This document summarizes key findings about HPV natural history and HPV testing for cervical cancer screening. It was found that HPV infection is very common but rarely leads to cancer. While persistent HPV infection can cause cervical cancer after 10-15 years, many cofactors are also involved in cancer development. Studies showed that HPV becomes undetectable within 2 years for most women. HPV testing was found to detect more pre-cancer than pap smears but also detected more lesions that may regress. HPV testing allows longer screening intervals for HPV-negative women and better protection against cancer compared to pap smears alone. While HPV testing is more effective, implementing new screening strategies poses challenges where pap smear systems are already in place.

1. HPV NATURAL HISTORY AND HPV
TESTING
Mario Sideri
Unità Ginecologia Preventiva
Istituto Europeo di Oncologia, Milano
Italian HPV Study Group (IHSG)

2. What’s new?
In the last 30 years the causal association
between HPV infection and cervical cancer
has been demonstrated
papillomavirus

3. The Nobel Prize in Physiology or Medicine 2008
Harald Zur Hausen for his discovery of human
Papilloma viruses causing cervical cancer

4. Vaccination Population at
risk (screening)
Detection & Intervention
(pre-cancer elimination)
OLD STRATEGYNEW STRATEGY

5. Papillomavirus is known from decades.
However only in the recent years we have
recognized the wide diffusion and the benign
meaning of HPV infection
What is HPV?

6. Human Papillomavirus

7.  Papillomavirus are species specific viruses
 HPV are very common viruses and are
present in almost all the species of
mammalians and birds
 More than 100 HPV types have been
described in humans
 Human PV infect the skin and mucous
membranes where they can cause typical
benign proliferations as warts and papillomas
Papillomavirus
De Villiers et al., Virology (2004)

8.  HPV infection causes in some
instances microproliferations not visible
with the naked eye
 HPV tends to prersist for long periods
of time, often as latent infection
 Some HPV associated lesions can
evolve into malignant neoplasia
Papillomavirus
De Villiers et al., Virology (2004)

9. HPV Infection
Langerhans
cells
Dendritic
cells
Dermis
Micro-wound
Epidermis
Draining lymphatics
Basement
membrane
CD 16

10.  90% of young women acquires the
virus with the beginning of sexual
intercourses
 Most of them become negative after
6-18 months of transient infection
 Only about 10% of young women
become persistently infected with HPV
for a longer period of time
HPV
natural history

11.  less than 30% of persitently infected
women develops a CIN lesion
 the vast majority of CIN clears
spontaneously
 some CIN persist, but even most of
persistent CIN3 will never become
cancer
HPV
natural history

12. In this way, the almost ubiquitary HPV
infection, very rarely ends up into cervical
cancer.
Conversely, the association of HPV
infection with cervical cancer offers unique
opportunities of cancer prevention
HPV and Cervical Cancer

13.  553 college students (mean age 19)
 HPV test and pap smear every 4 months for
5 years
 mean follow up 41.2 months
HPV natural history:
Seattle Study
Winer et al., Am J Epidemiol (2003)

14.  19.7% was HPV DNA positive at
enrollment
 During two years follow up 39% of
women negative at enrollment became
HPV DNA positive
 High risk HPV were found more
frequently, types 16,18,51,56,33,35,39
Winer et al., Am J Epidemiol (2003)
HPV natural history:
Seattle Study

15. Winer et al., Am J Epidemiol (2003)

16.  60 adolescents (14-17) were followed for a
mean time of 26 months
 Every three months were evaluated for HPV
infection
 In addition a weekly self sampling for HPV
was performed for a time lenght up to 15
weeks
Brown et al., J Infect Dis (2005)
HPV natural history:
Adolescent study

17. Timing HPV overall HPV oncogenic
Enrollment 28% 22%
Last visit 40% 37%
At least once* 82% 77%
Brown et al., J Infect Dis (2005)
* At least two positive samples
HPV natural history:
Adolescent study

18. Only 3 girls were always negative to vaginal
HPV testing
 All referred to be virgins
Brown et al., J Infect Dis (2005)
HPV natural history:
Adolescent study

19.  HPV detectability rarely persist for more
than 24 months
 in more than 90% of the cases HPV
becomes undetectable within 24 months
HPV
Natural history

20. Detectable HPV
Author Age 6 12 24
__________________________________
Woodman 20 24 4 <1
Mosicki 20 50 30 10
Ho 20 30 9
% persistent HPV
infection in months

21.  persistent HPV infection may cause the
development of invasive cervical cancer in 10
to 15 years
 many known and unknown co-factors are
responsible for cancer develpoment
HPV
Natural history

