Value of frozen section to tailor surgical staging in apparent early-stage epithelial ovarian cancer.

OBJECTIVE

Frozen section (FS) has been shown to have high accuracy in determining ovarian malignancy. However, its utility in guiding surgical approaches, particularly, lymph node staging, for early-stage epithelial ovarian cancer remains unclear. This study aimed to evaluate the post-test positive probability of FSs in identifying cases requiring lymph node or peritoneal staging. The secondary aims were sensitivity, specificity, and accuracy assessments.

METHODS

This retrospective study analyzed patients undergoing surgery for early-stage epithelial ovarian cancer with FS performed on ovarian masses between July 2007 and March 2023 at a tertiary center. The FS results were compared with the final histology (gold standard paraffin sections). The FS cases were categorized based on further actions as follows: lymph node staging (type A), peritoneal staging only (type B), or no additional procedures (type C). The patients were divided into group 1 (requiring lymph node and peritoneal staging) and group 2 (requiring only peritoneal staging). A comparison between specialized and general pathology diagnoses was also performed. Incorrect FS assessments were classified as under-diagnosed or over-diagnosed.

RESULTS

Of the 715 patients, group 1 had appropriate staging in 425 of 447 cases, with 4.9% over-treatment. In group 2, staging was correct in 109 of 195 cases, with 44.1% under-treatment. For type A FSs, the post-test positive probability was 95% (95% CI 93% to 97%), with sensitivity, specificity, and accuracy rates of 76.4%, 86.1%, and 78.6%, respectively. For type B FSs, the post-test positive probability was 56% (95% CI 50% to 61%), with sensitivity, specificity, and accuracy rates of 68.6%, 84.5%, and 81%, respectively. There was no significant difference in the agreement between the specialized and general pathology groups (p = 0.92).

CONCLUSIONS

Frozen sections suggestive of a cancer diagnosis requiring peritoneal and lymph node staging in a population with apparent early-stage epithelial ovarian cancer are highly reliable. In the case of FSs suggesting only peritoneal staging, malignancy is frequently underestimated.