Impact of prophylactic bilateral salpingo-oophorectomy in patients with colorectal cancer with peritoneal metastasis during cytoreductive surgery: dual-center cohort analysis.

BACKGROUND: Ovarian metastases are common in patients with colorectal cancer (CRC) with peritoneal metastases. For patients with bilateral macroscopically normal ovaries, prophylactic bilateral salpingo-oophorectomy (BSO) remains controversial. This study assessed the survival benefit of prophylactic BSO during cytoreductive surgery (CRS). METHODS: This retrospective cohort study included patients with CRC with peritoneal metastases who underwent CRS at two medical centres in southern China between 2017 and 2022. Patients achieving complete CRS with bilateral macroscopically normal ovaries were included in the subsequent analysis and divided into BSO and non-BSO groups. The primary outcomes of interest were the rates of synchronous and metachronous ovarian metastases. Clinical and surgical variables, including peritoneal carcinoma index (PCI) scores, were analysed for their correlation with these outcomes. Disease-free survival and overall survival were analysed using the Kaplan-Meier method, and prognostic variables were analysed using multivariate logistic regression. RESULTS: Of 237 consecutive patients who underwent CRS, 94 had macroscopically normal ovaries. Of these, 69 (29.1%) underwent complete CRS and were divided into two groups: 26 who underwent prophylactic BSO and 43 with organ preservation. In the BSO group, 7 patients (26.9%) had occult synchronous ovarian metastases. In the non-BSO group, 13 patients (30.2%) developed metachronous ovarian metastases, with 10 of these patients undergoing secondary surgery for ovarian metastases. Both synchronous and metachronous ovarian metastases were significantly associated with a higher PCI (P = 0.048). Premenopausal status was independently associated with metachronous ovarian metastases (hazard ratio 6.281; 95% confidence interval 1.364 to 28.922; P = 0.018). No significant differences were observed between the BSO and non-BSO groups in 2-year disease-free survival (P = 0.866) or overall survival (P = 0.557). CONCLUSION: For patients with CRC with peritoneal metastasis and bilateral macroscopically normal ovaries, prophylactic BSO does not improve mid-term survival.