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 Table of Contents  
ORIGINAL ARTICLE
Year : 2021  |  Volume : 12  |  Issue : 2  |  Page : 91-94

Comparative evaluation of centrifuged liquid-based cytology method over conventional brush cytology in normal oral mucosa


1 Department of Oral Pathology, Karpaga Vinayaga College of Dental Sciences, Maduranthakam, Chennai, India
2 Department of Oral Pathology, SRM Dental College, Chennai, India
3 Department of Oral Pathology, Adhiparasakthi Dental College and Hospital, Melmaruvathur, Tamil Nadu, India
4 Private Practice, Indira's Dental Clinic, Chennai, Tamil Nadu, India

Date of Submission01-Mar-2021
Date of Decision17-Apr-2021
Date of Acceptance17-Apr-2021
Date of Web Publication30-Jun-2021

Correspondence Address:
Dr. Nandhini Gunasekaran
Plot No. 1110, 2nd Main Road, Poombuhar Nagar, Kolathur, Chennai - 600 099, Tamil Nadu
India
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DOI: 10.4103/srmjrds.srmjrds_20_21

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  Abstract 


Introduction: Liquid-based cytology (LBC) is a new monolayer slide preparation method introduced to overcome the limitations of conventional Papanicolaou (PAP) smears which is used in cancer screening. The study was aimed to compare the efficacy of modified technique, centrifuged LBC (CLBC) with that of conventional brush cytology in normal oral mucosa. Materials and Methods: Two smears were obtained from 100 cases of normal mucosa using a cytobrush. One smear was spread on to the slide by conventional technique, and the other smear was prepared by CLBC. Regular PAP staining was done for both the smears. Both the smears were evaluated for cellularity, cell distribution, cellular overlapping, cell elongation, and cellular background and were graded using the grading criteria. Mann–Whitney U-test was used, and P ≤ 0.05 was considered statistically significant. Results: The mean score of the criterias was found to be more desirable in CLBC than conventional technique, but there was no statistical significance found. Conclusions: LBC offers a significant advantage over conventional smear preparation in most of the criteria to advocate its use for routine diagnostic and mass screening procedures.

Keywords: Brush cytology, liquid cytology, mucosa, oral, Papanicolaou


How to cite this article:
Arunachalam M, Gunasekaran N, Rajkumar K, Thayalan DK, Dinakaran J, Bharanidharan R. Comparative evaluation of centrifuged liquid-based cytology method over conventional brush cytology in normal oral mucosa. SRM J Res Dent Sci 2021;12:91-4

How to cite this URL:
Arunachalam M, Gunasekaran N, Rajkumar K, Thayalan DK, Dinakaran J, Bharanidharan R. Comparative evaluation of centrifuged liquid-based cytology method over conventional brush cytology in normal oral mucosa. SRM J Res Dent Sci [serial online] 2021 [cited 2021 Jul 31];12:91-4. Available from: https://www.srmjrds.in/text.asp?2021/12/2/91/319866




  Introduction Top


Exfoliative cytology is an economical and the easiest procedure for the initial evaluation and diagnosis of oral lesions.[1] It is useful in community screening programs, wherein repeated samples might be required.[2] Cytological smear is used in the early detection of premalignant or cancerous oral lesions and also lesions due to viral and fungal diseases.[3],[4]

Liquid-based cytology (LBC) was commenced in the year 1990 and has exhibited remarkable advantages to conventional cytological method. Previous studies have shown that the LBC helps in preparation of quality smears, largely reduces the sampling errors, and also reduction in false-negative results.[5],[6] Red blood cells, inflammatory cells, and mucous are considerably reduced, and the cells are uniformly distributed randomly throughout the slide prepared by LBC. In comparison to conventional cytological smears, liquid-based preparations substantially reduces the number of unsatisfactory slides, thereby declining the false-negative results.[7],[8]

LBC enhances both specificity and sensitivity, and it provides material for additional investigations such as immune cytochemistry, AgNOR staining, human papillomavirus testing, ploidy analysis, or laser scanning cytometry.[9],[10] In most published articles, LBC has shown better interobserver reproducibility.[11]

LBC is usually used for screening of cervical cancer and not oral precancer or cancer. This study was aimed to evaluate the quality of modified centrifuged LBC (CLBC) smears over that of conventional brush cytology smears in normal oral mucosa so that LBC if found superior could be used for early detection of oral lesions.


