Canadian Management of Serous Tubal Intraepithelial Carcinoma

OBJECTIVE: To assess the management and outcomes of patients diagnosed with an isolated serous tubal intraepithelial carcinoma lesion across Canada. METHODS: This retrospective study included consecutive patients with an isolated serous tubal intraepithelial carcinoma lesion diagnosed between 2006 and 2020 at 15 Canadian centers. Cases underwent multicenter panel pathology review. RESULTS: Of 107 patients, 41 serous tubal intraepithelial carcinoma cases (38.3%) were identified at prophylactic surgery for germline pathogenic variants, 36 (33.6%) at surgery for suspicion of malignancy, and 30 (28.0%) at surgery for benign conditions. Treatment groups included observation (n=62, 57.9%), staging surgery (n=35, 32.7%), and adjuvant chemotherapy (n=10, 9.3%). Median follow-up was 55.5 months (interquartile range 30.26-82.07 months). Overall, nine patients developed high-grade serous carcinoma. The cumulative incidence of high-grade serous carcinoma was not significantly different between treatment groups ( P =.181); however, no patient treated with chemotherapy developed high-grade serous carcinoma. The cumulative incidence of high-grade serous carcinoma was 1.1% (95% CI, 0.1-5.3%) at 2 years and 5.7% (95% CI, 1.8-13.1%) at 5 years. No significant predictive factors were found on univariate analysis. After multicenter pathology review of 59 cases (55.1%), consensus diagnosis was reached: 45 (76.3%) with serous tubal intraepithelial carcinoma, three (5.1%) with serous tubal intraepithelial lesion, seven (11.9%) with high-grade serous carcinoma, and two (3.4%) with normal tissue. Of the cases reviewed, only 1 of 45 patients (2.2%) with confirmed serous tubal intraepithelial carcinoma developed high-grade serous carcinoma at 73 months, indicating a 5-year cumulative incidence of cancer of 2.6% (95% CI, 0.2-11.7). CONCLUSION: Management of serous tubal intraepithelial carcinoma varied across centers. The 5-year cumulative incidence of high-grade serous carcinoma after isolated serous tubal intraepithelial carcinoma was 5.7%, consistent with recent literature. However, multicenter pathology review revealed initial underdiagnosed high-grade serous carcinoma, and 5-year cumulative incidence of high-grade serous carcinoma after confirmed serous tubal intraepithelial carcinoma decreased to 2.6%, underscoring the importance of diagnostic confirmation by expert pathologists to guide accurate management.