Clinical Outcome Trial of the ThinPrep® Pap Test
Objective
To evaluate the ThinPrep Pap Test and the conventional Pap smear for the detection of High Grade Squamous Intraepithelial and more severe
lesions (HSIL+).
Study Design*
- A multi-site, prospective, historically controlled, direct-to-vial study.
- Study sites consisted of ten leading academic hospitals in major metropolitan areas throughout the United States.
- From each site, patients were representative of a routine Pap test screening population and a referral population enrolled at the
time of colposcopic examination.
- 10,226 ThinPrep Pap Test specimens were collected prospectively and compared against an historical control cohort of 20,917
conventional Pap smears.
- Conventional Pap smears were collected sequentially from patients seen immediately prior to the initiation of the study by the same
clinics and clinicians (as available) used to collect the ThinPrep Pap Test specimens.
Conclusion
The ThinPrep Pap Test increased HSIL+ detection by 59.7%, as compared to the conventional Pap smear in a multi-site, historically controlled
study of routine screening and referral patient populations at ten leading academic institutions.1
HSIL+ Detection by Site2
| Site |
Total Conventional Pap Smear (n) |
HSIL+ |
Percent (%) |
Total ThinPrep Pap Test (n)* |
HSIL+ |
Percent (%) |
Percent Change (%) |
| S1 |
2,439 |
51 |
2.1 |
1,218 |
26 |
2.1 |
+2.1 |
| S2 |
2,075 |
44 |
2.1 |
1,001 |
57 |
5.7 |
+168.5 |
| S3 |
2,034 |
7 |
0.3 |
1,016 |
16 |
1.6 |
+357.6 |
| S4 |
2,043 |
14 |
0.7 |
1,000 |
19 |
1.9 |
+177.3 |
| S5 |
2,040 |
166 |
8.1 |
1,004 |
98 |
9.8 |
+20.0 |
| S6 |
2,011 |
37 |
1.8 |
1,004 |
39 |
3.9 |
+111.1 |
| S7 |
2,221 |
58 |
2.6 |
1,000 |
45 |
4.5 |
+72.3 |
| S8 |
2,039 |
61 |
3.0 |
983 |
44 |
4.5 |
+49.6 |
| S9 |
2,000 |
4 |
0.2 |
1,000 |
5 |
0.5 |
+150.0 |
| S10 |
2,015 |
69 |
3.4 |
1,000 |
50 |
5.0 |
+46.0 |
| Total |
20,917 |
511 |
2.4 |
10,226 |
399 |
3.9 |
+59.7 (p<0.001) |
Percent change (%) = ((TP HSIL+/TP Total)/(CP HSIL+/CP Total))-1 x 100
- 385 of the 511 conventional Pap smear HSIL+ cytology cases had biopsy correlation data.
- 358 of the 399 ThinPrep Pap Test HSIL+ cytology cases had biopsy correlation data.
Biopsy Results of HSIL+ Cytology Cases3
|
Total Conventional Pap Cytology |
ThinPrep Pap Cytology |
| Biopsy Result |
HSIL (N=361) |
Cancer (N=24) |
HSIL+ (N=385) |
HSIL (N=340) |
Cancer (N=18) |
HSIL+ (N=358) |
| Negative |
44 (12%) |
3 (12%) |
47 (12%) |
41 (12%) |
0 (0%) |
41 (11%) |
| LSIL |
80 (22%) |
1 (4%) |
81 (21%) |
64 (19%) |
0 (0%) |
64 (18%) |
| HSIL |
211 (58%) |
5 (21%) |
216 (56%) |
222 (65%) |
0 (0%) |
222 (62%) |
| Cancer |
26 (7%) |
15 (65%) |
41 (11%) |
13 (4%) |
18 (100%) |
31 (9%) |
| HSIL+ |
237 (66%) |
20 (86%) |
257 (67%) |
235 (69%) |
18 (100%) |
253 (71%) |
* Samples processed with the ThinPrep 2000 Processor.
1 ThinPrep Pap Test Package Insert "The results from this study showed a detection rate of 511/20,917 for the conventional
Pap smear versus 399/10,226 for the ThinPrep slides. For these clinical sites and these study populations, this indicates a 59.7% increase
in detection of HSIL+ lesions for the ThinPrep specimens."
2 ThinPrep Pap Test Package Insert.
3 Data on file, Cytyc Corporation 2001.
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