Thin-slice cytology is a specialized procedure used in gynecology to screen the cervix uteri (cervix) for neoplastic (newly formed) and pathologic (disease-related) changes. General cytology is the study of the cell. A cytological smear, or so-called exfoliative cytology, involves the exfoliation of cells from a tissue surface (e.g., using a spatula or brush) or the collection of already exfoliated cells from body fluids (e.g., urine), which are then smear onto a slide and analyzed microscopically. Such an examination provides valuable information about inflammatory processes or pathological degeneration of the cells. Exfoliative cytology in gynecology, known as cervical cytology, is one of the most effective preventive measures for the timely detection of neoplasia (neoplasm) of the cervix and thus cervical carcinoma (cancer of the uterine cervix). In 1940, Papanicolaou developed a method for staining the cells, thus enabling a comprehensive screening program. In Germany, the annual cytological smear test for young women over the age of 20 has been paid for by health insurance since 1971. However, thin-layer cytology is not paid for. The cytological smear is taken at the so-called transformation zone (transition from the multilayered squamous epithelium (an epithelium is a superficial cell boundary layer) of the vagina to the cylindrical epithelium of the cervix uteri). The cellular material is then spread on a labeled slide and fixed with a spray or ethyl alcohol for microscopic examination.
Indications (areas of application)
- Cervical cancer screening:By law, cytological smear tests (Pap tests) are performed once a year from the age of 20; from 2018, women will be tested as part of the early cancer detection measures (KFEM) as follows.Cervical cancer screening will be done as follows in the future:
- ≥ 20 years of age: annual palpation examination.
- 20 – 35 years of age: annual Pap smear (cytological examination according to Papanicolaou; cell smear from the cervix).
- ≥ 35 years of age: every 3 years combination examination:
- Test for genital infections with human papillomavirus (HPV).
- Pap smear
- In the case of abnormal Pap test (IIw, III, IIID), in addition to a repeat in three months, currently unspecified and not anchored as an algorithm, additional examinations are performed individually:
The procedure
Thin-layer cytology has been available since 1996 and represents an advanced method of general, cytological smear. However, it has not become established as the standard in Germany because the quality of previous studies does not adequately demonstrate its efficiency. In contrast to conventional cytology, the smear is not directly spread on a slide, but first prepared with an alcoholic solution. Interfering components such as blood or mucus are removed, and a larger number of cells can also be better fixed and preserved, which increases the sensitivity of the examination. Conventional smear method Thin layer cytology
The prepared sample is sent to a laboratory that performs thin-layer cytology. In addition, an HPV test can be performed as a supplement (the human papilloma virus (HPV virus) is a pathogen involved in the development of cervical cancer), since several preparations can be made from the same cell sample. Different ways of preparing a preparation are available for thin-layer cytology:
- Membrane filter system – The cell sample is aspirated to a membrane and then sprayed evenly onto the slide with air pressure.
- Density gradient centrifugation – The cell sample is first centrifuged. Then the centrifuged cellular components are removed and distributed on the slide.
