 + Se2)4	(Sp1 + Sp2) - 12	Min (Sp1, Sp2)

¹0% if (Se₁ + Se₂) ≤ 100%;

²0% if (Sp₁ + Sp₂) ≤ 100%;

³100% if (Sp₁ + Sp₂) ≥ 100%;

⁴100% if (Se₁ + Se₂) ≥ 100%. Se: Sensitivity; Sp: Specificity.

Table 14 Crude cancer prevalence and other data from 36 published DNA Cytometry studies from China, 2005-2013

Ref.	Invasive cancer cases	CIN2+ cases	Total screened	Crude cancer prevalence (per 100000 persons)	Crude CIN2+ prevalence (%)	Follow-up ratio	Ca/CIN2+ (× 10)
[110]	3	14	500	600	2.8		2.14
[82]	7	100	23698	29.5	0.42	0.38	0.7
[111]	48	103	4020	1194	2.56	0.78	4.66
[112]	1	22	1200	83.3	1.83		0.45
[113]	2	17	673	297.2	2.53		1.18
[114]	4	12	3551	112.6	0.34		3.33
[115]	2	15	3162	63.3	0.47	0.39	1.33
[116]	14	78	4109	340.7	1.9	0.93	1.79
[117]	4	84	9261	43.2	0.91	0.36	0.48
[118]	2	30	2599	77	1.15		0.67
[119]	3	65	1200	250	5.42		0.46
[120]	9	111	6793	132.5	1.63	1	0.81
[121]	0	16	2003	0	0.8		0
[122]	4	87	2153	185.8	4.04		0.46
[123]	3	56	12079	24.8	0.46		0.54
[124]	5	26	3000	166.7	0.87		1.92
[125]	8	142	5886	135.9	2.41	1	0.56
[126]	11	147	7735	142.2	1.9	1	0.75
[127]	1	41	4598	21.7	0.89		0.24
[128]	4	34	12278	32.6	0.28		1.18
[129]	2	11	3589	55.7	0.31		1.82
[130]	3	17	1806	166.1	0.94		1.76
[131]	0	10	1206	0	0.83		0
[132]	8	51	3603	222	1.42	1	1.57
[133]	106	168	23993	441.8	0.7		6.31
[134]	6	36	1220	491.8	2.95		1.67
[76]	15	124	19621	76.4	0.63		1.21
[55]	2	21	3070	65.1	0.68		0.95
[135]	1	15	2000	50	0.75		0.67
[136]	0	5	1256	0	0.4		0
[137]	30	172	18097	165.8	0.95		1.74
[138]	1	7	451	221.7	1.55		1.43
[139]	10	53	430	2325.6	12.33		1.89
[140]	6	12	2832	211.9	0.42		5
[141]	15	95	8670	173	1.1		1.58
[142]	30	187	22169	135.3	0.84		1.6

CIN2+: Cervical intraepithelial neoplasia, grade 2 or higher.

Table 15 Biopsy data for DNA Cytometry and hrHPV test results for 294 cases of Cytology ASCUS, from Ref[169]

	hrHPV	Histology
		Neg	CIN1	CIN2+
hrHPV Pos	216
Ploidy Neg		90	10	1
Ploidy Equ		22	25	8
Ploidy Pos		5	12	43
hrHPV Neg	78
Ploidy Neg		35	0	1
Ploidy Equ		12	0	0
Ploidy Pos		14	16	0

hrHPV: High risk HPV; CIN2+: Cervical intraepithelial neoplasia, grade 2 or higher; CIN1: Cervical intraepithelial neoplasia, grade 1.

Table 16 Test performance indicators for DNA Cytometry, hrHPV tests and combined DNA Cytometry and hrHPV tests, for Cytology ASCUS cases, Ref[169]

	875 Cases (157 CIN2+)	294 Cases (53 CIN2+)
Performance indicator for CIN2+ (%)	DNA Ploidy	hrHPV	DNA Ploidy	DNA Ploidy and hrHPV
bSensitivity	98.8	98.1	96.2	96.2
bSpecificity	47.5	32.0	56.0	73.4
bPPV	29.1	24.1	32.5	44.3
bNPV	99.4	98.7	98.5	98.9

hrHPV: High risk HPV; CIN2+: Cervical intraepithelial neoplasia, grade 2 or higher; PPV: Positive predictive value; NPV: Negative predictive value. Prefix “b”: From among biopsy cases only.

Table 17 Test performance indicators following re-analysis of the data of Table 16 from Ref[169]

	875 Cases (157 CIN2+)	294 Cases (53 CIN2+)
Performance indicator for CIN2+ (%)	DNA Ploidy	hrHPV	DNA Ploidy	DNA Ploidy and hrHPV
bSensitivity	98.8	98.1	96.2	96.2
bSpecificity	47.5	32.0	56.0	73.4
bPPV	40.8	24.1	47.8	71.7
bNPV	99.4	98.7	98.5	98.9

hrHPV: High risk HPV; CIN2+: Cervical intraepithelial neoplasia, grade 2 or higher; PPV: Positive predictive value; NPV: Negative predictive value. Prefix “b”: From among biopsy cases only.