22.  20.817 women with neagtive cytology at
baseline
 HPV test at enrollement
 Follow up for 10 years; endpoint CIN2-3
development
Natural history of HPV oncogenesis
Portland study
Kahn et al., JNCI (2005)

23. 0%
5%
10%
15%
20%
25%
0,0 4,5 15,0 27,0 39,0 51,0 63,0 75,0 87,0 99,0 111,0 119,5
Follow-Up Time (months)
CumulativeIncidenceRateof≥CIN3
HPV16
+
HPV18
+
HPV
+
HPV+/
HPV16-
/18-
HPV
-
Kahn et al., JNCI (2005)
CIN3 develpoment during follow
up in relation to HPV status

24. ALL
HPV 16
Rodriguez et al., Proceedings of 24th International HPV Conference and Clinical Workshop, China 2007. Abstract

25.  HPV persistent infection can cause the
development of invasive cervical cancer in 10
to 15 years
 many co-factors are involved in the process
of cancer development
Natural history of HPV infection

26. Few studies addressed
in longitudinal studies
HPV status in sex
couples
HPV:
what we know in sex couples?

27. ….In our current study, less than half
of the couples exhibited perfect HPV-
type specific concordance. More than
one third of couples had complete
discordance…..

28. Multivariate regression analysis.
Reporting a new sex partner or the same sex
partner or no sex partner was not significantly
associated with the risk of infection
reappearance.

29. HPV Clearance

30. HPV re-infection
(redection)

31. HPV infection is very common and is
not a disease
pre-cancer is a rare event
cancer is an exceptional event
HPV:
what we now know

32. HPV infection is very rarely
associated to cancer
development
However HPV is necessary for
cancer develpoment
HPV and Cervical Cancer

33. Cervical cancer screening
• Pap smear as primary screening test
• Identification of CIN3
• Elimination of CIN3 through excisional
conservative surgery
The historical strategy

34. Screening aim
To identify and eliminate this lesion

36. Vaccination Population at
risk (screening)
Detection & Intervention
(pre-cancer elimination)
USUAL STRATEGYNEW STRATEGY

37. Cervical cancer screening
• Testing the population for the
causative agent of cervical cancer
• Testing aimed to identifcation of CIN3
• Testing not aimed to detect infection
HPV TESTING

38. Cervical cancer screening
PROOF of PRINCIPLE
HPV TESTING

39. CERVICAL CANCER SCREENING IN INDIA
N = 131.476
Four arms randomized study:
•Control
•VIA
•Pap smear
•HPV test
HPV test
Pap smear
VIA
Control

41. Cervical cancer screening
known limitations of
cytology screening
PAP SMEAR

42. 30
40
50
60
70
80
90
100
1971 1973 1975 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001
8
9
10
11
12
13
14
15
16
17
18
Incidence/100000
ScreeningCoverage(%)
Cervical cancer screening
Start of organised screening

43. Never pap smear 162 62%
Pos. pap & adequate
follow-up
29 11%
False negative pap 37 14%
Previous abnormal
smear*
34 13%
TOTAL 262 100%
Screening “failures”
italian data
Amadori A. Int J Gynecol Cancer 1998
262 invasive cancer cases, TR Romagna and Toscana (1986-93).
* Repeat smear not done, colposcopy not done, colposcopy done late,
negative colposcopies, negative biopsies,
CIN3 diagnosed with no further action.

44. Cause, n (%)
Kaiser
study1
Swedish
study2
No recent screen 464 (56%) 789 (64%)
Cytology detection
failure
263 (32%) 300 (24%)
Failure of follow-up of
abnormal cytology
106 (13%) 91 (7%)
Screening history of women with
invasive cervical carcinoma
1. Leyden WA, et al. J Natl Cancer Inst 2005; 97:675683;
2. Andrae B, et al. J Natl Cancer Inst 2008; 100:622629.

46. Results of the NTCC study
(Nuove Tecnologie per lo Screening
del Cancro Cervicale)

47. Setting: population based screening programme
Prospective randomized study on new screening test
Accrual phase: March 2002 to December 2004
94,370 women aged 25–60 years were randomized
Arm A 47,001 = conventional cytology
Arm B 47,369 = HPV testing (HC2)
Two screening rounds were completed (6 years)
METHODS

48. Women were divided into two different age
groups:
• 25 to 34
• 35 to 60
METHODS

49. The primary endpoint was the detection of
grade 2 and 3 CIN, and of invasive cervical
cancers during the first and second screening
rounds.
Analysis was done by intention to screen.
METHODS

