Abstract
Introduction: We investigated the risk factors for ovarian metastasis of colorectal cancer and examined the significance of prophylactic oophorectomy. Materials and Methods: 552 women who had undergone a surgical resection for colorectal cancer within the past twenty years were studied. The characteristics of ovarian metastasis and reasons for oophorectomy were examined. Risk factors for ovarian metastasis were identified by multivariate analysis, and the prognosis was investigated.Results: Ovarian metastasis, including recurrence, was found in 26 cases (4.7%). Metastasis was observed in 14 of 38 cases (36.8%) showing morphological abnormalities of the ovary. Metastasis was found in case (8.3%) in which an ovary showing no abnormal morphology was resected because the contralateral ovary showed suspected metastatic findings. A multivariate analysis using a logistic regression method identified the following risk factors as being significantly associated with ovarian metastasis of colorectal cancer: age (p<0.0001), morphological abnormalities of the ovary (p=0.0164), depth of tumor invasion (se, a2, si, ai;p=0.0366), and peritoneal metastasis (p= 0.0004). The odds ratio was 0.9063 for age, 4.5499 for morphological abnormalities of the ovary, 3.1641 for depth of tumor invasion, and 8.1080 for peritoneal metastasis. The 5-year survival rate of all cases with ovarian metastasis was 29.1%. The 5-year survival rate of cases with metastasis to the ovary only was 67.5%. None of the patients who had distant metastasis to sites other than the ovary survived for 5 years, and a mainly palliative approach is recommended for these cases.Conclusion: The present results suggest that a prophylactic oophorectomy is of little significance in patients who do not have distant metastasis or morphological abnormalities of the ovary at the time of the primary resection, because of the low risk of ovarian metastasis.
