CORRELATION BETWEEN THE HUMAN PAPILLOMAVIRUS TYPE DISTRIBUTION IN MALIGNANT AND PREMALIGNANT CERVICAL LESIONS AT THE UNIVERSITY OF BENIN TEACHING HOSPITAL

Abstract

BACKGROUND: Cervical cancer is a preventable disease and has continued to
constitute a major public health problem. Persistent infection with high risk human
papillomavirus (HPV) types is said to play a major role in the causation of the disease.
Although, epidemiological studies have established HPV infection as the central cause of
invasive cervical cancer (ICC) and its precursor lesions, only a fraction of premalignant
lesions progress to ICC. It is important to know whether the HPV type distribution in
premalignant lesions is representative of those that go on to cause cancer. This may help
in planning more aggressive treatment modalities and more effective follow up measures
for premalignant lesions when such virulent HPV types are detected. It may as well help
in the evaluation of the potential impact of both existing and future prophylactic HPV
vaccines.
OBJECTIVES: To compare the type distribution of high risk HPVs in women with
malignant and premalignant cervical lesions in the University of Benin Teaching Hospital
(UBTH).
STUDY DESIGN: A case controlled study.
METHODS: Sixty women with histologically confirmed ICC and sixty controls with
histologically diagnosed cervical intraepithelial lesions (CINs), awaiting treatment at the
UBTH were recruited for the study. These had cervical swabs taken for HPV testing
using COBAS 4800. All collected specimens were transported to a central laboratory at
Access to Basic Medical Care (ABC) foundation, Ibadan, for assay. Data analysis was
done using the Statistical Package for Social Students (SPSS) version 20. Relationship
between variables was assessed using Chi square test or Fisher exact test where
appropriate. Pearson’s correlation was used to determine the relationship between HPV
types in premalignant and malignant lesions and significant differences between means
was determined using Student t test. The level of significance was set as p<0.05.

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RESULTS: 120 subjects who met the inclusion criteria participated in the study: 60
subjects with malignant cervical lesions (ICC) and 60 controls with premalignant cervical
lesions (CIN I, CIN II and CIN III). Of the sixty controls, 25 had CIN III, 19 had CIN II
while 16 had CIN I. While ninety percent (54) of the 60 subjects with invasive cervical
cancer tested positive to at least one hrHPV genotype, only sixty-five percent (39) of the
60 controls with premalignant lesions ( i.e. 80%, 57.9% and 50% of those with CIN III,
CIN II and CIN I respectively) tested positive to hr HPV testing. This too was statistically
significant (p=0.001). While HPV-16 is responsible for 63% of the malignant lesions, it
is only responsible for 25.6% of their premalignant counterparts. This was statistically
significant (p=0.001). HPV-16 was more likely to be found in malignant than
premalignant cervical lesion (OR=4.93, 95% CI=1.99-12.20, p=0.001). HPV-18 was less
likely to be found in malignant compared to premalignant cervical lesions. However, this
association was not statistically significant (OR=0.32, 95% CI =0.08-1.38, p=0.158).
Other hrHPV types were also less likely to be found in malignant compared to
premalignant cervical lesions. This was statistically significant (OR=0.32, 95% CI=
0.14-0.75, p=0.011).
CONCLUSION: This study has established the fact that the hrHPV genotypes in
malignant cervical lesions do not differ significantly from those in premalignant cervical
lesions, but the proportion of the genotypes in individual lesions may vary. HPV-16 and
18 account for about 70% of malignant cervical lesions and nearly 50% of premalignant
cervical lesions, and as such, premalignant lesions infected with these genotypes require a
more aggressive management and/or closer surveillance. However, a larger study with
HPV detection methods capable of detecting the other high risk HPVs individually
should be carried out to explore the potential effects of the other high risk HPVs on
cervical lesions in our environment.

CORRELATION BETWEEN THE HUMAN PAPILLOMAVIRUS TYPE DISTRIBUTION IN MALIGNANT AND PREMALIGNANT CERVICAL LESIONS AT THE UNIVERSITY OF BENIN TEACHING HOSPITAL