INTRODUCTION

Cervical cancer (CC) is one of the three most common cancers that affect women globally. The two most common subtypes are squamous cell carcinoma (SQCCA), constituting most of the cases, and adenocarcinoma (ADCA). Fortunately, in Saudi Arabia, which follows strict conservative religious restrictions regarding sexual behaviors, CC has a very low incidence, with 358 diagnosed cases and 179 deaths annually.[1,2] When diagnosed at an early stage, CC is curable by various methods,[3] and Pap smear screening is considered a valuable tool, along with human papillomavirus (HPV) cotesting, in detecting precancerous and cancerous lesions and reducing the CC incidence rate and mortality.[4]

In cytology, the method of communicating Pap smear interpretations to clinicians is very important for patient follow-up and management plans, and the best method is using The Bethesda System for Reporting Cervical Cytology (TBSRCC).[5] The TBSRCC was last updated in 2014, and it categorizes the results into the following categories: (i) Negative for intraepithelial lesion or malignancy; (ii) other, for endometrial cells of >45-year-old women (with specification of whether it is negative for squamous intraepithelial lesion [SIL]); (iii) epithelial cell abnormality (ECA); and (iv) other malignant neoplasm. ECA is further classified into the following categories: Atypical squamous cells of undetermined significance (ASC-US), atypical squamous cells that cannot exclude HSIL (ASC-H), low-grade SIL (LSIL), high-grade SIL (HSIL), SQCCA, atypical glandular cells (AGCs), and adenocarcinoma in situ (AIS) and ADCA.[6,7]

There are numerous metrics for quality assurance in cytology laboratories that are required by certification and/ or accreditation bodies. One method is to compare the percentages of each Pap smear category with benchmark data and provide an explanation of any outlier and calculate the ASC to SIL (ASC/SIL) ratio.[8,9] In this paper, we will share our data from a tertiary health-care facility in the western region of Saudi Arabia with other researchers in this field to potentially establish benchmark data based on a Saudi population.

MATERIAL AND METHODS

Pap smear data at King Fahd Armed Forces Hospital, Jeddah, Saudi Arabia, were collected from the laboratory information system for the period between 2010 and 2022. All Pap smears were reported by pathologists. Even after a cytotechnologist joined the facility in May 2019, 100% of Pap smears were rescreened and reported by pathologists. Using an Excel sheet, we distributed the data according to the designated year and then to its designated category. The total number and prevalence of abnormal Pap smears were ASCUS or higher were calculated. The ASC/SIL ratio was calculated as follows: ASC/SIL ratio = (ASC-US + ASC-H)/(LSIL + HSIL + ADCA + SQCCA). The prevalence of abnormal Pap smears and the ASC/SIL ratio were compared to the College of American Pathologists (CAP) benchmark data and published studies in Saudi Arabia.

RESULTS

Out of 14376 of pap smears, 11241 were conventional while 3135 were as LBC between 2019 – 2022 only [Table 1]. The ASC/SIL ratio and the prevalence of abnormal pap smears in our study were compared to published studies in Saudi Arabia covering the same period [Table 2].

Table 1: Numbers and percentages of abnormal Pap smears from 2010–2022.

Category Conv. + LBC
2010–2022 Conv. Only
2010–2022 LBC only
2019–2022 n % n % n % Total Pap smears 14376 - 11241 - 3135 - Unsatisfactory 1040 7.23 793 7.05 247 7.88 Abnormal Pap smears ASCUS 207 1.44 64 0.57 143 4.56 AGC 124 0.86 93 0.83 31 0.99 LSIL 38 0.26 21 0.19 17 0.54 ASC-H 20 0.14 12 0.11 8 0.26 HSIL 35 0.24 13 0.12 22 0.70 ADCA 11 0.08 8 0.07 3 0.10 SQCCA 3 0.02 3 0.03 0 0.00 TOTAL APS 438 3.05 214 1.90 224 7.15 ASC/SIL RATIO
(AGC EXCLUDED) 2.61 1.69 3.60

Table 2: Comparison of the number of Pap smears, prevalence of abnormal Pap smears, and ASC/SIL ratio between our study and published articles.

Published study Years covered Number of Pap smears Prevalence of abnormal Pap smears ASC/SIL ratio Mufti and Altaf, 2014 2000–2012 15805 14.52% 2.57 Al-Kadri et al., 2015 2008–2011 19650 4.28% 2.26 Nasser et al., 2017 2006–2016 19759 1.97% 2.19 Our study (this paper) 2010–2022
including LBC 14376 3.05% 2.61 DISCUSSION

Our institute shifted to liquid-based cytology (LBC) in late 2019, as it was proven to reduce the rate of unsatisfactory results.[10-12] However, our unsatisfactory rate remained high due to the intermittent supply of re-preparation reagents. The scope of the high unsatisfactory rate and cytologic-histologic correlations will be the focus of our next published studies. LBC also allows for the molecular testing of HPV from the same vial, as long as approximately 2 mL of sample is sent for molecular biology first (to avoid contamination), and then routine LBC preparation is carried out.[13,14] For laboratories accredited by CAP, the cytopathology checklist provides benchmarking data for the acceptable reporting-percentile rate (RPR) for each category and ASC/SIL ratio for each preparation type.[9] Our data, percentages and ASC/SIL ratios, as shown in [Table 1], were within the 5–95th RPR; due to copyright, we cannot share the CAP’s RPR in our study. Remarkably, in our study, LBC detected more abnormalities than the conventional method, except for SQCCA, which was not detected by LBC. The rate of adenocarcinomas was higher than that of SQCCAs (0.08% and 0.02%, respectively). This finding concurs with the findings of Al-Kadri et al., 2015 and Nasser et al., 2017, where n = 19,650 and 19,759, respectively, highlighting the need for greater focus on glandular abnormalities.[15,16] As shown in [Table 2], the prevalence of abnormal Pap smears in our study was 3.05% (conventional and LBC methods); in Saudi Arabia, the prevalence rate was 14.52% in a single study due to a high rate of ASCUS, which was within the range according to their ASC/SIL ratio.[17] For detailed statistical data, see Appendix 1 and 2.

SUMMARY

The prevalence of abnormal pap smears and the ASC/SIL ratio was within the ranges of the CAP benchmark data and published studies, highlighting the need for greater focus on glandular abnormalities.