  Materials and Methods Top


The study was approved by the Ethical committee and Institutional review board of SRM Dental College, SRM Institute of Science and Technology, Chennai. The study sample comprised 100 subjects attending the outpatient department of SRM Dental College, Chennai. The subjects were in the age group of 18–28 years with 50 males and 50 females having no systemic illness or oral lesions. Informed and written consent was obtained from all the individuals included in the study. Smears were acquired from normal buccal mucosa utilizing a cytobrush. Using conventional technique, one smear was prepared by spreading on to the slide and immediately fixed with 95% ethyl alcohol. For CLBC smear, the cytobrush with scraped material was dipped and shaken for 10 min in a suspending solution composed of 20 ml of 95% ethanol, 6 ml acetic acid, and 74 ml normal saline, and then it was spun in centrifuge for 10 min at 2000 rpm. The cell pellet so obtained was re-suspended in 95% alcohol, and the suspension was poured over a horizontally placed glass slide and left for 2 h to allow sedimentation of cells. Both the smears were then stained by routine Papanicolaou stain.

Evaluation of smear quality

The stained slides were evaluated for the quality of the sample in terms of cellularity, cell distribution, cell elongation, cellular overlapping, and cellular background. Using the grading criteria suggested by Alves et al. [Figure 1], individual parameter was graded and scored.[12] The scoring was done blindly by two observers for all the slides [Figure 2], and mean score was achieved for each parameter [Table 1].
Figure 1: Assessment parameter and their respective scores

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Figure 2: Mean score of each parameter

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Table 1: Score of each parameter

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  Results Top


The mean of cellularity is 2.5 for conventional brush cytology and 2.24 for LBC gives the result that cells are more in number in conventional brush cytology than in LBC. Mean of cellular back ground was 1.4 for conventional brush cytology and 1.82 for LBC and cellular distribution was 1.37 for conventional brush cytology and 1.77 for LBC. Although number of cells were less in LBC when compared to conventional cytology, cells in LBC had clear back ground and was more evenly distributed when compared to conventional brush cytology. The mean of cellular overlapping in LBC is 1.57 gives the result that cells have less overlapping and minimal clumping when compared to conventional brush cytology which has a mean of 1.09. The mean of cellular overlapping in LBC was 1.57 indicating that the cells had less overlapping and minimal clumping when compared to conventional brush cytology with a mean of 1.09. The mean of cellular elongation was 1.95 for LBC and 1.63 for conventional brush cytology implying that LBC cells were less morphological altered when compared to that of conventional brush cytology cells [Figure 3]. Mann–Whitney U-test was done to check the significance and overall no statistically significant difference was seen between two techniques (P value >0.05).
Figure 3: Photograph showing comparison between LBC & Conventional Brush Cytology

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  Discussion Top


In cervical cancer screening, LBC has become a revolution over conventional cytological methods by reduction in the problems such as the presence of blood, debris, mucous, and background artifacts.[13],[14],[15] LBC has also greatly reduced the false-negative rates seen in conventional smears.[8],[16] Since automated system requirement is not readily available in many small laboratories for LBC, there is shortage of studies on oral mucosa using LBC. In this study, we aimed to obtain smears by a modified technique, i.e., CLBC using simple and readily available equipment.

When various parameters were compared conventional brush cytology showed significantly high number of cells when compared to LBC in our study. Lower cellularity in CLBC may be due to loss of cells during sample processing. The background was more clear in LBC, when compared to conventional brush cytology. Previous studies have reported that blood, mucin, microbial colonies, debris, and other artifacts were removed by the acetic acid present in the suspending solution and also by cytocentrifugation.[17],[18]

In terms of distribution, LBC cells are more evenly distributed with mild clumping of cells when compared to conventional brush cytology. The reason for the clumping of cells in LBC could be because the cell sediment was allowed to settle slowly onto the slide and which could have resulted in clumps.

In terms of change in morphology, LBC cells showed less cellular elongation when compared to conventional brush cytology showing that a carefully performed centrifugation will not cause any significant distortion in cellular morphology of exfoliated cells and hence will not have any adverse effect on diagnostic efficacy of the smear. Although care should be taken to prevent overzealous centrifugation during separation of debris, as it might change the cellular morphology.[19] In our study, some of the slides exhibited elongation of cells which could be attributed to improper or overzealous centrifugation.

Delavarian et al. evaluated modified LBC using Oral CDx Brush in oral potentially malignant lesions and oral cancer and he concluded that the modified technique was a useful screening tool for detecting oral lesions.[19] This finding is concurrent with our finding that LBC scored better and significant results over the most of the criteria when compared to conventional brush cytology.

Nambiar et al. revealed LBC to have better efficacy over the conventional method, and it is cost effective and smear materials already available in the laboratory setup with limited resources.[20]


  Conclusions Top


To conclude with the results of our study, CLBC offers a pronounced advantage over the conventional smear preparation in most of the parameter to advocate its use for routine diagnostic and mass screening procedures. However, the clean, debris, blood, and microbe-free background achieved by this technique may be useful for advanced procedures such as immune cytochemistry specially in laboratories with limited access to expensive automated systems. Further studies with modifications and improvements may help in making this technique more useful.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Ahmed HG, Idris AM, Ibrahim SO. Study of oral epithelial atypia among Sudanese tobacco users by exfoliative cytology. Anticancer Res 2003;23:1943-9.  Back to cited text no. 1
    
