An analysis of ovarian tumor diameter and survival

Residual disease following primary debulking surgery is a recognized prognostic factor in ovarian cancer. Few studies have looked at the effect of initial ovarian tumor diameter on survival. As larger tumors are more likely to be detected by ultrasound, this information may be important in determining a survival benefit in screen-detected cancers. We reviewed the case notes and pathology of 168 consecutive cases of primary debulking surgery in epithelial ovarian cancer. We examined the influence of ovarian tumor diameter on survival and its relationship to CA125 levels and stage. For the purposes of analyses, we divided subjects into two groups: those with tumors < 6 cm and those with tumors > 6 cm. There were significant differences between the groups, with smaller tumors having more advanced stage disease compared to larger tumors (chi23 = 15.7, P = 0.0013) The median survival for tumors less than or equal to 6 cm was 17months (95% confidence interval [95% CI], 12 to 22), while for tumors greater than 6cm, the median survival was 36 months (95% CI, 13 to 59; logrank test = 8.61, P = 0.003). However, stage is also an important predictor of survival, and in a multivariate analysis, tumor size was not found to be an independent prognostic factor. There was no significant difference between the groups for CA125 levels. As larger diameter ovaries are more likely to be detected by ultrasound, it may be that screen-detected ovarian cancers will show a survival benefit simply because they detect a subset of ovarian cancers that are associated with a better prognosis.