In both procedures, the specimen is stained as in conventional cytology according to Papanicolaou and then microscopy.Microscopic findings are assessed using various schemes:
Munich Nomenclature III for gynecologic cytodiagnosis of the cervix:
| Group | Definition | Recommendations | Correlate in Bethesa system |
| 0 | Insufficient material | Swab repetition | Unsatisfactory for evaluation |
| I | Inconspicuous and unsuspicious findings | Smear at screening interval | NILM |
| II-a | Inconspicuous findings with a conspicuous history | If necessary, cytological control due to conspicuous anamnesis (cytological/histological/colposcopic/clinical findings) | NIML |
| II | Findings with limited protective value | ||
| II-p | Squamous cells with lower-grade nuclear changes than in CIN (cervical intraepithelial neoplasia; cervical intraepithelial neoplasia/neoplasia) 1, also with coilocytic cytoplasm/parakeratosis | If necessary, cytological control taking into account history and clinical findings (possibly after inflammatory treatment and/or hormonal lightening; in special cases, additive methods and/or colposcopy) | ASC-Us |
| II-g | Cervical (belonging to the cervix) glandular cells with abnormalities extending beyond the spectrum of reactive changes | If necessary, cytologic control depending on history and clinical findings (possibly after inflammatory treatment; in special cases, additive methods and/or colposcopy) | AGC endocervical NOS |
| II-e | Endometrial cells (endometrial cells) in women > 40 years of age in the second half of the cycle | Clinical control taking into account history and clinical findings. | Endometrial cells |
| III | Unclear or doubtful findings | ||
| III-p | CIN 2/CIN 3 /squamous cell carcinoma not to be excluded | Differential colposcopy, additive methods if necessary, possibly short-term cytological control after inflammatory treatment and/or hormonal whitening | ASC-H |
| III-g | Marked atypia of the glandular epithelium, adenocarcinoma in situ/invasive adenocarcinoma cannot be excluded | Differential colposcopy, additive methods if necessary. | AGC endocervial favor neoplastic |
| III-e | Abnormal endometrial cells (especially postmenopausal/after the last spontaneous menstrual period) | Further clinical diagnosis, with histologic clarification if necessary. | AGC endometrial |
| III-x | Doubtful glandular cells of uncertain origin. | Further diagnostics (e.g., fractionated abrasion; additive methods/differential colposcopy, if necessary) | AGC favor neoplastic |
| IIID | Dysplasia findings with a greater tendency to regression | ||
| IIID1 | Cellular pattern of mild dysplasia analogous to CIN 1. | Cytological control in six months, in case of persistence > one year: if necessary.additive methods/ differential colposcopy | LSIL (low grade squamous intraephitelial lesion). |
| IIID2 | Cellular picture of moderate dysplasia analogous to CIN 2. | Cytological control in three months, in case of persistence > six months: differential colposcopy, additive methods if necessary | HSIL (high grade squamous intraephitelial lesion). |
| IV | Immediate precancerous stages of cervical carcinoma | Differential colposcopy and therapy | |
| IVa-p | Cell image of severe dysplasia/carcinoma in situ analogous to CIN 3. | HSIL | |
| IVa-g | Cell image of adenocarcinoma in situ. | AIS (adenocarcinoma in situ) | |
| IVb-p | Cellular picture of a CIN 3, invasion cannot be excluded | HLS with features suspicious for invasion | |
| IVb-g | Cell image of adenocarcinoma in situ, invasion not excluded | AIS with features suspicious for invasion | |
| V | Malignancies | Advanced diagnostics with histology and therapy | |
| V-p | Squamous cell carcinoma | Squamous cell carcinoma | |
| V-g | Endocervical adenocarcinoma | Endocervical adenocarconoma | |
| V-e | Endometrial adenocarcinoma | Endometrial adenocarnoma | |
| V-x | Other malignancies (cancerous tumors), including those of unclear origin | Other malignant neoplasms |
Diagnostic procedure for abnormal recurrent (“recurrent”) cytology
Pap IIID/IVA: colposcopy (examination of the vagina (sheath) and cervix uteri (neck of the uterus) using a special microscope) → biopsy (removal of a tissue sample):
- CIN I → control
- CIN II/III → surgical removal (see surgery: preinvasive lesions).
Pap IV B: colposcopy → biopsy
- CIN III → surgery (see d.)
- Invasive carcinoma → surgery (s. d.)
Further notes
- Atypical glandular cells (AGC) are associated with a high and long-term increased risk of cervical cancer. In most cases, the AGC group is adenocarcinoma.
Your benefit
Regular cancer screening with thin-slice cytology provides effective risk reduction and rapid treatment in the event of a positive finding. The annual smear test, with both conventional cytology and thin-slice cytology results in a 98% reduction in cervical cancer with mortality (morbidity) approaching zero.
