# Optimizing Cervical Cancer Diagnosis with Feature Selection and Deep Learning
## 2 Materials and Methods
### Diagnostic Process Overview  
Cervical cancer diagnosis traditionally involves a multistage process that begins with a patient interview and physical examination. If abnormalities are suspected, cytological samples are collected from the cervix for further analysis. This subjective analysis often determines the patient's subsequent treatment plan. Over time, efforts have been made to improve the traditional method in order to increase its objectivity. According to [PERSON] et al., incorporating HPV testing into cervical screening protocols improved the sensitivity of detection of high-grade cervical intraepithelial neoplasia, indicating significant advances in the methods' ability to identify serious diseases [7]. In this paper, we use images from liquid-based cytology (LBC), which is the latest advancement in cytological examination techniques. Liquid-based cytology is becoming more popular than traditional cytology as it reduces variability in sample preparation and improves the quality of diagnostic slides [7]. Unlike the conventional smear method, LBC involves suspending cells in a liquid medium before processing them on a glass slide, resulting in cleaner and more uniform preparations (see Figure 1). In the next step, a slide is analyzed by a pathomorphologist. To standardize the interpretation and reporting of cervical cytological results, the Bethesda system is used. This system was developed in 1988 and was primarily used to report the results of cervical and vaginal cytology. Today, this system acts as a framework for consistent communication  
Figure 1: Comparison of cytological slide preparation methods. (**a**) Conventional cytology produces more variability and debris, making analysis challenging; (**b**) liquid-based cytology ensures cleaner and more uniform slides, providing improved quality for image analysis and feature extraction. between healthcare professionals, helping to effectively manage and treat irregularities in cervical cytology. [PERSON] played a crucial role in the development of cytological diagnostics, who, in 1941, described the usage of a vaginal smear in the diagnosis of uterine carcinoma [8] and in 1942 introduced a new staining procedure for these smears [9]. These advances have brought substantial improvements in cytological examinations, mainly by identifying atypical cells in smears. This technique, named after its creator, is now universally recognized as the Pap smear. Building on these basic techniques, the Bethesda system was established as a uniform method of reporting cervical and vaginal cytology findings. Having been revised on multiple occasions since its invention, it continues to facilitate efficient communication and handling of cervical cytological irregularities. In 2012, [PERSON] and [PERSON] described the Bethesda system (TBS) that details definitions, criteria, and terminological clarifications [10]. The TBS format is adaptable and designed to integrate both evolving diagnostic approaches for cervical cancer and advances in cervical pathology. This system employs a two-level reporting structure based on the condition of uterine cervix cells, which can be categorized into two distinct cases:  
* **Low-Grade Squamous Intraepithelial Lesion--**also called LSIL. This grade describes a non-cancerous lesion in which cells of the uterine cervix are slightly abnormal (see Figure 2b). * **High-Grade Squamous Intraepithelial Lesion--**also called HSIL. Describes these cases that can become cancerous. Here, uterine cervix cells are moderately or severely abnormal (see Figure 2c). In addition, the Bethesda system contains information about the method that was used for the slide preparation. To distinguish between LSIL and HSIL cases, pathomorphologists evaluate morphological differences, including cell size, nucleus size, and nucleus-to-cytoplasm ratio as key diagnostic features [4]. These features are crucial for an accurate diagnosis and the appropriate management of cervical cytological abnormalities.