Advent of liquid based preparations in India

Varsha Manucha

doi:10.4103/0970-9371.40659

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LETTER TO THE EDITOR

Year : 2008 | Volume : 25 | Issue : 1 | Page : 37-38

Advent of liquid based preparations in India

Varsha Manucha
Sir Ganga Ram Hospital, Rajinder Nagar, New Delhi 110060, India

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How to cite this article:
Manucha V. Advent of liquid based preparations in India. J Cytol 2008;25:37-8

How to cite this URL:
Manucha V. Advent of liquid based preparations in India. J Cytol [serial online] 2008 [cited 2023 Mar 23];25:37-8. Available from: https://www.jcytol.org/text.asp?2008/25/1/37/40659

To the Editor,

This is in reference to the article titled "Conventional Pap smear ^{More Details} and liquid-based cytology for cervical cancer screening: A comparative study," published in the last issue of the journal.^[1] It is extremely encouraging to note that liquid-based preparations (LBPs) are finally making an entry in India and arousing interest in pathologists.

LBPs were originally developed to minimize cell overlap so that automated screeners would perform better in the identification of abnormal cells. However, these preparations performed so well in clinical trials that they have almost replaced the use of conventional cervicovaginal smears in the developed world. ThinPrep™ (Cytyc Corporation, Boxborough, MA, USA) and SurePrep™ (TriPath imaging, Burlington, NC, USA) are the two approved liquid based methods that are used for the preparation of such smears. Both improve the quality of the cervical/endocervical sample through improved slide preparation. This is achieved by rinsing the collection device(s) in a preservative fluid to generate a suspension of cells that is processed to deposit a monolayer of cells on a microscope slide. The authors in this article have described the Cytospin preparation method in which they made direct smears (? conventional or ? monolayer) from the cell button that was prepared from the sample left after making the conventional smears. This does not conform to the original and the recommended LBP methods. ThinPrep™ makes a circle of 20 mm and SurePrep™ makes a circle of 13 mm in diameter in contrast to Cytospin, which makes a 6 mm circle.

The usefulness of LBP in a cervico-vaginal study has already been widely published. It has shown an increased percentage of specimens reported as "satisfactory", improved rate of detecting low-grade squamous intraepithelial lesions (LSILs) and high-grade squamous intraepithelial lesions (HSILs) over conventional Pap smears and a decrease in the reporting rate of atypical squamous cell of indeterminate significance (ASCUS).^[2],[3],[4] However, LBP has been found to be comparable but not superior than conventional Pap smears in diagnosing adenocarcinomas or other glandular lesions. Khalbuss et al. [5] found that Cytospin cervical cytology slides correlated very well with the corresponding conventional smears within major diagnostic categories. However, there is no published study yet that compares the Cytospin method with the ThinPrep™/SurePrep™ in gynecological cytology.

LBP is now also being increasingly used for a variety of other nongynecological cytology specimens such as body fluids, mucoid specimens, and even fine needle aspirates. The slides are easier and less time-consuming to screen and interpret because the cells are limited to smaller areas on clear backgrounds with excellent cellular presentation. Elsheikh et al. [6] compared ThinPrep™ with conventional Cytospins in nongynecological specimens. ThinPrep™ was preferred over Cytospin in the majority of cases by both cytotechnologists and pathologists. Cellularity, screening time, and specimen preparation were comparable although the latter was easier to standardize in ThinPrep™. In abnormal cases, ThinPrep™ was found to be three times more helpful than Cytospin in rendering a definitive diagnosis of malignancy. ThinPrep™ was finally found to be more cost-effective than Cytospin. PreservCyt collection medium used for ThinPrep Paps as a specimen collection medium has been approved to perform the Hybrid Capture 2 (HC2) human papilloma virus DNA assay.

The conventional Pap smear is one of the greatest success stories in medicine and has saved many lives. It continues to perform well, particularly when the most preventable causes of suboptimal smear preparation are addressed. On the other hand, liquid-based Pap smears demonstrate distinct advantages in slide quality and adjunctive HPV testing. Although the Cytospin method is being used for nongynecological specimens, its utility in examination of cervicovaginal smears is not yet established.

References

1.	Sherwani RK, Khan T, Akhtar K. Conventional Pap smear and liquid based cytology for cervical cancer screening: a comparative study. Journal of Cytology 2007;24:167-72.
2.	Lee KR, Ashfaq R, Birdsong GG, Corkill ME, McIntosh KM, Inhorn SL. Comparison of conventional Papanicolaou smears and a fluid -based, thin layer system for cervical screening. Obstet Gynecol 1997;90:278-87. [PUBMED] [FULLTEXT]
3.	Bernstein SJ, Sanchez-Ramos L, Ndubisi B. Liquid-based cervical cytologic smear study and conventional Papanicolaou smears: a meta-analysis of prospective studies comparing cytologic diagnosis and sample adequacy. Am J Obstet Gynecol 2001;185:305-17.
4.	Abulafia O, Pezzullo JC, Sherer DM. Performance of ThinPrep liquid-based cervical cytology in comparison with conventionally prepared Papanicolaou smears: a quantitative survey. Gynecol Oncol 2003;90:137-44. [PUBMED] [FULLTEXT]
5.	Khalbuss WE, Rudomina D, Kauff ND, Chuang L, Melamed MR. Spin Thin, a simple, inexpensive technique for preparation of thin-layer cervical cytology from liquid based specimens: data on 791 cases. Cancer 2000;90:135-42. [PUBMED] [FULLTEXT]
6.	Elsheikh TM, Kirkpatrick JL, Wu HW. Comparison of ThinPrep and cytospin preparations in the evaluation of exfoliative cytology specimens. Cancer Cytopathol 2006;108:144-9.