A comparative study of Pap smear cytology and histopathology of cervix biopsy

Background: Carcinoma cervix is one of the leading causes of death of the female population in developing countries. By virtue of its accessibility, cancer of the cervix can be readily diagnosed even in its preinvasive stage. If treated in the earlier stages the patient can often be cured of the disease. Carcinoma of the cervix is the fourth most frequent cancer in women worldwide and the leading cause of death from cancer in several developing countries including India. The use of cervical smear (Papanicolaou/Pap) as a screening tool has significantly reduced the incidence of cervical cancer. Materials and Methods: The present study was carried out in the department of pathology in a tertiary care hospital over a period of two years. In the two year study period, 2568 pap smears were received. Among these, 194 abnormal smears were identified and they were categorized under The Bethesda System 2014. The histopathological examination of biopsy cervix results of the smears was compared and analyzed. Results: Out of 194 smears studied, reactive changes was 69 (35.57%). Atypical squamous cells of undetermined significance were 47 (24.23%). Low grade squamous intraepithelial lesions were 3 (1.55%) and high grade squamous intraepithelial lesions were 29 (14.95%). Atypical endocervical cells were 2 (1.03%). Atypical endocervical cells favor neoplastic was 4 (2.06%) and endocervical adenocarcinoma in situ was 1 (0.5%). Squamous cell carcinoma was 39 (20.10%). The histopathological examination of biopsy cervix results of the above smears was compared and analyzed. Conclusion: This correlative study of Pap smear and histopathological examination of the cervix revealed the overall sensitivity of 97%, the specificity of 74% and an accuracy of 87%. The false-negative and false-positive cases in this study can be minimized by proper sampling, screening, interpretation and further follow up study of repeat smears.


Introduction
Carcinoma cervix is one of the leading causes of death of the female population in developing countries. According to Global cancer statistics 2018, cervical cancer is the fourth most frequent cancer in women with an estimated 570,000 new cases representing 6.6% of all female cancers. Approximately 90% of deaths from cervical cancer occurred in low-and middle-income countries.
By virtue of its accessibility, malignancy of the cervix can be readily diagnosed even in its preinvasive stage. If treated in the earlier stages the patient can often be cured of the disease. The introduction of cytological screening by George Papanicolaou in the late 1940s was a great public health success story in cervical cancer prevention [2].
Although Papanicolaou (Pap) cytology represents the most effective technique to prevent and detect the precancerous conditions of the uterine cervix before they become invasive cancer, its falsenegative yield due to the potential sampling and interpretation errors yield is still a reason of concern. Thus, the final diagnosis should be made on histologic examination to assess the accuracy of the cervical cytology. Cytohistopathological correlation of Pap smear is one of the recommendations of the European guidelines for quality assurance for the development of cytology laboratory performance and, in particular, to reduce false-negative results [3]. was 4(5.48%) and adenocarcinoma ( Figure 4) 6 (8.22%) [ Table 2].  smears and all of them are histopathologically proved to be adenocarcinoma. There is one case of adenocarcinoma in situ in cytology and that is turned out to be adenocarcinoma in biopsy [ Table   3].
Coming to the evaluation of the efficacy of the Pap smear test, True positive cases were 103, falsepositive cases were 23, True negative cases were 65, and false-negative cases were 3.
The overall sensitivity was 97%, specificity was 74% accuracy was87% and the positive predictive value was 82%.  [12] reported 5%, Banik et al [13] found the incidence to be 8.18%, Bukhari et al [17] reported 10.2%.  The results of the present study have shown a slightly raised incidence of ASCUS as compared to others probably due to the reason that the present study included females coming to gynecological OPD and hence more chances of the positive result.
In the present study, ASCUS and HSIL were found to be more as patients with complaints were included. Differences in other results may be attributed to inter-observer variation. In the present study 2 glandular cell abnormality was detected and 5 adenocarcinomas.
This most widely used screening test as of today is simple and acceptable, but it has been found to have false-negative results ranging from 1.1 to There are 23 false-positive cases in the present study. It may be due to inadequate biopsy or misinterpretation of the benign process. Anderson Tropical Journal of Pathology and Microbiology 2020;6(3) 234 And Jones documented patients with abnormal smears and initial lack of confirmation by biopsy require long term follow up to discover occult neoplastic lesion [22].
False positivity may be due to removal of the entire lesion by energetic brushing resulting in biopsies with denuded surface or misinterpretation of the cluster of endocervical cells with large nuclei and nucleoli, the cluster of endometrial cells or postmenopausal atrophic cells as abnormal cells.
Various studies mentioned the sensitivity and specificity of cytology for detecting cervical neoplasia that ranged from 50-98% [25].
There are different methods that were studied to improve cervical screening, but cervical biopsy has been considered as the gold standard for detecting cervical lesions [18,19].
In the present study, sensitivity and specificity of cervical cytology in detecting cervical malignancy

Conclusion
The study revealed a good correlation between cervical cytology and cervical biopsy. Pap smear is an important screening tool for the detection of precancerous and cancerous lesions of the cervix. It is a less invasive and simple procedure to perform on an OPD basis. Also, it is possible to issue reports within 24 hours of receipt of the specimen.
The present study also concluded that this correlative study of Pap smear and histopathological examination of the cervix revealed the overall sensitivity of 97%, the specificity of 74% and an accuracy of 87%. The false-negative and falsepositive cases can be minimized by proper sampling, screening, interpretation and further follow up study of repeat smears.
What does the study add to the existing knowledge? Tropical Journal of Pathology and Microbiology 2020;6(3)