2.
Jullien JA, Downer MC, Speight PM, Zakrzewska JM. Evaluation of health care workers' accuracy in recognising oral cancer and pre-cancer. Int Dent J 1996;46:334-9.  Back to cited text no. 2
    
3.
Mehrotra R, Gupta A, Singh M, Ibrahim R. Application of cytology and molecular biology in diagnosing premalignant or malignant oral lesions. Mol Cancer 2006;5:11.  Back to cited text no. 3
    
4.
Sugerman PB, Savage NW. Exfoliative cytology in clinical oral pathology. Aust Dent J 1996;41:71-4.  Back to cited text no. 4
    
5.
Bishop JW, Bigner SH, Colgan TJ, Husain M, Howell LP, McIntosh KM, et al. Multicenter masked evaluation of AutoCyte PREP thin layers with matched conventional smears. Including initial biopsy results. Acta Cytol 1998;42:189-97.  Back to cited text no. 5
    
6.
Howell LP, Davis RL, Belk TI, Agdigos R, Lowe J. The AutoCyte preparation system for gynecologic cytology. Acta Cytol 1998;42:171-7.  Back to cited text no. 6
    
7.
Linder J, Zahniser D. The ThinPrep Pap test. A review of clinical studies. Acta Cytol 1997;41:30-8.  Back to cited text no. 7
    
8.
Sprenger E, Schwarzmann P, Kirkpatrick M, Fox W, Heinzerling RH, Geyer JW, et al. The false negative rate in cervical cytology. Comparison of monolayers to conventional smears. Acta Cytol 1996;40:81-9.  Back to cited text no. 8
    
9.
Navone R, Burlo P, Pich A, Pentenero M, Broccoletti R, Marsico A, et al. The impact of liquid-based oral cytology on the diagnosis of oral squamous dysplasia and carcinoma. Cytopathology 2007;18:356-60.  Back to cited text no. 9
    
10.
Occhino JA, Smith KL, Dryfhout V. Finding of vaginitis on liquidbased Papanicolaou test compared to wet mount and DNA probe. Obstet Gynecol Surv 2009;64:99-100.  Back to cited text no. 10
    
11.
Piaton E, Hutin K, Faÿnel J, Ranchin MC, Cottier M. Cost efficiency analysis of modern cytocentrifugation methods versus liquid based (Cytyc Thinprep) processing of urinary samples. J Clin Pathol 2004;57:1208-12.  Back to cited text no. 11
    
12.
Alves VA, Bibbo M, Schmitt FC, Milanezi F, Longatto Filho A. Comparison of manual and automated methods of liquid-based cytology. A morphologic study. Acta Cytol 2004;48:187-93.  Back to cited text no. 12
    
13.
Karnon J, Peters J, Platt J, Chilcott J, McGoogan E, Brewer N. Liquid-based cytology in cervical screening: An updated rapid and systematic review and economic analysis. Health Technol Assess 2004;8:i1-78.  Back to cited text no. 13
    
14.
Sass MA. Use of a liquid-based, thin-layer Pap test in a community hospital. Impact on cytology performance and productivity. Acta Cytol 2004;48:17-22.  Back to cited text no. 14
    
15.
Grace A, McBrearty P, Troost S, Thornhill M, Kay E, Leader M. Comparative study: Conventional cervical and ThinPrep Pap tests in a routine clinical setting. Cytopathology 2002;13:200-5.  Back to cited text no. 15
    
16.
Vassilakos P, Cossali D, Albe X, Alonso L, Hohener R, Puget E. Efficacy of monolayer preparations for cervical cytology: Emphasis on suboptimal specimens. Acta Cytol 1996;40:496-500.  Back to cited text no. 16
    
17.
Kahn MA. Oral exfoliative cytology procedures: Conventional, brush biopsy and ThinPrep. J Tenn Dent Assoc 2001;81:17-20.  Back to cited text no. 17
    
18.
Hayama FH, Motta AC, Silva Ade P, Migliari DA. Liquid-based preparations versus conventional cytology: Specimen adequacy and diagnostic agreement in oral lesions. Med Oral Patol Oral Cir Bucal 2005;10:115-22.  Back to cited text no. 18
    
19.
Delavarian Z, Mohtasham N, Mosannen-Mozafari P, Pakfetrat A, Shakeri MT, Ghafoorian-Maddah R. Evaluation of the diagnostic value of a Modified Liquid-Based Cytology using OralCDx Brush in early detection of oral potentially malignant lesions and oral cancer. Med Oral Patol Oral Cir Bucal 2010;15:e671-6.  Back to cited text no. 19
    
20.
Nambiar S, Hegde V, Yadav N, Hallikeri K. Improvization of conventional cytology by centrifuged liquid-based cytology in oral exfoliative cytology specimen. J Cytol 2016;33:115-9.  Back to cited text no. 20
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