Multidrug resistance gene (MDR-1) and risk of brain metastasis in epithelial ovarian, fallopian tube, and peritoneal cancer.

BACKGROUND

To evaluate risk factors that predict brain metastasis in epithelial ovarian, fallopian tube, and peritoneal cancer.

METHODS

All patients with FIGO stage I to IV who underwent initial cytoreductive surgery between January 1995 and January 2009 were evaluated. The tumor samples were evaluated for 7 markers including multidrug resistance gene (MDR-1), DNA aneuploidity and S-phase fraction, human epidermal growth factor receptor 2, estrogen receptor, progesterone receptor, p53 mutation, epidermal growth factor receptor, and CD31. Biomarker expression was evaluated as a predictor of hematogenous metastasis to the following locations: (i) liver and spleen, (ii) lung, and (iii) brain.

RESULTS

There were 309 cases identified during the period. Of those, 5 (1.6%, 95% CI: 0.2%-3.0%) women developed brain metastasis. Time to onset of brain metastasis was significantly longer than that for other recurrent sites (median time to recurrence after initial cytoreduction, brain vs. lung vs. liver, 21.4 vs. 12.6 vs. 11.0 months, P< 0.05). Significantly increased expression of MDR-1 was seen in tumors from women who developed brain metastasis (brain vs. nonbrain sites, 80% vs. 4.2%-24.3%, P= 0.004). In multivariate analysis, MDR-1 was the only significant variable associated with the risk of brain metastasis. MDR-1 expression predicted brain metastasis (receiver-operator-characteristic curve analysis, AUC 0.808, P= 0.018), and with a 10% positive expression of MDR-1 as the cutoff value, sensitivity, specificity, positive predictive value, negative predictive value, accuracy of prediction of brain metastasis were 80%, 86.1%, 15.4%, 99.3%, and 85.9%, respectively (odds ratio: 24.7, 95% CI: 2.64-232, P= 0.002).

CONCLUSIONS

Increased expression of MDR-1 in the tumor tissue obtained at initial cytoreduction is associated with increased risk of developing brain metastases in women with epithelial ovarian, fallopian tube, or peritoneal cancer.