50. Relative detection (HPV vs cytology) was:
• 2·00 for CIN2
• 2·08 for CIN3
• 2·03 for CIN2 and 3
RESULTS: first round, 35-60 yrs
Meaning:
HPV test detects 2 times more CIN 2-3 than pap
In other words the pap smear is negative in 50% of
CIN2-3

51. Relative detection (HPV vs cytology) was:
• 2·00 for CIN2
• 2·08 for CIN3
• 2·03 for CIN2 and 3
RESULTS: first round, 35-60 yrs
Question:
Are these “new” CIN2-3 clinically relevant?
Go to the second round…

52. RESULTS: second round, 35-60 yrs
Meaning:
In the HPV group the CIN2-3 were identified
earlier than in the cytology arm
the relative detection (HPV vs cytology) was
• 0·54 for CIN2,
• 0·48 for CIN3
• 0·51 for CIN2 and 3

53. RESULTS: second round, 35-60 yrs
Question:
Which is the clincal value of the “anticipated”
diagnosis?
the relative detection (HPV vs cytology) was
• 0·54 for CIN2,
• 0·48 for CIN3
• 0·51 for CIN2 and 3

54. RESULTS: 35-60 yrs
Question:
Which is the clincal value of the “anticipated”
diagnosis?
It is safe to increase the intervals between two
screens.
But what about the invasive cancers?

55. First Round 6 8 0.61
Second Round 0 7 0.016
Total 6 15 0.052
HPV test pap smear P value
RESULTS: 35-60 yrs
Number of invasive cancers
Meaning:
Follow up of untreated CIN2-3 carries the risk
of cancer development

56. First Round 6 8 0.61
Second Round 0 7 0.016
Total 6 15 0.052
HPV test pap smear P value
RESULTS: 35-60 yrs
Number of invasive cancers
Clinical consequences of the study:
Stop pap smear screening and switch to HPV
testing

57. Relative detection (HPV vs cytology) round one
• 2·00 for CIN2
• 2·08 for CIN3
• 2·03 for CIN2 and 3 together.
Relative detection (HPV vs cytology) at round two
• 0·54 for CIN2
• 0·48 for CIN3
• 0·51 for CIN2 and 3 together.
RESULTS: 35-60 yrs
HPV testing:
•Reassure more than 90% of negative women
(negative is negative; interval increase)
•Offer better protection against cancer

58. RESULTS: 25-34 yrs
What about the young women,
aged 25 to 34?
Same results or different situation?

59. RESULTS: 25-34 yrs
The relative detection (HPV vs cytology) was:
Round 1
• 3·91 for CIN3 and AIS
Round two
• 0·20 for CIN3 and AIS.
Meaning:
Four times more CIN3 and AIS detected by
HPV testing
Five times less CIN3 and AIS in the subsequent
round (more evident effect in young women
than in older)

60. First Round 1 1 1.00
Second Round 0 2 0.50
Total 1 3 0.37
HPV test pap smear P value
RESULTS: 25-34 yrs
Number of invasive cancers
Clinical consequences of the study:
Some considerations….

61. RESULTS: 25-34 yrs
The relative detection (HPV vs cytology) was:
Round 1
• 3·91 for CIN3 and AIS
Round two
• 0·20 for CIN3 and AIS.
Considerations:
Double number of lesions in the whole period
(overdiagnosis-overtreatment)

62. First Round 1 1 1.00
Second Round 0 2 0.50
Total 1 3 0.37
HPV test pap smear P value
RESULTS: 25-34 yrs
Number of invasive cancers
Clinical consequences of the data 25-34 yrs:
The increment in cancer detection is counter balanced by an
increase in diagnosis and treatment of clinically non relevant
(regressing?) CIN2-3

63. First Round 7 9 0.62
Second Round 0 9 0.004
Total 7 18 0.028
HPV test pap smear P value
RESULTS: 25-60 yrs
Number of invasive cancers
The total figures of cancer reduction is still
impressive; this figure prompted GISCi to start
the long and difficult process to abandon pap
smear as primary screening test because it is
unethical to continue with pap smear screening

65. HPV TEST:
Which optimal use?
• HPV test has an high NPV
• HPV test is ideally suited to reassure the
negative HPV individuals and to increase
intervals between two subsequent screens
• at any age HPV negative test is reassuring

67. There are no scientific doubt
that HPV test should be used as
primary screening test.
Implementation is still a
problem where pap smear
screening system is in place
CONCLUSIONS
It is a Copernican revolution…
Copernicus was placed under investigation…..

71. 1940’ TECHNOLOGY

72. THANK YOU FOR YOUR
ATTENTION!
Mario Sideri
Unità Ginecologia Preventiva
Istituto Europeo di Oncologia, Milano
Italian HPV Study Group (IHSG)