The accuracy of intraoperative subareolar frozen section in nipple-sparing mastectomies.

BACKGROUND: Intraoperative subareolar frozen sections are used to assess the nipple areolar complex's suitability for preservation for patients selected for nipple-sparing mastectomy. We aim to investigate the accuracy and value of the frozen section compared to formal histopathologic results.
METHODS: In our 5-year retrospective study, 52 candidates for nipple-sparing mastectomies had subareolar frozen sections analyzed intraoperatively for malignant or atypical duct changes. Women were considered for nipple-sparing mastectomy if their primary breast malignancy was greater than 3 cm from the nipple-areolar complex and not multifocal in nature. Frozen-section results were compared to the formal histopathologic results, allowing analysis of the sensitivity, specificity, and predictive value. Causes of false negatives (negative frozen-section findings, positive histopathology findings) were then examined.
RESULTS: Of 52 frozen sections, 47 (90%) yielded negative results and 5 (10%) yielded positive results. Of the 47 negative results, 39 were true negatives while 8 were false negatives. Of the 5 positive results, all were true positives with no false positives. Therefore, the positive predictive value of subareolar frozen section is 100%, negative predictive value 83%, sensitivity 38%, and specificity 100%. Of the 8 false negatives, 4 (50%) were due to sampling errors, 3 (37.5%) were due to interpretation errors, and 1 (12.5%) was due to diathermy artifact.
CONCLUSION: Intraoperative subareolar frozen section is a specific but nonsensitive test. It is useful in nipple-sparing mastectomy because in 10% of cases a positive result allows immediate nipple and areolar excision. Its low sensitivity and negative predictive value means that 15% of patients will need a subsequent nipple and areolar excision. Eighty-five percent of patients can, however, have a single-stage excision.