6 - World Journal of Gastroenterology

%
Table 4 Positive predictive value and negative predictive value in percentage at 95% confidence interval of serum M2-pyruvate
kinase using various cut-off value settings for different colorectal lesions compared with 158 normal people in colorectal cancer
mass screening in Hangzhou, China, 2006-2008 (95% CI)
M2-PK
(U/mL)
2.00 49.73
(42.57-56.90)
2.50 55.35
(47.62-63.07)
3.00 60.71
(52.62-68.80)
3.50 62.31
(53.98-70.64)
4.00 64.96
(56.31-73.60)
100
90
80
70
60
50
40
30
20
10
0
Sens Spec
CRC
Figure 1 Comparison of diagnostic values between serum M2-pyruvate
kinase and carcinoembryonic antigen for positive colorectal lesions based
on sensitivity and specificity in Hangzhou, 2006-2008. M2-PK: M2-pyruvate
kinase; CEA: Carcinoembryonic antigen; CRC: Colorectal cancer; Adv.: Advanced;
Nonad.: Nonadenomatous; Sens: Sensitivity; Spec: Specificity.
DISCUSSION
Colorectal cancer Advanced adenoma Adenoma Nonadenomatous polyps
PPV NPV PPV NPV PPV NPV PPV NPV
Sens Spec
Adv. adenoma
100.00
(100.00-100.00)
94.57
(89.93-99.20)
92.79
(87.98-97.60)
90.08
(84.76-95.41)
87.31
(67.22-80.89)
Sens Spec
Adenoma
29.32
(21.59-37.06)
33.02
(24.07-41.97)
36.05
(25.90-46.19)
37.97
(27.27-48.68)
39.71
(28.08-51.34)
Sens Spec
Nonad. polvps
96.97
(92.83-100.00)
93.55
(88.56-98.54)
91.15
(85.91-96.39)
90.83
(85.67-96.00)
89.31
(84.02-94.60)
CEA
M2-PK
This study explored the potential value of serum M2-PK
in screening CRC and other colorectal lesions in the population
and compared its value to that of serum CEA.
Overall, the serum M2-PK has a higher diagnostic value
than CEA for all types of colorectal lesions except IBD.
The serum M2-PK has a moderate to high diagnostic
value for early and advanced stages of CRC but CEA has
a low to moderate diagnostic value for all stages of CRC.
For advanced adenoma the serum M2-PK has a moderate
diagnostic value while CEA has a low to moderate
value. For both adenoma and non-adenomatous polyps
the serum M2-PK has a low to moderate diagnostic value
while CEA has a zero to low value. According to this
study, both serum M2-PK and CEA have no diagnostic
value to IBD. The sensitivity of serum M2-PK is much
higher than that of serum CEA in diagnosing all positive
colorectal lesions except IBD. The post-hoc statistical
power in this study was 100% for all positive colorectal
lesions except IBD. Serum M2-PK has the capacity to
find more CRC and precancerous lesions than CEA.
54.59
(47.81-61.37)
57.99
(50.55-65.43)
60.43
(52.30-68.56)
61.42
(52.95-69.88)
62.39
(53.29-71.48)
M2-PK: M2-pyruvate kinase; PPV: Positive predictive value; NPV: Negative predictive value.
Meng W et al . Serum M2-PK and colorectal cancer screening
72.73
(63.42-82.03)
69.05
(60.98-77.12)
66.03
(58.59-73.46)
64.88
(57.66-72.10)
62.90
(55.96-69.85)
29.32
(21.59-37.06)
33.64
(24.69-42.60)
36.05
(25.90-46.19)
34.67
(23.90-45.44)
35.94
(24.18-47.69)
88.89
(81.63-96.15)
88.78
(82.23-95.03)
86.55
(80.43-92.68)
83.85
(77.52-90.17)
82.98
(76.78-89.18)
We used community patients’ samples to test the value
of serum M2-PK and found that serum M2-PK has
the advantage of detecting earlier stages of CRC. The
sensitivity of serum M2-PK for CRC was 100% in this
study when the cut-off value was set up at 2.00 U/mL,
much higher than that of colonoscopy, iFOBT, and fecal
M2-PK [17,31,32] . One of the major goals of CRC mass
screening is to reduce mortality through the detection
of early-stage CRC, adenocarcinoma and adenoma [31] . A
CRC mass screening should avoid missing any CRC cases
at the primary stage and confirm the diagnosis at the secondary
or later stage of screening, making it possible to
achieve the goal of fewer or no deaths from CRC. At this
point, a higher-sensitivity screening test is to be preferred
to a test with higher specificity in a primary screening.
In addition, a serum test avoids the inconvenience of a
fecal test and it is simpler, faster, and safer than colonoscopy.
Thus, the compliance rate for serum M2-PK in a
CRC mass screening is predicted to be higher than that
for fecal M2-PK, iFOBT, and colonoscopy. Using serum
M2-PK as a primary screening test, the effectiveness of
a CRC mass screening should be increased due to high
compliance and high sensitivity.
This study showed serum M2-PK is more useful than
serum CEA in CRC mass screening because of higher
sensitivity and diagnostic value in finding early CRC. The
sensitivities of serum CEA were 29.03%, 7.31%, 5.84%
and 6.38%, respectively, in diagnosing CRC, advanced adenomas,
adenomas, and non-adenomatous polyps, when the
serum CEA cut-off value was 5.00 ng/mL. The low sensitivity
of serum CEA in detecting early CRC and precancerous
lesions limits its application in CRC mass screening.
Adenoma is regarded as a precancerous lesion of
CRC. Advanced adenoma is a severe type and defined as
adenoma with a diameter of ≥ 10 mm, a villous adenoma,
and an adenoma with high grade dysplasia [4,31] . The detection
rates of early CRC and advanced adenoma have been
used as important indicators in evaluating the effectiveness
of a CRC mass screening programs [31] . The projected
annual transition rates from advanced adenoma to CRC
range from 2.6% to 5.6% among people ≥ 55 years old [33] .
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June 15, 2012|Volume 4|Issue 6|