Mucinous carcinoma accounts for 25% of Stage 1 epithelial ovarian cancers, but only 5% of advanced stage epithelial ovarian cancers. It is often confused with gastrointestinal cancers. Overall survival for Stage 1 is similar to high-grade serous cancers (about 85% five-year survival). When diagnosed in advanced stages, mortality is significantly higher than for high-grade serous. Current standard therapy is surgery, followed by paclitaxel/carboplatin chemotherapy.
It’s been established that there are key pathways and potential targets, particularly for patients with mucinous carcinoma who have recurred. For this subset of patients, there are several areas of potential promise.
- Bevacizumab can be an active agent, which means the angiogenesis pathway is a key pathway.
- 22% have MSI-H (high levels of microsatellite instability), which means they may be responsive to immune checkpoint inhibitors.
- 18% have HER-2/neu amplification. Breast cancer drugs, such as trastuzumab, that target HER-2/neu may also be active in patients who express HER-2/neu amplification.
- 40-50% of patients have a RAS genetic mutation, and MEK inhibitors may be active in tumors that express a RAS mutation.
Current research into mucinous carcinoma is focused on further investigating the use of hyperthermic intraperitoneal chemotherapy (HIPEC), and on potential transition to more common use of gastrointestinal chemotherapy regimens.
HIPEC for ovarian cancer in general has shown to produce mixed results. Most experts consider it to be investigational, rather than standard of care treatment. However, there is interest in applying HIPEC for mucinous ovarian cancer specifically, due to HIPEC’s possible efficacy against gastrointestinal cancers, which microscopically looks quite similar to mucinous carcinoma of the ovary.
- A randomized trial investigated use of a regimen commonly used to treat colorectal cancer–capecitabine/oxaliplatin–versus paclitaxel/carboplatin, with or without addition of bevacizumab, in patients with previously untreated mucinous ovarian cancer. The concept was to determine if by giving the standard gastrointestinal treatment regimen, patients would have a higher response rate and progression-free survival. The trial unfortunately closed early due to slow accrual, so will not have a conclusion.
- In more conclusive news, a retrospective multi-institutional study on patients with mucinous carcinoma showed that patients who received gastrointestinal treatment regimens had significantly better progression-free and overall survival rate than those who received the standard of paclitaxel/carboplatin. Because this was retrospective, and not a randomized clinical trial, more investigation is needed, but researchers believe this shows promise.