Frozen section: Its role in gynaecological oncology

Are blood parameters assessed before taking frozen sections useful in gynecological oncology?

Background/Aim: Inflammatory processes are often implicated in oncology, and inflammatory markers and indices have been much studied in this context. In gynecological surgery, frozen sections have proven valuable in decision-making. Here we aim to identify laboratory parameters that correlate with frozen section results and thus develop new indices in neoplastic decision-making. Methods: In this retrospective cross-sectional study at Bursa Yüksek İhtisas Training and Research Hospital, we evaluated 139 patients diagnosed with adnexal mass and endometrial intraepithelial neoplasia. We divided the patients whose frozen sections were reported as malignant, borderline, or benign into three groups and compared the pre-operative complete blood parameters. Results: The mean age of our patients was 57.3 (11.5) years, and frozen section reports were benign in 33 (23.7%), borderline in 43 (30.9%), and malignant in 63 (45.3%) patients. The mean corpuscular volume and mean platelet volume values ​​were different, and this difference was significant between borderline and malignant groups in post-hoc analyses (P = 0.04 and P = 0.03, respectively). While the percentage of lymphocytes was lower in malignant groups, the percentage of neutrophils was higher (P = 0.01 and P = 0.03, respectively). According to post-hoc analysis, the percentage of neutrophils differs between benign and malignant groups (P = 0.05). The difference in lymphocyte percentage was significant between benign-borderline and benign-malignant groups (P = 0.02, P = 0.05; respectively). The blood neutrophil/lymphocyte ratio was higher in the malignant groups compared to the other two groups (P = 0.02). We used the Multi Linear Regression Analysis method to analyze the factors that play a role in predicting the frozen outcome as malignant. Accordingly, the model with the best performance used lymphocyte percentage, neutrophil/lymphocyte ratio, and Ca-125 parameters (P = 0.03). Conclusion: This study indicates that inflammatory markers may give a clue about the character of the neoplastic mass before oncology surgery. Thus, we can make new contributions to the surgical and clinical approach in the literature by developing new malignancy indices.

A Real-World Study on Diagnosis and Treatment of Uterine Sarcoma in Western China

Uterine sarcomas constitute a rare heterogeneous group of gynecological malignancies with aggressive characteristics and poor prognosis. They have similar clinical features to benign leiomyomata making them difficult to reliably identify prior to hysterectomy. The preoperative prediction of uterine sarcoma remains a clinical dilemma. The current study conducted a multicentre, retrospective study to examine the accuracy of preoperative diagnosis, the consequent influence on therapy, and survival factors in patients with uterine sarcoma in Western China. Four affiliated hospitals of the medical college in Western China over a six-year period. One hundred and fourteen patients diagnosed with low-grade endometrial stromal sarcoma (LG-ESS), high-grade endometrial stromal sarcoma (HG-ESS), undifferentiated uterine sarcoma (UUS), leiomyosarcoma (LMS), or adenosarcoma (AS) were analyzed. The median age at diagnosis was 47 years. Eighty (70.2%) patients were premenopausal and 34 (29.8%) post-menopausal. The most common pathological type was LG-ESS (43.9%). The diagnostic sensitivity of ultrasound for uterine malignant tumors was 11.0%, much lower than MRI (35.3%) and CT (63.0%). Unlike MRI, most of the patients who underwent CT (88.2%) examination were at the advanced stage. Forty-seven (41.2%) patients with uterine sarcoma were diagnosed with uterine malignant tumor before operation. Thirty-two (47.8%) patients who were misdiagnosed before operation needed reoperation and five patients (4.6%) diagnosed after radical surgery developed distant metastasis simultaneously. The recommended treatment of 87.0% of the patients with uterine sarcoma was total hysterectomy and bilateral salpingooophorectomy, and 53.7% of patients received adjuvant chemotherapy after operation. Pelvic lymph node status were clarified in 47 patients (43.5%), which were higher in HG-ESS and UUS groups, and lower in LMS group (P = 0.013). In univariate analysis, we found a significant association between tumour histological types, tumour stage, menstrual status, elevated preoperative neutrophil/lymphocyte ratio and overall survival. In multivariate analysis, we only observed a significant association between tumour histological types and tumour stage and overall survival.

