Genetic testing for ovarian cancer
29 MAY 2016
PREVENTIVE MEASURES: A recent Malaysian study shows one in nine ovarian cancer patients inherited the BRCA1 or BRCA2 (breast cancer gene 1 or 2) mutation. This calls for greater awareness of genetic testing among patients, writes Fernando Fong.
ONE in nine ovarian cancer patients is a carrier and four in 10 carriers do not have any family history of breast or ovarian cancer. This was discovered in the first comprehensive Asian study published in the Gynecologic Oncology journal, which suggests for the first time that Asian women with epithelial ovarian cancer (See note below) should be provided genetic counselling and considered for testing for germline alterations in BRCA1 and BRCA2.
It was previously thought the frequency of mutations was much lower in ovarian cancer compared with breast cancer patients, and that only individuals with a relative affected by breast or ovarian cancer was at risk of being a carrier. Therefore, the current practice of offering genetic counselling and genetic testing only to women with a family history would mean that one in three BRCA1 carriers and one in two BRCA2 mutation carriers would not be offered the information that could help prevent cancers.
Professor Dr Teo Soo-Hwang, head of the Breast and Ovarian Cancer Research Programme at Cancer Research Malaysia (CRM) and adjunct professor at University Malaya and the study’s lead author, said: “Finding out whether there is a genetic risk to ovarian cancer enables women to be empowered to make choices that could save their lives, particularly for ovarian cancer where there is currently no effective screening method.” “Although the BRCA1 and BRCA2 genes were discovered more than 20 years ago, few women in Malaysia have access to genetic counselling and genetic testing in part because of cost. “In this study, we reported a new method that we have developed with the University of Melbourne.
“The test can now be offered for less than RM1,500 compared with the current market price of more than RM5,000 per patient,” she added. Consultant gynae-oncologist at University Malaya, Professor Dr Woo Yin Ling said the data was striking but what these results meant to the individual was unique to the patient and her circumstances. “It’s never just a matter of offering a genetic test but this must, and I emphasise must, go hand in hand with genetic counselling,” she said. Genetic counsellors are specially trained professionals who will be able to guide a patient and work with the physician on whether genetic testing is right for the patient, understand the impact of genetic test results and cancer risk assessments.
The study is a collaborative effort by CRM, University Malaya and University of Melbourne, with funding from the Ministry of Higher Education, Yayasan Sime Darby and Petronas, among others. The study was recently announced in conjunction with World Ovarian Cancer Day on May 8, which brings together organisations across the globe to raise awareness on the disease. In Malaysia, ovarian cancer is the fourth most common cancer with about 1,000 new cases per year in the country.
Between five and 10 per cent of the cancers are familial, while about 11 per cent of patients have gene changes in BRCA1 and BRCA2. All women are at risk of ovarian cancer. However, a woman is at higher risk if she is over 50 years of age, her family has a history of ovarian, breast, endometrial or colorectal cancer or she has a genetic mutation (for example, BRCA gene mutation) that is associated with ovarian cancer. Note: Epithelial ovarian cancer is the most common type, making up about 90 out of 100 tumours of the ovary.
Rarer types of ovarian cancer include germ cell tumours (cancer of the egg-making cells of the ovary) and sarcomas (a malignant tumour of connective or other non-epithelial tissue). Epithelial ovarian cancer generally starts in the surface layer covering the ovary.