Correspondence: re - Intra-operative frozen section analysis for suspected early-stage ovarian cancer - Twigg - 2012 - BJOG: An International Journal of Obstetrics & Gynaecology - Wiley Online Library

Intra-operative frozen section analysis for suspected early-stage ovarian cancer - Twigg - 2012 - BJOG: An International Journal of Obstetrics & Gynaecology

Correspondence

Volume 119, Issue 7, page 896, June 2012

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Sir,

We read with interest the article by Cross et al.¹ on the use of intra-operative frozen section for suspected early ovarian cancer. We would like to commend the authors for their work in providing these data and we recognise the need for mechanisms that can be used to address the National Institute for Health and Clinical Excellence (NICE) Guidelines CG122, which recommend assessment of the para-aortic lymph nodes in women with early ovarian cancer.²

However, there are a number of areas of practice that we feel need to be examined further before frozen section procedures can be used to alter the management of women with suspected early-stage ovarian cancer.

First, we are perplexed that the authors deemed it necessary to undertake para-aortic lymphadenectomy for women with borderline ovarian tumours. These are by nature an unpredictable class of tumour with mostly good outcomes and little in the way of nonsurgical treatment options when there is disseminated disease. Further, they are usually early-stage tumours and so the utility of a para-aortic lymph node dissection is questionable. If the authors had described the rate of disease in lymph nodes and the difference in outcome this provided for the woman with positive nodes their data would lend stronger support for more widespread implementation.

Accepting this and examining the authors data for ‘all comers’ (Table 1) we calculate that 28.8% (415) of women had an appropriate para-aortic lymph node dissection on the basis of the frozen section prediction, which represents the real-world scenario for the gynaecological oncology surgeon waiting in theatre for a frozen section analysis to be phoned back.

If the authors changed their protocol to only using dissection in women with malignancy on frozen section, 63.8% (918) of women would appropriately not undergo a para-aortic dissection. The total number of women correctly triaged by frozen section analysis would be 92.6%. Of the remainder, 7% would not undergo a para-aortic dissection that should and 0.35% would have a dissection they do not need. Such a protocol change compares with the authors’ figures who, when including a policy of para-aortic dissection for borderline tumours on frozen section, overtreated 8% of the women and undertreated 1.3%.

The answer to deciding which strategy one would wish to take up must come down to the differences in outcome for these women, defined by morbidity and mortality comparisons from overtreatment or undertreatment by surgery or chemotherapy, respectively, and any subsequent influence this has on overall survival. Unfortunately the authors do not provide this information, and only allude to data in preparation that indicate their ability to increase the stage of a woman’s disease. However, this figure can be calculated from their data in Table 1 to equate to 82 women (5.7%) who had a frozen section showing borderline disease but whose final paraffin section report showed a malignancy. Until other centres can validate their techniques and such practice can be shown to translate into a survival benefit for women, it is unlikely that their data will change surgical practice in women with early ovarian cancer.

References

• 1
  Cross P, Naik R, Patel A, Nayar A, Hemming J, Williamson S, et al. Intra-operative frozen section analysis for suspected early-stage ovarian cancer: 11 years of Gateshead Cancer Centre experience. BJOG 2012;119:194–201.
  

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• 2
  National Institute for Health and Clinical Excellence. The recognition and initial management of ovarian cancer. [http://www.nice.org.uk/CG122]. Accessed 20 January 2012. 
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abstract: A Systematic Review of Papers Examining the Use of Intraoperative Frozen Section in Predicting the Final Diagnosis of Ovarian Lesions Intl Jnl Gyn Pathology (clear cell, mucinous, borderline, invasive...)

Abstract

"This systematic review assesses the accuracy of the frozen section classification of benign and borderline lesions or invasive carcinoma when compared with the final diagnosis on paraffin section. A Pubmed database search identified 18 retrospective cohort studies, published since 2005 that satisfied the criteria, on the critical appraisal sheet of the center for evidence-based medicine, The University of Oxford.

The sensitivity, specificity, and negative and positive predictive values suggest that frozen section is more accurate at discriminating between benign lesions and invasive carcinoma than between benign and borderline or borderline lesions and invasive carcinoma and indicate a tendency to overcall benign tumors as borderline and borderline tumors as invasive malignancies.
A narrative review of individual papers and abstracts suggests that this particular difficulty is encountered when dealing with clear cell carcinoma and mucinous lesions of all sorts.
This may have greater importance in the future with the introduction of targeted chemotherapy requiring accurate typing to guide the use of genetic analysis. It would be beneficial if future researchers comparing the results of frozen section and paraffin sections presented their results in the context of preoperative assessment of the clinical and radiological findings or the intraoperative appearances of the tumor and abdominal cavity, which would allow the identification of those cases in which the frozen section allowed a refinement of the diagnoses made using these modalities."