An Evaluation of Frozen Section and Lymph Node Dissection Results for Mucinous Ovarian Tumors

OBJECTIVES

Intraoperative frozen section has greater than 90% accuracy for ovarian tumors; however, mucinous histology has been shown to be associated with increased frozen section inaccuracy. Recent data demonstrate that primary ovarian mucinous carcinomas have no lymph node involvement, even when extraovarian disease is present, and therefore may not require lymph node dissection. Our primary objective is to evaluate the accuracy of identifying mucinous histology on frozen section.

METHODS/MATERIALS

A cross-sectional review of mucinous ovarian tumors in surgical patients at one institution from 2006 to 2016 was performed. Cases reporting a mucinous ovarian tumor on frozen section or final pathology were identified. Frozen section results were compared with final diagnosis to calculate concordance rates. Analyses with χ and t tests were performed to identify variables associated with pathology discordance.

RESULTS

A total of 126 mucinous ovarian tumors were identified. Of these, 106 were reported as mucinous on frozen section and 103 (97.2%) were concordant on final pathology. Discordant cases included 2 serous and 1 clear cell tumor. Among the 103 mucinous tumors, classification as malignant, borderline, or benign was concordant in 74 (71.8%) of 103 cases, whereas 22 (21.4%) of 103 were discordant and 7 (6.8%) were deferred to final pathology. Lymph node dissection was performed in 33 cases; the only case with lymph node metastasis was a gastrointestinal mucinous adenocarcinoma. Discordance between frozen section and final pathology was associated with larger tumor size and diagnosis other than benign: discordant cases had a mean tumor size of 21.7 cm compared with 14.4 cm for concordant cases (P < 0.001), and 93.5% of discordant cases were borderline or malignant, compared with 30.5% of concordant cases (P < 0.001).

CONCLUSIONS

Intraoperative identification of mucinous histology by frozen section is reliable with a concordance rate to final pathology of 97.2%. No lymph node metastases were present in any malignant or borderline primary ovarian cases.

Intraoperative frozen section analysis for the diagnosis of early stage ovarian cancer in suspicious pelvic masses

BACKGROUND

Women with suspected early-stage ovarian cancer need surgical staging which involves taking samples from areas within the abdominal cavity and retroperitoneal lymph nodes in order to inform further treatment. One potential strategy is to surgically stage all women with suspicious ovarian masses, without any histological information during surgery. This avoids incomplete staging, but puts more women at risk of potential surgical over-treatment.A second strategy is to perform a two-stage procedure to remove the pelvic mass and subject it to paraffin sectioning, which involves formal tissue fixing with formalin and paraffin embedding, prior to ultrathin sectioning and multiple site sampling of the tumour. Surgeons may then base further surgical staging on this histology, reducing the rate of over-treatment, but conferring additional surgical and anaesthetic morbidity.A third strategy is to perform a rapid histological analysis on the ovarian mass during surgery, known as 'frozen section'. Tissues are snap frozen to allow fine tissue sections to be cut and basic histochemical staining to be performed. Surgeons can perform or avoid the full surgical staging procedure depending on the results. However, this is a relatively crude test compared to paraffin sections, which take many hours to perform. With frozen section there is therefore a risk of misdiagnosing malignancy and understaging women subsequently found to have a presumed early-stage malignancy (false negative), or overstaging women without a malignancy (false positive). Therefore it is important to evaluate the accuracy and usefulness of adding frozen section to the clinical decision-making process.

OBJECTIVES

To assess the diagnostic test accuracy of frozen section (index test) to diagnose histopathological ovarian cancer in women with suspicious pelvic masses as verified by paraffin section (reference standard).

