Papanicolaou test in the detection of high-grade cervical lesions: a re-evaluation based on cytohistologic non-correlation rates in 356 concurrently obtained samples.
Studies evaluating the routine Papanicolaou (Pap) test have traditionally used as the reference gold standard, the diagnoses on the follow-up histologic samples. Since the latter are typically obtained days to weeks after the Pap test, the accuracy of the resultant comparison may be affected by interim factors, such as regression of human papillomavirus, new lesion acquisitions or colposcopy-associated variability. A subset of our clinicians have routinely obtained cervical cytology samples immediately prior to their colposcopic procedures, which presented a unique opportunity to re-evaluate the test performance of liquid-based cervical cytology in detecting the most clinically significant lesions (i.e. cervical intraepithelial neoplasia 2 or worse: CIN2+), using as gold standard, diagnoses on cervical biopsies that were essentially obtained simultaneously. For each patient, cytohistologic non-correlation between the Pap test and biopsy was considered to be present when either modality displayed a high-grade squamous intraepithelial lesion (HGSIL)/CIN2+ while the other displayed a less severe lesion. Therefore, HGSIL/CIN2+ was present in both the Pap test and biopsy in true positives, and absent in both modalities in true negatives. In false positives, the Pap test showed HGSIL while the biopsy showed less than a CIN2+. In false negatives, Pap tests displaying less than a HGSIL were associated with biopsies displaying CIN2+. Combinations associated with "atypical" interpretations were excluded. A cytohistologic non-correlation was present in 17 (4.8%) of the 356 combinations reviewed. The non-correlation was attributed, by virtue of having the less severe interpretation, to the Pap test in all 17 cases. There were 17, 322, 0, and 17 true positives, true negatives, false positives and false negatives respectively. The sensitivity, specificity, positive predictive value and negative predictive value of the Pap test, at a diagnostic threshold of HGSIL, in identifying a CIN2+ lesion were 50%, 100%, 100% and 95% respectively. Even in Pap test/biopsy combinations obtained on the same day by the same colposcopist and evaluated by the same pathologist, there is a 4.8% (17/356) false negative rate associated with the Pap test. Our findings suggest that there may be an intrinsic error rate associated with this test modality.
Carns
Bhavini
B
Department of Pathology, Wilford Hall Medical Center, Lackland AFB, TX 78236, USA
Fadare
Oluwole
O
Acta Cytol. 2002 May-Jun;46(3):495-8
12040643
Acta Cytol. 1990 May-Jun;34(3):366-72
2111625
Cancer. 1989 Nov 15;64(10):2184-90
2804908
Cytopathology. 1993;4(6):331-7
8110972
Ann Intern Med. 2000 May 16;132(10):810-9
10819705
Semin Diagn Pathol. 2007 May;24(2):77-88
17633349
JAMA. 1989 Feb 3;261(5):737-43
2642983
Am J Clin Pathol. 2004 Mar;121(3):315-20
15023034
Acta Cytol. 2001 Jan-Feb;45(1):23-7
11213500
Gynecol Oncol. 1997 Oct;67(1):3-7
9345348
Diagn Cytopathol. 1994;10(1):68-75
8005047
Cancer. 2003 Jun 15;97(12 Suppl):3133-275
12784323
Br Med J (Clin Res Ed). 1984 Oct 6;289(6449):896-8
6434133
Cancer. 1994 Jan 1;73(1):140-7
8275416
Am J Obstet Gynecol. 1987 Sep;157(3):544-9
3631155
J Fam Pract. 1995 Jan;40(1):57-62
7807039
Cancer. 1993 Nov 15;72(10):3002-6
8221568
Am J Public Health. 2006 Mar;96(3):480-7
16449592
Obstet Gynecol. 1987 Jan;69(1):43-6
3540762
Arch Pathol Lab Med. 1996 Jun;120(6):523-31
8651852
J Reprod Med. 1989 Oct;34(10):815-7
2795564
Cytopathology. 1998 Jun;9(3):145-54
9638375
CA Cancer J Clin. 2007 Jan-Feb;57(1):43-66
17237035
Am J Obstet Gynecol. 1992 Apr;166(4):1254-9
1566781
Am J Epidemiol. 1995 Apr 1;141(7):680-9
7702044