Comparison between two cell collecting methods for liquid-based brush biopsies: a consecutive and retrospective study

Abstract

Background: This study compares two different cell collectors, the Orcellex Brush (rigid brush) and the Cytobrush GT (nylon brush), using liquid-based cytology. A comparison of their obtainment procedures was also considered. The aim was to determine the diagnostic accuracy for detection of malignancy in oral brush biopsies. PICO-Statement: In this consecutive and retrospective study we had as population of interests, patients with oral lesions, the intervention was the brush biopsy with two different cell collectors and the control was healthy oral mucosa. The outcome of the study was to compare both cell collectors.

Methods: From 2009 to 2018, 2018 patients with oral lesions were studied using the nylon brush (666 cases) and rigid brush (1352 cases). In the first cohort five smears per patient were taken with the nylon brush, while each patient received one smear with the rigid brush in the second cohort. These were further processed in a liquid-based procedure. Cytological evaluations were categorised into 'negative', which were considered as negative, whereas 'doubtful', 'suspicious' and 'positive' cytological results were overall considered as positive for malignancy in comparison to the final histological diagnoses. Additionally, the clinical expenditure for each collector was estimated.

Results: 2018 clinically and histologically proven diagnoses were established, including 181 cases of squamous cell carcinomas, 524 lichen, 454 leukoplakias, 34 erythroplakias and 825 other benign lesions. The sensitivity and specificity of the nylon brush was 93.8% (95% CI 91.6-95.5%) and 94.2% (95% CI 91.8-95.5%) respectively, whereas it was 95.6% (95% CI 94.4-96.6%) and 84.9% (95% CI 83.8-87.5%) for the rigid brush. The temporal advantage using the plastic brushes was 4× higher in comparison to the nylon brush. The risk suffering from a malignant oral lesion when the result of the brushes was positive, suspicious, or doubtful was significantly high for both tests (nylon brush OR: 246.3; rigid brush OR: 121.5).

Conclusions: Both systems have a similar sensitivity, although only the rigid brush achieved a satisfactory specificity. Additional methods, such as DNA image cytometry, should also be considered to improve the specificity. Furthermore, the rigid brush proved to be more effective at taking a sufficient number of cells, whilst also being quicker and presenting less stress for the patient.

Keywords: Brush biopsy; Liquid-based cytology; Oral cancer; Squamous cell carcinoma.

Fig. 1

Exemplary presentation of a nylon-based cell collector in front of a plaquelike oral lichen

Fig. 2

Plastic-based cell collector in front of an oral lichen

Fig. 3

a SurePath™, staining Papanicolaou, lens 10x. Clinically: Follow-up of oral lichen planus. Cell-rich thin-layer preparation, mature squamous epithelia, individual nucleus less keratinized plaques, with tendency to hypereosinophilia, partly also amphophilia of the cytoplasm, individual hydrophilic swollen nuclei. Diagnosis: Malignant cells not present. b SurePath™, staining Papanicolaou, lens 40×. Clinically: Follow-up of oral lichen planus. Central a cell with partly eosinophilic, partly basophilic cytoplasm (amphophilia), nuclei of the two basophilic cells below are slightly enlarged with coarse chromatin as an expression of degenerative changes. Diagnosis: Malignant cells not present

Fig. 4

a SurePath™, staining Papanicolaou, lens 10x. Clinically: Whitish mucosal lesions on the tongue surface, suspicion of candida. Moderately cell-rich thin-layer preparation, mature squamous epithelia, numerous nucleusless keratinized plaques, clear background, no suspicious nuclear lesions, no signs of fungi. Diagnosis: Malignant cells not present. The increased tendency to keratinisation mainly indicates a leukoplakia. There are no signs of candidiasis. b SurePath™, staining Papanicolaou, lens 40x. Clinically: Whitish mucosal lesions on the tongue surface, suspicion of candida. At high zoom mainly cell-free keratinized plaques, visible nuclei are small, plain and unsuspicious. Diagnosis: Malignant cells not present. The increased tendency to keratinisation mainly indicates a leukoplakia. There are no signs of candidiasis

Fig. 5

SurePath™, staining Papanicolaou, lens 40×. Clinical: an ulcerative lesion of the lateral border of the tongue. Immaturity, high nuclear/cytoplasmic ratio and anisonucleosis can be suspected in this magnification. The nuclei are haphazardly orientated, the axis of different nuclei is not parallel. Many nuclei show prominent nucleoli and/ or irregularities of the borders. Chromatin frequently is irregularly deposited with early condensation along the nuclear membrane. These changes may represent so called atypical tissue repair. The differential is high grade SIL or invasive SCC. The background may represent the ulcer or tumor diathesis. Diagnosis: Suspicious for malignant cells. We would try to confirm the suspicion with DNA-karyometry. A scalpel biopsy is strictly advised for further analysis

Fig. 6

a SurePath™, staining Papanicolaou, lens 10x. Clinical: erosion of oral mucosa (mandible), condition after extraction 3 years ago, 1–2 packs of cigarettes daily. Cell-rich thin-layer preparation, mature squamous epithelia, some nucleusless keratinized plaques, plenty of fibrin and lysed blood in the background, individual squamous epithelia with shifted nucleus-plasma ratio and arranged in differently sized, partly two-, mostly three-dimensional clusters. Diagnosis: Malignant cells present. The cell picture corresponds to a keratinising squamous cell carcinoma. b SurePath™, staining Papanicolaou, lens 40x. Clinical: erosion of oral mucosa (mandible), condition after extraction 3 years ago, 1–2 packs of cigarettes daily. Fibrillary material in the background (tumor diathesis), small group of tumor cells with large, mostly deformed nuclei and some recognizable macronucleoli. Diagnosis: Malignant cells present. The cell picture corresponds to a keratinising squamous cell carcinoma