SEARCH METHODS

We searched MEDLINE (January 1946 to January 2015), EMBASE (January 1980 to January 2015) and relevant Cochrane registers.

SELECTION CRITERIA

Studies that used frozen section for intraoperative diagnosis of ovarian masses suspicious of malignancy, provided there was sufficient data to construct 2 x 2 tables. We excluded articles without an available English translation.

DATA COLLECTION AND ANALYSIS

Authors independently assessed the methodological quality of included studies using the Quality Assessment of Diagnostic Accuracy Studies tool (QUADAS-2) domains: patient selection, index test, reference standard, flow and timing. Data extraction converted 3 x 3 tables of per patient results presented in articles into 2 x 2 tables, for two index test thresholds.

MAIN RESULTS

All studies were retrospective, and the majority reported consecutive sampling of cases. Sensitivity and specificity results were available from 38 studies involving 11,181 participants (3200 with invasive cancer, 1055 with borderline tumours and 6926 with benign tumours, determined by paraffin section as the reference standard). The median prevalence of malignancy was 29% (interquartile range (IQR) 23% to 36%, range 11% to 63%). We assessed test performance using two thresholds for the frozen section test. Firstly, we used a test threshold for frozen sections, defining positive test results as invasive cancer and negative test results as borderline and benign tumours. The average sensitivity was 90.0% (95% confidence interval (CI) 87.6% to 92.0%; with most studies typically reporting range of 71% to 100%), and average specificity was 99.5% (95% CI 99.2% to 99.7%; range 96% to 100%).Similarly, we analysed sensitivity and specificity using a second threshold for frozen section, where both invasive cancer and borderline tumours were considered test positive and benign cases were classified as negative. Average sensitivity was 96.5% (95% CI 95.5% to 97.3%; typical range 83% to 100%), and average specificity was 89.5% (95% CI 86.6% to 91.9%; typical range 58% to 99%).Results were available from the same 38 studies, including the subset of 3953 participants with a frozen section result of either borderline or invasive cancer, based on final diagnosis of malignancy. Studies with small numbers of disease-negative cases (borderline cases) had more variation in estimates of specificity. Average sensitivity was 94.0% (95% CI 92.0% to 95.5%; range 73% to 100%), and average specificity was 95.8% (95% CI 92.4% to 97.8%; typical range 81% to 100%).Our additional analyses showed that, if the frozen section showed a benign or invasive cancer, the final diagnosis would remain the same in, on average, 94% and 99% of cases, respectively.In cases where the frozen section diagnosis was a borderline tumour, on average 21% of the final diagnoses would turn out to be invasive cancer.In three studies, the same pathologist interpreted the index and reference standard tests, potentially causing bias. No studies reported blinding pathologists to index test results when reporting paraffin sections.In heterogeneity analyses, there were no statistically significant differences between studies with pathologists of different levels of expertise.

AUTHORS' CONCLUSIONS

In a hypothetical population of 1000 patients (290 with cancer and 80 with a borderline tumour), if a frozen section positive test result for invasive cancer alone was used to diagnose cancer, on average 261 women would have a correct diagnosis of a cancer, and 706 women would be correctly diagnosed without a cancer. However, 4 women would be incorrectly diagnosed with a cancer (false positive), and 29 with a cancer would be missed (false negative).If a frozen section result of either an invasive cancer or a borderline tumour was used as a positive test to diagnose cancer, on average 280 women would be correctly diagnosed with a cancer and 635 would be correctly diagnosed without. However, 75 women would be incorrectly diagnosed with a cancer and 10 women with a cancer would be missed.The largest discordance is within the reporting of frozen section borderline tumours. Investigation into factors leading to discordance within centres and standardisation of criteria for reporting borderline tumours may help improve accuracy. Some centres may choose to perform surgical staging in women with frozen section diagnosis of a borderline ovarian tumour to reduce the number of false positives. In their interpretation of this review, readers should evaluate results from studies most typical of their population of patients.