Poon Chian Hui - Straits Times Indonesia | November 18, 2011
More women in Singapore are coming down with an aggressive form of ovarian cancer whose symptoms are vague and survival rate low.
In 1988, 5.2 percent of all ovarian cancers were of the type called clear cell carcinoma. In 2007, the figure went up to 13.4 percent.
Less than 40 percent of women who get it survive, even when the cancer is detected early, said Associate Professor Tay Sun Kuie of the Singapore General Hospital (SGH).
In contrast, other types of ovarian cancer have a survival rate of as high as 70 percent when discovered early.
Prof Tay led a study which looked at the profiles of 256 ovarian cancer patients seen at SGH from 2004 to 2009, and examined national trends based on data from the Singapore Cancer Registry from 1988.
Ovarian cancer is the fifth most common among women in Singapore after breast, colorectal, lung and uterus, and nearly 300 are diagnosed with it every year.
It affects one out of 18 female cancer patients, and some 40 percent of cases occur in those aged 55 and above. The clear cell type usually crops up earlier, in those aged 40 onwards.
The symptoms for clear cell carcinoma are vague, but it has been found to occur in women who have painful and irregular periods and who are mysteriously losing weight or their appetite.
The study also found that women who were never pregnant are 14 percent more likely to get this aggressive cancer, compared with ovarian cancer patients who had at least one child.
There is also a link to endometriosis, a disorder where the womb lining responsible for menstruation is found outside the womb, leading to severe menstrual cramps, chronic pain in the pelvic region and infertility.
Patients who have the clear cell type are nearly five times more likely to have endometriosis than those with other types of ovarian cancer.
Clear cell carcinoma is the most lethal of all ovarian cancers. Even with surgery and chemotherapy, up to 80 percent of sufferers fail to improve, even if they were diagnosed at an early stage.
Prof Tay, a senior consultant in obstetrics and gynaecology, said the cancer cells have special genes that makes them more resistant to chemotherapy drugs. "Giving the cancer cells medicine is like giving them water - it doesn't kill them," he said.
SGH decided to research clear cell carcinoma because the cancerous cysts resemble ordinary ones in ultrasound and computed tomography (CT) scans.
Cysts in the ovaries are common and normally harmless.
"The cyst looks just like an empty fish bowl," said Prof Tay. "It can confuse doctors... because of the seemingly harmless appearance."
This was the case for a patient known only as Madam Lim in the study, which was first presented at the Singapore International Congress of Obstetrics and Gynaecology in August.
The 41-year-old manager, who was married but never pregnant, had a history of endometriosis.
When her pain flared up again, she underwent ultrasound and CT scans which revealed a large cyst measuring 15cm in diameter.
During the operation to remove it, doctors realized she actually had clear cell ovarian cancer.
Her condition is currently stable after treatment.
As doctors "cannot possibly take out every cyst in all women", Prof Tay hoped the study would help doctors in better diagnosing this cancer by pointing out, for example, the link with endometriosis.
He said women who experience an unexplained loss of appetite and worsening symptoms of endometriosis may want to seek medical advice early.
"This doesn't mean that one should be alarmist, but women ought to be more aware of changes in their body," he said.
Reprinted courtesy of Straits Times Indonesia. To subscribe to Straits Times Indonesia and/or the Jakarta Globe call 021 2553 5055.