Early diagnosis of peritoneal carcinoma based on a subtle rise in serum CA125 level within the normal range in a BRCA2 mutation carrier with serous tubal intraepithelial carcinoma discovered after risk-reducing salpingo-oophorectomy: A case report and literature review

Objectives To illustrate the potential benefit of surveillance strategies for early primary peritoneal cancer (PPC) detection in BRCA2 mutation carriers with serous tubal intraepithelial carcinoma (STIC) identified at risk-reducing salpingo-oophorectomy (RRSO). Case report A 74-year-old BRCA2 mutation carrier underwent at 71 years of old, with incidental STIC. She was monitored with CA125 and imaging. At 34 months postoperatively, a subtle but progressive CA125 increase, still within normal limits, led to further evaluation. Imaging and laparoscopy confirmed PPC. She received optimal cytoreductive surgery, chemotherapy, and maintenance olaparib, remaining disease-free at 20 months. Additionally, a literature review revealed a moderate negative correlation between age at RRSO and the interval from RRSO to PPC diagnosis (r = −0.481), although this was not statistically significant (p = 0.082). Conclusion This case underscores the utility of combining CA125 and imaging for early PPC detection in STIC-positive BRCA2 carriers, particularly in older patients. Olaparib may also offer therapeutic benefit.