Extremely poor postrecurrence oncological outcome for patients with recurrent mucinous ovarian cancer

Background This study was conducted to assess the long-term clinical outcome for patients with recurrent mucinous epithelial ovarian cancer (RmOC) in comparison with recurrent serous epithelial ovarian cancer (RsOC). Methods Three hundred and eighty-four patients with recurrent ovarian cancer, including 340 RsOC and 44 RmOC patients, were analyzed in this study. The pathological slides were evaluated under central pathological review. The prognostic significance of clinicopathological factors was evaluated employing both uni- and multivariable analysis. Results The 3- and 5-year postrecurrence survival (PRS) rates of patients with RmOC were 17.3, and 6.9 %, respectively. In contrast, those of patients with RsOC were 29.8 and 18.8 %, respectively. The PRS of patients with RmOC was significantly poorer than that of patients with RsOC (PRS: P = 0.0006). Moreover, either in the presence or absence of a residual tumor (RT) at initial surgery, the PRS of patients with RmOC was markedly poorer than that of patients with RsOC [RT (-): P < 0.0001: RT (+): P = 0.0912]. In multivariable analysis, a mucinous histology predicted a significantly poorer PRS (RmOC vs. RsOC: hazard ratio (HR) 2.080, 95 % confidence interval (CI) 1.434-3.016, P = 0.0001). Confining analysis to deceased patients (N = 302), the proportion of RmOC patients who died within 12 months following recurrence was markedly higher than that of RsOC [RmOC 69.2 %, RsOC: 41.1 % (P < 0.0001)]. Conclusions The clinical outcome after recurrence in patients with RmOC was extremely poor. This confirms that RmOC should be considered a different entity from other epithelial ovarian cancers.