Objective
To investigate the underestimation of atypical hyperplasia by frozen section biopsy for breast lesions and explore its influencing factors.
Methods
The data of 279 patients with atypical hyperplasia diagnosed by intraoperative frozen section biopsy in Guangdong Women and Children's Hospital,Guangzhou Medical University from January 2013 to March 2016 were analyzed retrospectively. All the specimens were examined by frozen section biopsy, and the remaining tissues were examined by routine paraffin sections. The pathological findings were compared between the frozen sections and the paraffin sections. The effect of clinicopathological characteristics on the diagnosis of atypical hyperplasia were analyzed. The composition ratio among groups was compared using χ2 test or Fisher exact probability method, and the Logistic regression model was used to analyze the influencing factors.
Results
According to the degree of certainty in frozen section diagnosis by pathologists, 211 cases of atypical hyperplasia (definite group) were definitely identified out of 279 patients, including 200 benign and 11 malignant confirmed by paraffin sections;68 cases of atypical hyperplasia were not definitely diagnosed in frozen section biopsy (indefinite group), including 33 benign and 38 malignant confirmed by paraffin sections. The consistent rate of atypical hyperplasia between frozen section and paraffin section diagnosis was 71.7%(200/279) and the underestimation rate was 3.9%(11/279). The diagnostic results of atypical hyperplasia showed statistically significant differences among patients with different age, lesion size, grade by breast MRI, ultrasonography or mammography (χ2=33.319,47.241,16.955,12.528,13.605, P＜0.050). Logistic regression analysis showed that age was the main factor causing underestimation of atypical hyperplasia by frozen sections biopsy (OR=0.052,95%CI=0.005-0.525,P=0.012). In the 211 patients with definite diagnosis of atypical hyperplasia, the results of paraffin section examination were significantly different among patients with different age, lesion size and grade by breast ultrasonography (χ2=14.395,19.851,7.952, P＜0.050); and Logistic regression analysis also showed that the age, lesion size and grade by breast ultrasonography were all influencing factors(OR=41.348,3.098,0.148;95%CI=3.807-449.106,1.010-9.507,0.032-0.685;P=0.002,0.048,0.015). In the 68 patients with indefinite diagnosis of atypical hyperplasia, the results of paraffin examination were significantly different among patients with different lesion size and grade by breast MRI (χ2 =6.136,5.965,both P＜0.050), but Logistic regression analysis showed that lesion size and breast MRI were not influencing factors (OR=2.094,1.547;95%CI=0.898-4.885, 0.325-7.353;P=0.087, 0.583). There were no significant differences in the consistent rate and underestimation rate in the diagnosis of atypical hyperplasia by pathologists with different years of service [≥10 years vs ＜10 years: 83.0%(191/230) vs 89.8%(44/49),χ2 =0.000,P=1.000;3.9%(9/230) vs 4.1%(2/49),χ2 =1.387,P=0.239].
Conclusion
Breast frozen section biopsy in the diagnosis of atypical hyperplasia has the risk of underestimation, and the doctors should take the patient's age,lesion size and imaging findings into consideration.