Introduction/Background High-grade serous ovarian cancer originates mainly from precursor lesions in the fallopian tube, called ‘Serous Tubal Intraepithelial Carcinoma’ (STIC). A STIC is indicated as ‘isolated’ when occurring without a concurrent carcinoma. In 3% of BRCA mutation carriers, an isolated STIC is found during preventive removal of the fallopian tubes and ovaries. Recently, a isolated STIC lesion in BRCA mutation carriers was associated with a high risk of peritoneal carcinomatosis. Currently, there is no clear management for patients with isolated STIC. This study aims to gain insight in professionals’ opinions and clinical practices regarding diagnosis, counseling, treatment, and follow-up of patients with isolated STIC. A secondary aim is to assess clinical guidelines.

Methodology Four online focus groups with an international panel of gynecologists, pathologists, and medical oncologists (n=49, 12 countries) were organized. A semi-structured interview-guide was used. Two independent researchers analyzed transcripts by open and axial coding. Lastly, all relevant national and international guidelines were screened for recommendations regarding isolated STIC.

Results Most professionals indicated the SEE-FIM protocol (Sectioning and Extensively Examining the FIMbriated end) as standard of care in high-risk patients whereas a wide variation still exists in the examination of tubes in the general population. Revision of STIC diagnosis by a specialized pathologist is recommended. Professionals discussed the potential of morphological criteria to stratify STIC in relation to their risk for peritoneal carcinomatosis. There is discordance in the necessity of additional diagnostics, staging surgery, and follow-up, and data on outcomes is limited. Chemotherapy and PARP inhibitors (poly ADP ribose polymerase) were mostly not recommended. Ten guidelines with recommendations were identified.

Conclusion We found variation and lack of evidence regarding the diagnosis and management of patients with isolated STIC; moreover, clinical guidelines are limited. International collaboration for prospective registration of cases is necessary given the rarity of STIC.

Disclosures None.