[Frozen section in oncologic endocrine surgery].

Background: The aim of the present study is to discuss the benefits of intraoperative frozen sections (FS) for the surgical management of endocrine tumors.

Methods: A systematic search of the literature of the last ten years on FS in the field of oncologic endocrine surgery was carried out and a discussion based on the available evidence and experience of the authors is provided.

Results: A group of publications focused on the role of intraoperative FS in thyroid surgery in identifying the malignant potential of thyroid nodules. The detection of lymph node metastasis and extrathyroidal growth in differentiated thyroid cancer (DTC) were also two other topical groups as well as the diagnosis of lymph node involvement based on stromal desmoplasia in medullary thyroid cancer (MTC). A further group investigated the possibilities of deep learning to overcome technical problems and another investigated the cost-benefit analyses. There is no relevant literature on the role of FS in the surgical treatment of parathyroid and adrenal cancers.

Discussion: The synthesis of the available evidence suggests that FS investigations of the thyroid glands should be restricted to Bethesda V nodules. The technical limitations in the exclusion of vascular and capsular invasion make the FS unsuitable for follicular neoplasms and oncocytic lesions. The Delphi lymph node seems to be suitable for investigation using FS and when positive represents an indication for lymphadenectomy in cN0 patients. Larger studies are necessary in the future to confirm if the absence of desmoplasia with an intact tumor capsule can reliably justify omitting lymph node resection in MTC, independent of the calcitonin level. The costs and benefits depend on the individual context so that generalization is difficult. Deep learning models could generally improve the performance of FS analysis in the future.

Conclusion: In thyroid surgery awareness of the technical limitations of FS is crucial for correct implementation and thus to optimize its performance. A preoperative fine needle biopsy and surgical experience help in selecting the nodules that can benefit from FS. Deep image learning could help to overcome current problems in the future. In adrenal and parathyroid oncologic surgery FS do not play a relevant role.