clear cell ovarian cancer
Clear cell ovarian cancer is the second to third 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.
It is called ‘clear cell’ because of how the cancer looks under the microscope. The cells in the tumour look clear, like bubbles
Symptoms
The symptoms of clear cell ovarian cancer are similar to those of other ovarian cancers and may include any of the following:
- bloating
- eating less and feeling fuller
- bowel habit changes; needing to pee more or urgently
- abdominal, pelvic or back pain
- fatigue
Painful intercourse, abnormal vaginal bleeding, and unexplained weight change are also possible.
In addition, thromboembolic complications, such as deep venous thrombosis and pulmonary embolism are more common with clear cell carcinoma compared to other ovarian cancers.
As with all ovarian cancers, symptoms that last for four weeks or longer, particularly if they are unusual, frequent or worsening, should be investigated.
Diagnosis of clear cell ovarian cancer
Clear cell ovarian cancer is an epithelial cancer. Epithelial tissues are widespread throughout the body and form the covering of all body surfaces (like the outer surface of our skin and eyes), line body cavities and hollow organs – they are the major tissue in glands.
Clear cell carcinoma is frequently associated with endometriosis, clear cell adenofibroma and clear cell atypical proliferative (borderline) tumours. Investigations for ovarian cancer usually include a pelvic examination, CA-125 blood test and imaging like a transvaginal ultrasound or CT.
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 other ovarian cancers.
Genetic risk factors
Clear cell ovarian cancer is associated with Lynch Syndrome, 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.
Treatments for clear cell ovarian cancer
In New Zealand, treatment decisions are made in a multi-disciplinary meeting. Doctors present individual cases to a group of specialists that includes gynae-oncologists, oncologists, pathologists and radiologists and collectively they decide what treatment should be offered.
Initial treatment usually consists of surgery and/or chemotherapy. Most people receive some form of carboplatin/paclitaxel chemotherapy. In certain circumstances some people may also be given a targeted treatment called bevacizumab which is an anti-vascular endothelial growth factor, during and after 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.
Recurrence of clear cell ovarian cancer
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.
Clinical trials
A clinical trial is 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 to participants.
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) and combinations such as immune check point inhibitor pembrolizumab with tyrosine kinase inhibitor lenvatanib.
For more information visit our clinical trials page.
Find out more information about ovarian cancer.
Note: this content has been reviewed by a gynaecological cancer specialist in New Zealand. Information is provided for general use and should not be a substitute for professional medical advice.
Last reviewed: 16 January 2024