Cure Our Ovarian Cancer NZ is the New Zealand Ovarian Cancer Charity. We are committed to improving the outcomes for people affected by ovarian cancer.

This page gives information about clear cell ovarian carcinoma (CCOC). It describes what clear cell is, how it is diagnosed and gives information about the treatments. It is designed to supplement our more comprehensive ovarian cancer guide.

Clear Cell Ovarian Carcinoma

Clear Cell Ovarian Cancer is the second most common type of ovarian cancer. It accounts for 5 to 10% of ovarian cancers and is more common in Eastern Asia. The median age of women with clear cell carcinoma is 55 years old.

Clear cell is named after how the cancer looks under the microscope. The cells in the tumor look clear, like bubbles.

Symptoms

The symptoms of clear cell ovarian cancer are similar to other ovarian cancers and may include any of the following: bloating, eating less and feeling fuller, bowel habit changes, needing to pee more/urgently, abdominal/pelvic/back pain. In addition thromboembolic complications, such as deep venous thrombosis and pulmonary embolism are more common with clear cell carcinoma than other ovarian cancers. As with all ovarian cancers symptoms that last for two weeks or longer, particularly if they are unusual, frequent or worsening should be investigated.

How is Clear Cell Ovarian Carcinoma diagnosed?

Clear cell ovarian cancer is an epithelial cancer. Epithelial tissues are widespread throughout the body. They form the covering of all body surfaces (like the outer surface of our skin, and eyes), line body cavities and hollow organs, and are the major tissue in glands. ⁠

Clear cell carcinoma is frequently associated with endometriosis, clear cell adenofibromas and clear cell atypical proliferative (borderline) tumours.

Investigations for ovarian cancer usually include a pelvic examination, CA-125 blood test (may be normal) and imaging like a transvaginal ultrasound or CT.

In order to confirm the diagnosis, a sample of the tumour is examined under a microscope by a specialist doctor called a pathologist.

Clear cell carcinoma tends to be diagnosed at an earlier stage than average for ovarian cancer.

Genetic risk factors

Clear cell ovarian cancer is associated with Lynch syndrome. Lynch Syndrome is a rare inherited condition caused by an abnormality in one of four mismatch repair genes (MLH1, MSH2, MSH6, and PMS2). It can increase the risk of a variety of cancers including colorectal, endometrial (uterine), stomach, ovarian, small intestine, kidney, brain or liver cancer.

A genetic blood test can identify whether someone is a carrier for a Lynch Syndrome mutation.

BRCA mutations may occur in clear cell ovarian cancer, but at a lower frequency than in high-grade serous ovarian cancer.

What are the treatments for clear cell ovarian cancer?

In New Zealand treatment decisions are made in a Multi-Disciplinary Meeting (MDM). Doctors present individual cases to a group of specialists who include gynae-oncologists, oncologists, pathologists and radiologists and collectively decide what treatment should be offered.

Initial treatment usually consists of surgery and/or chemotherapy. Chemotherapy may be administered through the veins (intravenous) or directly into the abdomen (intraperitoneal). Most people receive some form of carboplatin/paclitaxel chemotherapy. You can read more about the treatments for clear cell carcinoma in the NCCN Ovarian Cancer Guidelines. The NCCN guidelines are an American resource and some treatments may differ in New Zealand.

What if the cancer comes back?

If the cancer comes back surgery and/or chemotherapy may be an option. Possible chemotherapy treatments include platinum based regimens such as carboplatin and non-platinum based chemotherapies such as paclitaxel, gemcitabine, doxorubicin and topotecan.

Recurrent clear cell tumours are relatively resistant to chemotherapy.

Unfunded treatments and clinical trials

Unfunded treatments

Some ovarian cancer treatments available overseas are not funded in New Zealand, or may have additional restrictions as to their use. These include anti vascular endothelial growth factor (VEGF) agents like bevacizumab (Avastin); and chemotherapy agents like pegylated liposomal doxorubicin hydrochloride (Caelyx). People can ask their doctor if there are any unfunded treatments that could help them. Unfunded treatments can only be prescribed in the private healthcare system.

Some life insurance policies and health insurance may pay a lump sum following a cancer diagnosis, which can be used to pay for unfunded treatments. Other people decide to fundraise online.

Not everyone will benefit from an unfunded treatment.

We acknowledge this is an uncomfortable issue to talk about and as an organisation we are advocating strongly at a government level for greater funded treatment options. If people struggle with feelings around unfunded treatments it can be helpful to speak to a psychologist.

Clinical trials

A clinical trial is a type of research involving human participants. Clinical trials can offer new or different treatment options for people with ovarian cancer, and help doctors make better decisions for people in the future. Medications in a clinical trial are provided at no cost. There may be unknown benefits and unique risks to participating in a clinical trial. An oncologist or gynae-oncologist can advise if there are any clinical trials which people may be eligible for.

Agents currently being investigated overseas for clear cell carcinoma include treatments targeting blood vessel growth (bevacizumab, sunitinib, nintendanib) and immune checkpoint inhibitors (nivolumab, durvalumab).

There are currently (as of July 2021) no clinical trials specifically for clear cell carcinoma available in New Zealand but people should discuss with their oncologist whether there are any general trials which could be suitable.

Cure Our Ovarian Cancer strongly believes all people with ovarian cancer should have access to clinical trials for their cancer and we are advocating at a government level for funding to allow this.